mirror of
https://github.com/libretro/fixNES.git
synced 2025-04-03 05:21:37 +00:00
f5d72bb48e
-reworked most of the ppu, this gets rid of some small graphical glitches as well as further improve performance -improved cpu core to now do some rare operations more accurately -greatly improved soft reset to now work properly with multicart mappers and not cause any more weird freezing with certain games
117 lines
2.3 KiB
C
117 lines
2.3 KiB
C
/*
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* Copyright (C) 2017 - 2018 FIX94
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*
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* This software may be modified and distributed under the terms
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* of the MIT license. See the LICENSE file for details.
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*/
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#include <stdio.h>
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#include <stdbool.h>
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#include <inttypes.h>
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#include "cpu.h"
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static uint8_t vrc_irqCtr;
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static uint8_t vrc_irqCurCtr;
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static uint8_t vrc_irqPrescaler;
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static uint8_t vrc_irq_scanTblPos;
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static bool vrc_irqEnabled;
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static bool vrc_irqEnable_after_ack;
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static bool vrc_irqCyclemode;
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extern uint8_t interrupt;
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static uint8_t vrc_irq_scanTbl[3] = { 113, 113, 112 };
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void vrc_irq_init()
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{
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vrc_irqCtr = 0;
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vrc_irqCurCtr = 0;
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vrc_irqPrescaler = 0;
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vrc_irqEnabled = false;
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vrc_irqEnable_after_ack = false;
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vrc_irqCyclemode = false;
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vrc_irq_scanTblPos = 0;
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printf("Using Common VRC Mapper IRQ\n");
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}
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void vrc_irq_setlatch(uint16_t addr, uint8_t val)
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{
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(void)addr;
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vrc_irqCtr = val;
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}
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void vrc_irq_setlatchLo(uint16_t addr, uint8_t val)
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{
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(void)addr;
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vrc_irqCtr = (vrc_irqCtr&~0xF) | (val&0xF);
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}
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void vrc_irq_setlatchHi(uint16_t addr, uint8_t val)
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{
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(void)addr;
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vrc_irqCtr = (vrc_irqCtr&0xF) | ((val&0xF)<<4);
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}
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void vrc_irq_control(uint16_t addr, uint8_t val)
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{
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(void)addr;
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interrupt &= ~MAPPER_IRQ;
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vrc_irqEnable_after_ack = ((val&1) != 0);
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vrc_irqCyclemode = ((val&4) != 0);
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if((val&2) != 0)
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{
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vrc_irqEnabled = true;
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vrc_irqCurCtr = vrc_irqCtr;
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vrc_irqPrescaler = 0;
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vrc_irq_scanTblPos = 0;
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//printf("vrc_irq IRQ Reload with in %02x ctr %i\n", val, vrc_irqCtr);
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}
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else
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{
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vrc_irqEnabled = false;
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//printf("vrc_irq IRQ Write with in %02x ctr %i\n", val, vrc_irqCtr);
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}
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}
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void vrc_irq_ack(uint16_t addr, uint8_t val)
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{
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(void)addr; (void)val;
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interrupt &= ~MAPPER_IRQ;
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vrc_irqEnabled = vrc_irqEnable_after_ack;
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//printf("vrc_irq ACK IRQ Reload\n");
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}
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void vrc_irq_ctrcycle()
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{
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if(vrc_irqCurCtr == 0xFF)
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{
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//printf("vrc_irq Cycle Interrupt\n");
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interrupt |= MAPPER_IRQ;
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//vrc_irqEnabled = false;
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vrc_irqCurCtr = vrc_irqCtr;
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}
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else
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vrc_irqCurCtr++;
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}
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void vrc_irq_cycle()
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{
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if(vrc_irqEnabled)
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{
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if(vrc_irqCyclemode)
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vrc_irq_ctrcycle();
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else
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{
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if(vrc_irqPrescaler >= vrc_irq_scanTbl[vrc_irq_scanTblPos])
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{
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vrc_irq_ctrcycle();
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vrc_irq_scanTblPos++;
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if(vrc_irq_scanTblPos >= 3)
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vrc_irq_scanTblPos = 0;
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vrc_irqPrescaler = 0;
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}
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else
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vrc_irqPrescaler++;
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}
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}
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}
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