saturn-examples/scsp/sound_cpu.cpp
Zack Buhman f2b53ee62a m68k: more reasonable stack pointer value
The sound_cpu example works consistently on all emulators and real
hardware now.
2023-05-16 22:55:26 +00:00

44 lines
1.0 KiB
C++

#include <stdint.h>
#include "smpc.h"
#include "scsp.h"
#include "../common/copy.hpp"
extern void * _binary_m68k_slot_bin_start __asm("_binary_m68k_slot_bin_start");
extern void * _binary_m68k_slot_bin_size __asm("_binary_m68k_slot_bin_size");
void main()
{
/* SEGA SATURN TECHNICAL BULLETIN # 51
The document suggests that Sound RAM is (somewhat) preserved
during SNDOFF.
*/
while ((smpc.reg.SF & 1) != 0);
smpc.reg.SF = 1;
smpc.reg.COMREG = COMREG__SNDOFF;
while (smpc.reg.oreg[31] != OREG31__SNDOFF);
scsp.reg.ctrl.MIXER = MIXER__MEM4MB;
uint32_t * m68k_main_start = (uint32_t *)&_binary_m68k_slot_bin_start;
uint32_t m68k_main_size = (uint32_t)&_binary_m68k_slot_bin_size;
copy<uint32_t>(&scsp.ram.u32[0], m68k_main_start, m68k_main_size);
while ((smpc.reg.SF & 1) != 0);
smpc.reg.SF = 1;
smpc.reg.COMREG = COMREG__SNDON;
while (smpc.reg.oreg[31] != OREG31__SNDON);
// do nothing while the sound CPU manipulates the SCSP
}
extern "C"
void start(void)
{
main();
while (1);
}