Rewrite mapper 222 to use modular VRC2/4 emulation, and improve its IRQ counter.
This commit is contained in:
NewRisingSun
committed by
LibretroAdmin
LibretroAdmin
parent
6804388ac7
commit
af60e17d0b
135
src/boards/222.c
135
src/boards/222.c
@@ -1,7 +1,7 @@
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/* FCE Ultra - NES/Famicom Emulator
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*
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* Copyright notice for this file:
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* Copyright (C) 2005 CaH4e3
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* Copyright (C) 2025 NewRisingSun
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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@@ -16,86 +16,83 @@
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* (VRC4 mapper)
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*
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*/
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#include "mapinc.h"
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#include "vrc2and4.h"
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static uint8 IRQCount; /*, IRQPre; */
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static uint8 IRQa;
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static uint8 prg_reg[2];
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static uint8 chr_reg[8];
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static uint8 mirr;
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static uint8 clockMode;
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static uint8 pending;
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static uint8 counter1;
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static uint8 counter2;
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static uint8 prescaler;
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static SFORMAT StateRegs[] =
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{
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{ &IRQCount, 1, "IRQC" },
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{ &IRQa, 1, "IRQA" },
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{ prg_reg, 2, "PRG" },
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{ chr_reg, 8, "CHR" },
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{ &mirr, 1, "MIRR" },
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static SFORMAT Mapper222_stateRegs[] ={
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{ &clockMode, 1, "CLKM" },
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{ &pending, 1, "PEND" },
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{ &counter1, 1, "CNT1" },
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{ &counter2, 1, "CNT2" },
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{ &prescaler, 1, "PRES" },
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{ 0 }
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};
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static void M222IRQ(void) {
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if (IRQa) {
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IRQCount++;
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if (IRQCount >= 238) {
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X6502_IRQBegin(FCEU_IQEXT);
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/* IRQa=0; */
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static void sync () {
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VRC24_syncPRG(0x01F, 0x000);
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VRC24_syncCHR(0x1FF, 0x000);
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VRC24_syncMirror();
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}
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DECLFW(Mapper222_nibblizeCHR) {
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if (~A &1) {
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VRC24_writeReg(A, V);
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VRC24_writeReg(A |1, V >>4);
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}
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}
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DECLFW(Mapper222_writeIRQ) {
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switch(A &3) {
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case 0: clockMode =0;
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break;
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case 1: pending =false;
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if (!clockMode) {
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counter1 =V &0xF;
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counter2 =V >>4;
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}
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break;
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case 2: clockMode =1;
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break;
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}
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}
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void FP_FASTAPASS(1) Mapper222_cpuCycle(int a) {
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while (a--) {
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uint8 previousPrescaler =prescaler;
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if (pending)
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prescaler =0;
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else
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prescaler++;
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if (clockMode && ~previousPrescaler &0x40 && prescaler &0x40) {
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if (++counter1 ==0xF && ++counter2 ==0xF) pending =1;
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counter1 &=0xF;
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counter2 &=0xF;
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}
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if (pending)
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X6502_IRQBegin(FCEU_IQEXT);
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else
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X6502_IRQEnd(FCEU_IQEXT);
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}
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}
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static void Sync(void) {
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int i;
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setprg8(0x8000, prg_reg[0]);
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setprg8(0xA000, prg_reg[1]);
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for (i = 0; i < 8; i++)
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setchr1(i << 10, chr_reg[i]);
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setmirror(mirr ^ 1);
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void Mapper222_power(void) {
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clockMode =pending =counter1 =counter2 =prescaler =0;
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VRC24_power();
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SetWriteHandler(0xB000, 0xEFFF, Mapper222_nibblizeCHR);
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SetWriteHandler(0xF000, 0xFFFF, Mapper222_writeIRQ);
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}
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static DECLFW(M222Write) {
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switch (A & 0xF003) {
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case 0x8000: prg_reg[0] = V; break;
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case 0x9000: mirr = V & 1; break;
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case 0xA000: prg_reg[1] = V; break;
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case 0xB000: chr_reg[0] = V; break;
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case 0xB002: chr_reg[1] = V; break;
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case 0xC000: chr_reg[2] = V; break;
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case 0xC002: chr_reg[3] = V; break;
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case 0xD000: chr_reg[4] = V; break;
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case 0xD002: chr_reg[5] = V; break;
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case 0xE000: chr_reg[6] = V; break;
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case 0xE002: chr_reg[7] = V; break;
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#if 0
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case 0xF000: FCEU_printf("%04x:%02x %d\n",A,V,scanline); IRQa=V; if(!V)IRQPre=0; X6502_IRQEnd(FCEU_IQEXT); break;
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case 0xF001: FCEU_printf("%04x:%02x %d\n",A,V,scanline); IRQCount=V; break;
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case 0xF002: FCEU_printf("%04x:%02x %d\n",A,V,scanline); break;
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case 0xD001: IRQa=V; X6502_IRQEnd(FCEU_IQEXT); FCEU_printf("%04x:%02x %d\n",A,V,scanline); break;
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case 0xC001: IRQPre=16; FCEU_printf("%04x:%02x %d\n",A,V,scanline); break;
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#endif
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case 0xF000: IRQa = IRQCount = V; if (scanline < 240) IRQCount -= 8; else IRQCount += 4; X6502_IRQEnd(FCEU_IQEXT); break;
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}
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Sync();
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}
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static void M222Power(void) {
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setprg16(0xC000, ~0);
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SetReadHandler(0x8000, 0xFFFF, CartBR);
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SetWriteHandler(0x8000, 0xFFFF, M222Write);
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}
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static void StateRestore(int version) {
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Sync();
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}
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void Mapper222_Init(CartInfo *info) {
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info->Power = M222Power;
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GameHBIRQHook = M222IRQ;
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GameStateRestore = StateRestore;
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AddExState(&StateRegs, ~0, 0, 0);
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void Mapper222_Init (CartInfo *info) {
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VRC24_init(info, sync, 0x01, 0x02, 0, 0, 0);
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AddExState(Mapper222_stateRegs, ~0, 0, 0);
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info->Power =Mapper222_power;
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MapIRQHook =Mapper222_cpuCycle;
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}
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