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;
12 u32 OtherRead16End(u32 a, int realsize);
14 #ifdef _ASM_CD_MEMORY_C
15 static void OtherWrite8End(u32 a,u32 d,int realsize);
24 if(Pico.m.z80Run&1) return 0;
29 // Z80 disabled, do some faking
30 static u8 zerosent = 0;
31 if(a == Pico.m.z80_lastaddr) { // probably polling something
32 u8 d = Pico.m.z80_fakeval;
33 if((d & 0xf) == 0xf && !zerosent) {
41 Pico.m.z80_fakeval = 0;
45 Pico.m.z80_lastaddr = (u16) a;
52 u32 z80ReadBusReq(void)
54 u32 d=Pico.m.z80Run&1;
55 if (!d && Pico.m.scanline != -1) {
56 // needed by buggy Terminator (Sega CD)
57 int stop_before = SekCyclesDone() - z80stopCycle;
58 //elprintf(EL_BUSREQ, "get_zrun: stop before: %i", stop_before);
59 // note: if we use 20 or more here, Barkley Shut Up and Jam! will purposedly crash itself.
60 // but CD Terminator needs at least 32, so it only works because next frame cycle wrap.
61 if (stop_before > 0 && stop_before < 20) // Gens uses 16 here
62 d = 1; // bus not yet available
64 // |=0x80 for Shadow of the Beast & Super Offroad
65 elprintf(EL_BUSREQ, "get_zrun: %02x [%i] @%06x", d|0x80, SekCyclesDone(), SekPc);
72 void z80WriteBusReq(u32 d)
75 if (Pico.m.scanline != -1)
78 // this is for a nasty situation where Z80 was enabled and disabled in the same 68k timeslice (Golden Axe III)
81 z80stopCycle = SekCyclesDone();
83 lineCycles=(488-SekCyclesLeft)&0x1ff;
84 else lineCycles=z80stopCycle-z80startCycle; // z80 was started at current line
85 if (lineCycles > 0 && lineCycles <= 488) {
86 //dprintf("zrun: %i/%i cycles", lineCycles, (lineCycles>>1)-(lineCycles>>5));
87 lineCycles=(lineCycles>>1)-(lineCycles>>5);
93 z80startCycle = SekCyclesDone();
98 elprintf(EL_BUSREQ, "set_zrun: %i->%i [%i] @%06x", Pico.m.z80Run, d, SekCyclesDone(), SekPc);
102 #ifndef _ASM_MEMORY_C
105 u32 OtherRead16(u32 a, int realsize)
109 if ((a&0xffffe0)==0xa10000) { // I/O ports
112 case 0: d=Pico.m.hardware; break; // Hardware value (Version register)
113 case 1: d=PadRead(0); break;
114 case 2: d=PadRead(1); break;
115 default: d=Pico.ioports[a]; break; // IO ports can be used as RAM
121 // rotate fakes next fetched instruction for Time Killers
122 if (a==0xa11100) { // z80 busreq
123 d=(z80ReadBusReq()<<8)|Pico.m.rotate++;
127 if ((a&0xff0000)==0xa00000) {
128 if ((a&0x4000)==0x0000) { d=z80Read8(a); d|=d<<8; goto end; } // Z80 ram (not byteswaped)
129 if ((a&0x6000)==0x4000) { // 0x4000-0x5fff, Fudge if disabled
130 if(PicoOpt&1) d=YM2612Read();
131 else d=Pico.m.rotate++&3;
132 elprintf(EL_YM2612R, "read ym2612: %02x", d);
139 #ifndef _ASM_MEMORY_C
140 if ((a&0xe700e0)==0xc00000) { d=PicoVideoRead(a); goto end; }
143 d = OtherRead16End(a, realsize);
149 static void IoWrite8(u32 a, u32 d)
152 // 6 button gamepad: if TH went from 0 to 1, gamepad changes state
155 Pico.m.padDelay[0] = 0;
156 if(!(Pico.ioports[1]&0x40) && (d&0x40)) Pico.m.padTHPhase[0]++;
159 Pico.m.padDelay[1] = 0;
160 if(!(Pico.ioports[2]&0x40) && (d&0x40)) Pico.m.padTHPhase[1]++;
163 Pico.ioports[a]=(u8)d; // IO ports can be used as RAM
166 #ifndef _ASM_CD_MEMORY_C
169 void OtherWrite8(u32 a,u32 d)
171 #ifndef _ASM_MEMORY_C
172 if ((a&0xe700f9)==0xc00011||(a&0xff7ff9)==0xa07f11) { if(PicoOpt&2) SN76496Write(d); return; } // PSG Sound
173 if ((a&0xff4000)==0xa00000) { if(!(Pico.m.z80Run&1)) Pico.zram[a&0x1fff]=(u8)d; return; } // Z80 ram
174 if ((a&0xff6000)==0xa04000) { if(PicoOpt&1) emustatus|=YM2612Write(a&3, d); return; } // FM Sound
175 if ((a&0xffffe0)==0xa10000) { IoWrite8(a, d); return; } // I/O ports
177 if (a==0xa11100) { z80WriteBusReq(d); return; }
179 elprintf(EL_BUSREQ, "write z80Reset: %02x", d);
180 if(!(d&1)) z80_reset();
183 #ifndef _ASM_MEMORY_C
184 if ((a&0xff7f00)==0xa06000) // Z80 BANK register
186 Pico.m.z80_bank68k>>=1;
187 Pico.m.z80_bank68k|=(d&1)<<8;
188 Pico.m.z80_bank68k&=0x1ff; // 9 bits and filled in the new top one
192 if ((a&0xe700e0)==0xc00000) {
194 PicoVideoWrite(a,(u16)(d|(d<<8))); // Byte access gets mirrored
198 OtherWrite8End(a, d, 8);
202 #ifndef _ASM_CD_MEMORY_C
205 void OtherWrite16(u32 a,u32 d)
207 if ((a&0xe700e0)==0xc00000) { PicoVideoWrite(a,(u16)d); return; }
208 if (a==0xa11100) { z80WriteBusReq(d>>8); return; }
209 if (a==0xa11200) { dprintf("write z80reset: %04x", d); if(!(d&0x100)) z80_reset(); return; }
210 if ((a&0xffffe0)==0xa10000) { IoWrite8(a, d); return; } // I/O ports
211 if ((a&0xff4000)==0xa00000) { if(!(Pico.m.z80Run&1)) Pico.zram[a&0x1fff]=(u8)(d>>8); return; } // Z80 ram (MSB only)
212 if ((a&0xe700f8)==0xc00010||(a&0xff7ff8)==0xa07f10) { if(PicoOpt&2) SN76496Write(d); return; } // PSG Sound
213 if ((a&0xff6000)==0xa04000) { if(PicoOpt&1) emustatus|=YM2612Write(a&3, d); return; } // FM Sound (??)
214 if ((a&0xff7f00)==0xa06000) // Z80 BANK register
216 Pico.m.z80_bank68k>>=1;
217 Pico.m.z80_bank68k|=(d&1)<<8;
218 Pico.m.z80_bank68k&=0x1ff; // 9 bits and filled in the new top one
223 if (a >= SRam.start && a <= SRam.end) {
224 elprintf(EL_SRAMIO, "sram w16 [%06x] %04x @ %06x", a, d, SekPc);
225 if ((a&0x16)==0x10) { // detected, not EEPROM, write not disabled
226 u8 *pm=(u8 *)(SRam.data-SRam.start+a);
236 OtherWrite8End(a, d>>8, 16);
237 OtherWrite8End(a+1,d&0xff, 16);