From 1acedd70ed105b8e23d17c15d02f9ae51d50bcc6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sun, 21 Apr 2024 17:18:13 +0200
Subject: [PATCH 01/34] Add support for FlexPRET

---
 low_level_platform/api/CMakeLists.txt         |   2 +
 low_level_platform/api/low_level_platform.h   |   2 +
 .../api/platform/lf_flexpret_support.h        | 125 +++++++++++
 low_level_platform/impl/CMakeLists.txt        |   8 +
 low_level_platform/impl/src/lf_atomic_irq.c   |   6 +-
 .../impl/src/lf_flexpret_support.c            | 201 ++++++++++++++++++
 platform/impl/CMakeLists.txt                  |   4 +
 7 files changed, 347 insertions(+), 1 deletion(-)
 create mode 100644 low_level_platform/api/platform/lf_flexpret_support.h
 create mode 100644 low_level_platform/impl/src/lf_flexpret_support.c

diff --git a/low_level_platform/api/CMakeLists.txt b/low_level_platform/api/CMakeLists.txt
index b4598ed9c..3f3a50936 100644
--- a/low_level_platform/api/CMakeLists.txt
+++ b/low_level_platform/api/CMakeLists.txt
@@ -9,4 +9,6 @@ elseif(${CMAKE_SYSTEM_NAME} STREQUAL "Zephyr")
     target_compile_definitions(lf-low-level-platform-api INTERFACE PLATFORM_ZEPHYR)
 elseif(${CMAKE_SYSTEM_NAME} STREQUAL "Rp2040")
     target_compile_definitions(lf-low-level-platform-api INTERFACE PLATFORM_RP2040)
+elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
+    target_compile_definitions(lf-low-level-platform-api INTERFACE PLATFORM_FLEXPRET)
 endif()
diff --git a/low_level_platform/api/low_level_platform.h b/low_level_platform/api/low_level_platform.h
index 2867aa0f4..2ef93f24a 100644
--- a/low_level_platform/api/low_level_platform.h
+++ b/low_level_platform/api/low_level_platform.h
@@ -50,6 +50,8 @@ int lf_critical_section_exit(environment_t* env);
 #include "platform/lf_nrf52_support.h"
 #elif defined(PLATFORM_RP2040)
 #include "platform/lf_rp2040_support.h"
+#elif defined(PLATFORM_FLEXPRET)
+#include "platform/lf_flexpret_support.h"
 #elif defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__NT__)
 // Windows platforms
 #include "platform/lf_windows_support.h"
diff --git a/low_level_platform/api/platform/lf_flexpret_support.h b/low_level_platform/api/platform/lf_flexpret_support.h
new file mode 100644
index 000000000..058607669
--- /dev/null
+++ b/low_level_platform/api/platform/lf_flexpret_support.h
@@ -0,0 +1,125 @@
+/* FlexPRET API support for the C target of Lingua Franca. */
+
+/*************
+Copyright (c) 2021, The University of California at Berkeley.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+***************/
+
+/**
+ * FlexPRET API support for the C target of Lingua Franca.
+ *
+ * This is based on lf_nrf_support.h in icyphy/lf-buckler.
+ *  
+ * @author{Soroush Bateni <soroush@utdallas.edu>}
+ * @author{Abhi Gundrala <gundralaa@berkeley.edu>}
+ * @author{Shaokai Lin <shaokai@berkeley.edu>} 
+ */
+
+#ifndef LF_FLEXPRET_SUPPORT_H
+#define LF_FLEXPRET_SUPPORT_H
+
+#include <stdint.h>     // For fixed-width integral types
+#include <time.h>       // For CLOCK_MONOTONIC
+#include <stdbool.h>
+#include <stdarg.h>     // Defines va_list
+#include <stdio.h>      // Defines FILE
+#include <string.h>     // Defines strlen
+
+#include <flexpret/flexpret.h>
+
+
+/**
+ * printf.h does not include definitions of vfprintf, so to avoid linking
+ * newlib's vfprintf we replace all occurrances of it with just printf
+ * 
+ */
+#define PRINTF_ALIAS_STANDARD_FUNCTION_NAMES_HARD 0
+#define vfprintf(fp, fmt, args) vprintf(fmt, args)
+
+/**
+ * Like nRF52, for FlexPRET, each mutex will control an interrupt.
+ *
+ * The mutex holds the interrupt number.
+ * For example, a mutex might be defined for the GPIOTE peripheral interrupt number
+ * 
+ * When initialized, the interrupt is inserted into a global linked list
+ * for disabling and enabling all interrupts during sleep functions.
+ * - All interrupts are disabled by default after initialization
+ * - Priority levels are restricted between (0-7)
+ * 
+ */
+
+// Define PRINTF_TIME and PRINTF_MICROSTEP, which are the printf
+// codes (like the d in %d to print an int) for time and microsteps.
+// To use these, specify the printf as follows:
+//     printf("%" PRINTF_TIME "\n", time_value);
+// On most platforms, time is an signed 64-bit number (int64_t) and
+// the microstep is an unsigned 32-bit number (uint32_t).
+// Sadly, in C, there is no portable to print such numbers using
+// printf without getting a warning on some platforms.
+// On each platform, the code for printf if given by the macros
+// PRId64 and PRIu32 defined in inttypes.h.  Hence, here, we import
+// inttypes.h, then define PRINTF_TIME and PRINTF_MICROSTEP.
+// If you are targeting a platform that uses some other type
+// for time and microsteps, you can simply define
+// PRINTF_TIME and PRINTF_MICROSTEP directly in the same file that
+// defines the types _instant_t, _interval_t, and _microstep_t.
+#include <inttypes.h>  // Needed to define PRId64 and PRIu32
+#define PRINTF_TIME "%" PRId64
+#define PRINTF_MICROSTEP "%" PRIu32
+
+// For convenience, the following string can be inserted in a printf
+// format for printing both time and microstep as follows:
+//     printf("Tag is " PRINTF_TAG "\n", time_value, microstep);
+#define PRINTF_TAG "(%" PRId64 ", %" PRIu32 ")"
+
+/**
+ * Time instant. Both physical and logical times are represented
+ * using this typedef.
+ * WARNING: If this code is used after about the year 2262,
+ * then representing time as a 64-bit long long will be insufficient.
+ */
+typedef int64_t _instant_t;
+
+/**
+ * Interval of time.
+ */
+typedef int64_t _interval_t;
+
+/**
+ * Microstep instant.
+ */
+typedef uint32_t _microstep_t;
+
+#include <errno.h>
+#define _LF_TIMEOUT ETIMEDOUT
+
+// The underlying physical clock for Linux
+#define _LF_CLOCK CLOCK_MONOTONIC
+
+#if !defined(LF_SINGLE_THREADED)
+typedef fp_lock_t lf_mutex_t;
+typedef fp_thread_t lf_thread_t;
+typedef fp_cond_t lf_cond_t;
+#endif
+
+#endif // LF_FLEXPRET_SUPPORT_H
diff --git a/low_level_platform/impl/CMakeLists.txt b/low_level_platform/impl/CMakeLists.txt
index 5f6244664..a1c6a402f 100644
--- a/low_level_platform/impl/CMakeLists.txt
+++ b/low_level_platform/impl/CMakeLists.txt
@@ -39,6 +39,11 @@ elseif(${CMAKE_SYSTEM_NAME} STREQUAL "Rp2040")
         ${CMAKE_CURRENT_LIST_DIR}/src/lf_rp2040_support.c
         ${CMAKE_CURRENT_LIST_DIR}/src/lf_atomic_irq.c
     )
+elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
+    set(LF_LOW_LEVEL_PLATFORM_FILES
+        ${CMAKE_CURRENT_LIST_DIR}/src/lf_flexpret_support.c
+        ${CMAKE_CURRENT_LIST_DIR}/src/lf_atomic_irq.c
+    )
 else()
     message(FATAL_ERROR "Your platform is not supported! The C target supports Linux, MacOS, Windows, Zephyr, Nrf52 and RP2040.")
 endif()
@@ -54,6 +59,9 @@ if(${CMAKE_SYSTEM_NAME} STREQUAL "Zephyr")
     zephyr_library_named(lf-low-level-platform-impl)
     zephyr_library_sources(${LF_LOW_LEVEL_PLATFORM_FILES})
     zephyr_library_link_libraries(kernel)
+elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
+    add_library(lf-low-level-platform-impl STATIC ${LF_LOW_LEVEL_PLATFORM_FILES})
+    target_link_libraries(lf-low-level-platform-impl PRIVATE fp-sdk-if)
 else()
     add_library(lf-low-level-platform-impl STATIC ${LF_LOW_LEVEL_PLATFORM_FILES})
     # Link the platform to a threading library
diff --git a/low_level_platform/impl/src/lf_atomic_irq.c b/low_level_platform/impl/src/lf_atomic_irq.c
index 7be9aff34..9224fa615 100644
--- a/low_level_platform/impl/src/lf_atomic_irq.c
+++ b/low_level_platform/impl/src/lf_atomic_irq.c
@@ -1,4 +1,8 @@
-#if defined(PLATFORM_ARDUINO) || defined(PLATFORM_NRF52) || defined(PLATFORM_ZEPHYR) || defined(PLATFORM_RP2040)
+#if defined(PLATFORM_ARDUINO)  || \
+    defined(PLATFORM_NRF52)    || \
+    defined(PLATFORM_ZEPHYR)   || \
+    defined(PLATFORM_RP2040)   || \
+    defined(PLATFORM_FLEXPRET)
 /**
  * @author Erling Rennemo Jellum
  * @copyright (c) 2023
diff --git a/low_level_platform/impl/src/lf_flexpret_support.c b/low_level_platform/impl/src/lf_flexpret_support.c
new file mode 100644
index 000000000..f8f02f1c6
--- /dev/null
+++ b/low_level_platform/impl/src/lf_flexpret_support.c
@@ -0,0 +1,201 @@
+/*************
+Copyright (c) 2021, The University of California at Berkeley.
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+1. Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+***************/
+
+/** Support file for Bare-metal FlexPRET platform.
+ *  
+ *  @author{Shaokai Lin <shaokai@berkeley.edu>}
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include "low_level_platform.h"
+
+/**
+ * Used to keep track of the number of nested critical sections. 
+ * 
+ * We should only disable interrupts when this is zero and we enter a critical section
+ * We should only  enable interrupts when we exit a critical section and this is zero
+ */
+static int critical_section_num_nested[FP_THREADS] = 
+    THREAD_ARRAY_INITIALIZER(0);
+
+/**
+ * @return 0 for success, or -1 for failure
+ */
+
+static volatile uint32_t last_time = 0;
+static volatile uint64_t epoch = 0;
+#define EPOCH_DURATION_NS (1ULL << 32)
+int _lf_clock_gettime(instant_t* t) {
+    uint32_t now = rdtime();
+    if (now < last_time) {
+        epoch += EPOCH_DURATION_NS;
+    }
+    *t = now + epoch;
+    last_time = now;
+    return 0;
+}
+
+int _lf_interruptable_sleep_until_locked(environment_t *env, instant_t wakeup_time) {
+    int ret = 0;
+    if (wakeup_time < 0) {
+        return ret;
+    }
+
+    // Enable interrupts and execute wait until instruction
+    lf_critical_section_exit(env);
+
+    // Wait until will stop sleep if interrupt occurs
+    fp_wait_until(wakeup_time);
+
+    if ((instant_t) rdtime64() < wakeup_time) {
+        // Interrupt occurred because we did not wait full wakeup_time
+        ret = -1;
+    }
+
+    lf_critical_section_enter(env);
+    return ret;
+}
+
+int lf_sleep(interval_t sleep_duration) {
+    // FIXME: Handle sleep durations exceeding 32bit
+    fp_delay_for(sleep_duration);
+    return 0;
+}
+
+/**
+ * Initialize the LF clock.
+ */
+void _lf_initialize_clock() {
+    // FlexPRET does not require any initialization
+}
+
+int lf_disable_interrupts_nested() {
+    // In the special case where this function is called during an interrupt 
+    // subroutine (isr) it should have no effect
+    if ((read_csr(CSR_STATUS) & 0x04) == 0x04) return 0;
+
+    uint32_t hartid = read_hartid();
+
+    fp_assert(critical_section_num_nested[hartid] >= 0, "Number of nested critical sections less than zero.");
+    if (critical_section_num_nested[hartid]++ == 0) {
+        fp_interrupt_disable();
+    }
+    return 0;
+}
+
+int lf_enable_interrupts_nested() {
+    // In the special case where this function is called during an interrupt 
+    // subroutine (isr) it should have no effect
+    if ((read_csr(CSR_STATUS) & 0x04) == 0x04) return 0;
+
+    uint32_t hartid = read_hartid();
+
+    if (--critical_section_num_nested[hartid] == 0) {
+        fp_interrupt_enable();
+    }
+    fp_assert(critical_section_num_nested[hartid] >= 0, "Number of nested critical sections less than zero.");
+    return 0;
+}
+
+/**
+ * Pause execution for a number of nanoseconds.
+ *
+ * @return 0 for success, or -1 for failure. In case of failure, errno will be
+ *  set appropriately (see `man 2 clock_nanosleep`).
+ */
+int lf_nanosleep(interval_t requested_time) {
+    instant_t t;
+    _lf_clock_gettime(&t);
+    instant_t expire_time = t + requested_time;
+    while (t < expire_time) {
+        _lf_clock_gettime(&t);
+    }
+    return 0;
+}
+
+#if defined(LF_SINGLE_THREADED)
+
+int _lf_single_threaded_notify_of_event() {
+    // No need to do anything, because an interrupt will cancel wait until
+    // This is specific to FlexPRET
+    return 0;
+}
+
+#else // Multi threaded
+
+int lf_available_cores() {
+    return FP_THREADS; // Return the number of Flexpret HW threads
+}
+
+int lf_thread_create(lf_thread_t* thread, void *(*lf_thread) (void *), void* arguments) {
+    // TODO: Decide between HRTT or SRTT
+    return fp_thread_create(HRTT, thread, lf_thread, arguments);
+}
+
+int lf_thread_join(lf_thread_t thread, void** thread_return) {
+    return fp_thread_join(thread, thread_return);
+}
+
+int lf_mutex_init(lf_mutex_t* mutex) {
+    *mutex = (lf_mutex_t) FP_LOCK_INITIALIZER;
+    return 0;
+}
+
+int lf_mutex_lock(lf_mutex_t* mutex) {
+    fp_lock_acquire(mutex);
+    return 0;
+}
+
+int lf_mutex_unlock(lf_mutex_t* mutex) {
+    fp_lock_release(mutex);
+    return 0;
+}
+
+int lf_cond_init(lf_cond_t* cond, lf_mutex_t* mutex) {
+    *cond = (lf_cond_t) FP_COND_INITIALIZER(mutex);
+    return 0;
+}
+
+int lf_cond_broadcast(lf_cond_t* cond) {
+    return fp_cond_broadcast(cond);
+}
+
+int lf_cond_signal(lf_cond_t* cond) {
+    return fp_cond_signal(cond);
+}
+
+int lf_cond_wait(lf_cond_t* cond) {
+    return fp_cond_wait(cond);
+}
+
+int _lf_cond_timedwait(lf_cond_t* cond, instant_t absolute_time_ns) {
+    return fp_cond_timed_wait(cond, absolute_time_ns);
+}
+
+int lf_thread_id() {
+    return read_hartid();
+}
+
+void initialize_lf_thread_id() {
+    // TODO: Verify: Don't think anything is necessary here for FlexPRET
+}
+#endif
diff --git a/platform/impl/CMakeLists.txt b/platform/impl/CMakeLists.txt
index cef66b5ef..096b99e8d 100644
--- a/platform/impl/CMakeLists.txt
+++ b/platform/impl/CMakeLists.txt
@@ -5,6 +5,10 @@ if(${CMAKE_SYSTEM_NAME} STREQUAL "Zephyr")
     zephyr_library_named(lf-platform-impl)
     zephyr_library_sources(${LF_PLATFORM_FILES})
     zephyr_library_link_libraries(kernel)
+elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
+    add_library(lf-platform-impl STATIC)
+    target_sources(lf-platform-impl PUBLIC ${LF_PLATFORM_FILES})
+    target_link_libraries(lf-platform-impl PUBLIC fp-sdk-if)
 else()
     add_library(lf-platform-impl STATIC)
     target_sources(lf-platform-impl PUBLIC ${LF_PLATFORM_FILES})

From eb797206c781d956a2b7fcb8d06a1327e66996b5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Mon, 22 Apr 2024 20:10:48 +0200
Subject: [PATCH 02/34] Add FlexPRET to error message

---
 low_level_platform/impl/CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/low_level_platform/impl/CMakeLists.txt b/low_level_platform/impl/CMakeLists.txt
index a1c6a402f..1825cf98d 100644
--- a/low_level_platform/impl/CMakeLists.txt
+++ b/low_level_platform/impl/CMakeLists.txt
@@ -45,7 +45,7 @@ elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
         ${CMAKE_CURRENT_LIST_DIR}/src/lf_atomic_irq.c
     )
 else()
-    message(FATAL_ERROR "Your platform is not supported! The C target supports Linux, MacOS, Windows, Zephyr, Nrf52 and RP2040.")
+    message(FATAL_ERROR "Your platform is not supported! The C target supports Linux, MacOS, Windows, Zephyr, Nrf52, RP2040 and FlexPRET.")
 endif()
 
 list(APPEND LF_LOW_LEVEL_PLATFORM_FILES ${CMAKE_CURRENT_LIST_DIR}/src/lf_platform_util.c)

From cacaff12b0ce5b387df062bae6769b8677127693 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Wed, 24 Apr 2024 00:55:21 +0200
Subject: [PATCH 03/34] Add check on number of threads available in FlexPRET's
 hardware.

---
 low_level_platform/impl/CMakeLists.txt | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/low_level_platform/impl/CMakeLists.txt b/low_level_platform/impl/CMakeLists.txt
index 1825cf98d..c4e94c913 100644
--- a/low_level_platform/impl/CMakeLists.txt
+++ b/low_level_platform/impl/CMakeLists.txt
@@ -61,7 +61,23 @@ if(${CMAKE_SYSTEM_NAME} STREQUAL "Zephyr")
     zephyr_library_link_libraries(kernel)
 elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
     add_library(lf-low-level-platform-impl STATIC ${LF_LOW_LEVEL_PLATFORM_FILES})
-    target_link_libraries(lf-low-level-platform-impl PRIVATE fp-sdk-if)
+    target_link_libraries(lf-low-level-platform-impl PUBLIC fp-sdk)
+
+    if (DEFINED NUMBER_OF_WORKERS)
+        # Verify that FlexPRET has the number of requested workers
+        # That information is available in the SDK's hwconfig
+        include($ENV{FP_SDK_PATH}/flexpret/hwconfig.cmake)
+        math(EXPR FLEXPRET_AVAILABLE_WORKERS "${THREADS} - 1")
+
+        if (${NUMBER_OF_WORKERS} GREATER ${THREADS})
+            message(FATAL_ERROR
+                "Number of requested workers (${NUMBER_OF_WORKERS}) is higher \
+                than FlexPRET's number of available workers \
+                (${FLEXPET_AVAILABLE_WORKERS}). Note that FlexPRET uses \
+                hardware threads, not the usual software threads"
+            )
+        endif()
+    endif()
 else()
     add_library(lf-low-level-platform-impl STATIC ${LF_LOW_LEVEL_PLATFORM_FILES})
     # Link the platform to a threading library

From 74fc6015d7dc6d1274ee041d1c8935bd42c5febc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Thu, 25 Apr 2024 03:10:08 +0200
Subject: [PATCH 04/34] Fixes to CMakeLists

---
 low_level_platform/api/CMakeLists.txt  | 1 +
 low_level_platform/impl/CMakeLists.txt | 8 +++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/low_level_platform/api/CMakeLists.txt b/low_level_platform/api/CMakeLists.txt
index 3f3a50936..47817b59a 100644
--- a/low_level_platform/api/CMakeLists.txt
+++ b/low_level_platform/api/CMakeLists.txt
@@ -10,5 +10,6 @@ elseif(${CMAKE_SYSTEM_NAME} STREQUAL "Zephyr")
 elseif(${CMAKE_SYSTEM_NAME} STREQUAL "Rp2040")
     target_compile_definitions(lf-low-level-platform-api INTERFACE PLATFORM_RP2040)
 elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
+    target_link_libraries(lf-low-level-platform-api INTERFACE fp-sdk-if)
     target_compile_definitions(lf-low-level-platform-api INTERFACE PLATFORM_FLEXPRET)
 endif()
diff --git a/low_level_platform/impl/CMakeLists.txt b/low_level_platform/impl/CMakeLists.txt
index c4e94c913..28ae68c9e 100644
--- a/low_level_platform/impl/CMakeLists.txt
+++ b/low_level_platform/impl/CMakeLists.txt
@@ -61,12 +61,18 @@ if(${CMAKE_SYSTEM_NAME} STREQUAL "Zephyr")
     zephyr_library_link_libraries(kernel)
 elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
     add_library(lf-low-level-platform-impl STATIC ${LF_LOW_LEVEL_PLATFORM_FILES})
-    target_link_libraries(lf-low-level-platform-impl PUBLIC fp-sdk)
 
     if (DEFINED NUMBER_OF_WORKERS)
         # Verify that FlexPRET has the number of requested workers
         # That information is available in the SDK's hwconfig
         include($ENV{FP_SDK_PATH}/flexpret/hwconfig.cmake)
+        if (NOT DEFINED THREADS)
+            message(FATAL_ERROR
+                "Missing FlexPRET hardware configuration; check that FlexPRET has \
+                been installed to the SDK."
+            )
+        endif()
+
         math(EXPR FLEXPRET_AVAILABLE_WORKERS "${THREADS} - 1")
 
         if (${NUMBER_OF_WORKERS} GREATER ${THREADS})

From 14ed735138d41599d17c88a3bc13530380d6b5e0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Wed, 1 May 2024 23:06:23 +0200
Subject: [PATCH 05/34] Fix bug: lf_available_cores() needs to return 1 less
 than FP_THREADS.

---
 low_level_platform/impl/src/lf_flexpret_support.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/low_level_platform/impl/src/lf_flexpret_support.c b/low_level_platform/impl/src/lf_flexpret_support.c
index f8f02f1c6..178b4948a 100644
--- a/low_level_platform/impl/src/lf_flexpret_support.c
+++ b/low_level_platform/impl/src/lf_flexpret_support.c
@@ -143,7 +143,7 @@ int _lf_single_threaded_notify_of_event() {
 #else // Multi threaded
 
 int lf_available_cores() {
-    return FP_THREADS; // Return the number of Flexpret HW threads
+    return FP_THREADS-1; // Return the number of Flexpret HW threads
 }
 
 int lf_thread_create(lf_thread_t* thread, void *(*lf_thread) (void *), void* arguments) {

From 3bd8a108d078c58e881744d95ab42251116e334b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Thu, 2 May 2024 02:16:34 +0200
Subject: [PATCH 06/34] Fix typo

---
 low_level_platform/impl/CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/low_level_platform/impl/CMakeLists.txt b/low_level_platform/impl/CMakeLists.txt
index 28ae68c9e..80c90de5d 100644
--- a/low_level_platform/impl/CMakeLists.txt
+++ b/low_level_platform/impl/CMakeLists.txt
@@ -79,7 +79,7 @@ elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
             message(FATAL_ERROR
                 "Number of requested workers (${NUMBER_OF_WORKERS}) is higher \
                 than FlexPRET's number of available workers \
-                (${FLEXPET_AVAILABLE_WORKERS}). Note that FlexPRET uses \
+                (${FLEXPRET_AVAILABLE_WORKERS}). Note that FlexPRET uses \
                 hardware threads, not the usual software threads"
             )
         endif()

From 1afab5654c7f9690ae914bd2c813a5e5f7f8410d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Fri, 3 May 2024 02:26:42 +0200
Subject: [PATCH 07/34] Add hacky solution to code size for FlexPRET.

---
 low_level_platform/api/CMakeLists.txt         | 26 ++++++++++++++
 .../impl/src/lf_flexpret_stubs.c              | 36 +++++++++++++++++++
 2 files changed, 62 insertions(+)
 create mode 100644 low_level_platform/impl/src/lf_flexpret_stubs.c

diff --git a/low_level_platform/api/CMakeLists.txt b/low_level_platform/api/CMakeLists.txt
index 47817b59a..5e590e87f 100644
--- a/low_level_platform/api/CMakeLists.txt
+++ b/low_level_platform/api/CMakeLists.txt
@@ -12,4 +12,30 @@ elseif(${CMAKE_SYSTEM_NAME} STREQUAL "Rp2040")
 elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
     target_link_libraries(lf-low-level-platform-api INTERFACE fp-sdk-if)
     target_compile_definitions(lf-low-level-platform-api INTERFACE PLATFORM_FLEXPRET)
+
+    # This is explained in issue https://github.com/lf-lang/reactor-c/issues/418
+    # The stubs are found in `../impl/src/lf_flexpret_stubs.c`.
+    target_link_options(lf-low-level-platform-api INTERFACE
+        "-Wl,--wrap=_vfprintf_r" "-Wl,--wrap=__ssvfiscanf_r" "-Wl,--wrap=_svfiprintf_r"
+    )
+
+    # This is related to issue https://github.com/lf-lang/reactor-c/issues/418
+    # 
+    # The ordering of libraries passed to `gcc` matters
+    # (https://stackoverflow.com/a/2487723/16358883)
+    # Since we want `newlib` to link into our wrapper functions, our library
+    # needs to come after `newlib` on the command line. But we cannot choose
+    # where `newlib` is placed on the command line - and it is most likely at 
+    # the very end (because everything is expected to link into it).
+    #
+    # Therefore, just adding these three functions normally into the library
+    # will yield `undefined reference` errors. 
+    #
+    # The solution is to instead link in our three functions as an object file.
+    # The ordering of object files does not matter. To do this, we add the source
+    # as an interface, which means it will be passed onto the main target and
+    # compiled as an object file there.
+    target_sources(lf-low-level-platform-api INTERFACE
+        ${CMAKE_CURRENT_LIST_DIR}/../impl/src/lf_flexpret_stubs.c
+    )
 endif()
diff --git a/low_level_platform/impl/src/lf_flexpret_stubs.c b/low_level_platform/impl/src/lf_flexpret_stubs.c
new file mode 100644
index 000000000..c36201597
--- /dev/null
+++ b/low_level_platform/impl/src/lf_flexpret_stubs.c
@@ -0,0 +1,36 @@
+/**
+ * @file lf_flexpret_stubs.c
+ * @author Magnus Mæhlum (magnmaeh@stud.ntnu.no)
+ * @brief Contains stubs for large `newlib` functions to drastically reduce
+ *        code size for the FlexPRET target. This is necessary for FlexPRET
+ *        because it has a very limited amount of instruction memory space.
+ *
+ *        See issue https://github.com/lf-lang/reactor-c/issues/418
+ *        for a complete description of the problem.
+ *
+ *        Passing `-Wl,--wrap=function` causes linker to rename `function`
+ *        to `__real_function`. It also calls `__wrap_function` where `function`
+ *        used to be called. In this way, the user can implement wrapper functions
+ *        for already compiled functions like so:
+ *
+ *        void __wrap_function() {
+ *            printf("Wrapper code before function call\n");
+ *            __real_function(); // The actual function call
+ *           printf("Wrapper code after function call\n");
+ *        }
+ *
+ *        We instead use it to remove all references to `__real_function`,
+ *        which drastically reduces code size. If we do this, the function
+ *        signature of the original function does not matter either, so we can
+ *        just write `void __wrap_function(void)`.
+ * 
+ *        https://linux.die.net/man/1/ld (search for `--wrap=symbol`)
+ *
+ * @date 2024-05-03
+ * 
+ */
+
+// This reduces FlexPRET's code size by approximately 50%.
+void __wrap__vfprintf_r(void) {}
+void __wrap___ssvfiscanf_r(void) {}
+void __wrap__svfiprintf_r(void) {}

From bd54f002c307c6dd230260e14370131f1a2dd45c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Fri, 3 May 2024 13:26:27 +0200
Subject: [PATCH 08/34] Remove wrap hack and instead filter out newlib
 functions that cause large code size.

---
 core/threaded/reactor_threaded.c              |  5 +++
 low_level_platform/api/CMakeLists.txt         | 26 --------------
 .../api/platform/lf_flexpret_support.h        |  7 ++++
 .../impl/src/lf_flexpret_stubs.c              | 36 -------------------
 4 files changed, 12 insertions(+), 62 deletions(-)
 delete mode 100644 low_level_platform/impl/src/lf_flexpret_stubs.c

diff --git a/core/threaded/reactor_threaded.c b/core/threaded/reactor_threaded.c
index 57f888fc2..1d7598723 100644
--- a/core/threaded/reactor_threaded.c
+++ b/core/threaded/reactor_threaded.c
@@ -1072,8 +1072,13 @@ int lf_reactor_c_main(int argc, const char* argv[]) {
 
   LF_PRINT_DEBUG("Start time: " PRINTF_TIME "ns", start_time);
   struct timespec physical_time_timespec = {start_time / BILLION, start_time % BILLION};
+
+#ifdef NO_TTY
+  lf_print("---- Start execution ----");
+#else
   lf_print("---- Start execution at time %s---- plus %ld nanoseconds", ctime(&physical_time_timespec.tv_sec),
            physical_time_timespec.tv_nsec);
+#endif // NO_TTY
 
   // Create and initialize the environments for each enclave
   lf_create_environments();
diff --git a/low_level_platform/api/CMakeLists.txt b/low_level_platform/api/CMakeLists.txt
index 5e590e87f..47817b59a 100644
--- a/low_level_platform/api/CMakeLists.txt
+++ b/low_level_platform/api/CMakeLists.txt
@@ -12,30 +12,4 @@ elseif(${CMAKE_SYSTEM_NAME} STREQUAL "Rp2040")
 elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
     target_link_libraries(lf-low-level-platform-api INTERFACE fp-sdk-if)
     target_compile_definitions(lf-low-level-platform-api INTERFACE PLATFORM_FLEXPRET)
-
-    # This is explained in issue https://github.com/lf-lang/reactor-c/issues/418
-    # The stubs are found in `../impl/src/lf_flexpret_stubs.c`.
-    target_link_options(lf-low-level-platform-api INTERFACE
-        "-Wl,--wrap=_vfprintf_r" "-Wl,--wrap=__ssvfiscanf_r" "-Wl,--wrap=_svfiprintf_r"
-    )
-
-    # This is related to issue https://github.com/lf-lang/reactor-c/issues/418
-    # 
-    # The ordering of libraries passed to `gcc` matters
-    # (https://stackoverflow.com/a/2487723/16358883)
-    # Since we want `newlib` to link into our wrapper functions, our library
-    # needs to come after `newlib` on the command line. But we cannot choose
-    # where `newlib` is placed on the command line - and it is most likely at 
-    # the very end (because everything is expected to link into it).
-    #
-    # Therefore, just adding these three functions normally into the library
-    # will yield `undefined reference` errors. 
-    #
-    # The solution is to instead link in our three functions as an object file.
-    # The ordering of object files does not matter. To do this, we add the source
-    # as an interface, which means it will be passed onto the main target and
-    # compiled as an object file there.
-    target_sources(lf-low-level-platform-api INTERFACE
-        ${CMAKE_CURRENT_LIST_DIR}/../impl/src/lf_flexpret_stubs.c
-    )
 endif()
diff --git a/low_level_platform/api/platform/lf_flexpret_support.h b/low_level_platform/api/platform/lf_flexpret_support.h
index 058607669..0971846ae 100644
--- a/low_level_platform/api/platform/lf_flexpret_support.h
+++ b/low_level_platform/api/platform/lf_flexpret_support.h
@@ -122,4 +122,11 @@ typedef fp_thread_t lf_thread_t;
 typedef fp_cond_t lf_cond_t;
 #endif
 
+// FlexPRET has no tty
+#define NO_TTY
+
+// Likewise, fprintf is used to print to `stderr`, but FlexPRET has no `stderr`
+// We instead redirect its output to normal printf
+#define fprintf(stream, fmt, ...) printf(fmt, ##__VA_ARGS__)
+
 #endif // LF_FLEXPRET_SUPPORT_H
diff --git a/low_level_platform/impl/src/lf_flexpret_stubs.c b/low_level_platform/impl/src/lf_flexpret_stubs.c
deleted file mode 100644
index c36201597..000000000
--- a/low_level_platform/impl/src/lf_flexpret_stubs.c
+++ /dev/null
@@ -1,36 +0,0 @@
-/**
- * @file lf_flexpret_stubs.c
- * @author Magnus Mæhlum (magnmaeh@stud.ntnu.no)
- * @brief Contains stubs for large `newlib` functions to drastically reduce
- *        code size for the FlexPRET target. This is necessary for FlexPRET
- *        because it has a very limited amount of instruction memory space.
- *
- *        See issue https://github.com/lf-lang/reactor-c/issues/418
- *        for a complete description of the problem.
- *
- *        Passing `-Wl,--wrap=function` causes linker to rename `function`
- *        to `__real_function`. It also calls `__wrap_function` where `function`
- *        used to be called. In this way, the user can implement wrapper functions
- *        for already compiled functions like so:
- *
- *        void __wrap_function() {
- *            printf("Wrapper code before function call\n");
- *            __real_function(); // The actual function call
- *           printf("Wrapper code after function call\n");
- *        }
- *
- *        We instead use it to remove all references to `__real_function`,
- *        which drastically reduces code size. If we do this, the function
- *        signature of the original function does not matter either, so we can
- *        just write `void __wrap_function(void)`.
- * 
- *        https://linux.die.net/man/1/ld (search for `--wrap=symbol`)
- *
- * @date 2024-05-03
- * 
- */
-
-// This reduces FlexPRET's code size by approximately 50%.
-void __wrap__vfprintf_r(void) {}
-void __wrap___ssvfiscanf_r(void) {}
-void __wrap__svfiprintf_r(void) {}

From cc6163ed0b22b3a30bc8978afac44a93d1741913 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Fri, 3 May 2024 15:15:52 +0200
Subject: [PATCH 09/34] Fix small bug

---
 low_level_platform/impl/CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/low_level_platform/impl/CMakeLists.txt b/low_level_platform/impl/CMakeLists.txt
index 80c90de5d..c7c5e1b13 100644
--- a/low_level_platform/impl/CMakeLists.txt
+++ b/low_level_platform/impl/CMakeLists.txt
@@ -75,7 +75,7 @@ elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
 
         math(EXPR FLEXPRET_AVAILABLE_WORKERS "${THREADS} - 1")
 
-        if (${NUMBER_OF_WORKERS} GREATER ${THREADS})
+        if (${NUMBER_OF_WORKERS} GREATER ${FLEXPRET_AVAILABLE_WORKERS})
             message(FATAL_ERROR
                 "Number of requested workers (${NUMBER_OF_WORKERS}) is higher \
                 than FlexPRET's number of available workers \

From b1b9a91a617d001017ceebfef4d8cde5733b1ff9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Fri, 3 May 2024 15:19:50 +0200
Subject: [PATCH 10/34] Minor fixes

---
 low_level_platform/impl/src/lf_flexpret_support.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/low_level_platform/impl/src/lf_flexpret_support.c b/low_level_platform/impl/src/lf_flexpret_support.c
index 178b4948a..d7f910345 100644
--- a/low_level_platform/impl/src/lf_flexpret_support.c
+++ b/low_level_platform/impl/src/lf_flexpret_support.c
@@ -21,6 +21,7 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 /** Support file for Bare-metal FlexPRET platform.
  *  
  *  @author{Shaokai Lin <shaokai@berkeley.edu>}
+ *  @author{Magnus Mæhlum <magnmaeh@stud.ntnu.no>}
  */
 
 #include <stdio.h>
@@ -85,7 +86,7 @@ int lf_sleep(interval_t sleep_duration) {
  * Initialize the LF clock.
  */
 void _lf_initialize_clock() {
-    // FlexPRET does not require any initialization
+    // FlexPRET clock does not require any initialization
 }
 
 int lf_disable_interrupts_nested() {
@@ -196,6 +197,7 @@ int lf_thread_id() {
 }
 
 void initialize_lf_thread_id() {
-    // TODO: Verify: Don't think anything is necessary here for FlexPRET
+    // Nothing needed here; thread ID's are already available in harware registers
+    // which can be fetched with `read_hartid`.
 }
 #endif

From 50af7d4d00474136b72911f86252721423df1e38 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Fri, 3 May 2024 15:28:10 +0200
Subject: [PATCH 11/34] Remove unecessary link in platform impl CMakeLists.txt

---
 platform/impl/CMakeLists.txt | 1 -
 1 file changed, 1 deletion(-)

diff --git a/platform/impl/CMakeLists.txt b/platform/impl/CMakeLists.txt
index 096b99e8d..e98c1a8d5 100644
--- a/platform/impl/CMakeLists.txt
+++ b/platform/impl/CMakeLists.txt
@@ -8,7 +8,6 @@ if(${CMAKE_SYSTEM_NAME} STREQUAL "Zephyr")
 elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
     add_library(lf-platform-impl STATIC)
     target_sources(lf-platform-impl PUBLIC ${LF_PLATFORM_FILES})
-    target_link_libraries(lf-platform-impl PUBLIC fp-sdk-if)
 else()
     add_library(lf-platform-impl STATIC)
     target_sources(lf-platform-impl PUBLIC ${LF_PLATFORM_FILES})

From 596a344b3f94d701e2664ecba2de8b544e4f4ed7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Fri, 3 May 2024 16:16:39 +0200
Subject: [PATCH 12/34] Propagate low-level-platform interface to platform
 interface

---
 low_level_platform/api/platform/lf_flexpret_support.h | 10 +---------
 platform/api/CMakeLists.txt                           |  1 +
 platform/api/platform.h                               |  2 ++
 3 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/low_level_platform/api/platform/lf_flexpret_support.h b/low_level_platform/api/platform/lf_flexpret_support.h
index 0971846ae..07f059f10 100644
--- a/low_level_platform/api/platform/lf_flexpret_support.h
+++ b/low_level_platform/api/platform/lf_flexpret_support.h
@@ -46,15 +46,6 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <flexpret/flexpret.h>
 
-
-/**
- * printf.h does not include definitions of vfprintf, so to avoid linking
- * newlib's vfprintf we replace all occurrances of it with just printf
- * 
- */
-#define PRINTF_ALIAS_STANDARD_FUNCTION_NAMES_HARD 0
-#define vfprintf(fp, fmt, args) vprintf(fmt, args)
-
 /**
  * Like nRF52, for FlexPRET, each mutex will control an interrupt.
  *
@@ -128,5 +119,6 @@ typedef fp_cond_t lf_cond_t;
 // Likewise, fprintf is used to print to `stderr`, but FlexPRET has no `stderr`
 // We instead redirect its output to normal printf
 #define fprintf(stream, fmt, ...) printf(fmt, ##__VA_ARGS__)
+#define vfprintf(fp, fmt, args) vprintf(fmt, args)
 
 #endif // LF_FLEXPRET_SUPPORT_H
diff --git a/platform/api/CMakeLists.txt b/platform/api/CMakeLists.txt
index 88b8de512..e81bcdaf1 100644
--- a/platform/api/CMakeLists.txt
+++ b/platform/api/CMakeLists.txt
@@ -1,3 +1,4 @@
 add_library(lf-platform-api INTERFACE)
 add_library(lf::platform-api ALIAS lf-platform-api)
+target_link_libraries(lf-platform-api INTERFACE lf-low-level-platform-api)
 target_include_directories(lf-platform-api INTERFACE ${CMAKE_CURRENT_LIST_DIR})
diff --git a/platform/api/platform.h b/platform/api/platform.h
index 1b1950e8e..3e2f7d43c 100644
--- a/platform/api/platform.h
+++ b/platform/api/platform.h
@@ -9,6 +9,8 @@
  * @copyright Copyright (c) 2024
  */
 
+#include "low_level_platform.h"
+
 /**
  * @brief Pointer to the platform-specific implementation of a mutex.
  */

From 0366a731cdbd5bb3cdadbf8d031de4f89b756b70 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sat, 4 May 2024 14:10:30 +0200
Subject: [PATCH 13/34] Apply formatter

---
 .../api/platform/lf_flexpret_support.h        |  20 +-
 low_level_platform/impl/src/lf_atomic_irq.c   |   5 +-
 .../impl/src/lf_flexpret_support.c            | 171 +++++++++---------
 3 files changed, 92 insertions(+), 104 deletions(-)

diff --git a/low_level_platform/api/platform/lf_flexpret_support.h b/low_level_platform/api/platform/lf_flexpret_support.h
index 07f059f10..c614905f1 100644
--- a/low_level_platform/api/platform/lf_flexpret_support.h
+++ b/low_level_platform/api/platform/lf_flexpret_support.h
@@ -28,21 +28,21 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  * FlexPRET API support for the C target of Lingua Franca.
  *
  * This is based on lf_nrf_support.h in icyphy/lf-buckler.
- *  
+ *
  * @author{Soroush Bateni <soroush@utdallas.edu>}
  * @author{Abhi Gundrala <gundralaa@berkeley.edu>}
- * @author{Shaokai Lin <shaokai@berkeley.edu>} 
+ * @author{Shaokai Lin <shaokai@berkeley.edu>}
  */
 
 #ifndef LF_FLEXPRET_SUPPORT_H
 #define LF_FLEXPRET_SUPPORT_H
 
-#include <stdint.h>     // For fixed-width integral types
-#include <time.h>       // For CLOCK_MONOTONIC
+#include <stdint.h> // For fixed-width integral types
+#include <time.h>   // For CLOCK_MONOTONIC
 #include <stdbool.h>
-#include <stdarg.h>     // Defines va_list
-#include <stdio.h>      // Defines FILE
-#include <string.h>     // Defines strlen
+#include <stdarg.h> // Defines va_list
+#include <stdio.h>  // Defines FILE
+#include <string.h> // Defines strlen
 
 #include <flexpret/flexpret.h>
 
@@ -51,12 +51,12 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * The mutex holds the interrupt number.
  * For example, a mutex might be defined for the GPIOTE peripheral interrupt number
- * 
+ *
  * When initialized, the interrupt is inserted into a global linked list
  * for disabling and enabling all interrupts during sleep functions.
  * - All interrupts are disabled by default after initialization
  * - Priority levels are restricted between (0-7)
- * 
+ *
  */
 
 // Define PRINTF_TIME and PRINTF_MICROSTEP, which are the printf
@@ -74,7 +74,7 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 // for time and microsteps, you can simply define
 // PRINTF_TIME and PRINTF_MICROSTEP directly in the same file that
 // defines the types _instant_t, _interval_t, and _microstep_t.
-#include <inttypes.h>  // Needed to define PRId64 and PRIu32
+#include <inttypes.h> // Needed to define PRId64 and PRIu32
 #define PRINTF_TIME "%" PRId64
 #define PRINTF_MICROSTEP "%" PRIu32
 
diff --git a/low_level_platform/impl/src/lf_atomic_irq.c b/low_level_platform/impl/src/lf_atomic_irq.c
index 9224fa615..2854a6f11 100644
--- a/low_level_platform/impl/src/lf_atomic_irq.c
+++ b/low_level_platform/impl/src/lf_atomic_irq.c
@@ -1,7 +1,4 @@
-#if defined(PLATFORM_ARDUINO)  || \
-    defined(PLATFORM_NRF52)    || \
-    defined(PLATFORM_ZEPHYR)   || \
-    defined(PLATFORM_RP2040)   || \
+#if defined(PLATFORM_ARDUINO) || defined(PLATFORM_NRF52) || defined(PLATFORM_ZEPHYR) || defined(PLATFORM_RP2040) ||    \
     defined(PLATFORM_FLEXPRET)
 /**
  * @author Erling Rennemo Jellum
diff --git a/low_level_platform/impl/src/lf_flexpret_support.c b/low_level_platform/impl/src/lf_flexpret_support.c
index d7f910345..1da2350ba 100644
--- a/low_level_platform/impl/src/lf_flexpret_support.c
+++ b/low_level_platform/impl/src/lf_flexpret_support.c
@@ -19,7 +19,7 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ***************/
 
 /** Support file for Bare-metal FlexPRET platform.
- *  
+ *
  *  @author{Shaokai Lin <shaokai@berkeley.edu>}
  *  @author{Magnus Mæhlum <magnmaeh@stud.ntnu.no>}
  */
@@ -30,13 +30,12 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "low_level_platform.h"
 
 /**
- * Used to keep track of the number of nested critical sections. 
- * 
+ * Used to keep track of the number of nested critical sections.
+ *
  * We should only disable interrupts when this is zero and we enter a critical section
  * We should only  enable interrupts when we exit a critical section and this is zero
  */
-static int critical_section_num_nested[FP_THREADS] = 
-    THREAD_ARRAY_INITIALIZER(0);
+static int critical_section_num_nested[FP_THREADS] = THREAD_ARRAY_INITIALIZER(0);
 
 /**
  * @return 0 for success, or -1 for failure
@@ -46,75 +45,77 @@ static volatile uint32_t last_time = 0;
 static volatile uint64_t epoch = 0;
 #define EPOCH_DURATION_NS (1ULL << 32)
 int _lf_clock_gettime(instant_t* t) {
-    uint32_t now = rdtime();
-    if (now < last_time) {
-        epoch += EPOCH_DURATION_NS;
-    }
-    *t = now + epoch;
-    last_time = now;
-    return 0;
-}
-
-int _lf_interruptable_sleep_until_locked(environment_t *env, instant_t wakeup_time) {
-    int ret = 0;
-    if (wakeup_time < 0) {
-        return ret;
-    }
+  uint32_t now = rdtime();
+  if (now < last_time) {
+    epoch += EPOCH_DURATION_NS;
+  }
+  *t = now + epoch;
+  last_time = now;
+  return 0;
+}
+
+int _lf_interruptable_sleep_until_locked(environment_t* env, instant_t wakeup_time) {
+  int ret = 0;
+  if (wakeup_time < 0) {
+    return ret;
+  }
 
-    // Enable interrupts and execute wait until instruction
-    lf_critical_section_exit(env);
+  // Enable interrupts and execute wait until instruction
+  lf_critical_section_exit(env);
 
-    // Wait until will stop sleep if interrupt occurs
-    fp_wait_until(wakeup_time);
+  // Wait until will stop sleep if interrupt occurs
+  fp_wait_until(wakeup_time);
 
-    if ((instant_t) rdtime64() < wakeup_time) {
-        // Interrupt occurred because we did not wait full wakeup_time
-        ret = -1;
-    }
+  if ((instant_t)rdtime64() < wakeup_time) {
+    // Interrupt occurred because we did not wait full wakeup_time
+    ret = -1;
+  }
 
-    lf_critical_section_enter(env);
-    return ret;
+  lf_critical_section_enter(env);
+  return ret;
 }
 
 int lf_sleep(interval_t sleep_duration) {
-    // FIXME: Handle sleep durations exceeding 32bit
-    fp_delay_for(sleep_duration);
-    return 0;
+  // FIXME: Handle sleep durations exceeding 32bit
+  fp_delay_for(sleep_duration);
+  return 0;
 }
 
 /**
  * Initialize the LF clock.
  */
 void _lf_initialize_clock() {
-    // FlexPRET clock does not require any initialization
+  // FlexPRET clock does not require any initialization
 }
 
 int lf_disable_interrupts_nested() {
-    // In the special case where this function is called during an interrupt 
-    // subroutine (isr) it should have no effect
-    if ((read_csr(CSR_STATUS) & 0x04) == 0x04) return 0;
+  // In the special case where this function is called during an interrupt
+  // subroutine (isr) it should have no effect
+  if ((read_csr(CSR_STATUS) & 0x04) == 0x04)
+    return 0;
 
-    uint32_t hartid = read_hartid();
+  uint32_t hartid = read_hartid();
 
-    fp_assert(critical_section_num_nested[hartid] >= 0, "Number of nested critical sections less than zero.");
-    if (critical_section_num_nested[hartid]++ == 0) {
-        fp_interrupt_disable();
-    }
-    return 0;
+  fp_assert(critical_section_num_nested[hartid] >= 0, "Number of nested critical sections less than zero.");
+  if (critical_section_num_nested[hartid]++ == 0) {
+    fp_interrupt_disable();
+  }
+  return 0;
 }
 
 int lf_enable_interrupts_nested() {
-    // In the special case where this function is called during an interrupt 
-    // subroutine (isr) it should have no effect
-    if ((read_csr(CSR_STATUS) & 0x04) == 0x04) return 0;
+  // In the special case where this function is called during an interrupt
+  // subroutine (isr) it should have no effect
+  if ((read_csr(CSR_STATUS) & 0x04) == 0x04)
+    return 0;
 
-    uint32_t hartid = read_hartid();
+  uint32_t hartid = read_hartid();
 
-    if (--critical_section_num_nested[hartid] == 0) {
-        fp_interrupt_enable();
-    }
-    fp_assert(critical_section_num_nested[hartid] >= 0, "Number of nested critical sections less than zero.");
-    return 0;
+  if (--critical_section_num_nested[hartid] == 0) {
+    fp_interrupt_enable();
+  }
+  fp_assert(critical_section_num_nested[hartid] >= 0, "Number of nested critical sections less than zero.");
+  return 0;
 }
 
 /**
@@ -124,80 +125,70 @@ int lf_enable_interrupts_nested() {
  *  set appropriately (see `man 2 clock_nanosleep`).
  */
 int lf_nanosleep(interval_t requested_time) {
-    instant_t t;
+  instant_t t;
+  _lf_clock_gettime(&t);
+  instant_t expire_time = t + requested_time;
+  while (t < expire_time) {
     _lf_clock_gettime(&t);
-    instant_t expire_time = t + requested_time;
-    while (t < expire_time) {
-        _lf_clock_gettime(&t);
-    }
-    return 0;
+  }
+  return 0;
 }
 
 #if defined(LF_SINGLE_THREADED)
 
 int _lf_single_threaded_notify_of_event() {
-    // No need to do anything, because an interrupt will cancel wait until
-    // This is specific to FlexPRET
-    return 0;
+  // No need to do anything, because an interrupt will cancel wait until
+  // This is specific to FlexPRET
+  return 0;
 }
 
 #else // Multi threaded
 
 int lf_available_cores() {
-    return FP_THREADS-1; // Return the number of Flexpret HW threads
+  return FP_THREADS - 1; // Return the number of Flexpret HW threads
 }
 
-int lf_thread_create(lf_thread_t* thread, void *(*lf_thread) (void *), void* arguments) {
-    // TODO: Decide between HRTT or SRTT
-    return fp_thread_create(HRTT, thread, lf_thread, arguments);
+int lf_thread_create(lf_thread_t* thread, void* (*lf_thread)(void*), void* arguments) {
+  // TODO: Decide between HRTT or SRTT
+  return fp_thread_create(HRTT, thread, lf_thread, arguments);
 }
 
-int lf_thread_join(lf_thread_t thread, void** thread_return) {
-    return fp_thread_join(thread, thread_return);
-}
+int lf_thread_join(lf_thread_t thread, void** thread_return) { return fp_thread_join(thread, thread_return); }
 
 int lf_mutex_init(lf_mutex_t* mutex) {
-    *mutex = (lf_mutex_t) FP_LOCK_INITIALIZER;
-    return 0;
+  *mutex = (lf_mutex_t)FP_LOCK_INITIALIZER;
+  return 0;
 }
 
 int lf_mutex_lock(lf_mutex_t* mutex) {
-    fp_lock_acquire(mutex);
-    return 0;
+  fp_lock_acquire(mutex);
+  return 0;
 }
 
 int lf_mutex_unlock(lf_mutex_t* mutex) {
-    fp_lock_release(mutex);
-    return 0;
+  fp_lock_release(mutex);
+  return 0;
 }
 
 int lf_cond_init(lf_cond_t* cond, lf_mutex_t* mutex) {
-    *cond = (lf_cond_t) FP_COND_INITIALIZER(mutex);
-    return 0;
+  *cond = (lf_cond_t)FP_COND_INITIALIZER(mutex);
+  return 0;
 }
 
-int lf_cond_broadcast(lf_cond_t* cond) {
-    return fp_cond_broadcast(cond);
-}
+int lf_cond_broadcast(lf_cond_t* cond) { return fp_cond_broadcast(cond); }
 
-int lf_cond_signal(lf_cond_t* cond) {
-    return fp_cond_signal(cond);
-}
+int lf_cond_signal(lf_cond_t* cond) { return fp_cond_signal(cond); }
 
-int lf_cond_wait(lf_cond_t* cond) {
-    return fp_cond_wait(cond);
-}
+int lf_cond_wait(lf_cond_t* cond) { return fp_cond_wait(cond); }
 
 int _lf_cond_timedwait(lf_cond_t* cond, instant_t absolute_time_ns) {
-    return fp_cond_timed_wait(cond, absolute_time_ns);
+  return fp_cond_timed_wait(cond, absolute_time_ns);
 }
 
-int lf_thread_id() {
-    return read_hartid();
-}
+int lf_thread_id() { return read_hartid(); }
 
 void initialize_lf_thread_id() {
-    // Nothing needed here; thread ID's are already available in harware registers
-    // which can be fetched with `read_hartid`.
+  // Nothing needed here; thread ID's are already available in harware registers
+  // which can be fetched with `read_hartid`.
 }
 #endif

From 4764f1fd7a4db6fa44fdf3bb26d6f2027209296c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sat, 4 May 2024 15:36:16 +0200
Subject: [PATCH 14/34] Add guard to flexpret_support.c which solves build
 errors for Ardunio tests.

---
 low_level_platform/impl/src/lf_flexpret_support.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/low_level_platform/impl/src/lf_flexpret_support.c b/low_level_platform/impl/src/lf_flexpret_support.c
index 1da2350ba..ccfcc611c 100644
--- a/low_level_platform/impl/src/lf_flexpret_support.c
+++ b/low_level_platform/impl/src/lf_flexpret_support.c
@@ -1,3 +1,4 @@
+#if defined(PLATFORM_FLEXPRET)
 /*************
 Copyright (c) 2021, The University of California at Berkeley.
 Redistribution and use in source and binary forms, with or without modification,
@@ -192,3 +193,5 @@ void initialize_lf_thread_id() {
   // which can be fetched with `read_hartid`.
 }
 #endif
+
+#endif // PLATFORM_FLEXPRET

From 9c5baecb72cbbfed00c534a8b746f68ff5f7d6b0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sun, 5 May 2024 08:10:55 +0200
Subject: [PATCH 15/34] Revert changes to propagating low-level-platform
 interface

---
 core/utils/util.c           | 1 +
 platform/api/CMakeLists.txt | 1 -
 platform/api/platform.h     | 2 --
 3 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/core/utils/util.c b/core/utils/util.c
index 881b6dc05..27bfef871 100644
--- a/core/utils/util.c
+++ b/core/utils/util.c
@@ -32,6 +32,7 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "util.h"
+#include "low_level_platform.h"
 
 #ifndef STANDALONE_RTI
 #include "environment.h"
diff --git a/platform/api/CMakeLists.txt b/platform/api/CMakeLists.txt
index e81bcdaf1..88b8de512 100644
--- a/platform/api/CMakeLists.txt
+++ b/platform/api/CMakeLists.txt
@@ -1,4 +1,3 @@
 add_library(lf-platform-api INTERFACE)
 add_library(lf::platform-api ALIAS lf-platform-api)
-target_link_libraries(lf-platform-api INTERFACE lf-low-level-platform-api)
 target_include_directories(lf-platform-api INTERFACE ${CMAKE_CURRENT_LIST_DIR})
diff --git a/platform/api/platform.h b/platform/api/platform.h
index 3e2f7d43c..1b1950e8e 100644
--- a/platform/api/platform.h
+++ b/platform/api/platform.h
@@ -9,8 +9,6 @@
  * @copyright Copyright (c) 2024
  */
 
-#include "low_level_platform.h"
-
 /**
  * @brief Pointer to the platform-specific implementation of a mutex.
  */

From 9fdd18986f7cbb9f2f2860889a3b8c0c35160b4b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sun, 5 May 2024 14:40:35 +0200
Subject: [PATCH 16/34] Move a single CMake line for more consistency

---
 low_level_platform/api/CMakeLists.txt  | 1 -
 low_level_platform/impl/CMakeLists.txt | 1 +
 2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/low_level_platform/api/CMakeLists.txt b/low_level_platform/api/CMakeLists.txt
index 47817b59a..3f3a50936 100644
--- a/low_level_platform/api/CMakeLists.txt
+++ b/low_level_platform/api/CMakeLists.txt
@@ -10,6 +10,5 @@ elseif(${CMAKE_SYSTEM_NAME} STREQUAL "Zephyr")
 elseif(${CMAKE_SYSTEM_NAME} STREQUAL "Rp2040")
     target_compile_definitions(lf-low-level-platform-api INTERFACE PLATFORM_RP2040)
 elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
-    target_link_libraries(lf-low-level-platform-api INTERFACE fp-sdk-if)
     target_compile_definitions(lf-low-level-platform-api INTERFACE PLATFORM_FLEXPRET)
 endif()
diff --git a/low_level_platform/impl/CMakeLists.txt b/low_level_platform/impl/CMakeLists.txt
index c7c5e1b13..2266b67d1 100644
--- a/low_level_platform/impl/CMakeLists.txt
+++ b/low_level_platform/impl/CMakeLists.txt
@@ -60,6 +60,7 @@ if(${CMAKE_SYSTEM_NAME} STREQUAL "Zephyr")
     zephyr_library_sources(${LF_LOW_LEVEL_PLATFORM_FILES})
     zephyr_library_link_libraries(kernel)
 elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
+    target_link_libraries(lf-low-level-platform-api INTERFACE fp-sdk-if)
     add_library(lf-low-level-platform-impl STATIC ${LF_LOW_LEVEL_PLATFORM_FILES})
 
     if (DEFINED NUMBER_OF_WORKERS)

From e5216b61d956eb5a51d2ea61baf432ca26967e3c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Fri, 10 May 2024 14:15:02 +0200
Subject: [PATCH 17/34] Add explanation of #include platform in util.c

---
 core/utils/util.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/core/utils/util.c b/core/utils/util.c
index 27bfef871..4c14f406c 100644
--- a/core/utils/util.c
+++ b/core/utils/util.c
@@ -32,7 +32,15 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "util.h"
+
+#if defined(PLATFORM_FLEXPRET)
+/**
+ * For FlexPRET specifically, the header file contains macro overrides for
+ * `fprintf` and `vfprintf`, which reduces code size. Those are not applied
+ * unless the header file is included.
+ */
 #include "low_level_platform.h"
+#endif // defined(PLATFORM_FLEXPRET)
 
 #ifndef STANDALONE_RTI
 #include "environment.h"

From 2041aff7ee24ebab1fc756a927087dce51e97252 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Fri, 10 May 2024 14:17:46 +0200
Subject: [PATCH 18/34] Fix author in lf_flexpret_support.h

---
 low_level_platform/api/platform/lf_flexpret_support.h | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/low_level_platform/api/platform/lf_flexpret_support.h b/low_level_platform/api/platform/lf_flexpret_support.h
index c614905f1..27fe35104 100644
--- a/low_level_platform/api/platform/lf_flexpret_support.h
+++ b/low_level_platform/api/platform/lf_flexpret_support.h
@@ -27,11 +27,7 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 /**
  * FlexPRET API support for the C target of Lingua Franca.
  *
- * This is based on lf_nrf_support.h in icyphy/lf-buckler.
- *
- * @author{Soroush Bateni <soroush@utdallas.edu>}
- * @author{Abhi Gundrala <gundralaa@berkeley.edu>}
- * @author{Shaokai Lin <shaokai@berkeley.edu>}
+ * @author{Magnus Mæhlum <magnmaeh@stud.ntnu.no>}
  */
 
 #ifndef LF_FLEXPRET_SUPPORT_H

From c518fd442dc1fb9fd8e24f30a8e119b894326bbc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Fri, 10 May 2024 14:19:27 +0200
Subject: [PATCH 19/34] Alphabetical order on targets supported

---
 low_level_platform/impl/CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/low_level_platform/impl/CMakeLists.txt b/low_level_platform/impl/CMakeLists.txt
index 2266b67d1..657254f70 100644
--- a/low_level_platform/impl/CMakeLists.txt
+++ b/low_level_platform/impl/CMakeLists.txt
@@ -45,7 +45,7 @@ elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
         ${CMAKE_CURRENT_LIST_DIR}/src/lf_atomic_irq.c
     )
 else()
-    message(FATAL_ERROR "Your platform is not supported! The C target supports Linux, MacOS, Windows, Zephyr, Nrf52, RP2040 and FlexPRET.")
+    message(FATAL_ERROR "Your platform is not supported! The C target supports FlexPRET, Linux, MacOS, Nrf52, RP2040, Windows, and Zephyr.")
 endif()
 
 list(APPEND LF_LOW_LEVEL_PLATFORM_FILES ${CMAKE_CURRENT_LIST_DIR}/src/lf_platform_util.c)

From d388cac7d7d46927d25f455b6c6965b4b914d69c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Fri, 10 May 2024 14:32:29 +0200
Subject: [PATCH 20/34] Add link to issue of decide between HRTT and SRTT in
 lf_thread_create.

---
 low_level_platform/impl/src/lf_flexpret_support.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/low_level_platform/impl/src/lf_flexpret_support.c b/low_level_platform/impl/src/lf_flexpret_support.c
index ccfcc611c..6a90f6fc1 100644
--- a/low_level_platform/impl/src/lf_flexpret_support.c
+++ b/low_level_platform/impl/src/lf_flexpret_support.c
@@ -150,7 +150,10 @@ int lf_available_cores() {
 }
 
 int lf_thread_create(lf_thread_t* thread, void* (*lf_thread)(void*), void* arguments) {
-  // TODO: Decide between HRTT or SRTT
+  /**
+   * Need to select between HRTT or SRTT; see
+   * https://github.com/lf-lang/reactor-c/issues/421
+   */
   return fp_thread_create(HRTT, thread, lf_thread, arguments);
 }
 

From 7aecb2aa24619ec3f23c5a485f9dd80c14da8302 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sat, 11 May 2024 13:36:42 +0200
Subject: [PATCH 21/34] Fix 64-bit sleep and fix issues addressed in PR

---
 .../api/platform/lf_flexpret_support.h        | 34 -------
 .../impl/src/lf_flexpret_support.c            | 94 ++++++++++++-------
 2 files changed, 60 insertions(+), 68 deletions(-)

diff --git a/low_level_platform/api/platform/lf_flexpret_support.h b/low_level_platform/api/platform/lf_flexpret_support.h
index 27fe35104..44835687b 100644
--- a/low_level_platform/api/platform/lf_flexpret_support.h
+++ b/low_level_platform/api/platform/lf_flexpret_support.h
@@ -55,21 +55,6 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  */
 
-// Define PRINTF_TIME and PRINTF_MICROSTEP, which are the printf
-// codes (like the d in %d to print an int) for time and microsteps.
-// To use these, specify the printf as follows:
-//     printf("%" PRINTF_TIME "\n", time_value);
-// On most platforms, time is an signed 64-bit number (int64_t) and
-// the microstep is an unsigned 32-bit number (uint32_t).
-// Sadly, in C, there is no portable to print such numbers using
-// printf without getting a warning on some platforms.
-// On each platform, the code for printf if given by the macros
-// PRId64 and PRIu32 defined in inttypes.h.  Hence, here, we import
-// inttypes.h, then define PRINTF_TIME and PRINTF_MICROSTEP.
-// If you are targeting a platform that uses some other type
-// for time and microsteps, you can simply define
-// PRINTF_TIME and PRINTF_MICROSTEP directly in the same file that
-// defines the types _instant_t, _interval_t, and _microstep_t.
 #include <inttypes.h> // Needed to define PRId64 and PRIu32
 #define PRINTF_TIME "%" PRId64
 #define PRINTF_MICROSTEP "%" PRIu32
@@ -79,26 +64,7 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 //     printf("Tag is " PRINTF_TAG "\n", time_value, microstep);
 #define PRINTF_TAG "(%" PRId64 ", %" PRIu32 ")"
 
-/**
- * Time instant. Both physical and logical times are represented
- * using this typedef.
- * WARNING: If this code is used after about the year 2262,
- * then representing time as a 64-bit long long will be insufficient.
- */
-typedef int64_t _instant_t;
-
-/**
- * Interval of time.
- */
-typedef int64_t _interval_t;
-
-/**
- * Microstep instant.
- */
-typedef uint32_t _microstep_t;
-
 #include <errno.h>
-#define _LF_TIMEOUT ETIMEDOUT
 
 // The underlying physical clock for Linux
 #define _LF_CLOCK CLOCK_MONOTONIC
diff --git a/low_level_platform/impl/src/lf_flexpret_support.c b/low_level_platform/impl/src/lf_flexpret_support.c
index 6a90f6fc1..78fd4580b 100644
--- a/low_level_platform/impl/src/lf_flexpret_support.c
+++ b/low_level_platform/impl/src/lf_flexpret_support.c
@@ -38,48 +38,81 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 static int critical_section_num_nested[FP_THREADS] = THREAD_ARRAY_INITIALIZER(0);
 
-/**
- * @return 0 for success, or -1 for failure
- */
+static volatile bool _lf_async_event_occurred = false;
 
-static volatile uint32_t last_time = 0;
-static volatile uint64_t epoch = 0;
 #define EPOCH_DURATION_NS (1ULL << 32)
+
 int _lf_clock_gettime(instant_t* t) {
-  uint32_t now = rdtime();
-  if (now < last_time) {
-    epoch += EPOCH_DURATION_NS;
-  }
-  *t = now + epoch;
-  last_time = now;
+  *t = (instant_t) rdtime64();
   return 0;
 }
 
-int _lf_interruptable_sleep_until_locked(environment_t* env, instant_t wakeup_time) {
-  int ret = 0;
-  if (wakeup_time < 0) {
-    return ret;
+int _lf_sleep_common(instant_t wakeup_time, bool interruptable) {
+  // Store the number of epochs; i.e., how many times the 32-bit timer
+  // will overflow
+  uint32_t wakeup_time_epochs = 0;
+  uint32_t wakeup_time_after_epochs = 0;
+  uint32_t sleep_start = rdtime();
+
+  if (wakeup_time > (instant_t) EPOCH_DURATION_NS) {
+    wakeup_time_epochs = wakeup_time / EPOCH_DURATION_NS;
+    wakeup_time_after_epochs = wakeup_time % EPOCH_DURATION_NS;
+    
+    if (wakeup_time < sleep_start) {
+      // This means we need to do another epoch
+      wakeup_time_epochs++;
+    }
+  } else {
+    wakeup_time_epochs = 0;
+    wakeup_time_after_epochs = wakeup_time;
+    if (wakeup_time < sleep_start) {
+      // Nothing to do; should not happen
+      //LF_PRINT_DEBUG("FlexPRET: _lf_sleep_common called with wakeup_time < current time\n");
+      return 0;
+    }
+  }
+
+  const uint32_t max_uint32_value = 0xFFFFFFFF;
+  _lf_async_event_occurred = false;
+
+  for (uint32_t i = 0; i < wakeup_time_epochs; i++) {
+    // The first sleep until will only be partial
+    if (interruptable) {
+      // Can be interrupted
+      fp_wait_until(max_uint32_value);
+      if (_lf_async_event_occurred) break;
+    } else {
+      // Cannot be interrupted
+      fp_delay_until(max_uint32_value);
+    }
+  }
+
+  if (interruptable) {
+    if (!_lf_async_event_occurred) {
+      fp_wait_until(wakeup_time_after_epochs);
+    }
+  } else {
+    // Cannot be interrupted
+    fp_delay_until(wakeup_time_after_epochs);
   }
 
+  return _lf_async_event_occurred;
+}
+
+int _lf_interruptable_sleep_until_locked(environment_t* env, instant_t wakeup_time) {
   // Enable interrupts and execute wait until instruction
   lf_critical_section_exit(env);
 
   // Wait until will stop sleep if interrupt occurs
-  fp_wait_until(wakeup_time);
-
-  if ((instant_t)rdtime64() < wakeup_time) {
-    // Interrupt occurred because we did not wait full wakeup_time
-    ret = -1;
-  }
+  int ret = _lf_sleep_common(wakeup_time, true);
 
   lf_critical_section_enter(env);
   return ret;
 }
 
 int lf_sleep(interval_t sleep_duration) {
-  // FIXME: Handle sleep durations exceeding 32bit
-  fp_delay_for(sleep_duration);
-  return 0;
+  interval_t sleep_until = rdtime64() + sleep_duration;
+  return _lf_sleep_common(sleep_until, false);
 }
 
 /**
@@ -126,20 +159,13 @@ int lf_enable_interrupts_nested() {
  *  set appropriately (see `man 2 clock_nanosleep`).
  */
 int lf_nanosleep(interval_t requested_time) {
-  instant_t t;
-  _lf_clock_gettime(&t);
-  instant_t expire_time = t + requested_time;
-  while (t < expire_time) {
-    _lf_clock_gettime(&t);
-  }
-  return 0;
+  return lf_sleep(requested_time);
 }
 
 #if defined(LF_SINGLE_THREADED)
 
 int _lf_single_threaded_notify_of_event() {
-  // No need to do anything, because an interrupt will cancel wait until
-  // This is specific to FlexPRET
+  _lf_async_event_occurred = true;
   return 0;
 }
 
@@ -186,7 +212,7 @@ int lf_cond_signal(lf_cond_t* cond) { return fp_cond_signal(cond); }
 int lf_cond_wait(lf_cond_t* cond) { return fp_cond_wait(cond); }
 
 int _lf_cond_timedwait(lf_cond_t* cond, instant_t absolute_time_ns) {
-  return fp_cond_timed_wait(cond, absolute_time_ns);
+  return (fp_cond_timed_wait(cond, absolute_time_ns) == FP_TIMEOUT) ? LF_TIMEOUT : 0;
 }
 
 int lf_thread_id() { return read_hartid(); }

From 91102507ead45e8cb288628e50ffc4cc0342e854 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sat, 11 May 2024 13:40:32 +0200
Subject: [PATCH 22/34] Remove more redundant code

---
 low_level_platform/api/platform/lf_flexpret_support.h | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/low_level_platform/api/platform/lf_flexpret_support.h b/low_level_platform/api/platform/lf_flexpret_support.h
index 44835687b..9e426d86d 100644
--- a/low_level_platform/api/platform/lf_flexpret_support.h
+++ b/low_level_platform/api/platform/lf_flexpret_support.h
@@ -64,11 +64,6 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 //     printf("Tag is " PRINTF_TAG "\n", time_value, microstep);
 #define PRINTF_TAG "(%" PRId64 ", %" PRIu32 ")"
 
-#include <errno.h>
-
-// The underlying physical clock for Linux
-#define _LF_CLOCK CLOCK_MONOTONIC
-
 #if !defined(LF_SINGLE_THREADED)
 typedef fp_lock_t lf_mutex_t;
 typedef fp_thread_t lf_thread_t;

From 64f9339017c026c0bdbf0b9b66433d75a1953557 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sat, 11 May 2024 13:40:46 +0200
Subject: [PATCH 23/34] Add workflow

---
 .github/workflows/ci.yml | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 39267f34f..b43725b47 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -55,6 +55,14 @@ jobs:
       compiler-ref: ${{ needs.fetch-lf.outputs.ref }}
     if: ${{ !github.event.pull_request.draft ||contains( github.event.pull_request.labels.*.name, 'zephyr') }}
 
+  lf-default-flexpret:
+    needs: [fetch-lf]
+    uses: lf-lang/lingua-franca/.github/workflows/c-flexpret-tests.yml@master
+    with:
+      runtime-ref: ${{ github.ref }}
+      compiler-ref: ${{ needs.fetch-lf.outputs.ref }}
+    if: ${{ !github.event.pull_request.draft ||contains( github.event.pull_request.labels.*.name, 'flexpret') }}
+
   lf-default:
     needs: [fetch-lf]
     uses: lf-lang/lingua-franca/.github/workflows/c-tests.yml@master

From 81aa4629066465e41125e69c9100632dde30da32 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sat, 11 May 2024 13:42:53 +0200
Subject: [PATCH 24/34] Formatting

---
 low_level_platform/impl/src/lf_flexpret_support.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/low_level_platform/impl/src/lf_flexpret_support.c b/low_level_platform/impl/src/lf_flexpret_support.c
index 78fd4580b..1003ab4ec 100644
--- a/low_level_platform/impl/src/lf_flexpret_support.c
+++ b/low_level_platform/impl/src/lf_flexpret_support.c
@@ -43,7 +43,7 @@ static volatile bool _lf_async_event_occurred = false;
 #define EPOCH_DURATION_NS (1ULL << 32)
 
 int _lf_clock_gettime(instant_t* t) {
-  *t = (instant_t) rdtime64();
+  *t = (instant_t)rdtime64();
   return 0;
 }
 
@@ -54,10 +54,10 @@ int _lf_sleep_common(instant_t wakeup_time, bool interruptable) {
   uint32_t wakeup_time_after_epochs = 0;
   uint32_t sleep_start = rdtime();
 
-  if (wakeup_time > (instant_t) EPOCH_DURATION_NS) {
+  if (wakeup_time > (instant_t)EPOCH_DURATION_NS) {
     wakeup_time_epochs = wakeup_time / EPOCH_DURATION_NS;
     wakeup_time_after_epochs = wakeup_time % EPOCH_DURATION_NS;
-    
+
     if (wakeup_time < sleep_start) {
       // This means we need to do another epoch
       wakeup_time_epochs++;
@@ -67,7 +67,7 @@ int _lf_sleep_common(instant_t wakeup_time, bool interruptable) {
     wakeup_time_after_epochs = wakeup_time;
     if (wakeup_time < sleep_start) {
       // Nothing to do; should not happen
-      //LF_PRINT_DEBUG("FlexPRET: _lf_sleep_common called with wakeup_time < current time\n");
+      // LF_PRINT_DEBUG("FlexPRET: _lf_sleep_common called with wakeup_time < current time\n");
       return 0;
     }
   }
@@ -80,7 +80,8 @@ int _lf_sleep_common(instant_t wakeup_time, bool interruptable) {
     if (interruptable) {
       // Can be interrupted
       fp_wait_until(max_uint32_value);
-      if (_lf_async_event_occurred) break;
+      if (_lf_async_event_occurred)
+        break;
     } else {
       // Cannot be interrupted
       fp_delay_until(max_uint32_value);
@@ -158,9 +159,7 @@ int lf_enable_interrupts_nested() {
  * @return 0 for success, or -1 for failure. In case of failure, errno will be
  *  set appropriately (see `man 2 clock_nanosleep`).
  */
-int lf_nanosleep(interval_t requested_time) {
-  return lf_sleep(requested_time);
-}
+int lf_nanosleep(interval_t requested_time) { return lf_sleep(requested_time); }
 
 #if defined(LF_SINGLE_THREADED)
 

From 414cbba0e4e3cfdd8ecf61d47e008cc0c7408f30 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Tue, 14 May 2024 15:59:16 +0200
Subject: [PATCH 25/34] Fix issues that came from cmake changes in fp SDK

---
 core/utils/util.c                             | 19 ++++++++++++-------
 include/core/tracepoint.h                     |  2 ++
 low_level_platform/api/CMakeLists.txt         |  1 +
 .../api/platform/lf_flexpret_support.h        |  7 -------
 low_level_platform/impl/CMakeLists.txt        |  2 +-
 platform/impl/CMakeLists.txt                  |  1 +
 6 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/core/utils/util.c b/core/utils/util.c
index 4c14f406c..e131b1810 100644
--- a/core/utils/util.c
+++ b/core/utils/util.c
@@ -33,21 +33,26 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "util.h"
 
-#if defined(PLATFORM_FLEXPRET)
+#if !defined(PLATFORM_FLEXPRET)
+#include <stdio.h>
+#else
 /**
- * For FlexPRET specifically, the header file contains macro overrides for
- * `fprintf` and `vfprintf`, which reduces code size. Those are not applied
- * unless the header file is included.
+ * For FlexPRET specifically, a small footprint version of printf is used
  */
-#include "low_level_platform.h"
-#endif // defined(PLATFORM_FLEXPRET)
+#include <printf/printf.h>
+/**
+ * Also, fflush and stdout are not provided so we just implement stubs
+ * 
+ */
+#define stdout (void *)(1)
+int fflush(void *stream) { (void) stream; return 0; }
+#endif // PLATFORM_FLEXPRET
 
 #ifndef STANDALONE_RTI
 #include "environment.h"
 #endif
 
 #include <errno.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <assert.h>
 #include <string.h> // Defines memcpy()
diff --git a/include/core/tracepoint.h b/include/core/tracepoint.h
index c43763a07..db8b26f57 100644
--- a/include/core/tracepoint.h
+++ b/include/core/tracepoint.h
@@ -31,7 +31,9 @@
 #define TRACEPOINT_H
 
 #include "lf_types.h"
+#if !defined(PLATFORM_FLEXPRET)
 #include <stdio.h>
+#endif
 
 #ifdef FEDERATED
 #include "net_common.h"
diff --git a/low_level_platform/api/CMakeLists.txt b/low_level_platform/api/CMakeLists.txt
index 3f3a50936..6993dfa52 100644
--- a/low_level_platform/api/CMakeLists.txt
+++ b/low_level_platform/api/CMakeLists.txt
@@ -11,4 +11,5 @@ elseif(${CMAKE_SYSTEM_NAME} STREQUAL "Rp2040")
     target_compile_definitions(lf-low-level-platform-api INTERFACE PLATFORM_RP2040)
 elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
     target_compile_definitions(lf-low-level-platform-api INTERFACE PLATFORM_FLEXPRET)
+    target_link_libraries(lf-low-level-platform-api INTERFACE fp-sdk)
 endif()
diff --git a/low_level_platform/api/platform/lf_flexpret_support.h b/low_level_platform/api/platform/lf_flexpret_support.h
index 9e426d86d..17992a8bb 100644
--- a/low_level_platform/api/platform/lf_flexpret_support.h
+++ b/low_level_platform/api/platform/lf_flexpret_support.h
@@ -33,13 +33,6 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef LF_FLEXPRET_SUPPORT_H
 #define LF_FLEXPRET_SUPPORT_H
 
-#include <stdint.h> // For fixed-width integral types
-#include <time.h>   // For CLOCK_MONOTONIC
-#include <stdbool.h>
-#include <stdarg.h> // Defines va_list
-#include <stdio.h>  // Defines FILE
-#include <string.h> // Defines strlen
-
 #include <flexpret/flexpret.h>
 
 /**
diff --git a/low_level_platform/impl/CMakeLists.txt b/low_level_platform/impl/CMakeLists.txt
index 657254f70..8773f1e99 100644
--- a/low_level_platform/impl/CMakeLists.txt
+++ b/low_level_platform/impl/CMakeLists.txt
@@ -60,8 +60,8 @@ if(${CMAKE_SYSTEM_NAME} STREQUAL "Zephyr")
     zephyr_library_sources(${LF_LOW_LEVEL_PLATFORM_FILES})
     zephyr_library_link_libraries(kernel)
 elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
-    target_link_libraries(lf-low-level-platform-api INTERFACE fp-sdk-if)
     add_library(lf-low-level-platform-impl STATIC ${LF_LOW_LEVEL_PLATFORM_FILES})
+    target_link_libraries(lf-low-level-platform-impl PRIVATE fp-sdk)
 
     if (DEFINED NUMBER_OF_WORKERS)
         # Verify that FlexPRET has the number of requested workers
diff --git a/platform/impl/CMakeLists.txt b/platform/impl/CMakeLists.txt
index e98c1a8d5..bc12ff11c 100644
--- a/platform/impl/CMakeLists.txt
+++ b/platform/impl/CMakeLists.txt
@@ -8,6 +8,7 @@ if(${CMAKE_SYSTEM_NAME} STREQUAL "Zephyr")
 elseif(${CMAKE_SYSTEM_NAME} STREQUAL "FlexPRET")
     add_library(lf-platform-impl STATIC)
     target_sources(lf-platform-impl PUBLIC ${LF_PLATFORM_FILES})
+    target_link_libraries(lf-platform-impl PRIVATE fp-sdk)
 else()
     add_library(lf-platform-impl STATIC)
     target_sources(lf-platform-impl PUBLIC ${LF_PLATFORM_FILES})

From bb0a90bb47e845f40aaa7066d6c32839f9928db7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sat, 18 May 2024 11:51:38 +0200
Subject: [PATCH 26/34] Format fix

---
 core/utils/util.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/core/utils/util.c b/core/utils/util.c
index e131b1810..a20899fb0 100644
--- a/core/utils/util.c
+++ b/core/utils/util.c
@@ -42,10 +42,13 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <printf/printf.h>
 /**
  * Also, fflush and stdout are not provided so we just implement stubs
- * 
+ *
  */
-#define stdout (void *)(1)
-int fflush(void *stream) { (void) stream; return 0; }
+#define stdout (void*)(1)
+int fflush(void* stream) {
+  (void)stream;
+  return 0;
+}
 #endif // PLATFORM_FLEXPRET
 
 #ifndef STANDALONE_RTI

From 9a28f5eb6ca4aa20ff89dad86e6831d3e5e6b505 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sat, 18 May 2024 16:50:03 +0200
Subject: [PATCH 27/34] Rename NO_TTY -> NO_CLI and fix comments related to
 this.

---
 core/reactor.c                                        | 8 ++++----
 core/reactor_common.c                                 | 4 ++--
 core/threaded/reactor_threaded.c                      | 4 ++--
 core/utils/util.c                                     | 9 ++++++---
 low_level_platform/api/platform/lf_arduino_support.h  | 4 ++--
 low_level_platform/api/platform/lf_flexpret_support.h | 6 ++++--
 low_level_platform/api/platform/lf_nrf52_support.h    | 5 +++--
 low_level_platform/api/platform/lf_rp2040_support.h   | 3 ++-
 low_level_platform/api/platform/lf_zephyr_support.h   | 3 ++-
 9 files changed, 27 insertions(+), 19 deletions(-)

diff --git a/core/reactor.c b/core/reactor.c
index 00df9e07f..a3bc64260 100644
--- a/core/reactor.c
+++ b/core/reactor.c
@@ -18,8 +18,8 @@
 #include "reactor_common.h"
 #include "environment.h"
 
-// Embedded platforms with no TTY shouldnt have signals
-#if !defined(NO_TTY)
+// Embedded platforms with no command line interface shouldnt have signals
+#if !defined(NO_CLI)
 #include <signal.h> // To trap ctrl-c and invoke termination().
 #endif
 
@@ -319,8 +319,8 @@ int lf_reactor_c_main(int argc, const char* argv[]) {
     // The above handles only "normal" termination (via a call to exit).
     // As a consequence, we need to also trap Ctrl-C, which issues a SIGINT,
     // and cause it to call exit.
-    // Embedded platforms with NO_TTY have no concept of a signal; for those, we exclude this call.
-#ifndef NO_TTY
+    // Embedded platforms with NO_CLI have no concept of a signal; for those, we exclude this call.
+#ifndef NO_CLI
     signal(SIGINT, exit);
 #endif
     // Create and initialize the environment
diff --git a/core/reactor_common.c b/core/reactor_common.c
index b3f1d7b4d..6863e7bc2 100644
--- a/core/reactor_common.c
+++ b/core/reactor_common.c
@@ -852,7 +852,7 @@ void schedule_output_reactions(environment_t* env, reaction_t* reaction, int wor
 
 /**
  * Print a usage message.
- * TODO: This is not necessary for NO_TTY
+ * TODO: This is not necessary for NO_CLI
  */
 void usage(int argc, const char* argv[]) {
   printf("\nCommand-line arguments: \n\n");
@@ -890,7 +890,7 @@ const char** default_argv = NULL;
  * Process the command-line arguments. If the command line arguments are not
  * understood, then print a usage message and return 0. Otherwise, return 1.
  * @return 1 if the arguments processed successfully, 0 otherwise.
- * TODO: Not necessary for NO_TTY
+ * TODO: Not necessary for NO_CLI
  */
 int process_args(int argc, const char* argv[]) {
   int i = 1;
diff --git a/core/threaded/reactor_threaded.c b/core/threaded/reactor_threaded.c
index 1d7598723..d4fe5c498 100644
--- a/core/threaded/reactor_threaded.c
+++ b/core/threaded/reactor_threaded.c
@@ -1073,12 +1073,12 @@ int lf_reactor_c_main(int argc, const char* argv[]) {
   LF_PRINT_DEBUG("Start time: " PRINTF_TIME "ns", start_time);
   struct timespec physical_time_timespec = {start_time / BILLION, start_time % BILLION};
 
-#ifdef NO_TTY
+#ifdef MINIMAL_STDLIB
   lf_print("---- Start execution ----");
 #else
   lf_print("---- Start execution at time %s---- plus %ld nanoseconds", ctime(&physical_time_timespec.tv_sec),
            physical_time_timespec.tv_nsec);
-#endif // NO_TTY
+#endif // MINIMAL_STDLIB
 
   // Create and initialize the environments for each enclave
   lf_create_environments();
diff --git a/core/utils/util.c b/core/utils/util.c
index e131b1810..a20899fb0 100644
--- a/core/utils/util.c
+++ b/core/utils/util.c
@@ -42,10 +42,13 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <printf/printf.h>
 /**
  * Also, fflush and stdout are not provided so we just implement stubs
- * 
+ *
  */
-#define stdout (void *)(1)
-int fflush(void *stream) { (void) stream; return 0; }
+#define stdout (void*)(1)
+int fflush(void* stream) {
+  (void)stream;
+  return 0;
+}
 #endif // PLATFORM_FLEXPRET
 
 #ifndef STANDALONE_RTI
diff --git a/low_level_platform/api/platform/lf_arduino_support.h b/low_level_platform/api/platform/lf_arduino_support.h
index 94c5d4933..aa76af8e3 100644
--- a/low_level_platform/api/platform/lf_arduino_support.h
+++ b/low_level_platform/api/platform/lf_arduino_support.h
@@ -129,7 +129,7 @@ typedef void* lf_thread_t;
 #define LLONG_MIN (-LLONG_MAX - 1LL)
 #define ULLONG_MAX (LLONG_MAX * 2ULL + 1ULL)
 
-// Arduinos are embedded platforms with no tty
-#define NO_TTY
+// Arduinos are embedded platforms with no command line interface
+#define NO_CLI
 
 #endif // LF_ARDUINO_SUPPORT_H
diff --git a/low_level_platform/api/platform/lf_flexpret_support.h b/low_level_platform/api/platform/lf_flexpret_support.h
index 17992a8bb..2031bb0ac 100644
--- a/low_level_platform/api/platform/lf_flexpret_support.h
+++ b/low_level_platform/api/platform/lf_flexpret_support.h
@@ -63,8 +63,10 @@ typedef fp_thread_t lf_thread_t;
 typedef fp_cond_t lf_cond_t;
 #endif
 
-// FlexPRET has no tty
-#define NO_TTY
+// This will filter out some unecessary calls to standard library functions
+// and save code space
+#define NO_CLI
+#define MINIMAL_STDLIB
 
 // Likewise, fprintf is used to print to `stderr`, but FlexPRET has no `stderr`
 // We instead redirect its output to normal printf
diff --git a/low_level_platform/api/platform/lf_nrf52_support.h b/low_level_platform/api/platform/lf_nrf52_support.h
index 18613b2e0..8f9b46620 100644
--- a/low_level_platform/api/platform/lf_nrf52_support.h
+++ b/low_level_platform/api/platform/lf_nrf52_support.h
@@ -34,8 +34,9 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef LF_NRF52_SUPPORT_H
 #define LF_NRF52_SUPPORT_H
 
-// This embedded platform has no TTY suport
-#define NO_TTY
+// This embedded platform has no command line interface
+#define NO_CLI
+#define MINIMAL_STDLIB
 
 #include <stdint.h> // For fixed-width integral types
 #include <stdbool.h>
diff --git a/low_level_platform/api/platform/lf_rp2040_support.h b/low_level_platform/api/platform/lf_rp2040_support.h
index 1b23e3a2e..670f7afb4 100644
--- a/low_level_platform/api/platform/lf_rp2040_support.h
+++ b/low_level_platform/api/platform/lf_rp2040_support.h
@@ -10,7 +10,8 @@
 #include <pico/stdlib.h>
 #include <pico/sync.h>
 
-#define NO_TTY
+#define NO_CLI
+#define MINIMAL_STDLIB
 
 // Defines for formatting time in printf for pico
 #define PRINTF_TAG "(" PRINTF_TIME ", " PRINTF_MICROSTEP ")"
diff --git a/low_level_platform/api/platform/lf_zephyr_support.h b/low_level_platform/api/platform/lf_zephyr_support.h
index 0f7ab6b4d..724bbe4e5 100644
--- a/low_level_platform/api/platform/lf_zephyr_support.h
+++ b/low_level_platform/api/platform/lf_zephyr_support.h
@@ -39,7 +39,8 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <zephyr/kernel.h>
 
-#define NO_TTY
+#define NO_CLI
+#define MINIMAL_STDLIB
 #if !defined(LF_SINGLE_THREADED)
 
 typedef struct k_mutex lf_mutex_t;

From 9962705e4ef17773a66419c2459a8702673cc7f0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sat, 18 May 2024 17:49:11 +0200
Subject: [PATCH 28/34] Fix issue with vfprintf getting wrong declaration for
 FlexPRET.

---
 core/utils/util.c                             | 16 --------------
 include/core/tracepoint.h                     |  2 --
 .../api/platform/lf_flexpret_support.h        | 22 +++++++++++++++++++
 3 files changed, 22 insertions(+), 18 deletions(-)

diff --git a/core/utils/util.c b/core/utils/util.c
index a20899fb0..62de9fd27 100644
--- a/core/utils/util.c
+++ b/core/utils/util.c
@@ -33,23 +33,7 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "util.h"
 
-#if !defined(PLATFORM_FLEXPRET)
 #include <stdio.h>
-#else
-/**
- * For FlexPRET specifically, a small footprint version of printf is used
- */
-#include <printf/printf.h>
-/**
- * Also, fflush and stdout are not provided so we just implement stubs
- *
- */
-#define stdout (void*)(1)
-int fflush(void* stream) {
-  (void)stream;
-  return 0;
-}
-#endif // PLATFORM_FLEXPRET
 
 #ifndef STANDALONE_RTI
 #include "environment.h"
diff --git a/include/core/tracepoint.h b/include/core/tracepoint.h
index 3d356bae5..cfa1fb956 100644
--- a/include/core/tracepoint.h
+++ b/include/core/tracepoint.h
@@ -31,9 +31,7 @@
 #define TRACEPOINT_H
 
 #include "lf_types.h"
-#if !defined(PLATFORM_FLEXPRET)
 #include <stdio.h>
-#endif
 
 #ifdef FEDERATED
 #include "net_common.h"
diff --git a/low_level_platform/api/platform/lf_flexpret_support.h b/low_level_platform/api/platform/lf_flexpret_support.h
index 2031bb0ac..8a6296ee7 100644
--- a/low_level_platform/api/platform/lf_flexpret_support.h
+++ b/low_level_platform/api/platform/lf_flexpret_support.h
@@ -68,8 +68,30 @@ typedef fp_cond_t lf_cond_t;
 #define NO_CLI
 #define MINIMAL_STDLIB
 
+/**
+ * Need to include `stdio` here, because we #define `fprintf` and `vfprintf` below.
+ * Since stdio.h contains declarations for these functions, including it
+ * after will result in the following:
+ *
+ * #define fprintf(s, f, ...) printf(f, ##__VA_ARGS__)
+ *
+ * int	fprintf (FILE *__restrict, const char *__restrict, ...)
+ *             _ATTRIBUTE ((__format__ (__printf__, 2, 3)));
+ *
+ * Which the preprocessor will replace with:
+ *
+ * int	printf (FILE *__restrict, const char *__restrict, ...)
+ *             _ATTRIBUTE ((__format__ (__printf__, 2, 3)));
+ *
+ * Which will yield an error.
+ *
+ */
+#include <stdio.h>
+
 // Likewise, fprintf is used to print to `stderr`, but FlexPRET has no `stderr`
 // We instead redirect its output to normal printf
+// Note: Most compilers do not support passing this on the command line, so CMake
+//       will drop it if you try... But that would be the better option.
 #define fprintf(stream, fmt, ...) printf(fmt, ##__VA_ARGS__)
 #define vfprintf(fp, fmt, args) vprintf(fmt, args)
 

From 3015a0de0519c296427cad6cc039d53c50726b37 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sat, 18 May 2024 17:57:08 +0200
Subject: [PATCH 29/34] Uncomment reference to FlexPRET workflow file that does
 not exist in main repo yet.

---
 .github/workflows/ci.yml | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b43725b47..a36beae7b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -55,13 +55,15 @@ jobs:
       compiler-ref: ${{ needs.fetch-lf.outputs.ref }}
     if: ${{ !github.event.pull_request.draft ||contains( github.event.pull_request.labels.*.name, 'zephyr') }}
 
-  lf-default-flexpret:
-    needs: [fetch-lf]
-    uses: lf-lang/lingua-franca/.github/workflows/c-flexpret-tests.yml@master
-    with:
-      runtime-ref: ${{ github.ref }}
-      compiler-ref: ${{ needs.fetch-lf.outputs.ref }}
-    if: ${{ !github.event.pull_request.draft ||contains( github.event.pull_request.labels.*.name, 'flexpret') }}
+  # TODO: Comment in when FlexPRET tests are added to main LF repo: 
+  # https://github.com/lf-lang/lingua-franca/pull/2262
+  #lf-default-flexpret:
+  #  needs: [fetch-lf]
+  #  uses: lf-lang/lingua-franca/.github/workflows/c-flexpret-tests.yml@master
+  #  with:
+  #    runtime-ref: ${{ github.ref }}
+  #    compiler-ref: ${{ needs.fetch-lf.outputs.ref }}
+  #  if: ${{ !github.event.pull_request.draft ||contains( github.event.pull_request.labels.*.name, 'flexpret') }}
 
   lf-default:
     needs: [fetch-lf]

From 3bd912178b472488c84b05e770f5c0963e6c09ad Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sat, 18 May 2024 19:58:40 +0200
Subject: [PATCH 30/34] Try to run FlexPRET tests in CI

---
 .github/workflows/ci.yml | 14 +++++++-------
 lingua-franca-ref.txt    |  2 +-
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a36beae7b..92ffaa209 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -57,13 +57,13 @@ jobs:
 
   # TODO: Comment in when FlexPRET tests are added to main LF repo: 
   # https://github.com/lf-lang/lingua-franca/pull/2262
-  #lf-default-flexpret:
-  #  needs: [fetch-lf]
-  #  uses: lf-lang/lingua-franca/.github/workflows/c-flexpret-tests.yml@master
-  #  with:
-  #    runtime-ref: ${{ github.ref }}
-  #    compiler-ref: ${{ needs.fetch-lf.outputs.ref }}
-  #  if: ${{ !github.event.pull_request.draft ||contains( github.event.pull_request.labels.*.name, 'flexpret') }}
+  lf-default-flexpret:
+    needs: [fetch-lf]
+    uses: lf-lang/lingua-franca/.github/workflows/c-flexpret-tests.yml@add-flexpret-support
+    with:
+      runtime-ref: ${{ github.ref }}
+      compiler-ref: ${{ needs.fetch-lf.outputs.ref }}
+    if: ${{ !github.event.pull_request.draft ||contains( github.event.pull_request.labels.*.name, 'flexpret') }}
 
   lf-default:
     needs: [fetch-lf]
diff --git a/lingua-franca-ref.txt b/lingua-franca-ref.txt
index 1f7391f92..1f07782fc 100644
--- a/lingua-franca-ref.txt
+++ b/lingua-franca-ref.txt
@@ -1 +1 @@
-master
+add-flexpret-support

From 35ffd7b996bac4ec8c33803ba6eae1223caa2dd3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sat, 18 May 2024 20:02:17 +0200
Subject: [PATCH 31/34] Fix url to point at fork

---
 .github/workflows/ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 92ffaa209..7a79671ad 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -59,7 +59,7 @@ jobs:
   # https://github.com/lf-lang/lingua-franca/pull/2262
   lf-default-flexpret:
     needs: [fetch-lf]
-    uses: lf-lang/lingua-franca/.github/workflows/c-flexpret-tests.yml@add-flexpret-support
+    uses: magnmaeh/lingua-franca/.github/workflows/c-flexpret-tests.yml@add-flexpret-support
     with:
       runtime-ref: ${{ github.ref }}
       compiler-ref: ${{ needs.fetch-lf.outputs.ref }}

From b230677a09d20585b070f7d9ebb0ac6ee3f8658e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sat, 18 May 2024 20:03:56 +0200
Subject: [PATCH 32/34] Revert ref to master

---
 lingua-franca-ref.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lingua-franca-ref.txt b/lingua-franca-ref.txt
index 1f07782fc..1f7391f92 100644
--- a/lingua-franca-ref.txt
+++ b/lingua-franca-ref.txt
@@ -1 +1 @@
-add-flexpret-support
+master

From 869d7865e50549aa312178d3cd0f0991b3f5b839 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20M=C3=A6hlum?= <magnusmaehlum@outlook.com>
Date: Sat, 18 May 2024 20:16:06 +0200
Subject: [PATCH 33/34] Revert changes to CI and add warning about FlexPRET
 issue in lf_flexpret_support.c

---
 .github/workflows/ci.yml                          | 14 +++++++-------
 low_level_platform/impl/src/lf_flexpret_support.c |  4 ++++
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7a79671ad..a36beae7b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -57,13 +57,13 @@ jobs:
 
   # TODO: Comment in when FlexPRET tests are added to main LF repo: 
   # https://github.com/lf-lang/lingua-franca/pull/2262
-  lf-default-flexpret:
-    needs: [fetch-lf]
-    uses: magnmaeh/lingua-franca/.github/workflows/c-flexpret-tests.yml@add-flexpret-support
-    with:
-      runtime-ref: ${{ github.ref }}
-      compiler-ref: ${{ needs.fetch-lf.outputs.ref }}
-    if: ${{ !github.event.pull_request.draft ||contains( github.event.pull_request.labels.*.name, 'flexpret') }}
+  #lf-default-flexpret:
+  #  needs: [fetch-lf]
+  #  uses: lf-lang/lingua-franca/.github/workflows/c-flexpret-tests.yml@master
+  #  with:
+  #    runtime-ref: ${{ github.ref }}
+  #    compiler-ref: ${{ needs.fetch-lf.outputs.ref }}
+  #  if: ${{ !github.event.pull_request.draft ||contains( github.event.pull_request.labels.*.name, 'flexpret') }}
 
   lf-default:
     needs: [fetch-lf]
diff --git a/low_level_platform/impl/src/lf_flexpret_support.c b/low_level_platform/impl/src/lf_flexpret_support.c
index 1003ab4ec..9d83283c5 100644
--- a/low_level_platform/impl/src/lf_flexpret_support.c
+++ b/low_level_platform/impl/src/lf_flexpret_support.c
@@ -79,11 +79,15 @@ int _lf_sleep_common(instant_t wakeup_time, bool interruptable) {
     // The first sleep until will only be partial
     if (interruptable) {
       // Can be interrupted
+      // NOTE: Does not work until this issue is resolved:
+      // https://github.com/pretis/flexpret/issues/93
       fp_wait_until(max_uint32_value);
       if (_lf_async_event_occurred)
         break;
     } else {
       // Cannot be interrupted
+      // NOTE: Does not work until this issue is resolved:
+      // https://github.com/pretis/flexpret/issues/93
       fp_delay_until(max_uint32_value);
     }
   }

From 5b3a0933ae8687169c9ce9fab41ce51619692636 Mon Sep 17 00:00:00 2001
From: erlingrj <erling.jellum@gmail.com>
Date: Wed, 22 May 2024 09:38:47 +0200
Subject: [PATCH 34/34] Add back flexpret CI

---
 .github/workflows/ci.yml | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a36beae7b..4ba3c90c3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -55,15 +55,13 @@ jobs:
       compiler-ref: ${{ needs.fetch-lf.outputs.ref }}
     if: ${{ !github.event.pull_request.draft ||contains( github.event.pull_request.labels.*.name, 'zephyr') }}
 
-  # TODO: Comment in when FlexPRET tests are added to main LF repo: 
-  # https://github.com/lf-lang/lingua-franca/pull/2262
-  #lf-default-flexpret:
-  #  needs: [fetch-lf]
-  #  uses: lf-lang/lingua-franca/.github/workflows/c-flexpret-tests.yml@master
-  #  with:
-  #    runtime-ref: ${{ github.ref }}
-  #    compiler-ref: ${{ needs.fetch-lf.outputs.ref }}
-  #  if: ${{ !github.event.pull_request.draft ||contains( github.event.pull_request.labels.*.name, 'flexpret') }}
+  lf-default-flexpret:
+   needs: [fetch-lf]
+   uses: lf-lang/lingua-franca/.github/workflows/c-flexpret-tests.yml@master
+   with:
+     runtime-ref: ${{ github.ref }}
+     compiler-ref: ${{ needs.fetch-lf.outputs.ref }}
+   if: ${{ !github.event.pull_request.draft ||contains( github.event.pull_request.labels.*.name, 'flexpret') }}
 
   lf-default:
     needs: [fetch-lf]