/*=====================================================================
z80.c -> Header file related to the Z80 emulation code.
Please read documentation files to know how this works :)
Thanks to Marat Fayzullin for writing the "How to write a Computer
Eemulator" HOWTO. This emulator is based on his tutorials and the
code organization (very readable!) of his "Z80 Portable Emulator".
I've learnt a lot from it, and I've taken some ideas of his code
to write this emulator.I think that almost all of the undocumented
Z80 opcodes are covered on this emulator. I also asked Marat
Fayzullin (by email) about ideas and so on (his Z80 emulator is
quite good, so go check it :-).
Of course, I can't forget Raúl Gomez (he answered me thousands
of email questions) and Philip Kendall. Whitout his ___kind___
people surely you won't be reading this file now...
"Programming the Z80" (from Rodnay Zaks) and the comp.sys.sinclair
FAQ were another excelent sources of info!
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
Copyright (c) 2000 Santiago Romero Iglesias.
Email: sromero@escomposlinux.org
======================================================================*/
#ifndef Z80_H
#define Z80_H
#define USING_ALLEGRO
#define DEBUG
#define _DEV_DEBUG_ /* development debugging */
#define LOW_ENDIAN
/*#define HI_ENDIAN */
/* Used by the Z80Debug() function */
#define DEBUG_OK 1
#define DEBUG_QUIT 0
#define video vscreen
/*=== Some common standard data types: ==============================*/
typedef unsigned char byte;
typedef unsigned short word;
typedef unsigned long dword;
typedef signed char offset;
/*--- Thanks to Philip Kendall for it's help using the flags --------*/
extern byte halfcarry_add_table[];
extern byte halfcarry_sub_table[];
extern byte overflow_add_table[];
extern byte overflow_sub_table[];
extern byte sz53_table[];
extern byte sz53p_table[];
extern byte parity_table[];
extern byte ioblock_inc1_table[];
extern byte ioblock_dec1_table[];
extern byte ioblock_2_table[];
/*=====================================================================
Z80 Flag Register: ---------------------------------
| 7 6 5 4 3 2 1 0 |
---------------------------------
| S Z x H x O/P N C |
---------------------------------
If (1) means that: S = Negative result.
Z = Zero result.
x = special cases (by opcode)
H = Halfcarry/borrow.
O/P = Overflow/Parity Flag.
N = Substraction.
C = Carry/borrow.
====================================================================*/
#define S_FLAG 0x80
#define Z_FLAG 0x40
#define H_FLAG 0x10
#define P_FLAG 0x04
#define O_FLAG 0x04
#define N_FLAG 0x02
#define C_FLAG 0x01
/*
Defines for interrupts and special Z80Hardware() codes:
=======================================================================
INT_QUIT = Exit the emulation (for Z80Run())
INT_NOINT = No interrupt required
INT_IRQ = Standard RST 38h interrupt
INT_NMI = Non-maskerable interrupt
*/
#define INT_QUIT 0xFFFE
#define INT_NOINT 0xFFFF
#define INT_IRQ 0x0038
#define INT_NMI 0x0066
/*=== A register is defined as follows: =============================*/
typedef union
{
#ifdef LOW_ENDIAN
struct
{
byte l,h;
} B;
#else
struct
{
byte h,l;
} B;
#endif
word W;
} eword;
#define WE_ARE_ON_DD 1
#define WE_ARE_ON_FD 2
/*=== Now we define the Z80 registers using the previous definition =*/
typedef struct
{
char machine_type;
byte *RAM;
int we_are_on_ddfd;
/* general and shadow z80 registers */
eword AF, BC, DE, HL, IX, IY, PC, SP, R,
AFs, BCs, DEs, HLs;
/* IFF and I registers, used on interrupts. */
byte IFF1, IFF2, I, halted;
char IM;
word IRequest;
/* the following is to take care of cycle counting */
int IPeriod, ICount, IBackup;
/* DecodingErrors = set this to 1 for debugging purposes in order
to trap undocumented or non implemented opcodes.
Trace = set this to 1 to start tracing. It's also set
when PC reaches TrapAddress value. */
byte DecodingErrors;
word TrapAddress;
byte Trace, dobreak;
byte BorderColor;
} Z80Regs;
/*====================================================================
Function declarations, read the .c file to know what they do.
===================================================================*/
void Z80Reset( register Z80Regs *regs, int );
void Z80Interrupt( register Z80Regs *, register word );
word Z80Run( register Z80Regs *, int );
byte Z80MemRead( register word, Z80Regs * );
void Z80MemWrite( register word, register byte, Z80Regs * );
byte Z80InPort( register word );
void Z80OutPort( register Z80Regs *regs, register word, register byte );
void Z80Patch( register Z80Regs * );
byte Z80Debug( register Z80Regs * );
word Z80Hardware( register Z80Regs * );
void Z80FlagTables(void);
word ParseOpcode( char *, char *, char *, word, Z80Regs * );
word Z80Dissasembler ( Z80Regs *, char *, char * );
#endif