ref: 19a034bfe528ee39bb3b76e613cf2ae6bbdb7f13
dir: /snes/snes.c/
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <stdint.h> #include <stdbool.h> #include <assert.h> #include <stddef.h> #include "saveload.h" #include "snes.h" #include "cpu.h" #include "apu.h" #include "dma.h" #include "ppu.h" #include "cart.h" #include "input.h" #include "../tracing.h" #include "snes_regs.h" static const double apuCyclesPerMaster = (32040 * 32) / (1364 * 262 * 60.0); static void snes_runCpu(Snes* snes); static void snes_catchupApu(Snes* snes); static uint8_t snes_readReg(Snes* snes, uint16_t adr); static void snes_writeReg(Snes* snes, uint16_t adr, uint8_t val); static uint8_t snes_rread(Snes* snes, uint32_t adr); // wrapped by read, to set open bus static int snes_getAccessTime(Snes* snes, uint32_t adr); void zelda_apu_runcycles(); Snes* snes_init(uint8_t *ram) { Snes* snes = (Snes * )malloc(sizeof(Snes)); snes->ram = ram; snes->cpu = cpu_init(snes, 0); snes->apu = apu_init(); snes->dma = dma_init(snes); snes->ppu = ppu_init(snes); snes->cart = cart_init(snes); snes->input1 = input_init(snes); snes->input2 = input_init(snes); snes->debug_cycles = false; snes->disableHpos = false; return snes; } void snes_free(Snes* snes) { cpu_free(snes->cpu); apu_free(snes->apu); dma_free(snes->dma); ppu_free(snes->ppu); cart_free(snes->cart); input_free(snes->input1); input_free(snes->input2); free(snes); } void snes_saveload(Snes *snes, SaveLoadFunc *func, void *ctx) { cpu_saveload(snes->cpu, func, ctx); apu_saveload(snes->apu, func, ctx); dma_saveload(snes->dma, func, ctx); ppu_saveload(snes->ppu, func, ctx); cart_saveload(snes->cart, func, ctx); func(ctx, &snes->hPos, offsetof(Snes, openBus) + 1 - offsetof(Snes, hPos)); func(ctx, snes->ram, 0x20000); func(ctx, &snes->ramAdr, 4); snes->disableHpos = false; } void snes_reset(Snes* snes, bool hard) { cart_reset(snes->cart); // reset cart first, because resetting cpu will read from it (reset vector) cpu_reset(snes->cpu); apu_reset(snes->apu); dma_reset(snes->dma); ppu_reset(snes->ppu); input_reset(snes->input1); input_reset(snes->input2); if (hard) memset(snes->ram, 0, 0x20000); snes->ramAdr = 0; snes->hPos = 0; snes->vPos = 0; snes->frames = 0; snes->cpuCyclesLeft = 52; // 5 reads (8) + 2 IntOp (6) snes->cpuMemOps = 0; snes->apuCatchupCycles = 0.0; snes->hIrqEnabled = false; snes->vIrqEnabled = false; snes->nmiEnabled = false; snes->hTimer = 0x1ff; snes->vTimer = 0x1ff; snes->inNmi = false; snes->inIrq = false; snes->inVblank = false; memset(snes->portAutoRead, 0, sizeof(snes->portAutoRead)); snes->autoJoyRead = false; snes->autoJoyTimer = 0; snes->ppuLatch = false; snes->multiplyA = 0xff; snes->multiplyResult = 0xfe01; snes->divideA = 0xffff; snes->divideResult = 0x101; snes->fastMem = false; snes->openBus = 0; } static uint8_t g_last_module; void snes_printCpuLine(Snes *snes) { if (snes->debug_cycles) { static FILE *fout; if (!fout) fout = stdout; char line[80]; getProcessorStateCpu(snes, line); fputs(line, fout); fprintf(fout, " 0x%x", snes->ppu->vram[0]); fputs("\n", fout); fflush(fout); } } static void snes_runCpu(Snes* snes) { if(snes->cpuCyclesLeft == 0) { snes->cpuMemOps = 0; uint32_t pc = snes->cpu->pc | snes->cpu->k << 16; if (snes->debug_cycles) { char line[80]; getProcessorStateCpu(snes, line); puts(line); } int cycles = cpu_runOpcode(snes->cpu); snes->cpuCyclesLeft += (cycles - snes->cpuMemOps) * 6; } snes->cpuCyclesLeft -= 2; } static void snes_catchupApu(Snes* snes) { int catchupCycles = (int) snes->apuCatchupCycles; for(int i = 0; i < catchupCycles; i++) { apu_cycle(snes->apu); zelda_apu_runcycles(); } snes->apuCatchupCycles -= (double) catchupCycles; } void snes_doAutoJoypad(Snes* snes) { // TODO: improve? (now calls input_cycle) memset(snes->portAutoRead, 0, sizeof(snes->portAutoRead)); snes->input1->latchLine = true; snes->input2->latchLine = true; input_cycle(snes->input1); // latches the controllers input_cycle(snes->input2); snes->input1->latchLine = false; snes->input2->latchLine = false; for(int i = 0; i < 16; i++) { uint8_t val = input_read(snes->input1); snes->portAutoRead[0] |= ((val & 1) << (15 - i)); snes->portAutoRead[2] |= (((val >> 1) & 1) << (15 - i)); val = input_read(snes->input2); snes->portAutoRead[1] |= ((val & 1) << (15 - i)); snes->portAutoRead[3] |= (((val >> 1) & 1) << (15 - i)); } } uint8_t snes_readBBus(Snes* snes, uint8_t adr) { if(adr < 0x40) { return ppu_read(snes->ppu, adr); } if(adr < 0x80) { apu_cycle(snes->apu);//spc_runOpcode(snes->apu->spc); return snes->apu->outPorts[adr & 0x3]; } if(adr == 0x80) { uint8_t ret = snes->ram[snes->ramAdr++]; snes->ramAdr &= 0x1ffff; return ret; } return snes->openBus; } void snes_writeBBus(Snes* snes, uint8_t adr, uint8_t val) { if(adr < 0x40) { ppu_write(snes->ppu, adr, val); return; } if(adr < 0x80) { snes_catchupApu(snes); // catch up the apu before writing snes->apu->inPorts[adr & 0x3] = val; return; } switch(adr) { case 0x80: { snes->ram[snes->ramAdr++] = val; snes->ramAdr &= 0x1ffff; break; } case 0x81: { snes->ramAdr = (snes->ramAdr & 0x1ff00) | val; break; } case 0x82: { snes->ramAdr = (snes->ramAdr & 0x100ff) | (val << 8); break; } case 0x83: { snes->ramAdr = (snes->ramAdr & 0x0ffff) | ((val & 1) << 16); break; } } } static uint8_t snes_readReg(Snes* snes, uint16_t adr) { switch(adr) { case 0x4210: { uint8_t val = 0x2; // CPU version (4 bit) val |= snes->inNmi << 7; snes->inNmi = false; return val | (snes->openBus & 0x70); } case 0x4211: { uint8_t val = snes->inIrq << 7; snes->inIrq = false; snes->cpu->irqWanted = false; return val | (snes->openBus & 0x7f); } case 0x4212: { uint8_t val = (snes->autoJoyTimer > 0); val |= (snes->hPos >= 1024) << 6; val |= snes->inVblank << 7; return val | (snes->openBus & 0x3e); } case 0x4213: { return snes->ppuLatch << 7; // IO-port } case 0x4214: { return snes->divideResult & 0xff; } case 0x4215: { return snes->divideResult >> 8; } case 0x4216: { return snes->multiplyResult & 0xff; } case 0x4217: { return snes->multiplyResult >> 8; } case 0x4218: case 0x421a: case 0x421c: case 0x421e: { return snes->portAutoRead[(adr - 0x4218) / 2] & 0xff; } case 0x4219: case 0x421b: case 0x421d: case 0x421f: { return snes->portAutoRead[(adr - 0x4219) / 2] >> 8; } default: { return snes->openBus; } } } static void snes_writeReg(Snes* snes, uint16_t adr, uint8_t val) { switch(adr) { case 0x4200: { snes->autoJoyRead = val & 0x1; if(!snes->autoJoyRead) snes->autoJoyTimer = 0; snes->hIrqEnabled = val & 0x10; snes->vIrqEnabled = val & 0x20; snes->nmiEnabled = val & 0x80; if(!snes->hIrqEnabled && !snes->vIrqEnabled) { snes->inIrq = false; snes->cpu->irqWanted = false; } // TODO: enabling nmi during vblank with inNmi still set generates nmi // enabling virq (and not h) on the vPos that vTimer is at generates irq (?) break; } case 0x4201: { if(!(val & 0x80) && snes->ppuLatch) { // latch the ppu ppu_read(snes->ppu, 0x37); } snes->ppuLatch = val & 0x80; break; } case 0x4202: { snes->multiplyA = val; break; } case 0x4203: { snes->multiplyResult = snes->multiplyA * val; break; } case 0x4204: { snes->divideA = (snes->divideA & 0xff00) | val; break; } case 0x4205: { snes->divideA = (snes->divideA & 0x00ff) | (val << 8); break; } case 0x4206: { if(val == 0) { snes->divideResult = 0xffff; snes->multiplyResult = snes->divideA; } else { snes->divideResult = snes->divideA / val; snes->multiplyResult = snes->divideA % val; } break; } case 0x4207: { snes->hTimer = (snes->hTimer & 0x100) | val; break; } case 0x4208: { snes->hTimer = (snes->hTimer & 0x0ff) | ((val & 1) << 8); break; } case 0x4209: { snes->vTimer = (snes->vTimer & 0x100) | val; break; } case 0x420a: { snes->vTimer = (snes->vTimer & 0x0ff) | ((val & 1) << 8); break; } case 0x420b: { dma_startDma(snes->dma, val, false); break; } case 0x420c: { dma_startDma(snes->dma, val, true); break; } case 0x420d: { snes->fastMem = val & 0x1; break; } default: { break; } } } static uint8_t snes_rread(Snes* snes, uint32_t adr) { uint8_t bank = adr >> 16; adr &= 0xffff; if((bank & 0x7f) < 0x40 && adr < 0x4380) { if(adr < 0x2000) { return snes->ram[adr]; // ram mirror } if(adr >= 0x2100 && adr < 0x2200) { return snes_readBBus(snes, adr & 0xff); // B-bus } if(adr == 0x4016) { return input_read(snes->input1) | (snes->openBus & 0xfc); } if(adr == 0x4017) { return input_read(snes->input2) | (snes->openBus & 0xe0) | 0x1c; } if(adr >= 0x4200 && adr < 0x4220) { return snes_readReg(snes, adr); // internal registers } if(adr >= 0x4300 && adr < 0x4380) { return dma_read(snes->dma, adr); // dma registers } } else if ((bank & ~1) == 0x7e) { return snes->ram[((bank & 1) << 16) | adr]; // ram } // read from cart return cart_read(snes->cart, bank, adr); } int g_bp_addr = 0; void snes_write(Snes* snes, uint32_t adr, uint8_t val) { snes->openBus = val; uint8_t bank = adr >> 16; adr &= 0xffff; if(bank == 0x7e || bank == 0x7f) { if ((adr & 0xffff) == g_bp_addr && g_bp_addr) { printf("@0x%x: Writing1 0x%X to 0x%x (frame %d) %.2x %.2x %.2x\n", snes->cpu->k * 65536 + snes->cpu->pc, val, adr & 0xffff, snes->ram[0x1a], snes->ram[snes->cpu->sp+1], snes->ram[snes->cpu->sp+2], snes->ram[snes->cpu->sp+3]); } snes->ram[((bank & 1) << 16) | adr] = val; // ram } else if(bank < 0x40 || (bank >= 0x80 && bank < 0xc0)) { if (adr < 0x2000) { if ((adr & 0xffff) == g_bp_addr && g_bp_addr) { printf("@0x%x: Writing2 0x%X to 0x%x (frame %d) %.2x %.2x %.2x\n", snes->cpu->k * 65536 + snes->cpu->pc, val, adr & 0xffff, snes->ram[0x1a], snes->ram[snes->cpu->sp+1], snes->ram[snes->cpu->sp+2], snes->ram[snes->cpu->sp+3]); } snes->ram[adr] = val; // ram mirror } else if(adr >= 0x2100 && adr < 0x2200) { snes_writeBBus(snes, adr & 0xff, val); // B-bus } else if(adr == 0x4016) { snes->input1->latchLine = val & 1; snes->input2->latchLine = val & 1; } else if(adr >= 0x4200 && adr < 0x4220) { snes_writeReg(snes, adr, val); // internal registers } else if(adr >= 0x4300 && adr < 0x4380) { dma_write(snes->dma, adr, val); // dma registers } } cart_write(snes->cart, bank, adr, val); // write to cart } static int snes_getAccessTime(Snes* snes, uint32_t adr) { // optimization return 6; } uint8_t snes_read(Snes* snes, uint32_t adr) { uint8_t val = snes_rread(snes, adr); snes->openBus = val; return val; } uint8_t snes_cpuRead(Snes* snes, uint32_t adr) { snes->cpuMemOps++; snes->cpuCyclesLeft += snes_getAccessTime(snes, adr); return snes_read(snes, adr); } void snes_cpuWrite(Snes* snes, uint32_t adr, uint8_t val) { snes->cpuMemOps++; snes->cpuCyclesLeft += snes_getAccessTime(snes, adr); snes_write(snes, adr, val); } // debugging