79 lines
1.9 KiB
C
79 lines
1.9 KiB
C
/* FCE Ultra - NES/Famicom Emulator
|
|
*
|
|
* Copyright notice for this file:
|
|
* Copyright (C) 2025 NewRisingSun
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#include "mapinc.h"
|
|
#include "asic_vrc2and4.h"
|
|
|
|
static uint8 irqEnabled;
|
|
static uint8 irqCounter;
|
|
static uint8 irqPrescaler;
|
|
|
|
static SFORMAT stateRegs[] ={
|
|
{ &irqEnabled, 1, "IRQE" },
|
|
{ &irqCounter, 1, "CNTR" },
|
|
{ &irqPrescaler, 1, "IRQP" },
|
|
{ 0 }
|
|
};
|
|
|
|
static void sync () {
|
|
VRC24_syncPRG(0x01F, 0x000);
|
|
VRC24_syncCHR(0x1FF, 0x000);
|
|
VRC24_syncMirror();
|
|
}
|
|
|
|
static DECLFW (writeIRQ) {
|
|
switch(A &0x0C) {
|
|
case 0:
|
|
irqCounter = V;
|
|
irqPrescaler = 0;
|
|
X6502_IRQEnd(FCEU_IQEXT);
|
|
break;
|
|
case 4:
|
|
irqEnabled = V;
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void FP_FASTAPASS(1) cpuCycle (int a) {
|
|
while (a--) {
|
|
if (irqEnabled &1) {
|
|
irqPrescaler++;
|
|
if (irqPrescaler == 64 && !++irqCounter) X6502_IRQBegin(FCEU_IQEXT);
|
|
if (irqPrescaler == 112) irqPrescaler = 0;
|
|
} else {
|
|
irqPrescaler = 0;
|
|
X6502_IRQEnd(FCEU_IQEXT);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void power (void) {
|
|
irqEnabled = irqCounter = irqPrescaler = 0;
|
|
VRC24_power();
|
|
SetWriteHandler(0xF000, 0xFFFF, writeIRQ);
|
|
}
|
|
|
|
void Mapper565_Init (CartInfo *info) {
|
|
VRC2_init(info, sync, 0x08, 0x04, NULL, NULL, NULL, NULL);
|
|
AddExState(stateRegs, ~0, 0, 0);
|
|
info->Power = power;
|
|
MapIRQHook = cpuCycle;
|
|
}
|