mirror of
https://github.com/RaySollium99/picodrive.git
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efcba75f8a
git-svn-id: file:///home/notaz/opt/svn/PicoDrive@574 be3aeb3a-fb24-0410-a615-afba39da0efa
247 lines
6.5 KiB
C
247 lines
6.5 KiB
C
// common code for Memory.c and cd/Memory.c
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// (c) Copyright 2006-2007, Grazvydas "notaz" Ignotas
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#ifndef UTYPES_DEFINED
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typedef unsigned char u8;
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typedef unsigned short u16;
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typedef unsigned int u32;
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#define UTYPES_DEFINED
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#endif
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#ifndef _ASM_MEMORY_C
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static
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#endif
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u8 z80Read8(u32 a)
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{
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if(Pico.m.z80Run&1) return 0;
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a&=0x1fff;
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if (!(PicoOpt&POPT_EN_Z80))
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{
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// Z80 disabled, do some faking
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static u8 zerosent = 0;
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if(a == Pico.m.z80_lastaddr) { // probably polling something
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u8 d = Pico.m.z80_fakeval;
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if((d & 0xf) == 0xf && !zerosent) {
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d = 0; zerosent = 1;
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} else {
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Pico.m.z80_fakeval++;
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zerosent = 0;
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}
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return d;
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} else {
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Pico.m.z80_fakeval = 0;
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}
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}
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Pico.m.z80_lastaddr = (u16) a;
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return Pico.zram[a];
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}
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#ifndef _ASM_MEMORY_C
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static
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#endif
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u32 z80ReadBusReq(void)
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{
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u32 d=Pico.m.z80Run&1;
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if (!d) {
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// needed by buggy Terminator (Sega CD)
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int stop_before = SekCyclesDone() - z80stopCycle;
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//elprintf(EL_BUSREQ, "get_zrun: stop before: %i", stop_before);
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// note: if we use 20 or more here, Barkley Shut Up and Jam! will purposedly crash itself.
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// but CD Terminator needs at least 32, so it only works because next frame cycle wrap.
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if (stop_before > 0 && stop_before < 20) // Gens uses 16 here
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d = 1; // bus not yet available
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}
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elprintf(EL_BUSREQ, "get_zrun: %02x [%i] @%06x", d|0x80, SekCyclesDone(), SekPc);
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return d|0x80;
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}
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static void z80WriteBusReq(u32 d)
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{
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d&=1; d^=1;
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elprintf(EL_BUSREQ, "set_zrun: %i->%i [%i] @%06x", Pico.m.z80Run, d, SekCyclesDone(), SekPc);
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if (d ^ Pico.m.z80Run)
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{
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if (d)
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{
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z80_cycle_cnt = cycles_68k_to_z80(SekCyclesDone());
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}
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else
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{
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z80stopCycle = SekCyclesDone();
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if ((PicoOpt&POPT_EN_Z80) && !Pico.m.z80_reset)
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PicoSyncZ80(z80stopCycle);
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}
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Pico.m.z80Run=d;
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}
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}
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static void z80WriteReset(u32 d)
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{
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d&=1; d^=1;
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elprintf(EL_BUSREQ, "set_zreset: %i->%i [%i] @%06x", Pico.m.z80_reset, d, SekCyclesDone(), SekPc);
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if (d ^ Pico.m.z80_reset)
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{
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if (d)
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{
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if ((PicoOpt&POPT_EN_Z80) && Pico.m.z80Run)
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PicoSyncZ80(SekCyclesDone());
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}
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else
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{
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z80_cycle_cnt = cycles_68k_to_z80(SekCyclesDone());
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z80_reset();
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}
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YM2612ResetChip();
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timers_reset();
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Pico.m.z80_reset=d;
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}
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}
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#ifndef _ASM_MEMORY_C
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static
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#endif
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u32 OtherRead16(u32 a, int realsize)
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{
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u32 d=0;
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if ((a&0xffffe0)==0xa10000) { // I/O ports
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a=(a>>1)&0xf;
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switch(a) {
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case 0: d=Pico.m.hardware; break; // Hardware value (Version register)
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case 1: d=PadRead(0); break;
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case 2: d=PadRead(1); break;
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default: d=Pico.ioports[a]; break; // IO ports can be used as RAM
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}
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d|=d<<8;
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goto end;
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}
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// rotate fakes next fetched instruction for Time Killers
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if (a==0xa11100) { // z80 busreq
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d=(z80ReadBusReq()<<8)|Pico.m.rotate++;
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goto end;
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}
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if ((a&0xff0000)==0xa00000)
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{
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if (Pico.m.z80Run&1)
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elprintf(EL_ANOMALY, "68k z80 read with no bus! [%06x] @ %06x", a, SekPc);
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if ((a&0x4000)==0x0000) { d=z80Read8(a); d|=d<<8; goto end; } // Z80 ram (not byteswaped)
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if ((a&0x6000)==0x4000) { d=ym2612_read_local_68k(); goto end; } // 0x4000-0x5fff
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elprintf(EL_ANOMALY, "68k bad read [%06x]", a);
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d=0xffff;
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goto end;
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}
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d = PicoRead16Hook(a, realsize);
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end:
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return d;
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}
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static void IoWrite8(u32 a, u32 d)
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{
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a=(a>>1)&0xf;
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// 6 button gamepad: if TH went from 0 to 1, gamepad changes state
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if (PicoOpt&POPT_6BTN_PAD)
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{
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if (a==1) {
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Pico.m.padDelay[0] = 0;
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if(!(Pico.ioports[1]&0x40) && (d&0x40)) Pico.m.padTHPhase[0]++;
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}
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else if (a==2) {
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Pico.m.padDelay[1] = 0;
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if(!(Pico.ioports[2]&0x40) && (d&0x40)) Pico.m.padTHPhase[1]++;
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}
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}
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Pico.ioports[a]=(u8)d; // IO ports can be used as RAM
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}
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#ifndef _ASM_CD_MEMORY_C
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static
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#endif
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void OtherWrite8(u32 a,u32 d)
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{
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#if !defined(_ASM_MEMORY_C) || defined(_ASM_MEMORY_C_AMIPS)
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if ((a&0xe700f9)==0xc00011||(a&0xff7ff9)==0xa07f11) { if(PicoOpt&2) SN76496Write(d); return; } // PSG Sound
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if ((a&0xff4000)==0xa00000) { // z80 RAM
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SekCyclesBurn(2); // hack
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if (!(Pico.m.z80Run&1) && !Pico.m.z80_reset) Pico.zram[a&0x1fff]=(u8)d;
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else elprintf(EL_ANOMALY, "68k z80 write with no bus or reset! [%06x] %02x @ %06x", a, d&0xff, SekPc);
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return;
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}
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if ((a&0xff6000)==0xa04000) { if(PicoOpt&1) emustatus|=ym2612_write_local(a&3, d&0xff, 0)&1; return; } // FM Sound
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if ((a&0xffffe0)==0xa10000) { IoWrite8(a, d); return; } // I/O ports
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#endif
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if (a==0xa11100) { z80WriteBusReq(d); return; }
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if (a==0xa11200) { z80WriteReset(d); return; }
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#if !defined(_ASM_MEMORY_C) || defined(_ASM_MEMORY_C_AMIPS)
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if ((a&0xff7f00)==0xa06000) // Z80 BANK register
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{
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Pico.m.z80_bank68k>>=1;
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Pico.m.z80_bank68k|=(d&1)<<8;
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Pico.m.z80_bank68k&=0x1ff; // 9 bits and filled in the new top one
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elprintf(EL_Z80BNK, "z80 bank=%06x", Pico.m.z80_bank68k<<15);
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return;
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}
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#endif
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if ((a&0xe700e0)==0xc00000) {
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d&=0xff;
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PicoVideoWrite(a,(u16)(d|(d<<8))); // Byte access gets mirrored
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return;
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}
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PicoWrite8Hook(a, d&0xff, 8);
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}
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#ifndef _ASM_CD_MEMORY_C
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static
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#endif
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void OtherWrite16(u32 a,u32 d)
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{
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if (a==0xa11100) { z80WriteBusReq(d>>8); return; }
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if ((a&0xffffe0)==0xa10000) { IoWrite8(a, d); return; } // I/O ports
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if ((a&0xe700f8)==0xc00010||(a&0xff7ff8)==0xa07f10) { if(PicoOpt&2) SN76496Write(d); return; } // PSG Sound
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if ((a&0xff6000)==0xa04000) { if(PicoOpt&1) emustatus|=ym2612_write_local(a&3, d&0xff, 0)&1; return; } // FM Sound
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if ((a&0xff4000)==0xa00000) { // Z80 ram (MSB only)
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if (!(Pico.m.z80Run&1) && !Pico.m.z80_reset) Pico.zram[a&0x1fff]=(u8)(d>>8);
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else elprintf(EL_ANOMALY, "68k z80 write with no bus or reset! [%06x] %04x @ %06x", a, d&0xffff, SekPc);
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return;
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}
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if (a==0xa11200) { z80WriteReset(d>>8); return; }
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if ((a&0xff7f00)==0xa06000) // Z80 BANK register
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{
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Pico.m.z80_bank68k>>=1;
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Pico.m.z80_bank68k|=(d&1)<<8;
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Pico.m.z80_bank68k&=0x1ff; // 9 bits and filled in the new top one
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elprintf(EL_Z80BNK, "z80 bank=%06x", Pico.m.z80_bank68k<<15);
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return;
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}
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#ifndef _CD_MEMORY_C
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if (a >= SRam.start && a <= SRam.end) {
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elprintf(EL_SRAMIO, "sram w16 [%06x] %04x @ %06x", a, d, SekPc);
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if ((Pico.m.sram_reg&0x16)==0x10) { // detected, not EEPROM, write not disabled
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u8 *pm=(u8 *)(SRam.data-SRam.start+a);
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*pm++=d>>8;
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*pm++=d;
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SRam.changed = 1;
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}
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else
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SRAMWrite(a, d);
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return;
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}
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#endif
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PicoWrite16Hook(a, d&0xffff, 16);
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}
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