forked from KolibriOS/kolibrios
189 lines
6.1 KiB
C
189 lines
6.1 KiB
C
/*=====================================================================
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z80.c -> Header file related to the Z80 emulation code.
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Please read documentation files to know how this works :)
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Thanks to Marat Fayzullin for writing the "How to write a Computer
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Eemulator" HOWTO. This emulator is based on his tutorials and the
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code organization (very readable!) of his "Z80 Portable Emulator".
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I've learnt a lot from it, and I've taken some ideas of his code
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to write this emulator.I think that almost all of the undocumented
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Z80 opcodes are covered on this emulator. I also asked Marat
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Fayzullin (by email) about ideas and so on (his Z80 emulator is
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quite good, so go check it :-).
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Of course, I can't forget Raúl Gomez (he answered me thousands
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of email questions) and Philip Kendall. Whitout his ___kind___
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people surely you won't be reading this file now...
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"Programming the Z80" (from Rodnay Zaks) and the comp.sys.sinclair
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FAQ were another excelent sources of info!
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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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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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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., 675 Mass Ave, Cambridge, MA 02139, USA.
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Copyright (c) 2000 Santiago Romero Iglesias.
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Email: sromero@escomposlinux.org
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======================================================================*/
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#ifndef Z80_H
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#define Z80_H
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#define USING_ALLEGRO
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#define DEBUG
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#define _DEV_DEBUG_ /* development debugging */
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#define LOW_ENDIAN
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/*#define HI_ENDIAN */
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/* Used by the Z80Debug() function */
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#define DEBUG_OK 1
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#define DEBUG_QUIT 0
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#define video vscreen
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/*=== Some common standard data types: ==============================*/
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typedef unsigned char byte;
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typedef unsigned short word;
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typedef unsigned long dword;
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typedef signed char offset;
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/*--- Thanks to Philip Kendall for it's help using the flags --------*/
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extern byte halfcarry_add_table[];
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extern byte halfcarry_sub_table[];
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extern byte overflow_add_table[];
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extern byte overflow_sub_table[];
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extern byte sz53_table[];
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extern byte sz53p_table[];
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extern byte parity_table[];
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extern byte ioblock_inc1_table[];
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extern byte ioblock_dec1_table[];
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extern byte ioblock_2_table[];
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/*=====================================================================
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Z80 Flag Register: ---------------------------------
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| 7 6 5 4 3 2 1 0 |
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---------------------------------
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| S Z x H x O/P N C |
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---------------------------------
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If (1) means that: S = Negative result.
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Z = Zero result.
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x = special cases (by opcode)
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H = Halfcarry/borrow.
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O/P = Overflow/Parity Flag.
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N = Substraction.
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C = Carry/borrow.
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====================================================================*/
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#define S_FLAG 0x80
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#define Z_FLAG 0x40
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#define H_FLAG 0x10
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#define P_FLAG 0x04
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#define O_FLAG 0x04
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#define N_FLAG 0x02
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#define C_FLAG 0x01
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/*
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Defines for interrupts and special Z80Hardware() codes:
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=======================================================================
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INT_QUIT = Exit the emulation (for Z80Run())
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INT_NOINT = No interrupt required
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INT_IRQ = Standard RST 38h interrupt
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INT_NMI = Non-maskerable interrupt
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*/
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#define INT_QUIT 0xFFFE
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#define INT_NOINT 0xFFFF
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#define INT_IRQ 0x0038
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#define INT_NMI 0x0066
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/*=== A register is defined as follows: =============================*/
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typedef union
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{
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#ifdef LOW_ENDIAN
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struct
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{
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byte l,h;
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} B;
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#else
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struct
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{
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byte h,l;
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} B;
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#endif
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word W;
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} eword;
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#define WE_ARE_ON_DD 1
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#define WE_ARE_ON_FD 2
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/*=== Now we define the Z80 registers using the previous definition =*/
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typedef struct
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{
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char machine_type;
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byte *RAM;
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int we_are_on_ddfd;
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/* general and shadow z80 registers */
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eword AF, BC, DE, HL, IX, IY, PC, SP, R,
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AFs, BCs, DEs, HLs;
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/* IFF and I registers, used on interrupts. */
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byte IFF1, IFF2, I, halted;
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char IM;
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word IRequest;
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/* the following is to take care of cycle counting */
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int IPeriod, ICount, IBackup;
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/* DecodingErrors = set this to 1 for debugging purposes in order
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to trap undocumented or non implemented opcodes.
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Trace = set this to 1 to start tracing. It's also set
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when PC reaches TrapAddress value. */
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byte DecodingErrors;
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word TrapAddress;
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byte Trace, dobreak;
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byte BorderColor;
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} Z80Regs;
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/*====================================================================
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Function declarations, read the .c file to know what they do.
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===================================================================*/
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void Z80Reset( register Z80Regs *regs, int );
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void Z80Interrupt( register Z80Regs *, register word );
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word Z80Run( register Z80Regs *, int );
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byte Z80MemRead( register word, Z80Regs * );
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void Z80MemWrite( register word, register byte, Z80Regs * );
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byte Z80InPort( register word );
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void Z80OutPort( register Z80Regs *regs, register word, register byte );
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void Z80Patch( register Z80Regs * );
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byte Z80Debug( register Z80Regs * );
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word Z80Hardware( register Z80Regs * );
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void Z80FlagTables(void);
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word ParseOpcode( char *, char *, char *, word, Z80Regs * );
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word Z80Dissasembler ( Z80Regs *, char *, char * );
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#endif
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