int parse_instruction_65xx(struct _asm_context *asm_context, char *instr)
{
char token[TOKENLEN];
char instr_case[TOKENLEN];
char temp[80];
int token_type;
int opcode;
int mode;
int num;
int index;
int i;
// make lower case
lower_copy(instr_case, instr);
// get instruction index
index = -1;
for(i = 0; i < 56; i++)
{
if(strcmp(instr_case, opcodes_65xx[i].name) == 0)
{
index = i;
break;
}
}
// no instruction found
if(index == -1)
{
print_error_unexp(token, asm_context);
return -1;
}
// default
mode = MODE_IMPLIED;
// begin parsing
token_type=get_token(asm_context, token, TOKENLEN);
if (token_type==TOKEN_EOL) { goto skip; }
if(IS_TOKEN(token, '#'))
{
mode = MODE_IMMEDIATE;
if(eval_expression(asm_context, &num) != 0)
{
if(asm_context->pass == 1)
{
eat_operand(asm_context);
}
else
{
print_error_unexp(token, asm_context);
return -1;
}
}
num = (unsigned char)num;
if(num < 0 || num > 0xFF)
print_error_unexp(token, asm_context);
}
else
if(IS_TOKEN(token, '('))
{
mode = MODE_INDIRECT;
if(eval_expression(asm_context, &num) != 0)
{
if(asm_context->pass == 1)
{
eat_operand(asm_context);
}
else
{
print_error_unexp(token, asm_context);
return -1;
}
}
token_type = get_token(asm_context, token, TOKENLEN);
if (token_type==TOKEN_EOL) { goto skip; }
if(IS_TOKEN(token, ','))
{
if(num < 0 || num > 0xFF)
{
print_error("X-Indexed Indirect value out of range", asm_context);
return -1;
}
mode = MODE_X_INDEXED_INDIRECT;
token_type = get_token(asm_context, token, TOKENLEN);
if (token_type==TOKEN_EOL) { goto skip; }
if(IS_NOT_TOKEN(token, 'x') && IS_NOT_TOKEN(token, 'X'))
{
print_error_unexp(token, asm_context);
return -1;
}
token_type = get_token(asm_context, token, TOKENLEN);
if (token_type==TOKEN_EOL) { goto skip; }
if(IS_NOT_TOKEN(token, ')'))
{
print_error_unexp(token, asm_context);
return -1;
}
}
else
if(IS_TOKEN(token, ')'))
{
mode = MODE_INDIRECT;
token_type = get_token(asm_context, token, TOKENLEN);
if (token_type==TOKEN_EOL) { goto skip; }
if(IS_TOKEN(token, ','))
{
if(num < 0 || num > 0xFF)
{
print_error("Indirect Y-Indexed value out of range", asm_context);
return -1;
}
mode = MODE_INDIRECT_Y_INDEXED;
token_type = get_token(asm_context, token, TOKENLEN);
if (token_type==TOKEN_EOL) { goto skip; }
if(IS_NOT_TOKEN(token, 'y') && IS_NOT_TOKEN(token, 'Y'))
{
print_error_unexp(token, asm_context);
return -1;
}
token_type = get_token(asm_context, token, TOKENLEN);
}
}
}
else
{
pushback(asm_context, token, token_type);
if(eval_expression(asm_context, &num) != 0)
{
if(asm_context->pass == 1)
{
eat_operand(asm_context);
}
else
{
print_error_unexp(token, asm_context);
return -1;
}
}
// try zero page
if((num >= 0x01 && num <= 0xFF)
&& opcodes_65xx[index].opcode[MODE_ZEROPAGE] != 0xFF)
{
mode = MODE_ZEROPAGE;
}
else
{
mode = MODE_ABSOLUTE;
}
token_type = get_token(asm_context, token, TOKENLEN);
if (token_type==TOKEN_EOL) { goto skip; }
if(IS_TOKEN(token, ','))
{
token_type = get_token(asm_context, token, TOKENLEN);
if (token_type==TOKEN_EOL) { goto skip; }
if(IS_TOKEN(token, 'x') || IS_TOKEN(token, 'X'))
{
if((num >= 0x00 && num <= 0xFF)
&& opcodes_65xx[index].opcode[MODE_ZEROPAGE_X_INDEXED] != 0xFF)
{
mode = MODE_ZEROPAGE_X_INDEXED;
}
else
{
mode = MODE_ABSOLUTE_X_INDEXED;
}
}
else
if(IS_TOKEN(token, 'y') || IS_TOKEN(token, 'Y'))
{
if((num >= 0x00 && num <= 0xFF)
&& opcodes_65xx[index].opcode[MODE_ZEROPAGE_Y_INDEXED] != 0xFF)
{
mode = MODE_ZEROPAGE_Y_INDEXED;
}
else
{
mode = MODE_ABSOLUTE_Y_INDEXED;
}
}
else
{
print_error_unexp(token, asm_context);
return -1;
}
}
if(num < 0 || num > 0xFFFF)
{
print_error("Address out of range", asm_context);
return -1;
}
}
skip:
// branches are in table positions 3 - 10
if(index >= 3 && index <= 10)
{
if(mode == MODE_IMMEDIATE)
{
mode = MODE_RELATIVE;
num = (unsigned char)num;
}
else
{
mode = MODE_RELATIVE;
if(asm_context->pass == 2)
{
// calculate branch offset, need to add 2 to current
// address, since thats where the program counter would be
num -= (asm_context->address + 2);
if(num < -128 || num > 127)
{
print_error("Branch out of range", asm_context);
return -1;
}
num = (unsigned char)num;
}
}
}
// see if theres an opcode for this instruction and mode
opcode = opcodes_65xx[index].opcode[mode];
if(asm_context->pass == 2 && opcode == 0xFF)
{
sprintf(temp, "No instruction found for addressing mode %d", mode);
print_error(temp, asm_context);
return -1;
}
// warn if indirect JMP bug will happen
if((opcode == 0x6C) && ((num & 0xFF) == 0xFF))
{
print_error("Warning: Indirect JMP to upper page boundary (6502 bug)", asm_context);
}
//printf("address=%04x, num=%04x\n", asm_context->address, num);
// write opcode
//printf("%04x, %02x\n", asm_context->address, opcode & 0xFF);
add_bin8(asm_context, opcode & 0xFF, IS_OPCODE);
// write low byte first, if any
if(mode_bytes[mode] > 1)
{
//printf("%04x, %02x\n", asm_context->address, num & 0xFF);
add_bin8(asm_context, num & 0xFF, IS_OPCODE);
}
// then high byte, if any
if(mode_bytes[mode] > 2)
{
//printf("%04x, %02x\n", asm_context->address, (num >> 8) & 0xFF);
add_bin8(asm_context, (num >> 8) & 0xFF, IS_OPCODE);
}
int parse_instruction_6800(struct _asm_context *asm_context, char *instr)
{
char token[TOKENLEN];
int token_type;
char instr_case[TOKENLEN];
int operand_type;
int operand_value;
int address_size = 0;
int opcode = -1;
int n;
lower_copy(instr_case, instr);
do
{
token_type = tokens_get(asm_context, token, TOKENLEN);
if (token_type == TOKEN_EOL || token_type == TOKEN_EOF)
{
operand_type = OPERAND_NONE;
break;
}
if (token_type == TOKEN_POUND)
{
operand_type = OPERAND_NUMBER;
if (eval_expression(asm_context, &operand_value) != 0)
{
if (asm_context->pass == 2)
{
print_error_illegal_expression(instr, asm_context);
return -1;
}
eat_operand(asm_context);
operand_value = 0xffff;
}
}
else
{
operand_type = OPERAND_ADDRESS;
tokens_push(asm_context, token, token_type);
if (eval_expression(asm_context, &operand_value) != 0)
{
if (asm_context->pass == 2)
{
print_error_illegal_expression(instr, asm_context);
return -1;
}
eat_operand(asm_context);
operand_value = 0xffff;
}
token_type = tokens_get(asm_context, token, TOKENLEN);
if (token_type == TOKEN_EOL || token_type == TOKEN_EOF) { break; }
if (IS_NOT_TOKEN(token, ','))
{
print_error_unexp(token, asm_context);
return -1;
}
if (expect_token_s(asm_context, "x") != 0) { return -1; }
operand_type = OPERAND_ADDRESS_COMMA_X;
}
} while(0);
for (n = 0; n < 256; n++)
{
if (table_6800[n].instr == NULL) { continue; }
if (strcmp(instr_case, table_6800[n].instr) == 0)
{
if (table_6800[n].operand_type == M6800_OP_NONE &&
operand_type == OPERAND_NONE)
{
add_bin8(asm_context, n, IS_OPCODE);
return 1;
}
else
if (table_6800[n].operand_type == M6800_OP_REL_OFFSET &&
operand_type == OPERAND_ADDRESS)
{
int offset = operand_value - (asm_context->address + 2);
if (asm_context->pass != 1)
{
if (offset < -128 || offset > 127)
{
print_error_range("Offset", -128, 127, asm_context);
return -1;
}
}
add_bin8(asm_context, n, IS_OPCODE);
add_bin8(asm_context, offset & 0xff, IS_OPCODE);
return 1;
}
else
if (table_6800[n].operand_type == M6800_OP_IMM16 &&
operand_type == OPERAND_NUMBER)
{
add_bin8(asm_context, n, IS_OPCODE);
add_bin8(asm_context, operand_value >> 8, IS_OPCODE);
add_bin8(asm_context, operand_value & 0xff, IS_OPCODE);
return 3;
}
else
if (table_6800[n].operand_type == M6800_OP_IMM8 &&
operand_type == OPERAND_NUMBER)
{
if (asm_context->pass != 1)
{
if (operand_value < -128 || operand_value > 255)
{
print_error_range("Offset", -128, 255, asm_context);
return -1;
}
}
add_bin8(asm_context, n, IS_OPCODE);
add_bin8(asm_context, operand_value & 0xff, IS_OPCODE);
return 2;
}
else
if (table_6800[n].operand_type == M6800_OP_NN_X &&
operand_type == OPERAND_ADDRESS_COMMA_X)
{
int offset = operand_value-(asm_context->address + 2);
if (asm_context->pass != 1)
{
if (offset < -128 || offset > 127)
{
print_error_range("Offset", -128, 127, asm_context);
return -1;
}
}
add_bin8(asm_context, n, IS_OPCODE);
add_bin8(asm_context, offset & 0xff, IS_OPCODE);
return 2;
}
else
if (table_6800[n].operand_type == M6800_OP_DIR_PAGE_8 &&
operand_type == OPERAND_ADDRESS)
{
if (asm_context->pass == 1)
{
if (address_size == 0 && (operand_value >= 0 && operand_value <= 255))
{
address_size = 1;
opcode = n;
}
}
if (memory_read_m(&asm_context->memory, asm_context->address) == 1)
{
add_bin8(asm_context, n, IS_OPCODE);
add_bin8(asm_context, operand_value, IS_OPCODE);
return 2;
}
}
else
if (table_6800[n].operand_type == M6800_OP_ABSOLUTE_16 &&
operand_type == OPERAND_ADDRESS)
{
if (asm_context->pass == 1)
{
if (address_size == 0)
{
address_size = 2;
opcode=n;
}
}
if (memory_read_m(&asm_context->memory, asm_context->address)==2)
{
add_bin8(asm_context, n, IS_OPCODE);
add_bin8(asm_context, operand_value >> 8, IS_OPCODE);
add_bin8(asm_context, operand_value & 0xff, IS_OPCODE);
return 2;
}
}
