140 lines
6.5 KiB
C
140 lines
6.5 KiB
C
/** Z80: portable Z80 emulator *******************************/
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/** **/
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/** Z80.h **/
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/** **/
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/** This file contains declarations relevant to emulation **/
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/** of Z80 CPU. **/
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/** **/
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/** Copyright (C) Marat Fayzullin 1994,1995,1996,1997 **/
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/** You are not allowed to distribute this software **/
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/** commercially. Please, notify me, if you make any **/
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/** changes to this file. **/
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/*************************************************************/
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#ifndef Z80_H
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#define Z80_H
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/* Compilation options: */
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/* #define DEBUG */ /* Compile debugging version */
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/* #define LSB_FIRST */ /* Compile for low-endian CPU */
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/* #define MSB_FIRST */ /* Compile for hi-endian CPU */
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/* LoopZ80() may return: */
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#define INT_IRQ 0x0038 /* Standard RST 38h interrupt */
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#define INT_NMI 0x0066 /* Non-maskable interrupt */
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#define INT_NONE 0xFFFF /* No interrupt required */
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#define INT_QUIT 0xFFFE /* Exit the emulation */
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/* Bits in Z80 F register: */
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#define S_FLAG 0x80 /* 1: Result negative */
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#define Z_FLAG 0x40 /* 1: Result is zero */
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#define H_FLAG 0x10 /* 1: Halfcarry/Halfborrow */
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#define P_FLAG 0x04 /* 1: Result is even */
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#define V_FLAG 0x04 /* 1: Overflow occured */
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#define N_FLAG 0x02 /* 1: Subtraction occured */
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#define C_FLAG 0x01 /* 1: Carry/Borrow occured */
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/** Simple Datatypes *****************************************/
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/** NOTICE: sizeof(byte)=1 and sizeof(word)=2 **/
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/*************************************************************/
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typedef unsigned char byte;
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typedef unsigned short word;
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typedef signed char offset;
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/** Structured Datatypes *************************************/
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/** NOTICE: #define LSB_FIRST for machines where least **/
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/** signifcant byte goes first. **/
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/*************************************************************/
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typedef union
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{
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#ifdef LSB_FIRST
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struct { byte l,h; } B;
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#else
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struct { byte h,l; } B;
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#endif
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word W;
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} pair;
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typedef struct
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{
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pair AF,BC,DE,HL,IX,IY,PC,SP; /* Main registers */
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pair AF1,BC1,DE1,HL1; /* Shadow registers */
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byte IFF,I; /* Interrupt registers */
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int IPeriod,ICount; /* Set IPeriod to number of CPU cycles */
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/* between calls to LoopZ80() */
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int IBackup; /* Private, don't touch */
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word IRequest; /* Set to address of pending IRQ */
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void *User; /* Arbitrary user data (ID,RAM*,etc.) */
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byte TrapBadOps; /* Set to 1 to warn of illegal opcodes */
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word Trap; /* Set Trap to address to trace from */
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byte Trace; /* Set Trace=1 to start tracing */
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} Z80;
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/** ResetZ80() ***********************************************/
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/** This function can be used to reset the registers before **/
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/** starting execution with RunZ80(). It sets registers to **/
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/** their initial values. **/
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/*************************************************************/
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void ResetZ80(register Z80 *R);
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/** ExecZ80() ************************************************/
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/** This function will execute a single Z80 opcode. It will **/
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/** then return next PC, and current register values in R. **/
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/*************************************************************/
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word ExecZ80(register Z80 *R);
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/** IntZ80() *************************************************/
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/** This function will generate interrupt of given vector. **/
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/*************************************************************/
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void IntZ80(register Z80 *R,register word Vector);
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/** RunZ80() *************************************************/
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/** This function will run Z80 code until an LoopZ80() call **/
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/** returns INT_QUIT. It will return the PC at which **/
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/** emulation stopped, and current register values in R. **/
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/*************************************************************/
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word RunZ80(register Z80 *R);
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/** RdZ80()/WrZ80() ******************************************/
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/** These functions are called when access to RAM occurs. **/
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/** They allow to control memory access. **/
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/************************************ TO BE WRITTEN BY USER **/
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void WrZ80(register word Addr,register byte Value);
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byte RdZ80(register word Addr);
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/** InZ80()/OutZ80() *****************************************/
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/** Z80 emulation calls these functions to read/write from **/
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/** I/O ports. There can be 65536 I/O ports, but only first **/
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/** 256 are usually used **/
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/************************************ TO BE WRITTEN BY USER **/
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void OutZ80(register word Port,register byte Value);
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byte InZ80(register word Port);
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/** PatchZ80() ***********************************************/
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/** Z80 emulation calls this function when it encounters a **/
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/** special patch command (ED FE) provided for user needs. **/
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/** For example, it can be called to emulate BIOS calls, **/
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/** such as disk and tape access. Replace it with an empty **/
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/** macro for no patching. **/
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/************************************ TO BE WRITTEN BY USER **/
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void PatchZ80(register Z80 *R);
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/** DebugZ80() ***********************************************/
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/** This function should exist if DEBUG is #defined. When **/
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/** Trace!=0, it is called after each command executed by **/
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/** the CPU, and given the Z80 registers. Emulation exits **/
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/** if DebugZ80() returns 0. **/
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/*************************************************************/
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byte DebugZ80(register Z80 *R);
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/** LoopZ80() ************************************************/
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/** Z80 emulation calls this function periodically to check **/
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/** if the system hardware requires any interrupts. This **/
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/** function must return an address of the interrupt vector **/
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/** (0x0038, 0x0066, etc.) or INT_NONE for no interrupt. **/
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/** Return INT_QUIT to exit the emulation loop. **/
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/************************************ TO BE WRITTEN BY USER **/
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word LoopZ80(register Z80 *R);
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#endif /* Z80_H */
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