Refactor sound ticking to have a tick method

pyboy/core/mb.py

@@ -296,6 +296,7 @@ def tick(self):
                     min(
                         self.timer._cycles_to_interrupt,
                         self.lcd._cycles_to_interrupt,
+                        self.sound._cycles_to_interrupt, # TODO: Not implemented
                         # self.serial.cycles_to_interrupt(),
                         mode0_cycles
                     )
@@ -308,12 +309,7 @@ def tick(self):
             #TODO: Support General Purpose DMA
             # https://gbdev.io/pandocs/CGB_Registers.html#bit-7--0---general-purpose-dma
 
-            # TODO: Unify interface
-            sclock = self.sound.clock
-            if self.cgb and self.double_speed:
-                self.sound.clock = sclock + cycles//2
-            else:
-                self.sound.clock = sclock + cycles
+            self.sound.tick(self.cpu._cycles, self.double_speed)
 
             if self.timer.tick(self.cpu._cycles):
                 self.cpu.set_interruptflag(INTR_TIMER)
@@ -377,6 +373,7 @@ def getitem(self, i):
             elif i == 0xFF0F:
                 return self.cpu.interrupts_flag_register
             elif 0xFF10 <= i < 0xFF40:
+                self.sound.tick(self.cpu._cycles, self.double_speed)
                 return self.sound.get(i - 0xFF10)
             elif i == 0xFF40:
                 return self.lcd.get_lcdc()
@@ -502,6 +499,7 @@ def setitem(self, i, value):
             elif i == 0xFF0F:
                 self.cpu.interrupts_flag_register = value
             elif 0xFF10 <= i < 0xFF40:
+                self.sound.tick(self.cpu._cycles, self.double_speed)
                 self.sound.set(i - 0xFF10, value)
             elif i == 0xFF40:
                 self.lcd.set_lcdc(value)

pyboy/core/sound.pxd

@@ -4,7 +4,7 @@
 #
 
 cimport cython
-from libc.stdint cimport uint8_t, uint16_t, uint64_t
+from libc.stdint cimport int64_t, uint8_t, uint16_t, uint64_t
 
 from pyboy.logging.logging cimport Logger
 from pyboy.utils cimport IntIOInterface
@@ -28,6 +28,8 @@ cdef class Sound:
     cdef object audiobuffer
     cdef object audiobuffer_p
 
+    cdef uint64_t last_cycles
+    cdef int64_t _cycles_to_interrupt
     cdef int clock
 
     cdef bint poweron
@@ -42,6 +44,7 @@ cdef class Sound:
     cdef uint8_t get(self, uint8_t) noexcept nogil
     cdef void set(self, uint8_t, uint8_t) noexcept nogil
 
+    cdef void tick(self, int64_t, bint) noexcept nogil
     @cython.locals(nsamples=int, sample=int, i=int)
     cdef void sync(self) noexcept with gil # TODO: nogil
     @cython.locals(queued_time=int, samples_per_frame=int)

pyboy/core/sound.py

@@ -59,6 +59,8 @@ def __init__(self, enabled, emulate):
         self.audiobuffer = array("b", [0] * 4096) # Over 2 frames
         self.audiobuffer_p = c_void_p(self.audiobuffer.buffer_info()[0])
 
+        self.last_cycles = 0
+        self._cycles_to_interrupt = 1 << 16
         self.clock = 0
 
         self.poweron = True
@@ -150,6 +152,15 @@ def set(self, offset, value):
         else:
             raise IndexError(f"Attempted to write register {offset} in sound memory")
 
+    def tick(self, _cycles, double_speed):
+        cycles = _cycles - self.last_cycles
+        self.last_cycles = _cycles
+
+        if double_speed:
+            self.clock += cycles // 2
+        else:
+            self.clock += cycles
+
     def sync(self):
         """Run the audio for the number of clock cycles stored in self.clock"""
         if not self.emulate: