Files
ci-libretro-fceumm/src/boards/asic_vrc3.c

130 lines
2.9 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_VRC3.h"
static void (*VRC3_cbSync)();
static uint8 VRC3_prg;
static uint8 VRC3_irq;
static uint16 VRC3_count;
static uint16 VRC3_reload;
static SFORMAT VRC3_state[] = {
{&VRC3_prg, 1, "VC3P" },
{&VRC3_irq, 1, "VC3I" },
{&VRC3_count, 1, "VC3C" },
{&VRC3_reload, 1, "VC3R" },
{ 0 }
};
void VRC3_syncWRAM (int OR) {
if (PRGsize[0x10]) setprg8r(0x10, 0x6000, OR);
}
void VRC3_syncPRG (int AND, int OR) {
setprg16(0x8000, VRC3_prg &AND |OR);
setprg16(0xC000, 0xFF &AND |OR);
}
void VRC3_syncCHR (int AND, int OR) {
setchr8(OR);
}
DECLFW(VRC3_write) {
int shift;
switch (A >>12 &7) {
case 0: case 1: case 2: case 3:
V &=0xF;
shift = A >>10 &0xC;
VRC3_reload = VRC3_reload &~(0xF <<shift) | V <<shift;
break;
case 4:
VRC3_irq = V;
if (VRC3_irq &2) VRC3_count = VRC3_reload;
break;
case 5:
VRC3_irq = VRC3_irq &~2 | VRC3_irq <<1 &1;
X6502_IRQEnd(FCEU_IQEXT);
break;
case 7:
VRC3_prg = V;
VRC3_cbSync();
break;
}
}
void FP_FASTAPASS(1) VRC3_cpuCycle (int a) {
while (a--) {
int mask = VRC3_irq &4? 0xFF: 0xFFFF;
if ((VRC3_count++ &mask) == mask) {
VRC3_count = VRC3_reload;
X6502_IRQBegin(FCEU_IQEXT);
}
}
}
static void VRC3_clear () {
VRC3_prg = VRC3_irq = VRC3_count = VRC3_reload = 0;
X6502_IRQEnd(FCEU_IQEXT);
VRC3_cbSync();
}
static void VRC3_setHandlers () {
SetReadHandler (0x6000, 0xFFFF, CartBR);
SetWriteHandler(0x6000, 0x7FFF, CartBW);
SetWriteHandler(0x8000, 0xFFFF, VRC3_write);
MapIRQHook = VRC3_cpuCycle;
}
static void VRC3_configure (void (*sync)()) {
VRC3_cbSync = sync;
}
void VRC3_activate (uint8 clear, void (*sync)()) {
VRC3_configure(sync);
VRC3_setHandlers();
if (clear)
VRC3_clear();
else
VRC3_cbSync();
}
void VRC3_addExState () {
AddExState(VRC3_state, ~0, 0, 0);
}
void VRC3_restore (int version) {
VRC3_cbSync();
}
void VRC3_power () {
VRC3_setHandlers();
VRC3_clear();
}
void VRC3_init (CartInfo *info, void (*sync)()) {
VRC3_addExState();
VRC3_configure(sync);
info->Power = VRC3_power;
info->Reset = VRC3_cbSync;
GameStateRestore = VRC3_restore;
}