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core z80, some timing improvements

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kub 2024-03-03 13:01:51 +01:00
parent 56ec20d262
commit a17fb0210b
1 changed files with 16 additions and 6 deletions
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22
pico/memory.c
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@ -675,14 +675,15 @@ static void PicoWrite16_sram(u32 a, u32 d)
static u32 PicoRead8_z80(u32 a)
{
u32 d = 0xff;
if (((Pico.m.z80Run & 1) || Pico.m.z80_reset) && !(PicoIn.quirks & PQUIRK_NO_Z80_BUS_LOCK)) {
if ((Pico.m.z80Run | Pico.m.z80_reset | (z80_cycles_from_68k() < Pico.t.z80c_cnt)) && !(PicoIn.quirks & PQUIRK_NO_Z80_BUS_LOCK)) {
elprintf(EL_ANOMALY, "68k z80 read with no bus! [%06x] @ %06x", a, SekPc);
// open bus. Pulled down if MegaCD2 is attached.
return (PicoIn.AHW & PAHW_MCD ? 0 : d);
}
Pico.t.z80c_cnt += 3;
SekCyclesBurnRun(1);
if ((a & 0x4000) == 0x0000) {
SekCyclesBurnRun(1);
d = PicoMem.zram[a & 0x1fff];
} else if ((a & 0x6000) == 0x4000) // 0x4000-0x5fff
d = ym2612_read_local_68k();
@ -699,14 +700,15 @@ static u32 PicoRead16_z80(u32 a)
static void PicoWrite8_z80(u32 a, u32 d)
{
if (((Pico.m.z80Run & 1) || Pico.m.z80_reset) && !(PicoIn.quirks & PQUIRK_NO_Z80_BUS_LOCK)) {
if ((Pico.m.z80Run | Pico.m.z80_reset) && !(PicoIn.quirks & PQUIRK_NO_Z80_BUS_LOCK)) {
// verified on real hw
elprintf(EL_ANOMALY, "68k z80 write with no bus or reset! [%06x] %02x @ %06x", a, d&0xff, SekPc);
return;
}
Pico.t.z80c_cnt += 3;
SekCyclesBurnRun(1);
if ((a & 0x4000) == 0x0000) { // z80 RAM
SekCyclesBurnRun(1);
PicoMem.zram[a & 0x1fff] = (u8)d;
return;
}
@ -759,6 +761,8 @@ u32 PicoRead8_io(u32 a)
// bit8 seems to be readable in this range
if (!(a & 1)) {
d &= ~0x01;
// Z80 ahead of 68K only if in BUSREQ, BUSACK only after 68K reached Z80
d |= (z80_cycles_from_68k() < Pico.t.z80c_cnt);
d |= (Pico.m.z80Run | Pico.m.z80_reset) & 1;
elprintf(EL_BUSREQ, "get_zrun: %02x [%u] @%06x", d, SekCyclesDone(), SekPc);
}
@ -790,6 +794,7 @@ u32 PicoRead16_io(u32 a)
if ((a & 0xfc00) == 0x1000) {
if ((a & 0xff00) == 0x1100) { // z80 busreq
d &= ~0x0100;
d |= (z80_cycles_from_68k() < Pico.t.z80c_cnt) << 8;
d |= ((Pico.m.z80Run | Pico.m.z80_reset) & 1) << 8;
elprintf(EL_BUSREQ, "get_zrun: %04x [%u] @%06x", d, SekCyclesDone(), SekPc);
}
@ -1344,6 +1349,10 @@ void PicoWrite16_32x(u32 a, u32 d) {}
static void access_68k_bus(int delay) // bus delay as Q8
{
// TODO: if the 68K is in DMA wait, Z80 has to wait until DMA ends
if (Pico.video.status & (PVS_CPUWR|PVS_CPURD))
z80_subCLeft(z80_cyclesLeft); // rather rough on both condition and action
// 68k bus access delay for z80. The fractional part needs to be accumulated
// until an additional cycle is full. That is then added to the integer part.
Pico.t.z80_busdelay = (delay&0xff) + (Pico.t.z80_busdelay&0xff); // accumulate
@ -1379,7 +1388,7 @@ static unsigned char z80_md_vdp_read(unsigned short a)
static unsigned char z80_md_bank_read(unsigned short a)
{
unsigned int addr68k;
unsigned char ret;
unsigned char ret = 0xff;
// 68k bus access delay=3.3 per kabuto, but for notaz picotest 3.02<delay<3.32
access_68k_bus(0x340); // Q8, picotest: 0x306(>3.02)-0x351(<3.32)
@ -1387,7 +1396,8 @@ static unsigned char z80_md_bank_read(unsigned short a)
addr68k = Pico.m.z80_bank68k << 15;
addr68k |= a & 0x7fff;
ret = m68k_read8(addr68k);
if (addr68k < 0xe00000) // can't read from 68K RAM
ret = m68k_read8(addr68k);
elprintf(EL_Z80BNK, "z80->68k r8 [%06x] %02x", addr68k, ret);
return ret;