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1 | // common code for Memory.c and cd/Memory.c |
2 | // (c) Copyright 2006-2007, Grazvydas "notaz" Ignotas |
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3 | |
4 | static int PadRead(int i) |
5 | { |
6 | int pad=0,value=0,TH; |
7 | pad=~PicoPad[i]; // Get inverse of pad MXYZ SACB RLDU |
8 | TH=Pico.ioports[i+1]&0x40; |
9 | |
10 | if(PicoOpt & 0x20) { // 6 button gamepad enabled |
11 | int phase = Pico.m.padTHPhase[i]; |
12 | |
13 | if(phase == 2 && !TH) { |
14 | value=(pad&0xc0)>>2; // ?0SA 0000 |
15 | goto end; |
16 | } else if(phase == 3 && TH) { |
17 | value=(pad&0x30)|((pad>>8)&0xf); // ?1CB MXYZ |
18 | goto end; |
19 | } else if(phase == 3 && !TH) { |
20 | value=((pad&0xc0)>>2)|0x0f; // ?0SA 1111 |
21 | goto end; |
22 | } |
23 | } |
24 | |
25 | if(TH) value=(pad&0x3f); // ?1CB RLDU |
26 | else value=((pad&0xc0)>>2)|(pad&3); // ?0SA 00DU |
27 | |
28 | end: |
29 | |
30 | // orr the bits, which are set as output |
31 | value |= Pico.ioports[i+1]&Pico.ioports[i+4]; |
32 | |
33 | return value; // will mirror later |
34 | } |
35 | |
36 | |
37 | #ifndef _ASM_MEMORY_C |
38 | static |
39 | #endif |
40 | u8 z80Read8(u32 a) |
41 | { |
42 | if(Pico.m.z80Run&1) return 0; |
43 | |
44 | a&=0x1fff; |
45 | |
46 | if(!(PicoOpt&4)) { |
47 | // Z80 disabled, do some faking |
48 | static u8 zerosent = 0; |
49 | if(a == Pico.m.z80_lastaddr) { // probably polling something |
50 | u8 d = Pico.m.z80_fakeval; |
51 | if((d & 0xf) == 0xf && !zerosent) { |
52 | d = 0; zerosent = 1; |
53 | } else { |
54 | Pico.m.z80_fakeval++; |
55 | zerosent = 0; |
56 | } |
57 | return d; |
58 | } else { |
59 | Pico.m.z80_fakeval = 0; |
60 | } |
61 | } |
62 | |
63 | Pico.m.z80_lastaddr = (u16) a; |
64 | return Pico.zram[a]; |
65 | } |
66 | |
67 | |
68 | #ifndef _ASM_MEMORY_C |
69 | static |
70 | #endif |
71 | u32 OtherRead16(u32 a, int realsize) |
72 | { |
73 | u32 d=0; |
74 | |
75 | if ((a&0xff0000)==0xa00000) { |
76 | if ((a&0x4000)==0x0000) { d=z80Read8(a); d|=d<<8; goto end; } // Z80 ram (not byteswaped) |
77 | if ((a&0x6000)==0x4000) { // 0x4000-0x5fff, Fudge if disabled |
78 | if(PicoOpt&1) d=YM2612Read(); |
79 | else d=Pico.m.rotate++&3; |
80 | dprintf("read ym2612: %04x", d); |
81 | goto end; |
82 | } |
83 | d=0xffff; |
84 | goto end; |
85 | } |
86 | |
87 | if ((a&0xffffe0)==0xa10000) { // I/O ports |
88 | a=(a>>1)&0xf; |
89 | switch(a) { |
90 | case 0: d=Pico.m.hardware; break; // Hardware value (Version register) |
91 | case 1: d=PadRead(0); d|=Pico.ioports[1]&0x80; break; |
92 | case 2: d=PadRead(1); d|=Pico.ioports[2]&0x80; break; |
93 | default: d=Pico.ioports[a]; break; // IO ports can be used as RAM |
94 | } |
95 | d|=d<<8; |
96 | goto end; |
97 | } |
98 | |
99 | // |=0x80 for Shadow of the Beast & Super Offroad; rotate fakes next fetched instruction for Time Killers |
100 | if (a==0xa11100) { // z80 busreq |
101 | d=Pico.m.z80Run&1; |
721cd396 |
102 | #if 1 |
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103 | if (!d) { |
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104 | // needed by buggy Terminator (Sega CD) |
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105 | extern int z80stopCycle; |
106 | int stop_before = SekCyclesDone() - z80stopCycle; |
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107 | dprintf("stop before: %i", stop_before); |
108 | if (stop_before > 0 && stop_before <= 32) // Gens uses 16 here |
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109 | d = 1; // bus not yet available |
110 | } |
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111 | #endif |
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112 | d=(d<<8)|0x8000|Pico.m.rotate++; |
113 | dprintf("get_zrun: %04x [%i|%i] @%06x", d, Pico.m.scanline, SekCyclesDone(), SekPc); |
114 | goto end; |
115 | } |
116 | |
117 | #ifndef _ASM_MEMORY_C |
118 | if ((a&0xe700e0)==0xc00000) { d=PicoVideoRead(a); goto end; } |
119 | #endif |
120 | |
121 | d = OtherRead16End(a, realsize); |
122 | |
123 | end: |
124 | return d; |
125 | } |
126 | |
127 | |
128 | //extern UINT32 mz80GetRegisterValue(void *, UINT32); |
129 | |
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130 | #ifndef _ASM_CD_MEMORY_C |
131 | static |
132 | #endif |
133 | void OtherWrite8(u32 a,u32 d,int realsize) |
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134 | { |
135 | if ((a&0xe700f9)==0xc00011||(a&0xff7ff9)==0xa07f11) { if(PicoOpt&2) SN76496Write(d); return; } // PSG Sound |
136 | if ((a&0xff4000)==0xa00000) { if(!(Pico.m.z80Run&1)) Pico.zram[a&0x1fff]=(u8)d; return; } // Z80 ram |
137 | if ((a&0xff6000)==0xa04000) { if(PicoOpt&1) emustatus|=YM2612Write(a&3, d); return; } // FM Sound |
138 | if ((a&0xffffe0)==0xa10000) { // I/O ports |
139 | a=(a>>1)&0xf; |
140 | // 6 button gamepad: if TH went from 0 to 1, gamepad changes state |
141 | if(PicoOpt&0x20) { |
142 | if(a==1) { |
143 | Pico.m.padDelay[0] = 0; |
144 | if(!(Pico.ioports[1]&0x40) && (d&0x40)) Pico.m.padTHPhase[0]++; |
145 | } |
146 | else if(a==2) { |
147 | Pico.m.padDelay[1] = 0; |
148 | if(!(Pico.ioports[2]&0x40) && (d&0x40)) Pico.m.padTHPhase[1]++; |
149 | } |
150 | } |
151 | Pico.ioports[a]=(u8)d; // IO ports can be used as RAM |
152 | return; |
153 | } |
154 | if (a==0xa11100) { |
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155 | //int lineCycles=(488-SekCyclesLeft)&0x1ff; |
156 | d&=1; d^=1; |
157 | if(!d) { |
158 | // this is for a nasty situation where Z80 was enabled and disabled in the same 68k timeslice (Golden Axe III) |
159 | if (Pico.m.z80Run) { |
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160 | int lineCycles; |
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161 | z80stopCycle = SekCyclesDone(); |
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162 | if (Pico.m.z80Run&2) |
163 | lineCycles=(488-SekCyclesLeft)&0x1ff; |
164 | else lineCycles=z80stopCycle-z80startCycle; // z80 was started at current line |
165 | if (lineCycles > 0 && lineCycles <= 488) { |
166 | dprintf("zrun: %i/%i cycles", lineCycles, (lineCycles>>1)-(lineCycles>>5)); |
167 | lineCycles=(lineCycles>>1)-(lineCycles>>5); |
168 | z80_run(lineCycles); |
169 | } |
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170 | } |
171 | } else { |
172 | z80startCycle = SekCyclesDone(); |
173 | //if(Pico.m.scanline != -1) |
174 | } |
175 | dprintf("set_zrun: %02x [%i|%i] @%06x", d, Pico.m.scanline, SekCyclesDone(), /*mz80GetRegisterValue(NULL, 0),*/ SekPc); |
176 | Pico.m.z80Run=(u8)d; return; |
177 | } |
178 | if (a==0xa11200) { |
179 | dprintf("write z80Reset: %02x", d); |
180 | if(!(d&1)) z80_reset(); |
181 | return; |
182 | } |
183 | |
184 | if ((a&0xff7f00)==0xa06000) // Z80 BANK register |
185 | { |
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 |
189 | return; |
190 | } |
191 | |
192 | if ((a&0xe700e0)==0xc00000) { |
193 | PicoVideoWrite(a,(u16)(d|(d<<8))); // Byte access gets mirrored |
194 | return; |
195 | } |
196 | |
197 | OtherWrite8End(a, d, realsize); |
198 | } |
199 | |
200 | |
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201 | #ifndef _ASM_CD_MEMORY_C |
202 | static |
203 | #endif |
204 | void OtherWrite16(u32 a,u32 d) |
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205 | { |
206 | if ((a&0xe700e0)==0xc00000) { PicoVideoWrite(a,(u16)d); return; } |
207 | if ((a&0xff4000)==0xa00000) { if(!(Pico.m.z80Run&1)) Pico.zram[a&0x1fff]=(u8)(d>>8); return; } // Z80 ram (MSB only) |
208 | |
209 | if ((a&0xffffe0)==0xa10000) { // I/O ports |
210 | a=(a>>1)&0xf; |
211 | // 6 button gamepad: if TH went from 0 to 1, gamepad changes state |
212 | if(PicoOpt&0x20) { |
213 | if(a==1) { |
214 | Pico.m.padDelay[0] = 0; |
215 | if(!(Pico.ioports[1]&0x40) && (d&0x40)) Pico.m.padTHPhase[0]++; |
216 | } |
217 | else if(a==2) { |
218 | Pico.m.padDelay[1] = 0; |
219 | if(!(Pico.ioports[2]&0x40) && (d&0x40)) Pico.m.padTHPhase[1]++; |
220 | } |
221 | } |
222 | Pico.ioports[a]=(u8)d; // IO ports can be used as RAM |
223 | return; |
224 | } |
225 | if (a==0xa11100) { OtherWrite8(a, d>>8, 16); return; } |
226 | if (a==0xa11200) { dprintf("write z80reset: %04x", d); if(!(d&0x100)) z80_reset(); return; } |
227 | |
228 | OtherWrite8(a, d>>8, 16); |
229 | OtherWrite8(a+1,d&0xff, 16); |
230 | } |
231 | |
232 | |