__OSInitAudioSystem in SMS vs Datel Code

A_SuperMarioSunshine.c

void os::__OSInitAudioSystem(void)

{
  ushort uVar1;
  ushort uVar2;
  undefined2 uVar3;
  ushort uVar4;
  int iVar5;
  int iVar6;
  
  iVar5 = OSGetArenaHi();
  Runtime.PPCEABI.H::memcpy((void *)(iVar5 + -0x80),(void *)0x81000000,0x80);
  Runtime.PPCEABI.H::memcpy((void *)0x81000000,&DSPInitCode,0x80);
  DCFlushRange(0x81000000,0x80);
  write_volatile_2(DAT_cc005012,0x43);
  write_volatile_2(DAT_cc00500a,0x8ac);
  uVar1 = read_volatile_2(DAT_cc00500a);
  write_volatile_2(DAT_cc00500a,uVar1 | 1);
  do {
    uVar1 = read_volatile_2(DAT_cc00500a);
  } while ((uVar1 & 1) != 0);
  write_volatile_2(DAT_cc005000,0);
  do {
    uVar1 = read_volatile_2(DAT_cc005004);
  } while ((uVar1 & 0x8000) != 0);
  write_volatile_4(DAT_cc005020,0x1000000);
  write_volatile_4(DAT_cc005024,0);
  write_volatile_4(DAT_cc005028,0x20);
  uVar1 = read_volatile_2(DAT_cc00500a);
  while( true ) {
    if ((uVar1 & 0x20) != 0) break;
    uVar1 = read_volatile_2(DAT_cc00500a);
  }
  write_volatile_2(DAT_cc00500a,uVar1);
  iVar5 = OSGetTick();
  do {
    iVar6 = OSGetTick();
  } while (iVar6 - iVar5 < 0x892);
  write_volatile_4(DAT_cc005020,0x1000000);
  write_volatile_4(DAT_cc005024,0);
  write_volatile_4(DAT_cc005028,0x20);
  uVar1 = read_volatile_2(DAT_cc00500a);
  while( true ) {
    if ((uVar1 & 0x20) != 0) break;
    uVar1 = read_volatile_2(DAT_cc00500a);
  }
  write_volatile_2(DAT_cc00500a,uVar1);
  uVar2 = read_volatile_2(DAT_cc00500a);
  write_volatile_2(DAT_cc00500a,uVar2 & 0xf7ff);
  do {
    uVar2 = read_volatile_2(DAT_cc00500a);
  } while ((uVar2 & 0x400) != 0);
  uVar2 = read_volatile_2(DAT_cc00500a);
  write_volatile_2(DAT_cc00500a,uVar2 & 0xfffb);
  uVar2 = read_volatile_2(DAT_cc005004);
  while( true ) {
    if ((uVar2 & 0x8000) != 0) break;
    uVar2 = read_volatile_2(DAT_cc005004);
  }
  uVar4 = read_volatile_2(DAT_cc00500a);
  uVar3 = read_volatile_2(DAT_cc005006);
  write_volatile_2(DAT_cc00500a,uVar4 | 4);
  write_volatile_2(DAT_cc00500a,0x8ac);
  uVar4 = read_volatile_2(DAT_cc00500a);
  write_volatile_2(DAT_cc00500a,uVar4 | 1);
  do {
    uVar4 = read_volatile_2(DAT_cc00500a);
  } while ((uVar4 & 1) != 0);
  iVar5 = OSGetArenaHi(uVar1,uVar3,uVar2);
  Runtime.PPCEABI.H::memcpy((void *)0x81000000,(void *)(iVar5 + -0x80),0x80);
  return;
}

B_Datel.c

void FUN_800164f4(void)

{
  ushort uVar1;
  int iVar2;
  int iVar3;
  
  FUN_8002c004(&DAT_81000000,&DAT_80016bdc,0x80);
  FUN_800158e4(&DAT_81000000,0x80);
  write_volatile_2(DAT_cc005012,0x43);
  write_volatile_2(DAT_cc00500a,0x8ac);
  uVar1 = read_volatile_2(DAT_cc00500a);
  write_volatile_2(DAT_cc00500a,uVar1 | 1);
  do {
    uVar1 = read_volatile_2(DAT_cc00500a);
  } while ((uVar1 & 1) != 0);
  write_volatile_2(DAT_cc005000,uVar1 & 1);
  do {
    uVar1 = read_volatile_2(DAT_cc005004);
  } while ((uVar1 & 0x8000) != 0);
  write_volatile_4(DAT_cc005020,0x1000000);
  write_volatile_4(DAT_cc005024,(uint)(uVar1 & 0x8000) << 0x10);
  write_volatile_4(DAT_cc005028,0x20);
  do {
    uVar1 = read_volatile_2(DAT_cc00500a);
  } while ((uVar1 & 0x20) == 0);
  write_volatile_2(DAT_cc00500a,uVar1);
  iVar2 = FUN_8001435c();
  do {
    iVar3 = FUN_8001435c();
  } while (iVar3 == iVar2);
  write_volatile_4(DAT_cc005020,0x1000000);
  write_volatile_4(DAT_cc005024,0);
  write_volatile_4(DAT_cc005028,0x20);
  do {
    uVar1 = read_volatile_2(DAT_cc00500a);
  } while ((uVar1 & 0x20) == 0);
  write_volatile_2(DAT_cc00500a,uVar1);
  uVar1 = read_volatile_2(DAT_cc00500a);
  write_volatile_2(DAT_cc00500a,uVar1 & 0xff7f);
  do {
    uVar1 = read_volatile_2(DAT_cc00500a);
  } while ((uVar1 & 0x400) != 0);
  uVar1 = read_volatile_2(DAT_cc00500a);
  write_volatile_2(DAT_cc00500a,uVar1 & 0xfffb);
  do {
    uVar1 = read_volatile_2(DAT_cc005004);
  } while ((uVar1 & 0x8000) == 0);
  uVar1 = read_volatile_2(DAT_cc00500a);
  write_volatile_2(DAT_cc00500a,uVar1 | 4);
  write_volatile_2(DAT_cc00500a,0x8ac);
  uVar1 = read_volatile_2(DAT_cc00500a);
  write_volatile_2(DAT_cc00500a,uVar1 | 1);
  do {
    uVar1 = read_volatile_2(DAT_cc00500a);
  } while ((uVar1 & 1) != 0);
  return;
}

C_SuperMarioSunshine_simplified.c

void os::__OSInitAudioSystem(void)
{
  memcpy((void *)(OSGetArenaHi() + -0x80),(void *)0x81000000,0x80);
  memcpy((void *)0x81000000,&DSPInitCode,0x80);
  DCFlushRange((void*)0x81000000,0x80);

  write_volatile_2(AR_INFO,0x43);
  write_volatile_2(DSP_CONTROL,(DSPCR_DSPRESET|DSPCR_DSPINT|DSPCR_ARINT|DSPCR_AIINT|DSPCR_HALT));

  write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) | DSPCR_RESET);
  while ((read_volatile_2(DSP_CONTROL) & DSPCR_RESET) != 0) { /* wait for reset bit to clear*/ }

  write_volatile_2(DSP_MAIL_TO_DSP_HI,0);
  while ((read_volatile_2(DSP_MAIL_FROM_DSP_HI) & 0x8000) != 0) { /* wait for there to be no pending mail(?) */ }
  read_volatile_2(DSP_MAIL_FROM_DSP_LO); // Wasn't shown in decompiler before; did https://github.com/NationalSecurityAgency/ghidra/issues/1832 regress?

  write_volatile_4(AR_DMA_MMADDR,0x1000000);
  write_volatile_4(AR_DMA_ARADDR,0);
  write_volatile_4(AR_DMA_CNT,0x20);

  while ((read_volatile_2(DSP_CONTROL) & DSPCR_ARINT) == 0) { /* wait for AR interrupt */ }
  write_volatile_2(DSP_CONTROL, DSP_CONTROL); // clear interrupts (this is done using the value read from the loop above)

  u64 start_tick = OSGetTick();
  while (OSGetTick() - start_tick < 0x892) { /* delay a bit */ }

  write_volatile_4(AR_DMA_MMADDR,0x1000000);
  write_volatile_4(AR_DMA_ARADDR,0);
  write_volatile_4(AR_DMA_CNT,0x20);

  while ((read_volatile_2(DSP_CONTROL) & DSPCR_ARINT) == 0) { /* wait for AR interrupt */ }
  write_volatile_2(DSP_CONTROL, DSP_CONTROL); // clear interrupts (this is done using the value read from the loop above)

  write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) & ~DSPCR_DSPINIT);  // ~0x800, also called DSPCR_DSPRESET by libogc
  while ((read_volatile_2(DSP_CONTROL) & DSPCR_DSPINITCODE) != 0) { /* wait for 0x400 bit to clear, not named by libogc */ }

  write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) & ~DSPCR_HALT);

  while ((read_volatile_2(DSP_MAIL_FROM_DSP_HI) & 0x8000) == 0) { /* wait for the DSP to send mail */ }
  read_volatile_2(DSP_MAIL_FROM_DSP_LO);

  write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) | DSPCR_HALT);
  write_volatile_2(DSP_CONTROL,(DSPCR_DSPRESET|DSPCR_DSPINT|DSPCR_ARINT|DSPCR_AIINT|DSPCR_HALT));
  write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) | DSPCR_RESET);
  while ((read_volatile_2(DSP_CONTROL) & DSPCR_RESET) != 0) { /* wait for reset bit to clear */ }

  memcpy((void *)0x81000000,(void *)(OSGetArenaHi() + -0x80),0x80);
}

D_datel_simplified.c

void FUN_800164f4(void)
{
  // Datel doesn't care about saving what's already at 0x81000000
  memcpy((void *)0x81000000,&DAT_80016bdc,0x80);
  DCFlushRange((void*)0x81000000,0x80);

  write_volatile_2(AR_INFO,0x43);
  write_volatile_2(DSP_CONTROL,(DSPCR_DSPRESET|DSPCR_DSPINT|DSPCR_ARINT|DSPCR_AIINT|DSPCR_HALT));

  write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) | DSPCR_RESET);
  while ((read_volatile_2(DSP_CONTROL) & DSPCR_RESET) != 0) { /* wait for reset bit to clear*/ }

  write_volatile_2(DSP_MAIL_TO_DSP_HI,0);
  while ((read_volatile_2(DSP_MAIL_FROM_DSP_HI) & 0x8000) != 0) { /* wait for there to be no pending mail(?) */ }
  read_volatile_2(DSP_MAIL_FROM_DSP_LO); // Wasn't shown in decompiler before; did https://github.com/NationalSecurityAgency/ghidra/issues/1832 regress?

  write_volatile_4(AR_DMA_MMADDR,0x1000000);
  write_volatile_4(AR_DMA_ARADDR,0);
  write_volatile_4(AR_DMA_CNT,0x20);

  while ((read_volatile_2(DSP_CONTROL) & DSPCR_ARINT) == 0) { /* wait for AR interrupt */ }
  write_volatile_2(DSP_CONTROL, DSP_CONTROL); // clear interrupts (this is done using the value read from the loop above)

  u32 time = FUN_8001435c();
  while (FUN_8001435c() == time) { /* delay a bit - this is different logic from SMS. This function returns DAT_800ba834, which is incremented by a different function (maybe once each frame?) */ }

  write_volatile_4(AR_DMA_MMADDR,0x1000000);
  write_volatile_4(AR_DMA_ARADDR,0);
  write_volatile_4(AR_DMA_CNT,0x20);

  while ((read_volatile_2(DSP_CONTROL) & DSPCR_ARINT) == 0) { /* wait for AR interrupt */ }
  write_volatile_2(DSP_CONTROL, DSP_CONTROL); // clear interrupts (this is done using the value read from the loop above)

  write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) & ~DSPCR_DSPINT);  // ~0x80, this is a different value and probably a typo!
  while ((read_volatile_2(DSP_CONTROL) & DSPCR_DSPINITCODE) != 0) { /* wait for 0x400 bit to clear, not named by libogc */ }

  write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) & ~DSPCR_HALT);

  // The hang happens in this loop
  while ((read_volatile_2(DSP_MAIL_FROM_DSP_HI) & 0x8000) == 0) { /* wait for the DSP to send mail */ }
  read_volatile_2(DSP_MAIL_FROM_DSP_LO);

  write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) | DSPCR_HALT);
  write_volatile_2(DSP_CONTROL,(DSPCR_DSPRESET|DSPCR_DSPINT|DSPCR_ARINT|DSPCR_AIINT|DSPCR_HALT));
  write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) | DSPCR_RESET);
  while ((read_volatile_2(DSP_CONTROL) & DSPCR_RESET) != 0) { /* wait for reset bit to clear */ }

  // Datel didn't save the existing contents of 0x81000000, so they don't restore it either
}

E_simplified_diff.diff

-void os::__OSInitAudioSystem(void)
+void FUN_800164f4(void)
 {
-  memcpy((void *)(OSGetArenaHi() + -0x80),(void *)0x81000000,0x80);
-  memcpy((void *)0x81000000,&DSPInitCode,0x80);
+  // Datel doesn't care about saving what's already at 0x81000000
+  memcpy((void *)0x81000000,&DAT_80016bdc,0x80);
   DCFlushRange((void*)0x81000000,0x80);

   write_volatile_2(AR_INFO,0x43);
   write_volatile_2(DSP_CONTROL,(DSPCR_DSPRESET|DSPCR_DSPINT|DSPCR_ARINT|DSPCR_AIINT|DSPCR_HALT));

   write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) | DSPCR_RESET);
   while ((read_volatile_2(DSP_CONTROL) & DSPCR_RESET) != 0) { /* wait for reset bit to clear*/ }

   write_volatile_2(DSP_MAIL_TO_DSP_HI,0);
   while ((read_volatile_2(DSP_MAIL_FROM_DSP_HI) & 0x8000) != 0) { /* wait for there to be no pending mail(?) */ }
   read_volatile_2(DSP_MAIL_FROM_DSP_LO); // Wasn't shown in decompiler before; did https://github.com/NationalSecurityAgency/ghidra/issues/1832 regress?

   write_volatile_4(AR_DMA_MMADDR,0x1000000);
   write_volatile_4(AR_DMA_ARADDR,0);
   write_volatile_4(AR_DMA_CNT,0x20);

   while ((read_volatile_2(DSP_CONTROL) & DSPCR_ARINT) == 0) { /* wait for AR interrupt */ }
   write_volatile_2(DSP_CONTROL, DSP_CONTROL); // clear interrupts (this is done using the value read from the loop above)

-  u64 start_tick = OSGetTick();
-  while (OSGetTick() - start_tick < 0x892) { /* delay a bit */ }
+  u32 time = FUN_8001435c();
+  while (FUN_8001435c() == time) { /* delay a bit - this is different logic from SMS. This function returns DAT_800ba834, which is incremented by a different function (maybe once each frame?) */ }

   write_volatile_4(AR_DMA_MMADDR,0x1000000);
   write_volatile_4(AR_DMA_ARADDR,0);
   write_volatile_4(AR_DMA_CNT,0x20);

   while ((read_volatile_2(DSP_CONTROL) & DSPCR_ARINT) == 0) { /* wait for AR interrupt */ }
   write_volatile_2(DSP_CONTROL, DSP_CONTROL); // clear interrupts (this is done using the value read from the loop above)

-  write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) & ~DSPCR_DSPINIT);  // ~0x800, also called DSPCR_DSPRESET by libogc
+  write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) & ~DSPCR_DSPINT);  // ~0x80, this is a different value and probably a typo!
   while ((read_volatile_2(DSP_CONTROL) & DSPCR_DSPINITCODE) != 0) { /* wait for 0x400 bit to clear, not named by libogc */ }

   write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) & ~DSPCR_HALT);

+  // The hang happens in this loop
   while ((read_volatile_2(DSP_MAIL_FROM_DSP_HI) & 0x8000) == 0) { /* wait for the DSP to send mail */ }
   read_volatile_2(DSP_MAIL_FROM_DSP_LO);

   write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) | DSPCR_HALT);
   write_volatile_2(DSP_CONTROL,(DSPCR_DSPRESET|DSPCR_DSPINT|DSPCR_ARINT|DSPCR_AIINT|DSPCR_HALT));
   write_volatile_2(DSP_CONTROL,read_volatile_2(DSP_CONTROL) | DSPCR_RESET);
   while ((read_volatile_2(DSP_CONTROL) & DSPCR_RESET) != 0) { /* wait for reset bit to clear */ }

-  memcpy((void *)0x81000000,(void *)(OSGetArenaHi() + -0x80),0x80);
+  // Datel didn't save the existing contents of 0x81000000, so they don't restore it either
 }