1 // common code for Memory.c and cd/Memory.c
2 // (c) Copyright 2006-2007, Grazvydas "notaz" Ignotas
5 typedef unsigned char u8;
6 typedef unsigned short u16;
7 typedef unsigned int u32;
17 if(Pico.m.z80Run&1) return 0;
21 if (!(PicoOpt&POPT_EN_Z80))
23 // Z80 disabled, do some faking
24 static u8 zerosent = 0;
25 if(a == Pico.m.z80_lastaddr) { // probably polling something
26 u8 d = Pico.m.z80_fakeval;
27 if((d & 0xf) == 0xf && !zerosent) {
35 Pico.m.z80_fakeval = 0;
39 Pico.m.z80_lastaddr = (u16) a;
46 u32 z80ReadBusReq(void)
48 u32 d=Pico.m.z80Run&1;
49 if (!d && Pico.m.scanline != -1) {
50 // needed by buggy Terminator (Sega CD)
51 int stop_before = SekCyclesDone() - z80stopCycle;
52 //elprintf(EL_BUSREQ, "get_zrun: stop before: %i", stop_before);
53 // note: if we use 20 or more here, Barkley Shut Up and Jam! will purposedly crash itself.
54 // but CD Terminator needs at least 32, so it only works because next frame cycle wrap.
55 if (stop_before > 0 && stop_before < 20) // Gens uses 16 here
56 d = 1; // bus not yet available
58 // |=0x80 for Shadow of the Beast & Super Offroad
59 elprintf(EL_BUSREQ, "get_zrun: %02x [%i] @%06x", d|0x80, SekCyclesDone(), SekPc);
66 void z80WriteBusReq(u32 d)
72 // this is for a nasty situation where Z80 was enabled and disabled in the same 68k timeslice (Golden Axe III)
75 z80stopCycle = SekCyclesDone();
76 if ((Pico.m.z80Run&2) && Pico.m.scanline != -1)
77 lineCycles=(488-SekCyclesLeft)&0x1ff;
78 else lineCycles=z80stopCycle-z80startCycle; // z80 was started at current line
79 if (lineCycles > 0) { // && lineCycles <= 488) {
80 //dprintf("zrun: %i/%i cycles", lineCycles, (lineCycles>>1)-(lineCycles>>5));
81 lineCycles=(lineCycles>>1)-(lineCycles>>5);
82 z80_run_nr(lineCycles);
87 z80startCycle = SekCyclesDone();
92 elprintf(EL_BUSREQ, "set_zrun: %i->%i [%i] @%06x", Pico.m.z80Run, d, SekCyclesDone(), SekPc);
99 u32 OtherRead16(u32 a, int realsize)
103 if ((a&0xffffe0)==0xa10000) { // I/O ports
106 case 0: d=Pico.m.hardware; break; // Hardware value (Version register)
107 case 1: d=PadRead(0); break;
108 case 2: d=PadRead(1); break;
109 default: d=Pico.ioports[a]; break; // IO ports can be used as RAM
115 // rotate fakes next fetched instruction for Time Killers
116 if (a==0xa11100) { // z80 busreq
117 d=(z80ReadBusReq()<<8)|Pico.m.rotate++;
121 if ((a&0xff0000)==0xa00000) {
122 if ((a&0x4000)==0x0000) { d=z80Read8(a); d|=d<<8; goto end; } // Z80 ram (not byteswaped)
123 if ((a&0x6000)==0x4000) { // 0x4000-0x5fff, Fudge if disabled
124 if(PicoOpt&POPT_EN_FM) d=YM2612Read();
125 else d=Pico.m.rotate++&3;
126 elprintf(EL_YM2612R, "read ym2612: %02x", d);
133 d = PicoRead16Hook(a, realsize);
139 static void IoWrite8(u32 a, u32 d)
142 // 6 button gamepad: if TH went from 0 to 1, gamepad changes state
143 if(PicoOpt&POPT_6BTN_PAD)
146 Pico.m.padDelay[0] = 0;
147 if(!(Pico.ioports[1]&0x40) && (d&0x40)) Pico.m.padTHPhase[0]++;
150 Pico.m.padDelay[1] = 0;
151 if(!(Pico.ioports[2]&0x40) && (d&0x40)) Pico.m.padTHPhase[1]++;
154 Pico.ioports[a]=(u8)d; // IO ports can be used as RAM
157 #ifndef _ASM_CD_MEMORY_C
160 void OtherWrite8(u32 a,u32 d)
162 #if !defined(_ASM_MEMORY_C) || defined(_ASM_MEMORY_C_AMIPS)
163 if ((a&0xe700f9)==0xc00011||(a&0xff7ff9)==0xa07f11) { if(PicoOpt&2) SN76496Write(d); return; } // PSG Sound
164 if ((a&0xff4000)==0xa00000) { if(!(Pico.m.z80Run&1)) Pico.zram[a&0x1fff]=(u8)d; return; } // Z80 ram
165 if ((a&0xff6000)==0xa04000) { if(PicoOpt&1) emustatus|=YM2612Write(a&3, d)&1; return; } // FM Sound
166 if ((a&0xffffe0)==0xa10000) { IoWrite8(a, d); return; } // I/O ports
168 if (a==0xa11100) { z80WriteBusReq(d); return; }
170 elprintf(EL_BUSREQ, "write z80Reset: %02x", d);
171 if(!(d&1)) z80_reset();
174 #if !defined(_ASM_MEMORY_C) || defined(_ASM_MEMORY_C_AMIPS)
175 if ((a&0xff7f00)==0xa06000) // Z80 BANK register
177 Pico.m.z80_bank68k>>=1;
178 Pico.m.z80_bank68k|=(d&1)<<8;
179 Pico.m.z80_bank68k&=0x1ff; // 9 bits and filled in the new top one
183 if ((a&0xe700e0)==0xc00000) {
185 PicoVideoWrite(a,(u16)(d|(d<<8))); // Byte access gets mirrored
189 PicoWrite8Hook(a, d, 8);
193 #ifndef _ASM_CD_MEMORY_C
196 void OtherWrite16(u32 a,u32 d)
198 if (a==0xa11100) { z80WriteBusReq(d>>8); return; }
199 if (a==0xa11200) { elprintf(EL_BUSREQ, "write z80reset: %04x", d); if(!(d&0x100)) z80_reset(); return; }
200 if ((a&0xffffe0)==0xa10000) { IoWrite8(a, d); return; } // I/O ports
201 if ((a&0xff4000)==0xa00000) { if(!(Pico.m.z80Run&1)) Pico.zram[a&0x1fff]=(u8)(d>>8); return; } // Z80 ram (MSB only)
202 if ((a&0xe700f8)==0xc00010||(a&0xff7ff8)==0xa07f10) { if(PicoOpt&2) SN76496Write(d); return; } // PSG Sound
203 if ((a&0xff6000)==0xa04000) { if(PicoOpt&1) emustatus|=YM2612Write(a&3, d)&1; return; } // FM Sound (??)
204 if ((a&0xff7f00)==0xa06000) // Z80 BANK register
206 Pico.m.z80_bank68k>>=1;
207 Pico.m.z80_bank68k|=(d&1)<<8;
208 Pico.m.z80_bank68k&=0x1ff; // 9 bits and filled in the new top one
213 if (a >= SRam.start && a <= SRam.end) {
214 elprintf(EL_SRAMIO, "sram w16 [%06x] %04x @ %06x", a, d, SekPc);
215 if ((Pico.m.sram_reg&0x16)==0x10) { // detected, not EEPROM, write not disabled
216 u8 *pm=(u8 *)(SRam.data-SRam.start+a);
227 PicoWrite16Hook(a, d, 16);