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core, floating bus read for 68k in some more places

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kub 2024-03-16 15:58:38 +01:00
parent 71f9c68f5b
commit 9f29605f55
3 changed files with 26 additions and 16 deletions
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37
pico/memory.c
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@ -199,16 +199,25 @@ void cpu68k_map_all_funcs(u32 start_addr, u32 end_addr, u32 (*r8)(u32), u32 (*r1
r8map[i] = ar8, r16map[i] = ar16, w8map[i] = aw8, w16map[i] = aw16;
}
u32 PicoRead16_floating(u32 a)
{
// faking open bus
u32 d = (Pico.m.rotate += 0x41);
d ^= (d << 5) ^ (d << 8);
if ((a & 0xff0000) == 0xa10000) d = 0; // MegaCD pulldowns don't work here curiously
return (PicoIn.AHW & PAHW_MCD) ? 0x00 : d; // pulldown if MegaCD2 attached
}
static u32 m68k_unmapped_read8(u32 a)
{
elprintf(EL_UIO, "m68k unmapped r8 [%06x] @%06x", a, SekPc);
return (PicoIn.AHW & PAHW_MCD) ? 0x00 : 0xff; // pulldown if MegaCD2 attached
return (u8)PicoRead16_floating(a);
}
static u32 m68k_unmapped_read16(u32 a)
{
elprintf(EL_UIO, "m68k unmapped r16 [%06x] @%06x", a, SekPc);
return (PicoIn.AHW & PAHW_MCD) ? 0x00 : 0xffff;
return PicoRead16_floating(a);
}
static void m68k_unmapped_write8(u32 a, u32 d)
@ -680,12 +689,11 @@ static void PicoWrite16_sram(u32 a, u32 d)
// TODO: verify mirrors VDP and bank reg (bank area mirroring verified)
static u32 PicoRead8_z80(u32 a)
{
u32 d = 0xff;
u32 d;
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);
return (u8)PicoRead16_floating(a);
}
SekCyclesBurnRun(1);
@ -693,8 +701,10 @@ static u32 PicoRead8_z80(u32 a)
d = PicoMem.zram[a & 0x1fff];
} else if ((a & 0x6000) == 0x4000) // 0x4000-0x5fff
d = ym2612_read_local_68k();
else
else {
elprintf(EL_UIO|EL_ANOMALY, "68k bad read [%06x] @%06x", a, SekPc);
d = (u8)PicoRead16_floating(a);
}
return d;
}
@ -757,9 +767,7 @@ u32 PicoRead8_io(u32 a)
goto end;
}
// faking open bus (MegaCD pulldowns don't work here curiously)
d = Pico.m.rotate++;
d ^= d << 6;
d = PicoRead16_floating(a);
if ((a & 0xfc00) == 0x1000) {
if ((a & 0xff01) == 0x1100) { // z80 busreq (verified)
@ -791,9 +799,7 @@ u32 PicoRead16_io(u32 a)
goto end;
}
// faking open bus
d = (Pico.m.rotate += 0x41);
d ^= (d << 5) ^ (d << 8);
d = PicoRead16_floating(a);
// bit8 seems to be readable in this range
if ((a & 0xfc00) == 0x1000) {
@ -864,7 +870,7 @@ void PicoWrite16_io(u32 a, u32 d)
// TODO: verify if lower byte goes to PSG on word writes
u32 PicoRead8_vdp(u32 a)
{
u32 d = 0;
u32 d;
if ((a & 0x00f0) == 0x0000) {
switch (a & 0x0d)
{
@ -876,9 +882,12 @@ u32 PicoRead8_vdp(u32 a)
case 0x0c: d = PicoVideoRead8HV_H(0); break;
case 0x09:
case 0x0d: d = PicoVideoRead8HV_L(0); break;
default: d = (u8)PicoRead16_floating(a); break;
}
} else
} else {
elprintf(EL_UIO|EL_ANOMALY, "68k bad read [%06x] @%06x", a, SekPc);
d = (u8)PicoRead16_floating(a);
}
return d;
}