disas.c

/*
 * Z80 disassembler for	Z80-CPU	simulator
 *
 * Copyright (C) 1989-2007 by Udo Munk
 *
 * History:
 * 28-SEP-87 Development on TARGON/35 with AT&T Unix System V.3
 * 11-JAN-89 Release 1.1
 * 08-FEB-89 Release 1.2
 * 13-MAR-89 Release 1.3
 * 09-FEB-90 Release 1.4  Ported to TARGON/31 M10/30
 * 20-DEC-90 Release 1.5  Ported to COHERENT 3.0
 * 10-JUN-92 Release 1.6  long casting problem solved with COHERENT 3.2
 *			  and some optimization
 * 25-JUN-92 Release 1.7  comments in english and ported to COHERENT 4.0
 * 02-OCT-06 Release 1.8  modified to compile on modern POSIX OS's
 * 18-NOV-06 Release 1.9  modified to work with CP/M sources
 * 08-DEC-06 Release 1.10 modified MMU for working with CP/NET
 * 17-DEC-06 Release 1.11 TCP/IP sockets for CP/NET
 * 25-DEC-06 Release 1.12 CPU speed option
 * 19-FEB-07 Release 1.13 various improvements
 */

#include <stdio.h>

/*
 *	Forward	declarations
 */
static int opout(char *, char **);
static int nout(char *, unsigned char **);
static int iout(char *, unsigned char **);
static int rout(char *, char **);
static int nnout(char *, unsigned char **);
static int inout(char *, unsigned char **);
static int cbop(char *, unsigned char **);
static int edop(char *, unsigned char **);
static int ddfd(char *, unsigned char **);

/*
 *	Op-code	tables
 */
struct opt {
	int (*fun) ();
	char *text;
};

static struct opt optab[256] = {
	{ opout,  "NOP"			},	/* 0x00	*/
	{ nnout,  "LD\tBC,"		},	/* 0x01	*/
	{ opout,  "LD\t(BC),A"		},	/* 0x02	*/
	{ opout,  "INC\tBC"		},	/* 0x03	*/
	{ opout,  "INC\tB"		},	/* 0x04	*/
	{ opout,  "DEC\tB"		},	/* 0x05	*/
	{ nout,	  "LD\tB,"		},	/* 0x06	*/
	{ opout,  "RLCA"		},	/* 0x07	*/
	{ opout,  "EX\tAF,AF'"		},	/* 0x08	*/
	{ opout,  "ADD\tHL,BC"		},	/* 0x09	*/
	{ opout,  "LD\tA,(BC)"		},	/* 0x0a	*/
	{ opout,  "DEC\tBC"		},	/* 0x0b	*/
	{ opout,  "INC\tC"		},	/* 0x0c	*/
	{ opout,  "DEC\tC"		},	/* 0x0d	*/
	{ nout,	  "LD\tC,"		},	/* 0x0e	*/
	{ opout,  "RRCA"		},	/* 0x0f	*/
	{ rout,	  "DJNZ\t"		},	/* 0x10	*/
	{ nnout,  "LD\tDE,"		},	/* 0x11	*/
	{ opout,  "LD\t(DE),A"		},	/* 0x12	*/
	{ opout,  "INC\tDE"		},	/* 0x13	*/
	{ opout,  "INC\tD"		},	/* 0x14	*/
	{ opout,  "DEC\tD"		},	/* 0x15	*/
	{ nout,	  "LD\tD,"		},	/* 0x16	*/
	{ opout,  "RLA"			},	/* 0x17	*/
	{ rout,	  "JR\t"		},	/* 0x18	*/
	{ opout,  "ADD\tHL,DE"		},	/* 0x19	*/
	{ opout,  "LD\tA,(DE)"		},	/* 0x1a	*/
	{ opout,  "DEC\tDE"		},	/* 0x1b	*/
	{ opout,  "INC\tE"		},	/* 0x1c	*/
	{ opout,  "DEC\tE"		},	/* 0x1d	*/
	{ nout,	  "LD\tE,"		},	/* 0x1e	*/
	{ opout,  "RRA"			},	/* 0x1f	*/
	{ rout,	  "JR\tNZ,"		},	/* 0x20	*/
	{ nnout,  "LD\tHL,"		},	/* 0x21	*/
	{ inout,  "LD\t(%04x),HL"	},	/* 0x22	*/
	{ opout,  "INC\tHL"		},	/* 0x23	*/
	{ opout,  "INC\tH"		},	/* 0x24	*/
	{ opout,  "DEC\tH"		},	/* 0x25	*/
	{ nout,	  "LD\tH,"		},	/* 0x26	*/
	{ opout,  "DAA"			},	/* 0x27	*/
	{ rout,	  "JR\tZ,"		},	/* 0x28	*/
	{ opout,  "ADD\tHL,HL"		},	/* 0x29	*/
	{ inout,  "LD\tHL,(%04x)"	},	/* 0x2a	*/
	{ opout,  "DEC\tHL"		},	/* 0x2b	*/
	{ opout,  "INC\tL"		},	/* 0x2c	*/
	{ opout,  "DEC\tL"		},	/* 0x2d	*/
	{ nout,	  "LD\tL,"		},	/* 0x2e	*/
	{ opout,  "CPL"			},	/* 0x2f	*/
	{ rout,	  "JR\tNC,"		},	/* 0x30	*/
	{ nnout,  "LD\tSP,"		},	/* 0x31	*/
	{ inout,  "LD\t(%04x),A"	},	/* 0x32	*/
	{ opout,  "INC\tSP"		},	/* 0x33	*/
	{ opout,  "INC\t(HL)"		},	/* 0x34	*/
	{ opout,  "DEC\t(HL)"		},	/* 0x35	*/
	{ nout,	  "LD\t(HL),"		},	/* 0x36	*/
	{ opout,  "SCF"			},	/* 0x37	*/
	{ rout,	  "JR\tC,"		},	/* 0x38	*/
	{ opout,  "ADD\tHL,SP"		},	/* 0x39	*/
	{ inout,  "LD\tA,(%04x)"	},	/* 0x3a	*/
	{ opout,  "DEC\tSP"		},	/* 0x3b	*/
	{ opout,  "INC\tA"		},	/* 0x3c	*/
	{ opout,  "DEC\tA"		},	/* 0x3d	*/
	{ nout,	  "LD\tA,"		},	/* 0x3e	*/
	{ opout,  "CCF"			},	/* 0x3f	*/
	{ opout,  "LD\tB,B"		},	/* 0x40	*/
	{ opout,  "LD\tB,C"		},	/* 0x41	*/
	{ opout,  "LD\tB,D"		},	/* 0x42	*/
	{ opout,  "LD\tB,E"		},	/* 0x43	*/
	{ opout,  "LD\tB,H"		},	/* 0x44	*/
	{ opout,  "LD\tB,L"		},	/* 0x45	*/
	{ opout,  "LD\tB,(HL)"		},	/* 0x46	*/
	{ opout,  "LD\tB,A"		},	/* 0x47	*/
	{ opout,  "LD\tC,B"		},	/* 0x48	*/
	{ opout,  "LD\tC,C"		},	/* 0x49	*/
	{ opout,  "LD\tC,D"		},	/* 0x4a	*/
	{ opout,  "LD\tC,E"		},	/* 0x4b	*/
	{ opout,  "LD\tC,H"		},	/* 0x4c	*/
	{ opout,  "LD\tC,L"		},	/* 0x4d	*/
	{ opout,  "LD\tC,(HL)"		},	/* 0x4e	*/
	{ opout,  "LD\tC,A"		},	/* 0x4f	*/
	{ opout,  "LD\tD,B"		},	/* 0x50	*/
	{ opout,  "LD\tD,C"		},	/* 0x51	*/
	{ opout,  "LD\tD,D"		},	/* 0x52	*/
	{ opout,  "LD\tD,E"		},	/* 0x53	*/
	{ opout,  "LD\tD,H"		},	/* 0x54	*/
	{ opout,  "LD\tD,L"		},	/* 0x55	*/
	{ opout,  "LD\tD,(HL)"		},	/* 0x56	*/
	{ opout,  "LD\tD,A"		},	/* 0x57	*/
	{ opout,  "LD\tE,B"		},	/* 0x58	*/
	{ opout,  "LD\tE,C"		},	/* 0x59	*/
	{ opout,  "LD\tE,D"		},	/* 0x5a	*/
	{ opout,  "LD\tE,E"		},	/* 0x5b	*/
	{ opout,  "LD\tE,H"		},	/* 0x5c	*/
	{ opout,  "LD\tE,L"		},	/* 0x5d	*/
	{ opout,  "LD\tE,(HL)"		},	/* 0x5e	*/
	{ opout,  "LD\tE,A"		},	/* 0x5f	*/
	{ opout,  "LD\tH,B"		},	/* 0x60	*/
	{ opout,  "LD\tH,C"		},	/* 0x61	*/
	{ opout,  "LD\tH,D"		},	/* 0x62	*/
	{ opout,  "LD\tH,E"		},	/* 0x63	*/
	{ opout,  "LD\tH,H"		},	/* 0x64	*/
	{ opout,  "LD\tH,L"		},	/* 0x65	*/
	{ opout,  "LD\tH,(HL)"		},	/* 0x66	*/
	{ opout,  "LD\tH,A"		},	/* 0x67	*/
	{ opout,  "LD\tL,B"		},	/* 0x68	*/
	{ opout,  "LD\tL,C"		},	/* 0x69	*/
	{ opout,  "LD\tL,D"		},	/* 0x6a	*/
	{ opout,  "LD\tL,E"		},	/* 0x6b	*/
	{ opout,  "LD\tL,H"		},	/* 0x6c	*/
	{ opout,  "LD\tL,L"		},	/* 0x6d	*/
	{ opout,  "LD\tL,(HL)"		},	/* 0x6e	*/
	{ opout,  "LD\tL,A"		},	/* 0x6f	*/
	{ opout,  "LD\t(HL),B"		},	/* 0x70	*/
	{ opout,  "LD\t(HL),C"		},	/* 0x71	*/
	{ opout,  "LD\t(HL),D"		},	/* 0x72	*/
	{ opout,  "LD\t(HL),E"		},	/* 0x73	*/
	{ opout,  "LD\t(HL),H"		},	/* 0x74	*/
	{ opout,  "LD\t(HL),L"		},	/* 0x75	*/
	{ opout,  "HALT"		},	/* 0x76	*/
	{ opout,  "LD\t(HL),A"		},	/* 0x77	*/
	{ opout,  "LD\tA,B"		},	/* 0x78	*/
	{ opout,  "LD\tA,C"		},	/* 0x79	*/
	{ opout,  "LD\tA,D"		},	/* 0x7a	*/
	{ opout,  "LD\tA,E"		},	/* 0x7b	*/
	{ opout,  "LD\tA,H"		},	/* 0x7c	*/
	{ opout,  "LD\tA,L"		},	/* 0x7d	*/
	{ opout,  "LD\tA,(HL)"		},	/* 0x7e	*/
	{ opout,  "LD\tA,A"		},	/* 0x7f	*/
	{ opout,  "ADD\tA,B"		},	/* 0x80	*/
	{ opout,  "ADD\tA,C"		},	/* 0x81	*/
	{ opout,  "ADD\tA,D"		},	/* 0x82	*/
	{ opout,  "ADD\tA,E"		},	/* 0x83	*/
	{ opout,  "ADD\tA,H"		},	/* 0x84	*/
	{ opout,  "ADD\tA,L"		},	/* 0x85	*/
	{ opout,  "ADD\tA,(HL)"		},	/* 0x86	*/
	{ opout,  "ADD\tA,A"		},	/* 0x87	*/
	{ opout,  "ADC\tA,B"		},	/* 0x88	*/
	{ opout,  "ADC\tA,C"		},	/* 0x89	*/
	{ opout,  "ADC\tA,D"		},	/* 0x8a	*/
	{ opout,  "ADC\tA,E"		},	/* 0x8b	*/
	{ opout,  "ADC\tA,H"		},	/* 0x8c	*/
	{ opout,  "ADC\tA,L"		},	/* 0x8d	*/
	{ opout,  "ADC\tA,(HL)"		},	/* 0x8e	*/
	{ opout,  "ADC\tA,A"		},	/* 0x8f	*/
	{ opout,  "SUB\tB"		},	/* 0x90	*/
	{ opout,  "SUB\tC"		},	/* 0x91	*/
	{ opout,  "SUB\tD"		},	/* 0x92	*/
	{ opout,  "SUB\tE"		},	/* 0x93	*/
	{ opout,  "SUB\tH"		},	/* 0x94	*/
	{ opout,  "SUB\tL"		},	/* 0x95	*/
	{ opout,  "SUB\t(HL)"		},	/* 0x96	*/
	{ opout,  "SUB\tA"		},	/* 0x97	*/
	{ opout,  "SBC\tA,B"		},	/* 0x98	*/
	{ opout,  "SBC\tA,C"		},	/* 0x99	*/
	{ opout,  "SBC\tA,D"		},	/* 0x9a	*/
	{ opout,  "SBC\tA,E"		},	/* 0x9b	*/
	{ opout,  "SBC\tA,H"		},	/* 0x9c	*/
	{ opout,  "SBC\tA,L"		},	/* 0x9d	*/
	{ opout,  "SBC\tA,(HL)"		},	/* 0x9e	*/
	{ opout,  "SBC\tA,A"		},	/* 0x9f	*/
	{ opout,  "AND\tB"		},	/* 0xa0	*/
	{ opout,  "AND\tC"		},	/* 0xa1	*/
	{ opout,  "AND\tD"		},	/* 0xa2	*/
	{ opout,  "AND\tE"		},	/* 0xa3	*/
	{ opout,  "AND\tH"		},	/* 0xa4	*/
	{ opout,  "AND\tL"		},	/* 0xa5	*/
	{ opout,  "AND\t(HL)"		},	/* 0xa6	*/
	{ opout,  "AND\tA"		},	/* 0xa7	*/
	{ opout,  "XOR\tB"		},	/* 0xa8	*/
	{ opout,  "XOR\tC"		},	/* 0xa9	*/
	{ opout,  "XOR\tD"		},	/* 0xaa	*/
	{ opout,  "XOR\tE"		},	/* 0xab	*/
	{ opout,  "XOR\tH"		},	/* 0xac	*/
	{ opout,  "XOR\tL"		},	/* 0xad	*/
	{ opout,  "XOR\t(HL)"		},	/* 0xae	*/
	{ opout,  "XOR\tA"		},	/* 0xaf	*/
	{ opout,  "OR\tB"		},	/* 0xb0	*/
	{ opout,  "OR\tC"		},	/* 0xb1	*/
	{ opout,  "OR\tD"		},	/* 0xb2	*/
	{ opout,  "OR\tE"		},	/* 0xb3	*/
	{ opout,  "OR\tH"		},	/* 0xb4	*/
	{ opout,  "OR\tL"		},	/* 0xb5	*/
	{ opout,  "OR\t(HL)"		},	/* 0xb6	*/
	{ opout,  "OR\tA"		},	/* 0xb7	*/
	{ opout,  "CP\tB"		},	/* 0xb8	*/
	{ opout,  "CP\tC"		},	/* 0xb9	*/
	{ opout,  "CP\tD"		},	/* 0xba	*/
	{ opout,  "CP\tE"		},	/* 0xbb	*/
	{ opout,  "CP\tH"		},	/* 0xbc	*/
	{ opout,  "CP\tL"		},	/* 0xbd	*/
	{ opout,  "CP\t(HL)"		},	/* 0xbe	*/
	{ opout,  "CP\tA"		},	/* 0xbf	*/
	{ opout,  "RET\tNZ"		},	/* 0xc0	*/
	{ opout,  "POP\tBC"		},	/* 0xc1	*/
	{ nnout,  "JP\tNZ,"		},	/* 0xc2	*/
	{ nnout,  "JP\t"		},	/* 0xc3	*/
	{ nnout,  "CALL\tNZ,"		},	/* 0xc4	*/
	{ opout,  "PUSH\tBC"		},	/* 0xc5	*/
	{ nout,	  "ADD\tA,"		},	/* 0xc6	*/
	{ opout,  "RST\t0"		},	/* 0xc7	*/
	{ opout,  "RET\tZ"		},	/* 0xc8	*/
	{ opout,  "RET"			},	/* 0xc9	*/
	{ nnout,  "JP\tZ,"		},	/* 0xca	*/
	{ cbop,	  ""			},	/* 0xcb	*/
	{ nnout,  "CALL\tZ,"		},	/* 0xcc	*/
	{ nnout,  "CALL\t"		},	/* 0xcd	*/
	{ nout,	  "ADC\tA,"		},	/* 0xce	*/
	{ opout,  "RST\t8"		},	/* 0xcf	*/
	{ opout,  "RET\tNC"		},	/* 0xd0	*/
	{ opout,  "POP\tDE"		},	/* 0xd1	*/
	{ nnout,  "JP\tNC,"		},	/* 0xd2	*/
	{ iout,	  "OUT\t(%02x),A"	},	/* 0xd3	*/
	{ nnout,  "CALL\tNC,"		},	/* 0xd4	*/
	{ opout,  "PUSH\tDE"		},	/* 0xd5	*/
	{ nout,	  "SUB\t"		},	/* 0xd6	*/
	{ opout,  "RST\t10"		},	/* 0xd7	*/
	{ opout,  "RET\tC"		},	/* 0xd8	*/
	{ opout,  "EXX"			},	/* 0xd9	*/
	{ nnout,  "JP\tC,"		},	/* 0xda	*/
	{ iout,	  "IN\tA,(%02x)"	},	/* 0xdb	*/
	{ nnout,  "CALL\tC,"		},	/* 0xdc	*/
	{ ddfd,	  ""			},	/* 0xdd	*/
	{ nout,	  "SBC\tA,"		},	/* 0xde	*/
	{ opout,  "RST\t18"		},	/* 0xdf	*/
	{ opout,  "RET\tPO"		},	/* 0xe0	*/
	{ opout,  "POP\tHL"		},	/* 0xe1	*/
	{ nnout,  "JP\tPO,"		},	/* 0xe2	*/
	{ opout,  "EX\t(SP),HL"		},	/* 0xe3	*/
	{ nnout,  "CALL\tPO,"		},	/* 0xe4	*/
	{ opout,  "PUSH\tHL"		},	/* 0xe5	*/
	{ nout,	  "AND\t"		},	/* 0xe6	*/
	{ opout,  "RST\t20"		},	/* 0xe7	*/
	{ opout,  "RET\tPE"		},	/* 0xe8	*/
	{ opout,  "JP\t(HL)"		},	/* 0xe9	*/
	{ nnout,  "JP\tPE,"		},	/* 0xea	*/
	{ opout,  "EX\tDE,HL"		},	/* 0xeb	*/
	{ nnout,  "CALL\tPE,"		},	/* 0xec	*/
	{ edop,	  ""			},	/* 0xed	*/
	{ nout,	  "XOR\t"		},	/* 0xee	*/
	{ opout,  "RST\t28"		},	/* 0xef	*/
	{ opout,  "RET\tP"		},	/* 0xf0	*/
	{ opout,  "POP\tAF"		},	/* 0xf1	*/
	{ nnout,  "JP\tP,"		},	/* 0xf2	*/
	{ opout,  "DI"			},	/* 0xf3	*/
	{ nnout,  "CALL\tP,"		},	/* 0xf4	*/
	{ opout,  "PUSH\tAF"		},	/* 0xf5	*/
	{ nout,	  "OR\t"		},	/* 0xf6	*/
	{ opout,  "RST\t30"		},	/* 0xf7	*/
	{ opout,  "RET\tM"		},	/* 0xf8	*/
	{ opout,  "LD\tSP,HL"		},	/* 0xf9	*/
	{ nnout,  "JP\tM,"		},	/* 0xfa	*/
	{ opout,  "EI"			},	/* 0xfb	*/
	{ nnout,  "CALL\tM,"		},	/* 0xfc	*/
	{ ddfd,	  ""			},	/* 0xfd	*/
	{ nout,	  "CP\t"		},	/* 0xfe	*/
	{ opout,  "RST\t38"		}	/* 0xff	*/
};

static int addr;
static char *unkown = "???";
static char *reg[] = { "B", "C", "D", "E", "H",	"L", "(HL)", "A" };
static char *regix = "IX";
static char *regiy = "IY";

/*
 *	The function disass() is the only global function of
 *	this module. The first argument is a pointer to a
 *	unsigned char pointer, which points to the op-code
 *	to disassemble. The output of the disassembly goes
 *	to stdout, terminated by a newline. After the
 *	disassembly the pointer to the op-code will be
 *	increased by the size of the op-code, so that
 *	disass() can be called again.
 *	The second argument is the (Z80) address of the
 *	op-code to disassemble. It is used to calculate the
 *	destination address of relative jumps.
 */
void disass(unsigned char **p, int adr)
{
	register int len;

	addr = adr;
	len = (*optab[**p].fun)	(optab[**p].text, p);
	*p += len;
}

/*
 *	disassemble 1 byte op-codes
 */
static int opout(char *s, char **p)
{
	puts(s);
	return(1);
}

/*
 *	disassemble 2 byte op-codes of type "Op n"
 */
static int nout(char *s, unsigned char **p)
{
	printf("%s%02x\n", s, *(*p + 1));
	return(2);
}

/*
 *	disassemble 2 byte op-codes with indirect addressing
 */
static int iout(char *s, unsigned char **p)
{
	printf(s, *(*p + 1));
	putchar('\n');
	return(2);
}

/*
 *	disassemble 2 byte op-codes with relative addressing
 */
static int rout(char *s, char **p)
{
	printf("%s%04x\n", s, addr + *(*p + 1) + 2);
	return(2);
}

/*
 *	disassemble 3 byte op-codes of type "Op nn"
 */
static int nnout(char *s, unsigned char **p)
{
	register int i;

	i = *(*p + 1) +	(*(*p +	2) << 8);
	printf("%s%04x\n", s, i);
	return(3);
}

/*
 *	disassemble 3 byte op-codes with indirect addressing
 */
static int inout(char *s, unsigned char **p)
{
	register int i;

	i = *(*p + 1) +	(*(*p +	2) << 8);
	printf(s, i);
	putchar('\n');
	return(3);
}

/*
 *	disassemble multi byte op-codes with prefix 0xcb
 */
static int cbop(char *s, unsigned char **p)
{
	register int b2;

	b2 = *(*p + 1);
	if (b2 >= 0x00 && b2 <=	0x07) {
		printf("RLC\t");
		printf("%s\n", reg[b2 &	7]);
		return(2);
	}
	if (b2 >= 0x08 && b2 <=	0x0f) {
		printf("RRC\t");
		printf("%s\n", reg[b2 &	7]);
		return(2);
	}
	if (b2 >= 0x10 && b2 <=	0x17) {
		printf("RL\t");
		printf("%s\n", reg[b2 &	7]);
		return(2);
	}
	if (b2 >= 0x18 && b2 <=	0x1f) {
		printf("RR\t");
		printf("%s\n", reg[b2 &	7]);
		return(2);
	}
	if (b2 >= 0x20 && b2 <=	0x27) {
		printf("SLA\t");
		printf("%s\n", reg[b2 &	7]);
		return(2);
	}
	if (b2 >= 0x28 && b2 <=	0x2f) {
		printf("SRA\t");
		printf("%s\n", reg[b2 &	7]);
		return(2);
	}
	if (b2 >= 0x38 && b2 <=	0x3f) {
		printf("SRL\t");
		printf("%s\n", reg[b2 &	7]);
		return(2);
	}
	if (b2 >= 0x40 && b2 <=	0x7f) {
		printf("BIT\t");
		printf("%c,", ((b2 >> 3) & 7) +	'0');
		printf("%s\n", reg[b2 &	7]);
		return(2);
	}
	if (b2 >= 0x80 && b2 <=	0xbf) {
		printf("RES\t");
		printf("%c,", ((b2 >> 3) & 7) +	'0');
		printf("%s\n", reg[b2 &	7]);
		return(2);
	}
	if (b2 >= 0xc0)	{
		printf("SET\t");
		printf("%c,", ((b2 >> 3) & 7) +	'0');
		printf("%s\n", reg[b2 &	7]);
		return(2);
	}
	puts(unkown);
	return(2);
}

/*
 *	disassemble multi byte op-codes with prefix 0xed
 */
static int edop(char *s, unsigned char **p)
{
	register int b2, i;
	int len	= 2;

	b2 = *(*p + 1);
	switch (b2) {
	case 0x40:
		puts("IN\tB,(C)");
		break;
	case 0x41:
		puts("OUT\t(C),B");
		break;
	case 0x42:
		puts("SBC\tHL,BC");
		break;
	case 0x43:
		i = *(*p + 2) +	(*(*p +	3) << 8);
		printf("LD\t(%04x),BC\n", i);
		len = 4;
		break;
	case 0x44:
		puts("NEG");
		break;
	case 0x45:
		puts("RETN");
		break;
	case 0x46:
		puts("IM\t0");
		break;
	case 0x47:
		puts("LD\tI,A");
		break;
	case 0x48:
		puts("IN\tC,(C)");
		break;
	case 0x49:
		puts("OUT\t(C),C");
		break;
	case 0x4a:
		puts("ADC\tHL,BC");
		break;
	case 0x4b:
		i = *(*p + 2) +	(*(*p +	3) << 8);
		printf("LD\tBC,(%04x)\n", i);
		len = 4;
		break;
	case 0x4d:
		puts("RETI");
		break;
	case 0x4f:
		puts("LD\tR,A");
		break;
	case 0x50:
		puts("IN\tD,(C)");
		break;
	case 0x51:
		puts("OUT\t(C),D");
		break;
	case 0x52:
		puts("SBC\tHL,DE");
		break;
	case 0x53:
		i = *(*p + 2) +	(*(*p +	3) << 8);
		printf("LD\t(%04x),DE\n", i);
		len = 4;
		break;
	case 0x56:
		puts("IM\t1");
		break;
	case 0x57:
		puts("LD\tA,I");
		break;
	case 0x58:
		puts("IN\tE,(C)");
		break;
	case 0x59:
		puts("OUT\t(C),E");
		break;
	case 0x5a:
		puts("ADC\tHL,DE");
		break;
	case 0x5b:
		i = *(*p + 2) +	(*(*p +	3) << 8);
		printf("LD\tDE,(%04x)\n", i);
		len = 4;
		break;
	case 0x5e:
		puts("IM\t2");
		break;
	case 0x5f:
		puts("LD\tA,R");
		break;
	case 0x60:
		puts("IN\tH,(C)");
		break;
	case 0x61:
		puts("OUT\t(C),H");
		break;
	case 0x62:
		puts("SBC\tHL,HL");
		break;
	case 0x67:
		puts("RRD");
		break;
	case 0x68:
		puts("IN\tL,(C)");
		break;
	case 0x69:
		puts("OUT\t(C),L");
		break;
	case 0x6a:
		puts("ADC\tHL,HL");
		break;
	case 0x6f:
		puts("RLD");
		break;
	case 0x72:
		puts("SBC\tHL,SP");
		break;
	case 0x73:
		i = *(*p + 2) +	(*(*p +	3) << 8);
		printf("LD\t(%04x),SP\n", i);
		len = 4;
		break;
	case 0x78:
		puts("IN\tA,(C)");
		break;
	case 0x79:
		puts("OUT\t(C),A");
		break;
	case 0x7a:
		puts("ADC\tHL,SP");
		break;
	case 0x7b:
		i = *(*p + 2) +	(*(*p +	3) << 8);
		printf("LD\tSP,(%04x)\n", i);
		len = 4;
		break;
	case 0xa0:
		puts("LDI");
		break;
	case 0xa1:
		puts("CPI");
		break;
	case 0xa2:
		puts("INI");
		break;
	case 0xa3:
		puts("OUTI");
		break;
	case 0xa8:
		puts("LDD");
		break;
	case 0xa9:
		puts("CPD");
		break;
	case 0xaa:
		puts("IND");
		break;
	case 0xab:
		puts("OUTD");
		break;
	case 0xb0:
		puts("LDIR");
		break;
	case 0xb1:
		puts("CPIR");
		break;
	case 0xb2:
		puts("INIR");
		break;
	case 0xb3:
		puts("OTIR");
		break;
	case 0xb8:
		puts("LDDR");
		break;
	case 0xb9:
		puts("CPDR");
		break;
	case 0xba:
		puts("INDR");
		break;
	case 0xbb:
		puts("OTDR");
		break;
	default:
		puts(unkown);
	}
	return(len);
}

/*
 *	disassemble multi byte op-codes with prefix 0xdd and 0xfd
 */
static int ddfd(char *s, unsigned char **p)
{
	register int b2;
	register char *ireg;
	int len	= 3;

	if (**p	== 0xdd)
		ireg = regix;
	else
		ireg = regiy;
	b2 = *(*p + 1);
	if (b2 >= 0x70 && b2 <=	0x77) {
		printf("LD\t(%s+%02x),%s\n", ireg, *(*p	+ 2), reg[b2 & 7]);
		return(3);
	}
	switch (b2) {
	case 0x09:
		printf("ADD\t%s,BC\n", ireg);
		len = 2;
		break;
	case 0x19:
		printf("ADD\t%s,DE\n", ireg);
		len = 2;
		break;
	case 0x21:
		printf("LD\t%s,%04x\n",	ireg, *(*p + 2)	+ (*(*p	+ 3) <<	8));
		len = 4;
		break;
	case 0x22:
		printf("LD\t(%04x),%s\n", *(*p + 2) + (*(*p + 3) << 8),	ireg);
		len = 4;
		break;
	case 0x23:
		printf("INC\t%s\n", ireg);
		len = 2;
		break;
	case 0x29:
		if (**p	== 0xdd)
			printf("ADD\tIX,IX\n");
		else
			printf("ADD\tIY,IY\n");
		len = 2;
		break;
	case 0x2a:
		printf("LD\t%s,(%04x)\n", ireg,	*(*p + 2) + (*(*p + 3) << 8));
		len = 4;
		break;
	case 0x2b:
		printf("DEC\t%s\n", ireg);
		len = 2;
		break;
	case 0x34:
		printf("INC\t(%s+%02x)\n", ireg, *(*p +	2));
		break;
	case 0x35:
		printf("DEC\t(%s+%02x)\n", ireg, *(*p +	2));
		break;
	case 0x36:
		printf("LD\t(%s+%02x),%02x\n", ireg, *(*p + 2),	*(*p + 3));
		len = 4;
		break;
	case 0x39:
		printf("ADD\t%s,SP\n", ireg);
		len = 2;
		break;
	case 0x46:
		printf("LD\tB,(%s+%02x)\n", ireg, *(*p + 2));
		break;
	case 0x4e:
		printf("LD\tC,(%s+%02x)\n", ireg, *(*p + 2));
		break;
	case 0x56:
		printf("LD\tD,(%s+%02x)\n", ireg, *(*p + 2));
		break;
	case 0x5e:
		printf("LD\tE,(%s+%02x)\n", ireg, *(*p + 2));
		break;
	case 0x66:
		printf("LD\tH,(%s+%02x)\n", ireg, *(*p + 2));
		break;
	case 0x6e:
		printf("LD\tL,(%s+%02x)\n", ireg, *(*p + 2));
		break;
	case 0x7e:
		printf("LD\tA,(%s+%02x)\n", ireg, *(*p + 2));
		break;
	case 0x86:
		printf("ADD\tA,(%s+%02x)\n", ireg, *(*p	+ 2));
		break;
	case 0x8e:
		printf("ADC\tA,(%s+%02x)\n", ireg, *(*p	+ 2));
		break;
	case 0x96:
		printf("SUB\t(%s+%02x)\n", ireg, *(*p +	2));
		break;
	case 0x9e:
		printf("SBC\tA,(%s+%02x)\n", ireg, *(*p	+ 2));
		break;
	case 0xa6:
		printf("AND\t(%s+%02x)\n", ireg, *(*p +	2));
		break;
	case 0xae:
		printf("XOR\t(%s+%02x)\n", ireg, *(*p +	2));
		break;
	case 0xb6:
		printf("OR\t(%s+%02x)\n", ireg,	*(*p + 2));
		break;
	case 0xbe:
		printf("CP\t(%s+%02x)\n", ireg,	*(*p + 2));
		break;
	case 0xcb:
		switch (*(*p + 3)) {
		case 0x06:
			printf("RLC\t(%s+%02x)\n", ireg, *(*p +	2));
			break;
		case 0x0e:
			printf("RRC\t(%s+%02x)\n", ireg, *(*p +	2));
			break;
		case 0x16:
			printf("RL\t(%s+%02x)\n", ireg,	*(*p + 2));
			break;
		case 0x1e:
			printf("RR\t(%s+%02x)\n", ireg,	*(*p + 2));
			break;
		case 0x26:
			printf("SLA\t(%s+%02x)\n", ireg, *(*p +	2));
			break;
		case 0x2e:
			printf("SRA\t(%s+%02x)\n", ireg, *(*p +	2));
			break;
		case 0x3e:
			printf("SRL\t(%s+%02x)\n", ireg, *(*p +	2));
			break;
		case 0x46:
			printf("BIT\t0,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0x4e:
			printf("BIT\t1,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0x56:
			printf("BIT\t2,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0x5e:
			printf("BIT\t3,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0x66:
			printf("BIT\t4,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0x6e:
			printf("BIT\t5,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0x76:
			printf("BIT\t6,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0x7e:
			printf("BIT\t7,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0x86:
			printf("RES\t0,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0x8e:
			printf("RES\t1,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0x96:
			printf("RES\t2,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0x9e:
			printf("RES\t3,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0xa6:
			printf("RES\t4,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0xae:
			printf("RES\t5,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0xb6:
			printf("RES\t6,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0xbe:
			printf("RES\t7,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0xc6:
			printf("SET\t0,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0xce:
			printf("SET\t1,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0xd6:
			printf("SET\t2,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0xde:
			printf("SET\t3,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0xe6:
			printf("SET\t4,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0xee:
			printf("SET\t5,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0xf6:
			printf("SET\t6,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		case 0xfe:
			printf("SET\t7,(%s+%02x)\n", ireg, *(*p	+ 2));
			break;
		default:
			puts(unkown);
		}
		len = 4;
		break;
	case 0xe1:
		printf("POP\t%s\n", ireg);
		len = 2;
		break;
	case 0xe3:
		printf("EX\t(SP),%s\n",	ireg);
		len = 2;
		break;
	case 0xe5:
		printf("PUSH\t%s\n", ireg);
		len = 2;
		break;
	case 0xe9:
		printf("JP\t(%s)\n", ireg);
		len = 2;
		break;
	case 0xf9:
		printf("LD\tSP,%s\n", ireg);
		len = 2;
		break;
	default:
		puts(unkown);
	}
	return(len);
}