/*
 * Value handling
 *
 *  Copyright (C) 2006-2007  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: value.c 2064 2008-04-14 01:48:02Z peter $");

#include "libyasm-stdint.h"
#include "coretype.h"
#include "bitvect.h"

#include "errwarn.h"
#include "intnum.h"
#include "floatnum.h"
#include "expr.h"
#include "value.h"
#include "symrec.h"

#include "bytecode.h"
#include "section.h"

#include "arch.h"


void
yasm_value_initialize(/*@out@*/ yasm_value *value,
                      /*@null@*/ /*@kept@*/ yasm_expr *e, unsigned int size)
{
    value->abs = e;
    value->rel = NULL;
    value->wrt = NULL;
    value->seg_of = 0;
    value->rshift = 0;
    value->curpos_rel = 0;
    value->ip_rel = 0;
    value->jump_target = 0;
    value->section_rel = 0;
    value->no_warn = 0;
    value->sign = 0;
    value->size = size;
}

void
yasm_value_init_sym(/*@out@*/ yasm_value *value, /*@null@*/ yasm_symrec *sym,
                    unsigned int size)
{
    value->abs = NULL;
    value->rel = sym;
    value->wrt = NULL;
    value->seg_of = 0;
    value->rshift = 0;
    value->curpos_rel = 0;
    value->ip_rel = 0;
    value->jump_target = 0;
    value->section_rel = 0;
    value->no_warn = 0;
    value->sign = 0;
    value->size = size;
}

void
yasm_value_init_copy(yasm_value *value, const yasm_value *orig)
{
    value->abs = orig->abs ? yasm_expr_copy(orig->abs) : NULL;
    value->rel = orig->rel;
    value->wrt = orig->wrt;
    value->seg_of = orig->seg_of;
    value->rshift = orig->rshift;
    value->curpos_rel = orig->curpos_rel;
    value->ip_rel = orig->ip_rel;
    value->jump_target = orig->jump_target;
    value->section_rel = orig->section_rel;
    value->no_warn = orig->no_warn;
    value->sign = orig->sign;
    value->size = orig->size;
}

void
yasm_value_delete(yasm_value *value)
{
    if (value->abs)
        yasm_expr_destroy(value->abs);
    value->abs = NULL;
    value->rel = NULL;
}

void
yasm_value_set_curpos_rel(yasm_value *value, yasm_bytecode *bc,
                          unsigned int ip_rel)
{
    value->curpos_rel = 1;
    value->ip_rel = ip_rel;
    /* In order for us to correctly output curpos-relative values, we must
     * have a relative portion of the value.  If one doesn't exist, point
     * to a custom absolute symbol.
     */
    if (!value->rel) {
        yasm_object *object = yasm_section_get_object(yasm_bc_get_section(bc));
        value->rel = yasm_symtab_abs_sym(object->symtab);
    }
}

static int
value_finalize_scan(yasm_value *value, yasm_expr *e,
                    /*@null@*/ yasm_bytecode *expr_precbc, int ssym_not_ok)
{
    int i;
    /*@dependent@*/ yasm_section *sect;
    /*@dependent@*/ /*@null@*/ yasm_bytecode *precbc;

    unsigned long shamt;    /* for SHR */

    /* Yes, this has a maximum upper bound on 32 terms, based on an
     * "insane number of terms" (and ease of implementation) WAG.
     * The right way to do this would be a stack-based alloca, but that's
     * not ISO C.  We really don't want to malloc here as this function is
     * hit a lot!
     *
     * This is a bitmask to keep things small, as this is a recursive
     * routine and we don't want to eat up stack space.
     */
    unsigned long used;     /* for ADD */

    /* Thanks to this running after a simplify, we don't need to iterate
     * down through IDENTs or handle SUB.
     *
     * We scan for a single symrec, gathering info along the way.  After
     * we've found the symrec, we keep scanning but error if we find
     * another one.  We pull out the single symrec and any legal operations
     * performed on it.
     *
     * Also, if we find a float anywhere, we don't allow mixing of a single
     * symrec with it.
     */
    switch (e->op) {
        case YASM_EXPR_ADD:
            /* Okay for single symrec anywhere in expr.
             * Check for single symrec anywhere.
             * Handle symrec-symrec by checking for (-1*symrec)
             * and symrec term pairs (where both symrecs are in the same
             * segment).
             */
            if (e->numterms > 32)
                yasm__fatal(N_("expression on line %d has too many add terms;"
                               " internal limit of 32"), e->line);

            used = 0;

            for (i=0; i<e->numterms; i++) {
                int j;
                yasm_expr *sube;
                yasm_intnum *intn;
                yasm_symrec *sym;
                /*@dependent@*/ yasm_section *sect2;
                /*@dependent@*/ /*@null@*/ yasm_bytecode *precbc2;

                /* First look for an (-1*symrec) term */
                if (e->terms[i].type != YASM_EXPR_EXPR)
                    continue;
                sube = e->terms[i].data.expn;

                if (sube->op != YASM_EXPR_MUL || sube->numterms != 2) {
                    /* recurse instead */
                    if (value_finalize_scan(value, sube, expr_precbc,
                                            ssym_not_ok))
                        return 1;
                    continue;
                }

                if (sube->terms[0].type == YASM_EXPR_INT &&
                    sube->terms[1].type == YASM_EXPR_SYM) {
                    intn = sube->terms[0].data.intn;
                    sym = sube->terms[1].data.sym;
                } else if (sube->terms[0].type == YASM_EXPR_SYM &&
                           sube->terms[1].type == YASM_EXPR_INT) {
                    sym = sube->terms[0].data.sym;
                    intn = sube->terms[1].data.intn;
                } else {
                    if (value_finalize_scan(value, sube, expr_precbc,
                                            ssym_not_ok))
                        return 1;
                    continue;
                }

                if (!yasm_intnum_is_neg1(intn)) {
                    if (value_finalize_scan(value, sube, expr_precbc,
                                            ssym_not_ok))
                        return 1;
                    continue;
                }

                /* Look for the same symrec term; even if both are external,
                 * they should cancel out.
                 */
                for (j=0; j<e->numterms; j++) {
                    if (e->terms[j].type == YASM_EXPR_SYM
                        && e->terms[j].data.sym == sym
                        && (used & (1<<j)) == 0) {
                        /* Mark as used */
                        used |= 1<<j;

                        /* Replace both symrec portions with 0 */
                        yasm_expr_destroy(sube);
                        e->terms[i].type = YASM_EXPR_INT;
                        e->terms[i].data.intn = yasm_intnum_create_uint(0);
                        e->terms[j].type = YASM_EXPR_INT;
                        e->terms[j].data.intn = yasm_intnum_create_uint(0);

                        break;  /* stop looking */
                    }
                }
                if (j != e->numterms)
                    continue;

                if (!yasm_symrec_get_label(sym, &precbc)) {
                    if (value_finalize_scan(value, sube, expr_precbc,
                                            ssym_not_ok))
                        return 1;
                    continue;
                }
                sect2 = yasm_bc_get_section(precbc);

                /* Now look for a unused symrec term in the same segment */
                for (j=0; j<e->numterms; j++) {
                    if (e->terms[j].type == YASM_EXPR_SYM
                        && yasm_symrec_get_label(e->terms[j].data.sym,
                                                 &precbc2)
                        && (sect = yasm_bc_get_section(precbc2))
                        && sect == sect2
                        && (used & (1<<j)) == 0) {
                        /* Mark as used */
                        used |= 1<<j;
                        break;  /* stop looking */
                    }
                }

                /* We didn't match in the same segment.  If the
                 * -1*symrec is actually -1*curpos, we can match
                 * unused symrec terms in other segments and generate
                 * a curpos-relative reloc.
                 *
                 * Similarly, handle -1*symrec in other segment via the
                 * following transformation:
                 * other-this = (other-.)+(.-this)
                 * We can only do this transformation if "this" is in
                 * this expr's segment.
                 *
                 * Don't do this if we've already become curpos-relative.
                 * The unmatched symrec will be caught below.
                 */
                if (j == e->numterms && !value->curpos_rel
                    && (yasm_symrec_is_curpos(sym)
                        || (expr_precbc
                            && sect2 == yasm_bc_get_section(expr_precbc)))) {
                    for (j=0; j<e->numterms; j++) {
                        if (e->terms[j].type == YASM_EXPR_SYM
                            && !yasm_symrec_get_equ(e->terms[j].data.sym)
                            && !yasm_symrec_is_special(e->terms[j].data.sym)
                            && (used & (1<<j)) == 0) {
                            /* Mark as used */
                            used |= 1<<j;
                            /* Mark value as curpos-relative */
                            if (value->rel || ssym_not_ok)
                                return 1;
                            value->rel = e->terms[j].data.sym;
                            value->curpos_rel = 1;
                            if (yasm_symrec_is_curpos(sym)) {
                                /* Replace both symrec portions with 0 */
                                yasm_expr_destroy(sube);
                                e->terms[i].type = YASM_EXPR_INT;
                                e->terms[i].data.intn =
                                    yasm_intnum_create_uint(0);
                                e->terms[j].type = YASM_EXPR_INT;
                                e->terms[j].data.intn =
                                    yasm_intnum_create_uint(0);
                            } else {
                                /* Replace positive portion with curpos */
                                yasm_object *object =
                                    yasm_section_get_object(sect2);
                                yasm_symtab *symtab = object->symtab;
                                e->terms[j].data.sym =
                                    yasm_symtab_define_curpos
                                    (symtab, ".", expr_precbc, e->line);
                            }
                            break;      /* stop looking */
                        }
                    }
                }


                if (j == e->numterms)
                    return 1;   /* We didn't find a match! */
            }

            /* Look for unmatched symrecs.  If we've already found one or
             * we don't WANT to find one, error out.
             */
            for (i=0; i<e->numterms; i++) {
                if (e->terms[i].type == YASM_EXPR_SYM
                    && (used & (1<<i)) == 0) {
                    if (value->rel || ssym_not_ok)
                        return 1;
                    value->rel = e->terms[i].data.sym;
                    /* and replace with 0 */
                    e->terms[i].type = YASM_EXPR_INT;
                    e->terms[i].data.intn = yasm_intnum_create_uint(0);
                }
            }
            break;
        case YASM_EXPR_SHR:
            /* Okay for single symrec in LHS and constant on RHS.
             * Single symrecs are not okay on RHS.
             * If RHS is non-constant, don't allow single symrec on LHS.
             * XXX: should rshift be an expr instead??
             */

            /* Check for not allowed cases on RHS */
            switch (e->terms[1].type) {
                case YASM_EXPR_REG:
                case YASM_EXPR_FLOAT:
                    return 1;           /* not legal */
                case YASM_EXPR_SYM:
                    return 1;
                case YASM_EXPR_EXPR:
                    if (value_finalize_scan(value, e->terms[1].data.expn,
                                            expr_precbc, 1))
                        return 1;
                    break;
                default:
                    break;
            }

            /* Check for single sym and allowed cases on LHS */
            switch (e->terms[0].type) {
                /*case YASM_EXPR_REG:   ????? should this be illegal ????? */
                case YASM_EXPR_FLOAT:
                    return 1;           /* not legal */
                case YASM_EXPR_SYM:
                    if (value->rel || ssym_not_ok)
                        return 1;
                    value->rel = e->terms[0].data.sym;
                    /* and replace with 0 */
                    e->terms[0].type = YASM_EXPR_INT;
                    e->terms[0].data.intn = yasm_intnum_create_uint(0);
                    break;
                case YASM_EXPR_EXPR:
                    /* recurse */
                    if (value_finalize_scan(value, e->terms[0].data.expn,
                                            expr_precbc, ssym_not_ok))
                        return 1;
                    break;
                default:
                    break;      /* ignore */
            }

            /* Handle RHS */
            if (!value->rel)
                break;          /* no handling needed */
            if (e->terms[1].type != YASM_EXPR_INT)
                return 1;       /* can't shift sym by non-constant integer */
            shamt = yasm_intnum_get_uint(e->terms[1].data.intn);
            if ((shamt + value->rshift) > YASM_VALUE_RSHIFT_MAX)
                return 1;       /* total shift would be too large */
            value->rshift += shamt;

            /* Just leave SHR in place */
            break;
        case YASM_EXPR_SEG:
            /* Okay for single symrec (can only be done once).
             * Not okay for anything BUT a single symrec as an immediate
             * child.
             */
            if (e->terms[0].type != YASM_EXPR_SYM)
                return 1;

            if (value->seg_of)
                return 1;       /* multiple SEG not legal */
            value->seg_of = 1;

            if (value->rel || ssym_not_ok)
                return 1;       /* got a relative portion somewhere else? */
            value->rel = e->terms[0].data.sym;

            /* replace with ident'ed 0 */
            e->op = YASM_EXPR_IDENT;
            e->terms[0].type = YASM_EXPR_INT;
            e->terms[0].data.intn = yasm_intnum_create_uint(0);
            break;
        case YASM_EXPR_WRT:
            /* Okay for single symrec in LHS and either a register or single
             * symrec (as an immediate child) on RHS.
             * If a single symrec on RHS, can only be done once.
             * WRT reg is left in expr for arch to look at.
             */

            /* Handle RHS */
            switch (e->terms[1].type) {
                case YASM_EXPR_SYM:
                    if (value->wrt)
                        return 1;
                    value->wrt = e->terms[1].data.sym;
                    /* and drop the WRT portion */
                    e->op = YASM_EXPR_IDENT;
                    e->numterms = 1;
                    break;
                case YASM_EXPR_REG:
                    break;  /* ignore */
                default:
                    return 1;
            }

            /* Handle LHS */
            switch (e->terms[0].type) {
                case YASM_EXPR_SYM:
                    if (value->rel || ssym_not_ok)
                        return 1;
                    value->rel = e->terms[0].data.sym;
                    /* and replace with 0 */
                    e->terms[0].type = YASM_EXPR_INT;
                    e->terms[0].data.intn = yasm_intnum_create_uint(0);
                    break;
                case YASM_EXPR_EXPR:
                    /* recurse */
                    return value_finalize_scan(value, e->terms[0].data.expn,
                                               expr_precbc, ssym_not_ok);
                default:
                    break;  /* ignore */
            }

            break;
        default:
            /* Single symrec not allowed anywhere */
            for (i=0; i<e->numterms; i++) {
                switch (e->terms[i].type) {
                    case YASM_EXPR_SYM:
                        return 1;
                    case YASM_EXPR_EXPR:
                        /* recurse */
                        return value_finalize_scan(value,
                                                   e->terms[i].data.expn,
                                                   expr_precbc, 1);
                    default:
                        break;
                }
            }
            break;
    }

    return 0;
}

int
yasm_value_finalize_expr(yasm_value *value, yasm_expr *e,
                         yasm_bytecode *precbc, unsigned int size)
{
    if (!e) {
        yasm_value_initialize(value, NULL, size);
        return 0;
    }

    yasm_value_initialize(value,
                          yasm_expr__level_tree(e, 1, 1, 0, 0, NULL, NULL),
                          size);

    /* quit early if there was an issue in simplify() */
    if (yasm_error_occurred())
        return 1;

    /* Strip top-level AND masking to an all-1s mask the same size
     * of the value size.  This allows forced avoidance of overflow warnings.
     */
    if (value->abs->op == YASM_EXPR_AND) {
        int term;

        /* Calculate 1<<size - 1 value */
        yasm_intnum *mask = yasm_intnum_create_uint(1);
        yasm_intnum *mask_tmp = yasm_intnum_create_uint(value->size);
        yasm_intnum_calc(mask, YASM_EXPR_SHL, mask_tmp);
        yasm_intnum_set_uint(mask_tmp, 1);
        yasm_intnum_calc(mask, YASM_EXPR_SUB, mask_tmp);
        yasm_intnum_destroy(mask_tmp);

        /* Walk terms and delete matching masks */
        for (term=value->abs->numterms-1; term>=0; term--) {
            if (value->abs->terms[term].type == YASM_EXPR_INT &&
                yasm_intnum_compare(value->abs->terms[term].data.intn,
                                    mask) == 0) {
                /* Delete the intnum */
                yasm_intnum_destroy(value->abs->terms[term].data.intn);

                /* Slide everything to its right over by 1 */
                if (term != value->abs->numterms-1) /* if it wasn't last.. */
                    memmove(&value->abs->terms[term],
                            &value->abs->terms[term+1],
                            (value->abs->numterms-1-term)*
                                sizeof(yasm_expr__item));

                /* Update numterms */
                value->abs->numterms--;

                /* Indicate warnings have been disabled */
                value->no_warn = 1;
            }
        }
        if (value->abs->numterms == 1)
            value->abs->op = YASM_EXPR_IDENT;
        yasm_intnum_destroy(mask);
    }

    /* Handle trivial (IDENT) cases immediately */
    if (value->abs->op == YASM_EXPR_IDENT) {
        switch (value->abs->terms[0].type) {
            case YASM_EXPR_INT:
                if (yasm_intnum_is_zero(value->abs->terms[0].data.intn)) {
                    yasm_expr_destroy(value->abs);
                    value->abs = NULL;
                }
                return 0;
            case YASM_EXPR_REG:
            case YASM_EXPR_FLOAT:
                return 0;
            case YASM_EXPR_SYM:
                value->rel = value->abs->terms[0].data.sym;
                yasm_expr_destroy(value->abs);
                value->abs = NULL;
                return 0;
            case YASM_EXPR_EXPR:
                /* Bring up lower values. */
                while (value->abs->op == YASM_EXPR_IDENT
                       && value->abs->terms[0].type == YASM_EXPR_EXPR) {
                    yasm_expr *sube = value->abs->terms[0].data.expn;
                    yasm_xfree(value->abs);
                    value->abs = sube;
                }
                break;
            default:
                yasm_internal_error(N_("unexpected expr term type"));
        }
    }

    if (value_finalize_scan(value, value->abs, precbc, 0))
        return 1;

    value->abs = yasm_expr__level_tree(value->abs, 1, 1, 0, 0, NULL, NULL);

    /* Simplify 0 in abs to NULL */
    if (value->abs->op == YASM_EXPR_IDENT
        && value->abs->terms[0].type == YASM_EXPR_INT
        && yasm_intnum_is_zero(value->abs->terms[0].data.intn)) {
        yasm_expr_destroy(value->abs);
        value->abs = NULL;
    }
    return 0;
}

int
yasm_value_finalize(yasm_value *value, yasm_bytecode *precbc)
{
    unsigned int valsize = value->size;
    return yasm_value_finalize_expr(value, value->abs, precbc, valsize);
}

yasm_intnum *
yasm_value_get_intnum(yasm_value *value, yasm_bytecode *bc, int calc_bc_dist)
{
    /*@dependent@*/ /*@null@*/ yasm_intnum *intn = NULL;
    /*@only@*/ yasm_intnum *outval;
    int sym_local;

    if (value->abs) {
        /* Handle integer expressions, if non-integer or too complex, return
         * NULL.
         */
        intn = yasm_expr_get_intnum(&value->abs, calc_bc_dist);
        if (!intn)
            return NULL;
    }

    if (value->rel) {
        /* If relative portion is not in bc section, return NULL.
         * Otherwise get the relative portion's offset.
         */
        /*@dependent@*/ yasm_bytecode *rel_prevbc;
        unsigned long dist;

        if (!bc)
            return NULL;    /* Can't calculate relative value */

        sym_local = yasm_symrec_get_label(value->rel, &rel_prevbc);
        if (value->wrt || value->seg_of || value->section_rel || !sym_local)
            return NULL;    /* we can't handle SEG, WRT, or external symbols */
        if (rel_prevbc->section != bc->section)
            return NULL;    /* not in this section */
        if (!value->curpos_rel)
            return NULL;    /* not PC-relative */

        /* Calculate value relative to current assembly position */
        dist = yasm_bc_next_offset(rel_prevbc);
        if (dist < bc->offset) {
            outval = yasm_intnum_create_uint(bc->offset - dist);
            yasm_intnum_calc(outval, YASM_EXPR_NEG, NULL);
        } else {
            dist -= bc->offset;
            outval = yasm_intnum_create_uint(dist);
        }

        if (value->rshift > 0) {
            /*@only@*/ yasm_intnum *shamt =
                yasm_intnum_create_uint((unsigned long)value->rshift);
            yasm_intnum_calc(outval, YASM_EXPR_SHR, shamt);
            yasm_intnum_destroy(shamt);
        }
        /* Add in absolute portion */
        if (intn)
            yasm_intnum_calc(outval, YASM_EXPR_ADD, intn);
        return outval;
    }

    if (intn)
        return yasm_intnum_copy(intn);
    
    /* No absolute or relative portions: output 0 */
    return yasm_intnum_create_uint(0);
}

int
yasm_value_output_basic(yasm_value *value, /*@out@*/ unsigned char *buf,
                        size_t destsize, yasm_bytecode *bc, int warn,
                        yasm_arch *arch)
{
    /*@dependent@*/ /*@null@*/ yasm_intnum *intn = NULL;
    /*@only@*/ yasm_intnum *outval;
    int sym_local;
    int retval = 1;
    unsigned int valsize = value->size;

    if (value->no_warn)
        warn = 0;

    if (value->abs) {
        /* Handle floating point expressions */
        if (!value->rel && value->abs->op == YASM_EXPR_IDENT
            && value->abs->terms[0].type == YASM_EXPR_FLOAT) {
            if (yasm_arch_floatnum_tobytes(arch, value->abs->terms[0].data.flt,
                                           buf, destsize, valsize, 0, warn))
                return -1;
            else
                return 1;
        }

        /* Check for complex float expressions */
        if (yasm_expr__contains(value->abs, YASM_EXPR_FLOAT)) {
            yasm_error_set(YASM_ERROR_FLOATING_POINT,
                           N_("floating point expression too complex"));
            return -1;
        }

        /* Handle normal integer expressions */
        intn = yasm_expr_get_intnum(&value->abs, 1);

        if (!intn) {
            /* Second try before erroring: yasm_expr_get_intnum doesn't handle
             * SEG:OFF, so try simplifying out any to just the OFF portion,
             * then getting the intnum again.
             */
            yasm_expr *seg = yasm_expr_extract_deep_segoff(&value->abs);
            if (seg)
                yasm_expr_destroy(seg);
            intn = yasm_expr_get_intnum(&value->abs, 1);
        }

        if (!intn) {
            /* Still don't have an integer! */
            yasm_error_set(YASM_ERROR_TOO_COMPLEX,
                           N_("expression too complex"));
            return -1;
        }
    }

    /* Adjust warn for signed/unsigned integer warnings */
    if (warn != 0)
        warn = value->sign ? -1 : 1;

    if (value->rel) {
        /* If relative portion is not in bc section, don't try to handle it
         * here.  Otherwise get the relative portion's offset.
         */
        /*@dependent@*/ yasm_bytecode *rel_prevbc;
        unsigned long dist;

        sym_local = yasm_symrec_get_label(value->rel, &rel_prevbc);
        if (value->wrt || value->seg_of || value->section_rel || !sym_local)
            return 0;       /* we can't handle SEG, WRT, or external symbols */
        if (rel_prevbc->section != bc->section)
            return 0;       /* not in this section */
        if (!value->curpos_rel)
            return 0;       /* not PC-relative */

        /* Calculate value relative to current assembly position */
        dist = yasm_bc_next_offset(rel_prevbc);
        if (dist < bc->offset) {
            outval = yasm_intnum_create_uint(bc->offset - dist);
            yasm_intnum_calc(outval, YASM_EXPR_NEG, NULL);
        } else {
            dist -= bc->offset;
            outval = yasm_intnum_create_uint(dist);
        }

        if (value->rshift > 0) {
            /*@only@*/ yasm_intnum *shamt =
                yasm_intnum_create_uint((unsigned long)value->rshift);
            yasm_intnum_calc(outval, YASM_EXPR_SHR, shamt);
            yasm_intnum_destroy(shamt);
        }
        /* Add in absolute portion */
        if (intn)
            yasm_intnum_calc(outval, YASM_EXPR_ADD, intn);
        /* Output! */
        if (yasm_arch_intnum_tobytes(arch, outval, buf, destsize, valsize, 0,
                                     bc, warn))
            retval = -1;
        yasm_intnum_destroy(outval);
        return retval;
    }

    if (value->seg_of || value->rshift || value->curpos_rel || value->ip_rel
        || value->section_rel)
        return 0;   /* We can't handle this with just an absolute */

    if (intn) {
        /* Output just absolute portion */
        if (yasm_arch_intnum_tobytes(arch, intn, buf, destsize, valsize, 0, bc,
                                     warn))
            retval = -1;
    } else {
        /* No absolute or relative portions: output 0 */
        outval = yasm_intnum_create_uint(0);
        if (yasm_arch_intnum_tobytes(arch, outval, buf, destsize, valsize, 0,
                                     bc, warn))
            retval = -1;
        yasm_intnum_destroy(outval);
    }
    return retval;
}

void
yasm_value_print(const yasm_value *value, FILE *f, int indent_level)
{
    fprintf(f, "%*s%u-bit, %ssigned", indent_level, "", value->size,
            value->sign ? "" : "un");
    fprintf(f, "%*sAbsolute portion=", indent_level, "");
    yasm_expr_print(value->abs, f);
    fprintf(f, "\n");
    if (value->rel) {
        fprintf(f, "%*sRelative to=%s%s\n", indent_level, "",
                value->seg_of ? "SEG " : "",
                yasm_symrec_get_name(value->rel));
        if (value->wrt)
            fprintf(f, "%*s(With respect to=%s)\n", indent_level, "",
                    yasm_symrec_get_name(value->wrt));
        if (value->rshift > 0)
            fprintf(f, "%*s(Right shifted by=%u)\n", indent_level, "",
                    value->rshift);
        if (value->curpos_rel)
            fprintf(f, "%*s(Relative to current position)\n", indent_level,
                    "");
        if (value->ip_rel)
            fprintf(f, "%*s(IP-relative)\n", indent_level, "");
        if (value->jump_target)
            fprintf(f, "%*s(Jump target)\n", indent_level, "");
        if (value->section_rel)
            fprintf(f, "%*s(Section-relative)\n", indent_level, "");
        if (value->no_warn)
            fprintf(f, "%*s(Overflow warnings disabled)\n", indent_level, "");
    }
}