From: kub Date: Sat, 16 Mar 2024 14:58:38 +0000 (+0100) Subject: core, floating bus read for 68k in some more places X-Git-Tag: v2.00~91 X-Git-Url: https://notaz.gp2x.de/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9f29605f55460e6f5094e41d74ce4f7726097237;p=picodrive.git core, floating bus read for 68k in some more places --- diff --git a/pico/memory.c b/pico/memory.c index bedcc1d3..1bd230d0 100644 --- a/pico/memory.c +++ b/pico/memory.c @@ -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; } diff --git a/pico/pico_int.h b/pico/pico_int.h index 5535e142..31802f4c 100644 --- a/pico/pico_int.h +++ b/pico/pico_int.h @@ -740,6 +740,7 @@ void PicoDrawSetOutputSMS(pdso_t which); // memory.c PICO_INTERNAL void PicoMemSetup(void); +PICO_INTERNAL u32 PicoRead16_floating(u32 a); u32 PicoRead8_io(u32 a); u32 PicoRead16_io(u32 a); void PicoWrite8_io(u32 a, u32 d); diff --git a/pico/videoport.c b/pico/videoport.c index 73c90edb..d4a986f1 100644 --- a/pico/videoport.c +++ b/pico/videoport.c @@ -1087,7 +1087,7 @@ PICO_INTERNAL_ASM u32 PicoVideoRead(u32 a) return d; } - if ((a&0x1c)==0x08) + if (a == 0x08) { unsigned int c; u32 d; @@ -1106,7 +1106,7 @@ PICO_INTERNAL_ASM u32 PicoVideoRead(u32 a) return VideoRead(0); } - return 0; + return PicoRead16_floating(a | 0xc00000); } unsigned char PicoVideoRead8DataH(int is_from_z80)