decode.c File Reference

#include "decode.h"
#include "defs.h"
#include <stdio.h>
#include <stdlib.h>

Macros
#define	DEFINE_LABELS   (args & C8_DECODE_DEFINE_LABELS)
#define	PRINT_ADDRESSES   (args & C8_DECODE_PRINT_ADDRESSES)

Functions
void	c8_decode (FILE *input, FILE *output, int args)
	Convert bytecode from input to assembly and writes it to output. More...
char *	c8_decode_instruction (uint16_t in, uint8_t *label_map)
	Decode in and return its assembly value. More...
uint16_t	jump (uint16_t in)
	Returns the value to jump to if n is a jump instruction, or 0. More...

Variables
char	result [32]

Detailed Description

Stuff for disassembling bytecode.

Macro Definition Documentation

DEFINE_LABELS

#define DEFINE_LABELS   (args & C8_DECODE_DEFINE_LABELS)

PRINT_ADDRESSES

#define PRINT_ADDRESSES   (args & C8_DECODE_PRINT_ADDRESSES)

Function Documentation

c8_decode()

void c8_decode	(	FILE *	input,
		FILE *	output,
		int	args
	)

Convert bytecode from input to assembly and writes it to output.

ARG_PRINT_ADDRESSES should be AND'd to args to print addresses before each assembly instruction.

ARG_DEFINE_LABELS should be AND'd to args to define labels.

Parameters

input	the CHIP-8 ROM file to disassemble
output	the file to write the assembly to
args	0 with ARG_PRINT_ADDRESSES and/or ARG_DEFINE_LABELS optionally OR'd

c8_decode_instruction()

char * c8_decode_instruction	(	uint16_t	in,
		uint8_t *	label_map
	)

Decode in and return its assembly value.

Gets the assembly value of instruction in, stores it in the global variable result, and returns result.

If label_map is not NULL, it should point to an aray of size MEMSIZE, with all "labeled" elements set to a unique, non-zero integer. All other elements should be zero.

If label_map is not NULL, label_map[nnn] is greater than 0, and the instruction contains a nnn argument, a label name will be generated and used in the resulting string.

Parameters

in	The instruction to decode
label_map	The label map (can be NULL for no labels)

Returns

result containing the associated assembly instruction

jump()

uint16_t jump

(

uint16_t

in

)

Returns the value to jump to if n is a jump instruction, or 0.

Parameters

in	The instruction to check

Returns

in's nnn value if it exists, 0 otherwise.

Variable Documentation

result

char result[32]