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More NR43 obscurities

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This commit is contained in:
Lior Halphon 2021-01-24 20:57:46 +02:00
parent 8e1e889ce0
commit ef9671010b
1 changed files with 18 additions and 10 deletions
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20
Core/apu.c
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@ -762,7 +762,7 @@ static inline uint16_t effective_channel4_counter(GB_gameboy_t *gb)
// case GB_MODEL_CGB_A:
case GB_MODEL_CGB_C:
if (effective_counter & 8) {
effective_counter |= 0xE;
effective_counter |= 0xE; // Sometimes F on some instances
}
if (effective_counter & 0x80) {
effective_counter |= 0xFF;
@ -777,6 +777,9 @@ static inline uint16_t effective_channel4_counter(GB_gameboy_t *gb)
effective_counter |= 0x4;
}
if (effective_counter & 0x800) {
if ((gb->io_registers[GB_IO_NR43] & 8)) {
effective_counter |= 0x400;
}
effective_counter |= 0x8;
}
if (effective_counter & 0x1000) {
@ -788,7 +791,7 @@ static inline uint16_t effective_channel4_counter(GB_gameboy_t *gb)
break;
#if 0
case GB_MODEL_CGB_D:
if (effective_counter & 0x40) {
if (effective_counter & ((gb->io_registers[GB_IO_NR43] & 8) ?0x80 : 0x40)) { // This is so weird
effective_counter |= 0xFF;
}
if (effective_counter & 0x100) {
@ -809,7 +812,7 @@ static inline uint16_t effective_channel4_counter(GB_gameboy_t *gb)
break;
#endif
case GB_MODEL_CGB_E:
if (effective_counter & 0x40) {
if (effective_counter & ((gb->io_registers[GB_IO_NR43] & 8) ?0x80 : 0x40)) { // This is so weird
effective_counter |= 0xFF;
}
if (effective_counter & 0x1000) {
@ -822,7 +825,7 @@ static inline uint16_t effective_channel4_counter(GB_gameboy_t *gb)
/* For the most part, AGS seems to do:
0x20 -> 0xA0
0x200 -> 0xA00
0x1000 -> 0x1010
0x1000 -> 0x1010, but only if wide
*/
break;
}
@ -1250,8 +1253,9 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
}
}
/* TODO: These two are quite weird. Verify further */
if (gb->model <= GB_MODEL_CGB_C && gb->cgb_double_speed) {
/* TODO: These are quite weird. Verify further */
if (gb->model <= GB_MODEL_CGB_C) {
if (gb->cgb_double_speed) {
if (!(gb->io_registers[GB_IO_NR43] & 0xF0) && (gb->io_registers[GB_IO_NR43] & 0x07)) {
gb->apu.noise_channel.counter_countdown -= 1;
}
@ -1259,6 +1263,10 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
gb->apu.noise_channel.counter_countdown += 1;
}
}
else {
gb->apu.noise_channel.counter_countdown -= 2;
}
}
gb->apu.noise_channel.current_volume = gb->io_registers[GB_IO_NR42] >> 4;