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disassem.c
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disassem.c
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/*-----------------------------------------------------------------------*\
| disassem.c -- Z80 disassembler |
| |
| Originally by T.J. Merritt but modified and debugged to run in the |
| Z80 emulator instead of being standalone. |
| |
| Copyright 1986-1988 by Parag Patel. All Rights Reserved. |
| Copyright 1994-1995 by CodeGen, Inc. All Rights Reserved. |
\*-----------------------------------------------------------------------*/
#include "defs.h"
#include <stdio.h>
#include <string.h>
#define bits(l, r) (((z80->mem[loc]) >> (r)) & mask[(l) - (r)])
#define put_cc(cc) put_str(cc_names[cc])
#define OPC_LD "LD "
#define OPC_INC "INC "
#define OPC_DEC "DEC "
#define OPC_ADD "ADD "
#define OPC_RET "RET "
#define OPC_POP "POP "
#define OPC_EXX "EXX "
#define OPC_JP "JP "
#define OPC_OUT "OUT "
#define OPC_IN "IN "
#define OPC_EX "EX "
#define OPC_DI "DI "
#define OPC_EI "EI "
#define OPC_CALL "CALL "
#define OPC_PUSH "PUSH "
#define OPC_ILLEGAL "***"
#define OPC_RST "RST "
static int mask[] = {0x001, 0x003, 0x007, 0x00F, 0x01F, 0x03F, 0x07F, 0x0FF};
static char *rr_names[] = {"B", "C", "D", "E", "H", "L", "(HL)", "A"};
static char *dd_names[] = {"BC", "DE", "HL", "SP"};
static char *qq_names[] = {"BC", "DE", "HL", "AF"};
static char *cc_names[] = {"NZ", "Z", "NC", "C", "PO", "PE", "P", "M"};
static char *op_names[] = {
"ADD A,", "ADC A,", "SUB ", "SBC A,", "AND ", "XOR ", "OR ", "CP ",
};
static char *jr_op_names[] = {0, 0, "DJNZ ", "JR ", "JR NZ,", "JR Z,", "JR NC,", "JR C,"};
static char *log_op_names[] = {"RLCA", "RRCA", "RLA", "RRA", "DAA", "CPL", "SCF", "CCF"};
static char *shf_op_names[] = {"RLC ", "RRC ", "RL ", "RR ", "SLA ", "SRA ", "SLL? ", "SRL "};
static char *bit_op_names[] = {
0,
"BIT ",
"RES ",
"SET ",
};
static char *rep_op_names[] = {"LDI", "CPI", "INI", "OUTI", "LDD", "CPD", "IND", "OUTD", "LDIR", "CPIR", "INIR", "OTIR", "LDDR", "CPDR", "INDR", "OTDR"};
static char *index_reg;
static int str_length;
static FILE *fp;
static void put_byte(byte b) {
fprintf(fp, "%02X", b & 0x0FF);
str_length += 2;
}
static void put_addr(z80info *z80, int loc) {
put_byte(z80->mem[loc]);
put_byte(z80->mem[(loc - 1) & 0x0FFFF]);
}
static void put_word(word w) {
fprintf(fp, "%04X", w & 0x0FFFF);
str_length += 4;
}
static void put_digit(byte digit) {
fprintf(fp, "%01X", digit & 0x00F);
str_length += 1;
}
static void put_char(char ch) {
putc(ch, fp);
str_length += 1;
}
static void put_str(char *str) {
fprintf(fp, "%s", str);
str_length += strlen(str);
}
static void put_reg(z80info *z80, int reg_num, int loc) {
int d;
if (index_reg && (reg_num == 6)) {
put_str("(");
put_str(index_reg);
d = (signed char)z80->mem[loc + 1];
if (d < 0) {
put_str("-");
put_byte(-d);
} else {
put_str("+");
put_byte(d);
}
put_str(")");
} else {
put_str(rr_names[reg_num]);
}
}
static void put_dd_reg(int reg_num) {
if (index_reg) {
if (reg_num == 2)
put_str(index_reg);
else if (reg_num == 3)
put_str("SP");
else
put_str(OPC_ILLEGAL);
} else
put_str(dd_names[reg_num]);
}
static void put_qq_reg(int reg_num) {
if (index_reg) {
if (reg_num == 2)
put_str(index_reg);
else
put_str(OPC_ILLEGAL);
} else
put_str(qq_names[reg_num]);
}
int disassemlen(void) { return str_length; }
int disassem(z80info *z80, word start, FILE *file) {
word loc;
int byte_count;
byte last_byte;
loc = start;
byte_count = 0;
str_length = 0;
if (file != NULL) {
fp = file;
index_reg = NULL;
}
switch (bits(7, 6)) {
case 0:
switch (bits(3, 0)) {
case 0:
case 8:
if (bits(5, 3) == 0) {
put_str("NOP");
break;
}
if (bits(5, 3) == 1) {
put_str("EX AF,AF'");
break;
}
put_str(jr_op_names[bits(5, 3)]);
loc++;
byte_count++;
put_word((signed char)z80->mem[loc] + (int)loc + 1);
break;
case 1:
put_str(OPC_LD);
put_dd_reg(bits(5, 4));
put_char(',');
byte_count += 2;
loc += 2;
put_addr(z80, loc);
break;
case 2:
last_byte = z80->mem[loc];
put_str(OPC_LD);
switch (bits(5, 4)) {
case 0:
put_str("(BC)");
break;
case 1:
put_str("(DE)");
break;
case 2:
case 3:
put_char('(');
byte_count += 2;
loc += 2;
put_addr(z80, loc);
put_char(')');
break;
}
if ((last_byte & 0x030) == 0x020) {
put_char(',');
if (index_reg)
put_str(index_reg);
else
put_str("HL");
} else {
put_str(",A");
}
break;
case 3:
put_str(OPC_INC);
put_dd_reg(bits(5, 4));
break;
case 4:
case 0x0C:
put_str(OPC_INC);
put_reg(z80, bits(5, 3), loc);
break;
case 5:
case 0x0D:
put_str(OPC_DEC);
put_reg(z80, bits(5, 3), loc);
break;
case 6:
case 0x0E:
put_str(OPC_LD);
put_reg(z80, bits(5, 3), loc);
put_char(',');
if (index_reg && (bits(5, 3) == 6)) {
loc++;
byte_count++;
}
loc++;
byte_count++;
put_byte(z80->mem[loc]);
break;
case 7:
case 0x0F:
put_str(log_op_names[bits(5, 3)]);
break;
case 9:
put_str(OPC_ADD);
put_str("HL,");
put_dd_reg(bits(5, 4));
break;
case 0x0A:
put_str(OPC_LD);
if (bits(5, 4) == 2) {
if (index_reg) {
put_str(index_reg);
put_str(",");
} else
put_str("HL,");
} else {
put_str("A,");
}
switch (bits(5, 4)) {
case 0:
put_str("(BC)");
break;
case 1:
put_str("(DE)");
break;
case 2:
case 3:
put_char('(');
byte_count += 2;
loc += 2;
put_addr(z80, loc);
put_char(')');
break;
}
break;
case 0x0B:
put_str(OPC_DEC);
put_dd_reg(bits(5, 4));
break;
}
break;
case 1:
/* if ((bits(5,3) != 6) && (bits(2,0) != 6)) */
if (z80->mem[loc] == 0x76) {
put_str("HALT");
} else {
put_str(OPC_LD);
put_reg(z80, bits(5, 3), loc);
put_char(',');
put_reg(z80, bits(2, 0), loc);
}
break;
case 2:
put_str(op_names[bits(5, 3)]);
put_reg(z80, bits(2, 0), loc);
break;
case 3:
if (z80->mem[loc] == 0xCB) {
loc++;
byte_count++;
if (bits(7, 6) == 0) {
put_str(shf_op_names[bits(5, 3)]);
} else {
put_str(bit_op_names[bits(7, 6)]);
put_digit(bits(5, 3));
put_char(',');
}
put_reg(z80, bits(2, 0), loc);
break;
}
/*if ((z80->mem[loc] & 0x0DD) == 0x0DD)*/
if (z80->mem[loc] == 0xDD) {
if (bits(5, 5))
index_reg = "IY";
else
index_reg = "IX";
byte_count = disassem(z80, loc + 1, NULL);
loc += byte_count;
break;
}
if (z80->mem[loc] == 0xED) {
loc++;
byte_count++;
switch (bits(7, 6)) {
case 0:
put_str(OPC_ILLEGAL);
break;
case 1:
switch (bits(3, 0)) {
case 0:
case 8:
put_str("IN ");
put_reg(z80, bits(5, 3), loc);
put_str(",[C]");
break;
case 1:
case 9:
put_str("OUT [C],");
put_reg(z80, bits(5, 3), loc);
break;
case 2:
put_str("SBC HL,");
put_dd_reg(bits(5, 4));
break;
case 0xA:
put_str("ADC HL,");
put_dd_reg(bits(5, 4));
break;
case 3:
put_str(OPC_LD);
put_char('(');
put_addr(z80, loc + 2);
put_str("),");
put_dd_reg(bits(5, 4));
byte_count += 2;
loc += 2;
break;
case 0xB:
put_str(OPC_LD);
put_dd_reg(bits(5, 4));
put_str(",(");
byte_count += 2;
loc += 2;
put_addr(z80, loc);
put_char(')');
break;
case 4:
if (bits(5, 4) == 0)
put_str("NEG");
else
put_str(OPC_ILLEGAL);
break;
case 0xC:
put_str(OPC_ILLEGAL);
break;
case 5:
if (bits(5, 4) == 0)
put_str("RETN");
else
put_str(OPC_ILLEGAL);
break;
case 0xD:
if (bits(5, 4) == 0)
put_str("RETI");
else
put_str(OPC_ILLEGAL);
break;
case 6:
if (bits(5, 4) == 0)
put_str("IM 0");
else if (bits(5, 4) == 1)
put_str("IM 1");
else
put_str(OPC_ILLEGAL);
break;
case 0xE:
if (bits(5, 4) == 1)
put_str("IM 2");
else
put_str(OPC_ILLEGAL);
break;
case 7:
if (bits(5, 4) == 0)
put_str("LD I,A");
else if (bits(5, 4) == 1)
put_str("LD A,I");
else if (bits(5, 4) == 2)
put_str("RRD");
else
put_str(OPC_ILLEGAL);
break;
case 0xF:
if (bits(5, 4) == 0)
put_str("LD R,A");
else if (bits(5, 4) == 1)
put_str("LD A,R");
else if (bits(5, 4) == 2)
put_str("RLD");
else
put_str(OPC_ILLEGAL);
break;
}
break;
case 2:
if (bits(5, 5) == 0) {
put_str(OPC_ILLEGAL);
break;
}
if (bits(2, 2) == 1) {
put_str(OPC_ILLEGAL);
break;
}
put_str(rep_op_names[((z80->mem[loc] >> 1) & 0xC) | (z80->mem[loc] & 3)]);
break;
case 3:
put_str(OPC_ILLEGAL);
break;
}
break;
}
if ((z80->mem[loc] & 0x06) == 0x06) {
put_str(op_names[bits(5, 3)]);
loc++;
byte_count++;
put_byte(z80->mem[loc]);
break;
}
switch (bits(2, 0)) {
case 0:
put_str(OPC_RET);
put_cc(bits(5, 3));
break;
case 1:
switch (bits(5, 3)) {
case 0:
case 2:
case 4:
case 6:
put_str(OPC_POP);
put_qq_reg(bits(5, 4));
break;
case 1:
put_str(OPC_RET);
break;
case 3:
put_str(OPC_EXX);
break;
case 5:
put_str(OPC_JP);
if (index_reg) {
put_str("(");
put_str(index_reg);
put_str(")");
} else
put_str("(HL)");
break;
case 7:
put_str(OPC_LD);
put_str("SP,");
if (index_reg)
put_str(index_reg);
else
put_str("HL");
break;
}
break;
case 2:
put_str(OPC_JP);
put_cc(bits(5, 3));
put_char(',');
byte_count += 2;
loc += 2;
put_addr(z80, loc);
break;
case 3:
switch (bits(5, 3)) {
case 0:
put_str(OPC_JP);
byte_count += 2;
loc += 2;
put_addr(z80, loc);
break;
case 2:
loc++;
byte_count++;
put_str(OPC_OUT);
put_char('(');
put_byte(z80->mem[loc]);
put_str("),A");
break;
case 3:
loc++;
byte_count++;
put_str(OPC_IN);
put_str("A,(");
put_byte(z80->mem[loc]);
put_char(')');
break;
case 4:
put_str(OPC_EX);
put_str("(SP),");
if (index_reg)
put_str(index_reg);
else
put_str("HL");
break;
case 5:
put_str(OPC_EX);
put_str("HL,DE");
break;
case 6:
put_str(OPC_DI);
break;
case 7:
put_str(OPC_EI);
break;
}
break;
case 4:
put_str(OPC_CALL);
put_cc(bits(5, 3));
put_char(',');
byte_count += 2;
loc += 2;
put_addr(z80, loc);
break;
case 5:
if (bits(3, 3)) {
put_str(OPC_CALL);
byte_count += 2;
loc += 2;
put_addr(z80, loc);
} else {
put_str(OPC_PUSH);
put_qq_reg(bits(5, 4));
}
break;
case 6:
put_str(OPC_ILLEGAL);
break;
case 7:
put_str(OPC_RST);
put_byte(z80->mem[loc] & 0x038);
break;
}
break;
}
loc++;
byte_count++;
return byte_count;
}