| 1 | /* |
| 2 | * common code for base/cd/32x |
| 3 | * (C) notaz, 2007-2009,2013 |
| 4 | * (C) irixxxx, 2020-2024 |
| 5 | * |
| 6 | * This work is licensed under the terms of MAME license. |
| 7 | * See COPYING file in the top-level directory. |
| 8 | */ |
| 9 | |
| 10 | #define CYCLES_M68K_LINE 488 // suitable for both PAL/NTSC |
| 11 | #define CYCLES_M68K_VINT_LAG 112 |
| 12 | |
| 13 | // pad delay (for 6 button pads) |
| 14 | #define PAD_DELAY() { \ |
| 15 | if(Pico.m.padDelay[0]++ > 25) Pico.m.padTHPhase[0]=0; \ |
| 16 | if(Pico.m.padDelay[1]++ > 25) Pico.m.padTHPhase[1]=0; \ |
| 17 | } |
| 18 | |
| 19 | // CPUS_RUN |
| 20 | #ifndef CPUS_RUN |
| 21 | #define CPUS_RUN(m68k_cycles) \ |
| 22 | SekRunM68k(m68k_cycles) |
| 23 | #endif |
| 24 | |
| 25 | // sync m68k to Pico.t.m68c_aim |
| 26 | static void SekExecM68k(int cyc_do) |
| 27 | { |
| 28 | Pico.t.m68c_cnt += cyc_do; |
| 29 | |
| 30 | #if defined(EMU_C68K) |
| 31 | PicoCpuCM68k.cycles = cyc_do; |
| 32 | CycloneRun(&PicoCpuCM68k); |
| 33 | Pico.t.m68c_cnt -= PicoCpuCM68k.cycles; |
| 34 | #elif defined(EMU_M68K) |
| 35 | Pico.t.m68c_cnt += m68k_execute(cyc_do) - cyc_do; |
| 36 | #elif defined(EMU_F68K) |
| 37 | Pico.t.m68c_cnt += fm68k_emulate(&PicoCpuFM68k, cyc_do, 0) - cyc_do; |
| 38 | #endif |
| 39 | SekCyclesLeft = 0; |
| 40 | } |
| 41 | |
| 42 | static int SekSyncM68k(int once) |
| 43 | { |
| 44 | int cyc_do; |
| 45 | |
| 46 | pprof_start(m68k); |
| 47 | pevt_log_m68k_o(EVT_RUN_START); |
| 48 | |
| 49 | while ((cyc_do = Pico.t.m68c_aim - Pico.t.m68c_cnt) > 0) { |
| 50 | // the Z80 CPU is stealing some bus cycles from the 68K main CPU when |
| 51 | // accessing the main bus. Account for these by shortening the time |
| 52 | // the 68K CPU runs. |
| 53 | int z80_buscyc = Pico.t.z80_buscycles >> (4+(~Pico.m.scanline & 1)); |
| 54 | // NB the Z80 isn't fast enough to steal more than half the bandwidth. |
| 55 | // the fastest would be POP cc which takes 10+~3.3*2 z-cyc (~35 cyc) for a |
| 56 | // 16 bit value, but 68k is only blocked for ~16 cyc for the 2 bus cycles. |
| 57 | if (z80_buscyc > cyc_do/2) |
| 58 | z80_buscyc = cyc_do/2; |
| 59 | SekExecM68k(cyc_do - z80_buscyc); |
| 60 | Pico.t.m68c_cnt += z80_buscyc; |
| 61 | Pico.t.z80_buscycles -= z80_buscyc<<4; |
| 62 | if (once) break; |
| 63 | } |
| 64 | |
| 65 | SekTrace(0); |
| 66 | pevt_log_m68k_o(EVT_RUN_END); |
| 67 | pprof_end(m68k); |
| 68 | |
| 69 | return Pico.t.m68c_aim > Pico.t.m68c_cnt; |
| 70 | } |
| 71 | |
| 72 | static __inline void SekAimM68k(int cyc, int mult) |
| 73 | { |
| 74 | // refresh slowdown, for cart: 2 cycles every 128 - make this 1 every 64, |
| 75 | // for RAM: seems to be 0-3 every 128. Carts usually run from the cart |
| 76 | // area, but MCD games only use RAM, hence a different multiplier is needed. |
| 77 | // NB must be quite accurate, so handle fractions as well (c/f OutRunners) |
| 78 | int delay = (Pico.t.refresh_delay += cyc*mult) >> 14; |
| 79 | Pico.t.m68c_cnt += delay; |
| 80 | Pico.t.refresh_delay -= delay << 14; |
| 81 | Pico.t.m68c_aim += cyc; |
| 82 | } |
| 83 | |
| 84 | static __inline void SekRunM68k(int cyc) |
| 85 | { |
| 86 | // TODO 0x100 would be 2 cycles/128, moreover far too sensitive |
| 87 | SekAimM68k(cyc, 0x108); // OutRunners, testpico, VDPFIFOTesting |
| 88 | SekSyncM68k(0); |
| 89 | } |
| 90 | |
| 91 | static void SyncCPUs(unsigned int cycles) |
| 92 | { |
| 93 | // sync cpus |
| 94 | if (Pico.m.z80Run && !Pico.m.z80_reset && (PicoIn.opt&POPT_EN_Z80)) |
| 95 | PicoSyncZ80(cycles); |
| 96 | |
| 97 | #ifdef PICO_CD |
| 98 | if (PicoIn.AHW & PAHW_MCD) |
| 99 | pcd_sync_s68k(cycles, 0); |
| 100 | #endif |
| 101 | #ifdef PICO_32X |
| 102 | p32x_sync_sh2s(cycles); |
| 103 | #endif |
| 104 | } |
| 105 | |
| 106 | static void do_hint(struct PicoVideo *pv) |
| 107 | { |
| 108 | pv->pending_ints |= 0x10; |
| 109 | if (pv->reg[0] & 0x10) { |
| 110 | elprintf(EL_INTS, "hint: @ %06x [%u]", SekPc, SekCyclesDone()); |
| 111 | if (SekIrqLevel < pv->hint_irq) |
| 112 | SekInterrupt(pv->hint_irq); |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | static void do_timing_hacks_end(struct PicoVideo *pv) |
| 117 | { |
| 118 | PicoVideoFIFOSync(CYCLES_M68K_LINE); |
| 119 | |
| 120 | // need rather tight Z80 sync for emulation of main bus cycle stealing |
| 121 | if (Pico.m.scanline&1) |
| 122 | if (Pico.m.z80Run && !Pico.m.z80_reset && (PicoIn.opt&POPT_EN_Z80)) |
| 123 | PicoSyncZ80(Pico.t.m68c_aim); |
| 124 | } |
| 125 | |
| 126 | static void do_timing_hacks_start(struct PicoVideo *pv) |
| 127 | { |
| 128 | int cycles = PicoVideoFIFOHint(); |
| 129 | |
| 130 | SekCyclesBurn(cycles); // prolong cpu HOLD if necessary |
| 131 | // XXX how to handle Z80 bus cycle stealing during DMA correctly? |
| 132 | if ((Pico.t.z80_buscycles -= cycles<<4) < 0) |
| 133 | Pico.t.z80_buscycles = 0; |
| 134 | Pico.t.m68c_aim += Pico.m.scanline&1; // add 1 every 2 lines for 488.5 cycles |
| 135 | } |
| 136 | |
| 137 | static int PicoFrameHints(void) |
| 138 | { |
| 139 | struct PicoVideo *pv = &Pico.video; |
| 140 | int lines, y, lines_vis, skip; |
| 141 | int hint; // Hint counter |
| 142 | |
| 143 | pevt_log_m68k_o(EVT_FRAME_START); |
| 144 | |
| 145 | skip = PicoIn.skipFrame; |
| 146 | |
| 147 | Pico.t.m68c_frame_start = Pico.t.m68c_aim; |
| 148 | PsndStartFrame(); |
| 149 | |
| 150 | hint = pv->hint_cnt; |
| 151 | |
| 152 | // === active display === |
| 153 | pv->status |= PVS_ACTIVE; |
| 154 | |
| 155 | for (y = 0; y < 240; y++) |
| 156 | { |
| 157 | if (y == 224 && !(pv->reg[1] & 8)) |
| 158 | break; |
| 159 | |
| 160 | Pico.m.scanline = y; |
| 161 | pv->v_counter = PicoVideoGetV(y, 0); |
| 162 | |
| 163 | PAD_DELAY(); |
| 164 | |
| 165 | // H-Interrupts: |
| 166 | if (--hint < 0) |
| 167 | { |
| 168 | hint = pv->reg[10]; // Reload H-Int counter |
| 169 | do_hint(pv); |
| 170 | } |
| 171 | |
| 172 | // decide if we draw this line |
| 173 | if (unlikely(PicoIn.opt & POPT_ALT_RENDERER) && !skip) |
| 174 | { |
| 175 | // find the right moment for frame renderer, when display is no longer blanked |
| 176 | if ((pv->reg[1]&0x40) || y > 100) { |
| 177 | if (Pico.est.rendstatus & PDRAW_SYNC_NEEDED) |
| 178 | PicoFrameFull(); |
| 179 | #ifdef DRAW_FINISH_FUNC |
| 180 | DRAW_FINISH_FUNC(); |
| 181 | #endif |
| 182 | Pico.est.rendstatus &= ~PDRAW_SYNC_NEEDED; |
| 183 | skip = 1; |
| 184 | } |
| 185 | } |
| 186 | |
| 187 | // Run scanline: |
| 188 | Pico.t.m68c_line_start = Pico.t.m68c_aim; |
| 189 | do_timing_hacks_start(pv); |
| 190 | CPUS_RUN(CYCLES_M68K_LINE); |
| 191 | do_timing_hacks_end(pv); |
| 192 | |
| 193 | if (PicoLineHook) PicoLineHook(); |
| 194 | pevt_log_m68k_o(EVT_NEXT_LINE); |
| 195 | } |
| 196 | |
| 197 | SyncCPUs(Pico.t.m68c_aim); |
| 198 | |
| 199 | if (!skip) |
| 200 | { |
| 201 | if (Pico.est.DrawScanline < y) |
| 202 | PicoVideoSync(-1); |
| 203 | #ifdef DRAW_FINISH_FUNC |
| 204 | DRAW_FINISH_FUNC(); |
| 205 | #endif |
| 206 | Pico.est.rendstatus &= ~PDRAW_SYNC_NEEDED; |
| 207 | } |
| 208 | #ifdef PICO_32X |
| 209 | p32x_render_frame(); |
| 210 | #endif |
| 211 | |
| 212 | // === VBLANK, 1st line === |
| 213 | lines_vis = (pv->reg[1] & 8) ? 240 : 224; |
| 214 | if (y == lines_vis) |
| 215 | pv->status &= ~PVS_ACTIVE; |
| 216 | Pico.m.scanline = y; |
| 217 | pv->v_counter = PicoVideoGetV(y, 0); |
| 218 | |
| 219 | memcpy(PicoIn.padInt, PicoIn.pad, sizeof(PicoIn.padInt)); |
| 220 | PAD_DELAY(); |
| 221 | |
| 222 | // Last H-Int (normally): |
| 223 | if (--hint < 0) |
| 224 | { |
| 225 | hint = pv->reg[10]; // Reload H-Int counter |
| 226 | do_hint(pv); |
| 227 | } |
| 228 | |
| 229 | pv->status |= SR_VB | PVS_VB2; // go into vblank |
| 230 | #ifdef PICO_32X |
| 231 | p32x_start_blank(); |
| 232 | #endif |
| 233 | |
| 234 | // the following SekRun is there for several reasons: |
| 235 | // there must be a delay after vblank bit is set and irq is asserted (Mazin Saga) |
| 236 | // also delay between F bit (bit 7) is set in SR and IRQ happens (Ex-Mutants) |
| 237 | // also delay between last H-int and V-int (Golden Axe 3) |
| 238 | Pico.t.m68c_line_start = Pico.t.m68c_aim; |
| 239 | PicoVideoFIFOMode(pv->reg[1]&0x40, pv->reg[12]&1); |
| 240 | do_timing_hacks_start(pv); |
| 241 | CPUS_RUN(CYCLES_M68K_VINT_LAG); |
| 242 | |
| 243 | SyncCPUs(Pico.t.m68c_aim); |
| 244 | |
| 245 | // slot 0x00 |
| 246 | pv->status |= SR_F; |
| 247 | pv->pending_ints |= 0x20; |
| 248 | |
| 249 | if (pv->reg[1] & 0x20) { |
| 250 | // as per https://gendev.spritesmind.net/forum/viewtopic.php?t=2202, IRQ |
| 251 | // is usually sampled after operand reading, so the next instruction will |
| 252 | // be executed before the IRQ is taken. |
| 253 | if (Pico.t.m68c_cnt - Pico.t.m68c_aim < 40) // CPU blocked? |
| 254 | SekExecM68k(4); |
| 255 | elprintf(EL_INTS, "vint: @ %06x [%u]", SekPc, SekCyclesDone()); |
| 256 | // TODO: IRQ usually sampled after operand reading, so insn can't turn it |
| 257 | // off? single exception is MOVE.L which samples IRQ after the 1st write? |
| 258 | SekInterrupt(6); |
| 259 | } |
| 260 | |
| 261 | // slot 0x01 |
| 262 | if (pv->reg[12] & 2) |
| 263 | pv->status ^= SR_ODD; // change odd bit in interlace modes |
| 264 | else |
| 265 | pv->status &= ~SR_ODD; // never set in non-interlace modes |
| 266 | |
| 267 | // assert Z80 interrupt for one scanline even in busrq hold (Teddy Blues) |
| 268 | if (/*Pico.m.z80Run &&*/ !Pico.m.z80_reset && (PicoIn.opt&POPT_EN_Z80)) { |
| 269 | elprintf(EL_INTS, "zint"); |
| 270 | z80_int_assert(1); |
| 271 | } |
| 272 | |
| 273 | // Run scanline: |
| 274 | CPUS_RUN(CYCLES_M68K_LINE - CYCLES_M68K_VINT_LAG); |
| 275 | do_timing_hacks_end(pv); |
| 276 | |
| 277 | if (PicoLineHook) PicoLineHook(); |
| 278 | pevt_log_m68k_o(EVT_NEXT_LINE); |
| 279 | |
| 280 | if (Pico.m.z80Run && !Pico.m.z80_reset && (PicoIn.opt&POPT_EN_Z80)) |
| 281 | PicoSyncZ80(Pico.t.m68c_aim); |
| 282 | z80_int_assert(0); |
| 283 | |
| 284 | // === VBLANK === |
| 285 | lines = Pico.m.pal ? 313 : 262; |
| 286 | for (y++; y < lines - 1; y++) |
| 287 | { |
| 288 | Pico.m.scanline = y; |
| 289 | pv->v_counter = PicoVideoGetV(y, 1); |
| 290 | |
| 291 | PAD_DELAY(); |
| 292 | |
| 293 | if (unlikely(pv->status & PVS_ACTIVE) && --hint < 0) |
| 294 | { |
| 295 | hint = pv->reg[10]; // Reload H-Int counter |
| 296 | do_hint(pv); |
| 297 | } |
| 298 | |
| 299 | // Run scanline: |
| 300 | Pico.t.m68c_line_start = Pico.t.m68c_aim; |
| 301 | do_timing_hacks_start(pv); |
| 302 | CPUS_RUN(CYCLES_M68K_LINE); |
| 303 | do_timing_hacks_end(pv); |
| 304 | |
| 305 | if (PicoLineHook) PicoLineHook(); |
| 306 | pevt_log_m68k_o(EVT_NEXT_LINE); |
| 307 | } |
| 308 | |
| 309 | if (unlikely(PicoIn.overclockM68k)) { |
| 310 | unsigned int l = PicoIn.overclockM68k * lines / 100; |
| 311 | while (l-- > 0) { |
| 312 | Pico.t.m68c_cnt -= CYCLES_M68K_LINE; |
| 313 | do_timing_hacks_start(pv); |
| 314 | SekSyncM68k(0); |
| 315 | do_timing_hacks_end(pv); |
| 316 | } |
| 317 | } |
| 318 | |
| 319 | // === VBLANK last line === |
| 320 | pv->status &= ~(SR_VB | PVS_VB2); |
| 321 | pv->status |= ((pv->reg[1] >> 3) ^ SR_VB) & SR_VB; // forced blanking |
| 322 | |
| 323 | // last scanline |
| 324 | Pico.m.scanline = y++; |
| 325 | pv->v_counter = 0xff; |
| 326 | |
| 327 | PAD_DELAY(); |
| 328 | |
| 329 | if (unlikely(pv->status & PVS_ACTIVE)) { |
| 330 | if (--hint < 0) { |
| 331 | hint = pv->reg[10]; // Reload H-Int counter |
| 332 | do_hint(pv); |
| 333 | } |
| 334 | } |
| 335 | else |
| 336 | hint = pv->reg[10]; |
| 337 | |
| 338 | // Run scanline: |
| 339 | Pico.t.m68c_line_start = Pico.t.m68c_aim; |
| 340 | PicoVideoFIFOMode(pv->reg[1]&0x40, pv->reg[12]&1); |
| 341 | do_timing_hacks_start(pv); |
| 342 | CPUS_RUN(CYCLES_M68K_LINE); |
| 343 | do_timing_hacks_end(pv); |
| 344 | |
| 345 | if (PicoLineHook) PicoLineHook(); |
| 346 | pevt_log_m68k_o(EVT_NEXT_LINE); |
| 347 | |
| 348 | SyncCPUs(Pico.t.m68c_aim); |
| 349 | #ifdef PICO_32X |
| 350 | p32x_end_blank(); |
| 351 | #endif |
| 352 | |
| 353 | // get samples from sound chips |
| 354 | PsndGetSamples(y); |
| 355 | |
| 356 | timers_cycle(cycles_68k_to_z80(Pico.t.m68c_aim - Pico.t.m68c_frame_start)); |
| 357 | z80_resetCycles(); |
| 358 | |
| 359 | pv->hint_cnt = hint; |
| 360 | |
| 361 | return 0; |
| 362 | } |
| 363 | |
| 364 | #undef PAD_DELAY |
| 365 | #undef CPUS_RUN |
| 366 | |
| 367 | // vim:shiftwidth=2:ts=2:expandtab |