modules/arch/lc3b/lc3bbc.c

/*
 * LC-3b bytecode utility functions
 *
 *  Copyright (C) 2003  Peter Johnson
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND OTHER CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR OTHER CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
#include <util.h>
/*@unused@*/ RCSID("$Id$");

#define YASM_LIB_INTERNAL
#define YASM_BC_INTERNAL
#include <libyasm.h>

#include "lc3barch.h"


/* Bytecode callback function prototypes */

static void lc3b_bc_insn_destroy(void *contents);
static void lc3b_bc_insn_print(const void *contents, FILE *f,
			       int indent_level);
static yasm_bc_resolve_flags lc3b_bc_insn_resolve
    (yasm_bytecode *bc, int save, yasm_calc_bc_dist_func calc_bc_dist);
static int lc3b_bc_insn_tobytes(yasm_bytecode *bc, unsigned char **bufp,
				void *d, yasm_output_value_func output_value,
				/*@null@*/ yasm_output_reloc_func output_reloc);

/* Bytecode callback structures */

static const yasm_bytecode_callback lc3b_bc_callback_insn = {
    lc3b_bc_insn_destroy,
    lc3b_bc_insn_print,
    yasm_bc_finalize_common,
    lc3b_bc_insn_resolve,
    lc3b_bc_insn_tobytes
};


void
yasm_lc3b__bc_transform_insn(yasm_bytecode *bc, lc3b_insn *insn)
{
    yasm_bc_transform(bc, &lc3b_bc_callback_insn, insn);
}

static void
lc3b_bc_insn_destroy(void *contents)
{
    lc3b_insn *insn = (lc3b_insn *)contents;
    yasm_value_delete(&insn->imm);
    yasm_xfree(contents);
}

static void
lc3b_bc_insn_print(const void *contents, FILE *f, int indent_level)
{
    const lc3b_insn *insn = (const lc3b_insn *)contents;

    fprintf(f, "%*s_Instruction_\n", indent_level, "");
    fprintf(f, "%*sImmediate Value:", indent_level, "");
    if (!insn->imm.abs)
	fprintf(f, " (nil)\n");
    else {
	indent_level++;
	fprintf(f, "\n");
	yasm_value_print(&insn->imm, f, indent_level);
	fprintf(f, "%*sType=", indent_level, "");
	switch (insn->imm_type) {
	    case LC3B_IMM_NONE:
		fprintf(f, "NONE-SHOULDN'T HAPPEN");
		break;
	    case LC3B_IMM_4:
		fprintf(f, "4-bit");
		break;
	    case LC3B_IMM_5:
		fprintf(f, "5-bit");
		break;
	    case LC3B_IMM_6_WORD:
		fprintf(f, "6-bit, word-multiple");
		break;
	    case LC3B_IMM_6_BYTE:
		fprintf(f, "6-bit, byte-multiple");
		break;
	    case LC3B_IMM_8:
		fprintf(f, "8-bit, word-multiple");
		break;
	    case LC3B_IMM_9:
		fprintf(f, "9-bit, signed, word-multiple");
		break;
	    case LC3B_IMM_9_PC:
		fprintf(f, "9-bit, signed, word-multiple, PC-relative");
		break;
	}
	indent_level--;
    }
    /* FIXME
    fprintf(f, "\n%*sOrigin=", indent_level, "");
    if (insn->origin) {
	fprintf(f, "\n");
	yasm_symrec_print(insn->origin, f, indent_level+1);
    } else
	fprintf(f, "(nil)\n");
    */
    fprintf(f, "%*sOpcode: %04x\n", indent_level, "",
	    (unsigned int)insn->opcode);
}

static yasm_bc_resolve_flags
lc3b_bc_insn_resolve(yasm_bytecode *bc, int save,
		     yasm_calc_bc_dist_func calc_bc_dist)
{
    lc3b_insn *insn = (lc3b_insn *)bc->contents;
    yasm_bytecode *target_prevbc;
    /*@only@*/ yasm_intnum *num;
    long rel;

    /* Fixed size instruction length */
    bc->len = 2;

    /* Only need to worry about out-of-range to PC-relative, and only if we're
     * saving.
     */
    if (insn->imm_type != LC3B_IMM_9_PC || !save)
	return YASM_BC_RESOLVE_MIN_LEN;

    if (!insn->imm.rel)
	num = yasm_intnum_create_uint(0);
    else if (!yasm_symrec_get_label(insn->imm.rel, &target_prevbc)
	     || target_prevbc->section != insn->origin_prevbc->section
	     || !(num = calc_bc_dist(insn->origin_prevbc, target_prevbc))) {
	/* External or out of segment, so we can't check distance. */
	return YASM_BC_RESOLVE_MIN_LEN;
    }

    if (insn->imm.abs) {
	/*@only@*/ yasm_expr *temp = yasm_expr_copy(insn->imm.abs);
	/*@dependent@*/ /*@null@*/ yasm_intnum *num2;
	num2 = yasm_expr_get_intnum(&temp, calc_bc_dist);
	if (!num2) {
	    yasm__error(bc->line, N_("jump target too complex"));
	    yasm_expr_destroy(temp);
	    return YASM_BC_RESOLVE_ERROR | YASM_BC_RESOLVE_UNKNOWN_LEN;
	}
	yasm_intnum_calc(num, YASM_EXPR_ADD, num2, bc->line);
	yasm_expr_destroy(temp);
    }

    rel = yasm_intnum_get_int(num);
    yasm_intnum_destroy(num);
    rel -= 2;
    /* 9-bit signed, word-multiple displacement */
    if (rel < -512 || rel > 511) {
	yasm__error(bc->line, N_("target out of range"));
	return YASM_BC_RESOLVE_ERROR | YASM_BC_RESOLVE_UNKNOWN_LEN;
    }
    return YASM_BC_RESOLVE_MIN_LEN;
}

static int
lc3b_bc_insn_tobytes(yasm_bytecode *bc, unsigned char **bufp, void *d,
		     yasm_output_value_func output_value,
		     /*@unused@*/ yasm_output_reloc_func output_reloc)
{
    lc3b_insn *insn = (lc3b_insn *)bc->contents;
    /*@only@*/ yasm_intnum *delta;

    /* Output opcode */
    YASM_SAVE_16_L(*bufp, insn->opcode);

    /* Insert immediate into opcode. */
    switch (insn->imm_type) {
	case LC3B_IMM_NONE:
	    break;
	case LC3B_IMM_4:
	    if (output_value(&insn->imm, *bufp, 2, 4, 0, 0, bc, 1, d))
		return 1;
	    break;
	case LC3B_IMM_5:
	    if (output_value(&insn->imm, *bufp, 2, 5, 0, 0, bc, 1, d))
		return 1;
	    break;
	case LC3B_IMM_6_WORD:
	    if (output_value(&insn->imm, *bufp, 2, 6, -1, 0, bc, 1, d))
		return 1;
	    break;
	case LC3B_IMM_6_BYTE:
	    if (output_value(&insn->imm, *bufp, 2, 6, 0, 0, bc, 1, d))
		return 1;
	    break;
	case LC3B_IMM_8:
	    if (output_value(&insn->imm, *bufp, 2, 8, -1, 0, bc, 1, d))
		return 1;
	    break;
	case LC3B_IMM_9_PC:
	    /* Adjust relative displacement to end of bytecode */
	    delta = yasm_intnum_create_int(-(long)bc->len);
	    if (!insn->imm.abs)
		insn->imm.abs = yasm_expr_create_ident(yasm_expr_int(delta),
						       bc->line);
	    else
		insn->imm.abs =
		    yasm_expr_create(YASM_EXPR_ADD,
				     yasm_expr_expr(insn->imm.abs),
				     yasm_expr_int(delta), bc->line);

	    if (output_value(&insn->imm, *bufp, 2, 9, -1, 0, bc, 1, d))
		return 1;
	    break;
	case LC3B_IMM_9:
	    if (output_value(&insn->imm, *bufp, 2, 9, -1, 0, bc, 1, d))
		return 1;
	    break;
	default:
	    yasm_internal_error(N_("Unrecognized immediate type"));
    }

    *bufp += 2;	    /* all instructions are 2 bytes in size */
    return 0;
}

int
yasm_lc3b__intnum_tobytes(yasm_arch *arch, const yasm_intnum *intn,
			  unsigned char *buf, size_t destsize, size_t valsize,
			  int shift, const yasm_bytecode *bc, int warn,
			  unsigned long line)
{
    /* Write value out. */
    yasm_intnum_get_sized(intn, buf, destsize, valsize, shift, 0, warn,
			  line);
    return 0;
}