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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: lc3bbc.c 1168 2004-10-31 01:07:52Z peter $");

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

#include "lc3barch.h"


/* Bytecode types */

typedef struct lc3b_insn {
    yasm_bytecode bc;         /* base structure */

    /*@null@*/ yasm_expr *imm;      /* immediate or relative value */
    lc3b_imm_type imm_type;   /* size of the immediate */

    /*@null@*/ /*@dependent@*/ yasm_symrec *origin; /* PC origin if needed */

    unsigned int opcode;      /* opcode */
} lc3b_insn;

/* Bytecode callback function prototypes */

static void lc3b_bc_insn_destroy(yasm_bytecode *bc);
static void lc3b_bc_insn_print(const yasm_bytecode *bc, 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_expr_func output_expr,
                        /*@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,
    lc3b_bc_insn_resolve,
    lc3b_bc_insn_tobytes
};


/*@-compmempass -mustfree@*/
yasm_bytecode *
yasm_lc3b__bc_create_insn(lc3b_new_insn_data *d)
{
    lc3b_insn *insn;
   
    insn = (lc3b_insn *)yasm_bc_create_common(&lc3b_bc_callback_insn,
                                    sizeof(lc3b_insn), d->line);

    insn->imm = d->imm;
    if (d->imm)
      insn->imm_type = d->imm_type;
    else
      insn->imm_type = LC3B_IMM_NONE;
    insn->origin = d->origin;
    insn->opcode = d->opcode;

    return (yasm_bytecode *)insn;
}
/*@=compmempass =mustfree@*/

static void
lc3b_bc_insn_destroy(yasm_bytecode *bc)
{
    lc3b_insn *insn = (lc3b_insn *)bc;
    if (insn->imm)
      yasm_expr_destroy(insn->imm);
}

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

    fprintf(f, "%*s_Instruction_\n", indent_level, "");
    fprintf(f, "%*sImmediate Value:", indent_level, "");
    if (!insn->imm)
      fprintf(f, " (nil)\n");
    else {
      indent_level++;
      fprintf(f, "\n%*sVal=", indent_level, "");
      yasm_expr_print(insn->imm, f);
      fprintf(f, "\n%*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--;
    }
    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;
    /*@null@*/ yasm_expr *temp;
    /*@dependent@*/ /*@null@*/ const 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;

    temp = yasm_expr_copy(insn->imm);
    temp = yasm_expr_create(YASM_EXPR_SUB, yasm_expr_expr(temp),
                      yasm_expr_sym(insn->origin), bc->line);
    num = yasm_expr_get_intnum(&temp, calc_bc_dist);
    if (!num) {
      yasm__error(bc->line, N_("target external or out of segment"));
      yasm_expr_destroy(temp);
      return YASM_BC_RESOLVE_ERROR | YASM_BC_RESOLVE_UNKNOWN_LEN;
    }
    rel = yasm_intnum_get_int(num);
    rel -= 2;
    yasm_expr_destroy(temp);
    /* 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_expr_func output_expr,
                 /*@unused@*/ yasm_output_reloc_func output_reloc)
{
    lc3b_insn *insn = (lc3b_insn *)bc;

    /* 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_expr(&insn->imm, *bufp, 2, 4, 0, 0, bc, 0, 1, d))
            return 1;
          break;
      case LC3B_IMM_5:
          if (output_expr(&insn->imm, *bufp, 2, 5, 0, 0, bc, 0, 1, d))
            return 1;
          break;
      case LC3B_IMM_6_WORD:
          if (output_expr(&insn->imm, *bufp, 2, 6, -1, 0, bc, 0, 1, d))
            return 1;
          break;
      case LC3B_IMM_6_BYTE:
          if (output_expr(&insn->imm, *bufp, 2, 6, 0, 0, bc, 0, 1, d))
            return 1;
          break;
      case LC3B_IMM_8:
          if (output_expr(&insn->imm, *bufp, 2, 8, -1, 0, bc, 0, 1, d))
            return 1;
          break;
      case LC3B_IMM_9_PC:
          insn->imm = yasm_expr_create(YASM_EXPR_SUB,
            yasm_expr_expr(insn->imm), yasm_expr_sym(insn->origin),
            bc->line);
          if (output_expr(&insn->imm, *bufp, 2, 9, -1, 0, bc, 1, 1, d))
            return 1;
          break;
      case LC3B_IMM_9:
          if (output_expr(&insn->imm, *bufp, 2, 9, -1, 0, bc, 0, 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_fixup_rel(yasm_arch *arch, yasm_intnum *intn,
                      size_t valsize, const yasm_bytecode *bc,
                      unsigned long line)
{
    yasm_intnum *delta;
    if (valsize != 9)
      yasm_internal_error(
          N_("tried to do PC-relative offset from invalid sized value"));
    delta = yasm_intnum_create_uint(bc->len);
    yasm_intnum_calc(intn, YASM_EXPR_SUB, delta, line);
    yasm_intnum_destroy(delta);
    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;
}

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