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164 lines
4.4 KiB
C
164 lines
4.4 KiB
C
// This unit has been copied from libz80 into Collapse OS and was slighly changed
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/* =============================================================================
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* libz80 - Z80 emulation library
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* =============================================================================
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*
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* (C) Gabriel Gambetta (gabriel.gambetta@gmail.com) 2000 - 2012
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*
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* Version 2.1.0
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*
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* -----------------------------------------------------------------------------
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*
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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.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#pragma once
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#include <stdio.h>
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typedef unsigned short ushort;
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typedef unsigned char byte;
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/** Function type to emulate data read. */
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typedef byte (*Z80DataIn) (int param, ushort address);
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/** Function type to emulate data write. */
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typedef void (*Z80DataOut) (int param, ushort address, byte data);
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/**
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* A Z80 register set.
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* An union is used since we want independent access to the high and low bytes of the 16-bit registers.
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*/
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typedef union
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{
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/** Word registers. */
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struct
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{
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ushort AF, BC, DE, HL, IX, IY, SP;
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} wr;
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/** Byte registers. Note that SP can't be accessed partially. */
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struct
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{
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byte F, A, C, B, E, D, L, H, IXl, IXh, IYl, IYh;
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} br;
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} Z80Regs;
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/** The Z80 flags */
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typedef enum
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{
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F_C = 1, /**< Carry */
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F_N = 2, /**< Sub / Add */
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F_PV = 4, /**< Parity / Overflow */
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F_3 = 8, /**< Reserved */
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F_H = 16, /**< Half carry */
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F_5 = 32, /**< Reserved */
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F_Z = 64, /**< Zero */
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F_S = 128 /**< Sign */
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} Z80Flags;
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/** A Z80 execution context. */
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typedef struct
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{
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Z80Regs R1; /**< Main register set (R) */
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Z80Regs R2; /**< Alternate register set (R') */
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ushort PC; /**< Program counter */
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byte R; /**< Refresh */
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byte I;
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byte IFF1; /**< Interrupt Flipflop 1 */
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byte IFF2; /**< Interrupt Flipflop 2 */
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byte IM; /**< Instruction mode */
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Z80DataIn memRead;
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Z80DataOut memWrite;
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int memParam;
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Z80DataIn ioRead;
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Z80DataOut ioWrite;
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int ioParam;
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byte halted;
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unsigned tstates;
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/* Below are implementation details which may change without
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* warning; they should not be relied upon by any user of this
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* library.
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*/
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/* If true, an NMI has been requested. */
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byte nmi_req;
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/* If true, a maskable interrupt has been requested. */
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byte int_req;
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/* If true, defer checking maskable interrupts for one
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* instruction. This is used to keep an interrupt from happening
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* immediately after an IE instruction. */
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byte defer_int;
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/* When a maskable interrupt has been requested, the interrupt
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* vector. For interrupt mode 1, it's the opcode to execute. For
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* interrupt mode 2, it's the LSB of the interrupt vector address.
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* Not used for interrupt mode 0.
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*/
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byte int_vector;
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/* If true, then execute the opcode in int_vector. */
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byte exec_int_vector;
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} Z80Context;
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/** Execute the next instruction. */
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void Z80Execute (Z80Context* ctx);
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/** Execute enough instructions to use at least tstates cycles.
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* Returns the number of tstates actually executed. Note: Resets
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* ctx->tstates.*/
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unsigned Z80ExecuteTStates(Z80Context* ctx, unsigned tstates);
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/** Decode the next instruction to be executed.
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* dump and decode can be NULL if such information is not needed
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*
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* @param dump A buffer which receives the hex dump
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* @param decode A buffer which receives the decoded instruction
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*/
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void Z80Debug (Z80Context* ctx, char* dump, char* decode);
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/** Resets the processor. */
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void Z80RESET (Z80Context* ctx);
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/** Generates a hardware interrupt.
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* Some interrupt modes read a value from the data bus; this value must be provided in this function call, even
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* if the processor ignores that value in the current interrupt mode.
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*
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* @param value The value to read from the data bus
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*/
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void Z80INT (Z80Context* ctx, byte value);
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/** Generates a non-maskable interrupt. */
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void Z80NMI (Z80Context* ctx);
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