instruction.c File Reference

#include "c8/private/instruction.h"
#include "c8/decode.h"
#include "c8/defs.h"
#include "c8/font.h"
#include "c8/private/exception.h"
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

Macros
#define	VERBOSE(c)   (c->flags & C8_FLAG_VERBOSE)
#define	SCHIP_EXCLUSIVE(c)
#define	XOCHIP_EXCLUSIVE(c)
#define	QUIRK_BITWISE(c)
#define	QUIRK_DRAW(c)
#define	QUIRK_LOADSTORE(c)
#define	QUIRK_SHIFT(c)
#define	BORROWS(x, y)   ((((int) x) - y) < 0)
#define	CARRIES(x, y)   ((((int) x) + y) > UINT8_MAX)

Functions
int	parse_instruction (c8_t *c8)
	Execute the instruction at c8->pc

Detailed Description

Note

NOT EXPORTED

This file contains the implementation of the instruction parsing and execution for the CHIP-8 interpreter.

Macro Definition Documentation

BORROWS

#define BORROWS	(		x,
			y
	)		((((int) x) - y) < 0)

CARRIES

#define CARRIES	(		x,
			y
	)		((((int) x) + y) > UINT8_MAX)

QUIRK_BITWISE

#define QUIRK_BITWISE

(

c

)

Value:

    if (c->flags & C8_FLAG_QUIRK_BITWISE) { \
        c->V[0xF] = 0; \
    }

QUIRK_DRAW

#define QUIRK_DRAW

(

c

)

Value:

    if (c->flags & C8_FLAG_QUIRK_DRAW) { \
        if () \
    }

QUIRK_LOADSTORE

#define QUIRK_LOADSTORE

(

c

)

Value:

    if (c->flags & C8_FLAG_QUIRK_LOADSTORE) { \
        c->I += x + 1; \
    }

QUIRK_SHIFT

#define QUIRK_SHIFT

(

c

)

Value:

    if (c->flags & C8_FLAG_QUIRK_SHIFT) { \
        y = x; \
    }

SCHIP_EXCLUSIVE

#define SCHIP_EXCLUSIVE

(

c

)

Value:

    if (c->mode == C8_MODE_CHIP8) { \
        C8_EXCEPTION(INVALID_INSTRUCTION_EXCEPTION, "SCHIP instruction detected in CHIP-8 mode.\n"); \
        return INVALID_INSTRUCTION_EXCEPTION; \
    }

VERBOSE

#define VERBOSE

(

c

)

(c->flags & C8_FLAG_VERBOSE)

XOCHIP_EXCLUSIVE

#define XOCHIP_EXCLUSIVE

(

c

)

Value:

    if (c->mode != C8_MODE_XOCHIP) { \
        const char *modeStr = (c->mode == C8_MODE_CHIP8) ? "CHIP-8" : "SCHIP"; \
        C8_EXCEPTION(INVALID_INSTRUCTION_EXCEPTION, "XOCHIP instruction detected in %s mode.\n", modeStr); \
        return INVALID_INSTRUCTION_EXCEPTION; \
    }

Function Documentation

parse_instruction()

int parse_instruction

(

c8_t *

c8

)

Execute the instruction at c8->pc

This function parses and executes the instruction at the current program counter.

If verbose flag is set, this will print the instruction to stdout as well.

Parameters

c8	the c8_t to execute the instruction from

Returns

amount to increase the program counter, or an exception code if an error occurs.