mirror of
https://github.com/RaySollium99/picodrive.git
synced 2025-09-05 07:17:45 -04:00
347 lines
8.3 KiB
C
347 lines
8.3 KiB
C
/*
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* common code for base/cd/32x
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* (C) notaz, 2007-2009,2013
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*
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* This work is licensed under the terms of MAME license.
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* See COPYING file in the top-level directory.
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*/
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#define CYCLES_M68K_LINE 488 // suitable for both PAL/NTSC
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#define CYCLES_M68K_VINT_LAG 112
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// pad delay (for 6 button pads)
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#define PAD_DELAY() { \
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if(Pico.m.padDelay[0]++ > 25) Pico.m.padTHPhase[0]=0; \
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if(Pico.m.padDelay[1]++ > 25) Pico.m.padTHPhase[1]=0; \
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}
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// CPUS_RUN
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#ifndef CPUS_RUN
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#define CPUS_RUN(m68k_cycles) \
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SekRunM68k(m68k_cycles)
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#endif
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// sync m68k to Pico.t.m68c_aim
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static void SekExecM68k(int cyc_do)
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{
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Pico.t.m68c_cnt += cyc_do;
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#if defined(EMU_C68K)
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PicoCpuCM68k.cycles = cyc_do;
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CycloneRun(&PicoCpuCM68k);
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Pico.t.m68c_cnt -= PicoCpuCM68k.cycles;
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#elif defined(EMU_M68K)
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Pico.t.m68c_cnt += m68k_execute(cyc_do) - cyc_do;
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#elif defined(EMU_F68K)
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Pico.t.m68c_cnt += fm68k_emulate(&PicoCpuFM68k, cyc_do, 0) - cyc_do;
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#endif
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SekCyclesLeft = 0;
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}
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static int SekSyncM68k(int once)
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{
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int cyc_do;
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pprof_start(m68k);
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pevt_log_m68k_o(EVT_RUN_START);
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while ((cyc_do = Pico.t.m68c_aim - Pico.t.m68c_cnt) > 0) {
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// the Z80 CPU is stealing some bus cycles from the 68K main CPU when
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// accessing the main bus. Account for these by shortening the time
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// the 68K CPU runs.
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int z80_buscyc = Pico.t.z80_buscycles >> (~Pico.m.scanline & 1);
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if (z80_buscyc <= cyc_do)
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SekExecM68k(cyc_do - z80_buscyc);
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else
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z80_buscyc = cyc_do;
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Pico.t.m68c_cnt += z80_buscyc;
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Pico.t.z80_buscycles -= z80_buscyc;
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if (once) break;
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}
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SekTrace(0);
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pevt_log_m68k_o(EVT_RUN_END);
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pprof_end(m68k);
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return Pico.t.m68c_aim > Pico.t.m68c_cnt;
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}
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static __inline void SekAimM68k(int cyc, int mult)
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{
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// refresh slowdown, for cart: 2 cycles every 128 - make this 1 every 64,
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// for RAM: seems to be 0-3 every 128. Carts usually run from the cart
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// area, but MCD games only use RAM, hence a different multiplier is needed.
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// NB must be quite accurate, so handle fractions as well (c/f OutRunners)
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int delay = (Pico.t.refresh_delay += cyc*mult) >> 14;
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Pico.t.m68c_cnt += delay;
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Pico.t.refresh_delay -= delay << 14;
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Pico.t.m68c_aim += cyc;
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}
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static __inline void SekRunM68k(int cyc)
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{
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// TODO 0x100 would by 2 cycles/128, moreover far too sensitive
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SekAimM68k(cyc, 0x10c); // OutRunners, testpico, VDPFIFOTesting
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SekSyncM68k(0);
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}
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static void SyncCPUs(unsigned int cycles)
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{
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// sync cpus
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if (Pico.m.z80Run && !Pico.m.z80_reset && (PicoIn.opt&POPT_EN_Z80))
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PicoSyncZ80(cycles);
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#ifdef PICO_CD
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if (PicoIn.AHW & PAHW_MCD)
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pcd_sync_s68k(cycles, 0);
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#endif
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#ifdef PICO_32X
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p32x_sync_sh2s(cycles);
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#endif
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}
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static void do_hint(struct PicoVideo *pv)
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{
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pv->pending_ints |= 0x10;
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if (pv->reg[0] & 0x10) {
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elprintf(EL_INTS, "hint: @ %06x [%u]", SekPc, SekCyclesDone());
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if (SekIrqLevel < 4)
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SekInterrupt(4);
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}
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}
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static void do_timing_hacks_end(struct PicoVideo *pv)
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{
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PicoVideoFIFOSync(CYCLES_M68K_LINE);
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// need rather tight Z80 sync for emulation of main bus cycle stealing
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if (Pico.m.scanline&1)
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if (Pico.m.z80Run && !Pico.m.z80_reset && (PicoIn.opt&POPT_EN_Z80))
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PicoSyncZ80(Pico.t.m68c_aim);
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}
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static void do_timing_hacks_start(struct PicoVideo *pv)
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{
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int cycles = PicoVideoFIFOHint();
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SekCyclesBurn(cycles); // prolong cpu HOLD if necessary
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// XXX how to handle Z80 bus cycle stealing during DMA correctly?
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if ((Pico.t.z80_buscycles -= cycles) < 0)
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Pico.t.z80_buscycles = 0;
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if (Pico.m.scanline&1)
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Pico.t.m68c_aim += 1; // add cycle each other line for 488.5 cycles/line
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}
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static int PicoFrameHints(void)
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{
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struct PicoVideo *pv = &Pico.video;
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int lines, y, lines_vis, skip;
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int hint; // Hint counter
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pevt_log_m68k_o(EVT_FRAME_START);
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skip = PicoIn.skipFrame;
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Pico.t.m68c_frame_start = Pico.t.m68c_aim;
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z80_resetCycles();
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PsndStartFrame();
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hint = pv->hint_cnt;
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// === active display ===
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pv->status |= PVS_ACTIVE;
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for (y = 0;; y++)
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{
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Pico.m.scanline = y;
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pv->v_counter = PicoVideoGetV(y);
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lines_vis = (pv->reg[1] & 8) ? 240 : 224;
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if (y == lines_vis)
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break;
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PAD_DELAY();
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// H-Interrupts:
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if (--hint < 0)
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{
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hint = pv->reg[10]; // Reload H-Int counter
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do_hint(pv);
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}
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// decide if we draw this line
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if ((PicoIn.opt & POPT_ALT_RENDERER) && !skip)
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{
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// find the right moment for frame renderer, when display is no longer blanked
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if ((pv->reg[1]&0x40) || y > 100) {
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if (Pico.est.rendstatus & PDRAW_SYNC_NEEDED)
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PicoFrameFull();
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#ifdef DRAW_FINISH_FUNC
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DRAW_FINISH_FUNC();
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#endif
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Pico.est.rendstatus &= ~PDRAW_SYNC_NEEDED;
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skip = 1;
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}
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}
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// Run scanline:
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Pico.t.m68c_line_start = Pico.t.m68c_aim;
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do_timing_hacks_start(pv);
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CPUS_RUN(CYCLES_M68K_LINE);
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do_timing_hacks_end(pv);
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if (PicoLineHook) PicoLineHook();
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pevt_log_m68k_o(EVT_NEXT_LINE);
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}
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SyncCPUs(Pico.t.m68c_aim);
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if (!skip)
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{
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if (Pico.est.DrawScanline < y)
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PicoVideoSync(-1);
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#ifdef DRAW_FINISH_FUNC
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DRAW_FINISH_FUNC();
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#endif
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Pico.est.rendstatus &= ~PDRAW_SYNC_NEEDED;
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}
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#ifdef PICO_32X
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p32x_render_frame();
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#endif
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// === VBLANK, 1st line ===
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lines_vis = (pv->reg[1] & 8) ? 240 : 224;
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if (y == lines_vis)
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pv->status &= ~PVS_ACTIVE;
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memcpy(PicoIn.padInt, PicoIn.pad, sizeof(PicoIn.padInt));
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PAD_DELAY();
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// Last H-Int (normally):
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if (--hint < 0)
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{
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hint = pv->reg[10]; // Reload H-Int counter
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do_hint(pv);
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}
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pv->status |= SR_VB | PVS_VB2; // go into vblank
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#ifdef PICO_32X
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p32x_start_blank();
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#endif
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// the following SekRun is there for several reasons:
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// there must be a delay after vblank bit is set and irq is asserted (Mazin Saga)
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// also delay between F bit (bit 7) is set in SR and IRQ happens (Ex-Mutants)
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// also delay between last H-int and V-int (Golden Axe 3)
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Pico.t.m68c_line_start = Pico.t.m68c_aim;
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PicoVideoFIFOMode(pv->reg[1]&0x40, pv->reg[12]&1);
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do_timing_hacks_start(pv);
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CPUS_RUN(CYCLES_M68K_VINT_LAG);
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SyncCPUs(Pico.t.m68c_aim);
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pv->status |= SR_F;
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pv->pending_ints |= 0x20;
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if (pv->reg[1] & 0x20) {
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if (Pico.t.m68c_cnt - Pico.t.m68c_aim < 60) // CPU blocked?
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SekExecM68k(11); // HACK
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elprintf(EL_INTS, "vint: @ %06x [%u]", SekPc, SekCyclesDone());
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SekInterrupt(6);
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}
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if (Pico.m.z80Run && !Pico.m.z80_reset && (PicoIn.opt&POPT_EN_Z80)) {
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elprintf(EL_INTS, "zint");
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z80_int();
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}
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// Run scanline:
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CPUS_RUN(CYCLES_M68K_LINE - CYCLES_M68K_VINT_LAG);
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do_timing_hacks_end(pv);
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if (PicoLineHook) PicoLineHook();
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pevt_log_m68k_o(EVT_NEXT_LINE);
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// === VBLANK ===
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lines = Pico.m.pal ? 313 : 262;
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for (y++; y < lines - 1; y++)
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{
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Pico.m.scanline = y;
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pv->v_counter = PicoVideoGetV(y);
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PAD_DELAY();
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if (unlikely(pv->status & PVS_ACTIVE) && --hint < 0)
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{
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hint = pv->reg[10]; // Reload H-Int counter
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do_hint(pv);
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}
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// Run scanline:
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Pico.t.m68c_line_start = Pico.t.m68c_aim;
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do_timing_hacks_start(pv);
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CPUS_RUN(CYCLES_M68K_LINE);
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do_timing_hacks_end(pv);
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if (PicoLineHook) PicoLineHook();
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pevt_log_m68k_o(EVT_NEXT_LINE);
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}
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if (unlikely(PicoIn.overclockM68k)) {
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unsigned int l = PicoIn.overclockM68k * lines / 100;
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while (l-- > 0) {
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Pico.t.m68c_cnt -= CYCLES_M68K_LINE;
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do_timing_hacks_start(pv);
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SekSyncM68k(0);
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do_timing_hacks_end(pv);
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}
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}
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// === VBLANK last line ===
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pv->status &= ~(SR_VB | PVS_VB2);
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pv->status |= ((pv->reg[1] >> 3) ^ SR_VB) & SR_VB; // forced blanking
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// last scanline
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Pico.m.scanline = y++;
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pv->v_counter = 0xff;
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PAD_DELAY();
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if (unlikely(pv->status & PVS_ACTIVE)) {
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if (--hint < 0) {
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hint = pv->reg[10]; // Reload H-Int counter
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do_hint(pv);
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}
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}
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else
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hint = pv->reg[10];
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// Run scanline:
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Pico.t.m68c_line_start = Pico.t.m68c_aim;
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PicoVideoFIFOMode(pv->reg[1]&0x40, pv->reg[12]&1);
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do_timing_hacks_start(pv);
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CPUS_RUN(CYCLES_M68K_LINE);
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do_timing_hacks_end(pv);
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if (PicoLineHook) PicoLineHook();
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pevt_log_m68k_o(EVT_NEXT_LINE);
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SyncCPUs(Pico.t.m68c_aim);
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#ifdef PICO_32X
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p32x_end_blank();
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#endif
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// get samples from sound chips
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PsndGetSamples(y);
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timers_cycle(Pico.t.z80c_aim);
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pv->hint_cnt = hint;
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return 0;
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}
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#undef PAD_DELAY
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#undef CPUS_RUN
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// vim:shiftwidth=2:ts=2:expandtab
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