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https://github.com/libretro/RACE.git
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101 lines
2.7 KiB
C
101 lines
2.7 KiB
C
/*---------------------------------------------------------------------------
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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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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version. See also the license.txt file for
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* additional informations.
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*---------------------------------------------------------------------------
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*/
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/*
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* Support functions for interfacing with DrZ80
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*/
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#include "types.h"
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#include "main.h"
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#include "race-memory.h"
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#include "DrZ80_support.h"
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#define INT_IRQ 0x01
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#define NMI_IRQ 0x08
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struct Z80_Regs Z80;
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#define Z80_INT() Z80.regs.Z80_IRQ = INT_IRQ
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#define Z80_NMI() Z80.regs.Z80IF |= NMI_IRQ
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static unsigned int z80_rebaseSP(unsigned short address)
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{
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Z80.regs.Z80SP_BASE = (unsigned int)&mainram[0x3000];
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Z80.regs.Z80SP = Z80.regs.Z80SP_BASE + address;
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return Z80.regs.Z80SP_BASE + address;
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}
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static unsigned int z80_rebasePC(unsigned short address)
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{
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Z80.regs.Z80PC_BASE = (unsigned int)&mainram[0x3000];
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Z80.regs.Z80PC = Z80.regs.Z80PC_BASE + address;
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return Z80.regs.Z80PC_BASE + address;
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}
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static void z80_irq_callback(void)
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{
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Z80.regs.Z80_IRQ = 0x00;
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}
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/****************************************************************************
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* Reset registers to their initial values
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****************************************************************************/
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void Z80_Reset(void)
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{
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memset (&Z80, 0, sizeof(struct Z80_Regs));
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Z80.regs.z80_rebasePC=z80_rebasePC;
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Z80.regs.z80_rebaseSP=z80_rebaseSP /* 0 */;
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Z80.regs.z80_read8 =z80MemReadB; /* z80_read8 */
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Z80.regs.z80_read16 =z80MemReadW;
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Z80.regs.z80_write8 =DrZ80ngpMemWriteB;
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Z80.regs.z80_write16 =DrZ80ngpMemWriteW;
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Z80.regs.z80_in =DrZ80ngpPortReadB;
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Z80.regs.z80_out =DrZ80ngpPortWriteB;
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Z80.regs.z80_irq_callback=z80_irq_callback;
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Z80.regs.Z80BC = 0013;
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Z80.regs.Z80DE = 0x00D8;
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Z80.regs.Z80HL = 0x014D;
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Z80.regs.Z80PC=Z80.regs.z80_rebasePC(0);
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Z80.regs.Z80SP=Z80.regs.z80_rebaseSP(0xFFFE);
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Z80_Clear_Pending_Interrupts();
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}
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void Z80_Cause_Interrupt(int type)
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{
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if (type == Z80_NMI_INT)
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{
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Z80_NMI();
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}
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else if (type != Z80_IGNORE_INT)
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{
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Z80_INT();
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}
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}
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void Z80_Clear_Pending_Interrupts(void)
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{
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Z80.regs.Z80_IRQ = 0x00;
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}
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/****************************************************************************
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* Execute IPeriod T-states. Return number of T-states really executed
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****************************************************************************/
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int Z80_Execute(int cycles)
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{
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Z80.regs.cycles = cycles;
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DrZ80Run(&Z80.regs, cycles);
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return cycles; /* (cycles-Z80.regs.cycles); */
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}
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