From fb4cf0462b591532de349bbbbeba1bbd93ca87da Mon Sep 17 00:00:00 2001
From: Martin Schoeberl <martin@jopdesign.com>
Date: Thu, 18 Jul 2024 12:36:01 +0200
Subject: [PATCH] Blinking LED

---
 Makefile         |  2 +-
 TODO.md          |  1 +
 asm/blink.s      | 19 ++++++++++++
 asm/test/blink.s | 79 ------------------------------------------------
 4 files changed, 21 insertions(+), 80 deletions(-)
 create mode 100644 asm/blink.s
 delete mode 100644 asm/test/blink.s

diff --git a/Makefile b/Makefile
index e477fe8..bbfb8eb 100644
--- a/Makefile
+++ b/Makefile
@@ -32,7 +32,7 @@ swsim:
 	sbt -Dprogram=$(APP) "testOnly leros.sim.LerosSimTest"
 
 hw:
-	sbt "runMain leros.Leros asm/test/$(APP).s"
+	sbt "runMain leros.Leros asm/$(APP).s"
 
 test-alu:
 	sbt "test:runMain leros.AluTester"
diff --git a/TODO.md b/TODO.md
index c84e308..01f684e 100644
--- a/TODO.md
+++ b/TODO.md
@@ -44,6 +44,7 @@
     * wondering on timing and layout in Quartus
  - [ ] Get rid of code duplication in Decode
  - [ ] Do memory mapped IO
+ - [ ] Be able to simulate source in asm
  - [x] Setup FPGA (Nexys A7)
    - [x] Use chipdesign1 for synthesis, OpenOCD for configuration
  - [ ] get a blinking LED running
diff --git a/asm/blink.s b/asm/blink.s
new file mode 100644
index 0000000..698b720
--- /dev/null
+++ b/asm/blink.s
@@ -0,0 +1,19 @@
+// Blinking LEDs
+
+// We need 2.500.000 iterations for a 100 ms tick
+//
+
+    loadi 0
+    store r2
+loop:
+    loadi 255
+    loadhi 255
+    loadh2i 38
+l1:
+    subi 1
+    brnz l1  // one loop iteration is 4 cc
+    load r2
+    stind 0
+    addi 1
+    store r2
+    br loop
\ No newline at end of file
diff --git a/asm/test/blink.s b/asm/test/blink.s
deleted file mode 100644
index d29fa64..0000000
--- a/asm/test/blink.s
+++ /dev/null
@@ -1,79 +0,0 @@
-// work in progress
-// branch does not yet work!!!
-
-    loadi 0
-    scall 0
-    store r2
-loop:
-    loadi 127
-// loadhi ...
-l1:
-    subi 1
-    nop
-    brnz l1
-
-
-    loadi 0
-    store r5
-start:
-	loadi 0
-//     loadhi 2
-	store r0
-ll1:
-    loadi 127
-// loadhi 255
-ll2:
-    subi 1
-	nop
-	brnz ll2
-	nop
-	load r0
-	subi 1
-	store r0
-	brnz ll1	
-	nop
-
-	load r5
-	addi 3
-	store r5
-	// loadi 0
-	stind 0
-
-	// loadi 1
-    // nop
-    // brnz start
-
-	loadi 0
-//  loadhi 2
-	store r0
-ll3:
-	loadi 255
-// loadhi 255
-ll4:
-	subi 1
-	nop
-	brnz ll4
-	nop
-	load r0
-	subi 1
-	store r0
-	brnz ll3	
-	nop
-
-	loadi 2
-	stind 0
-
-	loadi 1
-	nop
-	nop
-	nop
-	brnz start
-
-	loadi 2
-	nop
-	nop
-	nop
-
-    loadi 0
-	    scall 0
-