nasm/nasmlib.c

/* nasmlib.c	library routines for the Netwide Assembler
 *
 * The Netwide Assembler is copyright (C) 1996 Simon Tatham and
 * Julian Hall. All rights reserved. The software is
 * redistributable under the licence given in the file "Licence"
 * distributed in the NASM archive.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "nasm.h"
#include "nasmlib.h"
#include "insns.h"              /* For MAX_KEYWORD */

static efunc nasm_malloc_error;

#ifdef LOGALLOC
static FILE *logfp;
#endif

void nasm_set_malloc_error(efunc error)
{
    nasm_malloc_error = error;
#ifdef LOGALLOC
    logfp = fopen("malloc.log", "w");
    setvbuf(logfp, NULL, _IOLBF, BUFSIZ);
    fprintf(logfp, "null pointer is %p\n", NULL);
#endif
}

#ifdef LOGALLOC
void *nasm_malloc_log(char *file, int line, size_t size)
#else
void *nasm_malloc(size_t size)
#endif
{
    void *p = malloc(size);
    if (!p)
        nasm_malloc_error(ERR_FATAL | ERR_NOFILE, "out of memory");
#ifdef LOGALLOC
    else
        fprintf(logfp, "%s %d malloc(%ld) returns %p\n",
                file, line, (long)size, p);
#endif
    return p;
}

#ifdef LOGALLOC
void *nasm_realloc_log(char *file, int line, void *q, size_t size)
#else
void *nasm_realloc(void *q, size_t size)
#endif
{
    void *p = q ? realloc(q, size) : malloc(size);
    if (!p)
        nasm_malloc_error(ERR_FATAL | ERR_NOFILE, "out of memory");
#ifdef LOGALLOC
    else if (q)
        fprintf(logfp, "%s %d realloc(%p,%ld) returns %p\n",
                file, line, q, (long)size, p);
    else
        fprintf(logfp, "%s %d malloc(%ld) returns %p\n",
                file, line, (long)size, p);
#endif
    return p;
}

#ifdef LOGALLOC
void nasm_free_log(char *file, int line, void *q)
#else
void nasm_free(void *q)
#endif
{
    if (q) {
        free(q);
#ifdef LOGALLOC
        fprintf(logfp, "%s %d free(%p)\n", file, line, q);
#endif
    }
}

#ifdef LOGALLOC
char *nasm_strdup_log(char *file, int line, const char *s)
#else
char *nasm_strdup(const char *s)
#endif
{
    char *p;
    int size = strlen(s) + 1;

    p = malloc(size);
    if (!p)
        nasm_malloc_error(ERR_FATAL | ERR_NOFILE, "out of memory");
#ifdef LOGALLOC
    else
        fprintf(logfp, "%s %d strdup(%ld) returns %p\n",
                file, line, (long)size, p);
#endif
    strcpy(p, s);
    return p;
}

#ifdef LOGALLOC
char *nasm_strndup_log(char *file, int line, char *s, size_t len)
#else
char *nasm_strndup(char *s, size_t len)
#endif
{
    char *p;
    int size = len + 1;

    p = malloc(size);
    if (!p)
        nasm_malloc_error(ERR_FATAL | ERR_NOFILE, "out of memory");
#ifdef LOGALLOC
    else
        fprintf(logfp, "%s %d strndup(%ld) returns %p\n",
                file, line, (long)size, p);
#endif
    strncpy(p, s, len);
    p[len] = '\0';
    return p;
}

#if !defined(stricmp) && !defined(strcasecmp)
int nasm_stricmp(const char *s1, const char *s2)
{
    while (*s1 && tolower(*s1) == tolower(*s2))
        s1++, s2++;
    if (!*s1 && !*s2)
        return 0;
    else if (tolower(*s1) < tolower(*s2))
        return -1;
    else
        return 1;
}
#endif

#if !defined(strnicmp) && !defined(strncasecmp)
int nasm_strnicmp(const char *s1, const char *s2, int n)
{
    while (n > 0 && *s1 && tolower(*s1) == tolower(*s2))
        s1++, s2++, n--;
    if ((!*s1 && !*s2) || n == 0)
        return 0;
    else if (tolower(*s1) < tolower(*s2))
        return -1;
    else
        return 1;
}
#endif

#define lib_isnumchar(c)   ( isalnum(c) || (c) == '$')
#define numvalue(c)  ((c)>='a' ? (c)-'a'+10 : (c)>='A' ? (c)-'A'+10 : (c)-'0')

long readnum(char *str, int *error)
{
    char *r = str, *q;
    long radix;
    unsigned long result, checklimit;
    int digit, last;
    int warn = FALSE;
    int sign = 1;

    *error = FALSE;

    while (isspace(*r))
        r++;                    /* find start of number */

    /*
     * If the number came from make_tok_num (as a result of an %assign), it
     * might have a '-' built into it (rather than in a preceeding token).
     */
    if (*r == '-') {
        r++;
        sign = -1;
    }

    q = r;

    while (lib_isnumchar(*q))
        q++;                    /* find end of number */

    /*
     * If it begins 0x, 0X or $, or ends in H, it's in hex. if it
     * ends in Q, it's octal. if it ends in B, it's binary.
     * Otherwise, it's ordinary decimal.
     */
    if (*r == '0' && (r[1] == 'x' || r[1] == 'X'))
        radix = 16, r += 2;
    else if (*r == '$')
        radix = 16, r++;
    else if (q[-1] == 'H' || q[-1] == 'h')
        radix = 16, q--;
    else if (q[-1] == 'Q' || q[-1] == 'q' || q[-1] == 'O' || q[-1] == 'o')
        radix = 8, q--;
    else if (q[-1] == 'B' || q[-1] == 'b')
        radix = 2, q--;
    else
        radix = 10;

    /*
     * If this number has been found for us by something other than
     * the ordinary scanners, then it might be malformed by having
     * nothing between the prefix and the suffix. Check this case
     * now.
     */
    if (r >= q) {
        *error = TRUE;
        return 0;
    }

    /*
     * `checklimit' must be 2**32 / radix. We can't do that in
     * 32-bit arithmetic, which we're (probably) using, so we
     * cheat: since we know that all radices we use are even, we
     * can divide 2**31 by radix/2 instead.
     */
    checklimit = 0x80000000UL / (radix >> 1);

    /*
     * Calculate the highest allowable value for the last digit
     * of a 32 bit constant... in radix 10, it is 6, otherwise it is 0
     */
    last = (radix == 10 ? 6 : 0);

    result = 0;
    while (*r && r < q) {
        if (*r < '0' || (*r > '9' && *r < 'A')
            || (digit = numvalue(*r)) >= radix) {
            *error = TRUE;
            return 0;
        }
        if (result > checklimit || (result == checklimit && digit >= last)) {
            warn = TRUE;
        }

        result = radix * result + digit;
        r++;
    }

    if (warn)
        nasm_malloc_error(ERR_WARNING | ERR_PASS1 | ERR_WARN_NOV,
                          "numeric constant %s does not fit in 32 bits",
                          str);

    return result * sign;
}

long readstrnum(char *str, int length, int *warn)
{
    long charconst = 0;
    int i;

    *warn = FALSE;

    str += length;
    for (i = 0; i < length; i++) {
        if (charconst & 0xff000000UL) {
            *warn = TRUE;
        }
        charconst = (charconst << 8) + (unsigned char)*--str;
    }
    return charconst;
}

static long next_seg;

void seg_init(void)
{
    next_seg = 0;
}

long seg_alloc(void)
{
    return (next_seg += 2) - 2;
}

void fwriteshort(int data, FILE * fp)
{
    fputc((int)(data & 255), fp);
    fputc((int)((data >> 8) & 255), fp);
}

void fwritelong(long data, FILE * fp)
{
    fputc((int)(data & 255), fp);
    fputc((int)((data >> 8) & 255), fp);
    fputc((int)((data >> 16) & 255), fp);
    fputc((int)((data >> 24) & 255), fp);
}

void standard_extension(char *inname, char *outname, char *extension,
                        efunc error)
{
    char *p, *q;

    if (*outname)               /* file name already exists, */
        return;                 /* so do nothing */
    q = inname;
    p = outname;
    while (*q)
        *p++ = *q++;            /* copy, and find end of string */
    *p = '\0';                  /* terminate it */
    while (p > outname && *--p != '.') ;        /* find final period (or whatever) */
    if (*p != '.')
        while (*p)
            p++;                /* go back to end if none found */
    if (!strcmp(p, extension)) {        /* is the extension already there? */
        if (*extension)
            error(ERR_WARNING | ERR_NOFILE,
                  "file name already ends in `%s': "
                  "output will be in `nasm.out'", extension);
        else
            error(ERR_WARNING | ERR_NOFILE,
                  "file name already has no extension: "
                  "output will be in `nasm.out'");
        strcpy(outname, "nasm.out");
    } else
        strcpy(p, extension);
}

#define LEAFSIZ (sizeof(RAA)-sizeof(RAA_UNION)+sizeof(RAA_LEAF))
#define BRANCHSIZ (sizeof(RAA)-sizeof(RAA_UNION)+sizeof(RAA_BRANCH))

#define LAYERSIZ(r) ( (r)->layers==0 ? RAA_BLKSIZE : RAA_LAYERSIZE )

static struct RAA *real_raa_init(int layers)
{
    struct RAA *r;
    int i;

    if (layers == 0) {
        r = nasm_malloc(LEAFSIZ);
        r->layers = 0;
        memset(r->u.l.data, 0, sizeof(r->u.l.data));
        r->stepsize = 1L;
    } else {
        r = nasm_malloc(BRANCHSIZ);
        r->layers = layers;
        for (i = 0; i < RAA_LAYERSIZE; i++)
            r->u.b.data[i] = NULL;
        r->stepsize = RAA_BLKSIZE;
        while (--layers)
            r->stepsize *= RAA_LAYERSIZE;
    }
    return r;
}

struct RAA *raa_init(void)
{
    return real_raa_init(0);
}

void raa_free(struct RAA *r)
{
    if (r->layers == 0)
        nasm_free(r);
    else {
        struct RAA **p;
        for (p = r->u.b.data; p - r->u.b.data < RAA_LAYERSIZE; p++)
            if (*p)
                raa_free(*p);
    }
}

long raa_read(struct RAA *r, long posn)
{
    if (posn >= r->stepsize * LAYERSIZ(r))
        return 0;               /* Return 0 for undefined entries */
    while (r->layers > 0) {
        ldiv_t l;
        l = ldiv(posn, r->stepsize);
        r = r->u.b.data[l.quot];
        posn = l.rem;
        if (!r)
            return 0;           /* Return 0 for undefined entries */
    }
    return r->u.l.data[posn];
}

struct RAA *raa_write(struct RAA *r, long posn, long value)
{
    struct RAA *result;

    if (posn < 0)
        nasm_malloc_error(ERR_PANIC, "negative position in raa_write");

    while (r->stepsize * LAYERSIZ(r) <= posn) {
        /*
         * Must add a layer.
         */
        struct RAA *s;
        int i;

        s = nasm_malloc(BRANCHSIZ);
        for (i = 0; i < RAA_LAYERSIZE; i++)
            s->u.b.data[i] = NULL;
        s->layers = r->layers + 1;
        s->stepsize = LAYERSIZ(r) * r->stepsize;
        s->u.b.data[0] = r;
        r = s;
    }

    result = r;

    while (r->layers > 0) {
        ldiv_t l;
        struct RAA **s;
        l = ldiv(posn, r->stepsize);
        s = &r->u.b.data[l.quot];
        if (!*s)
            *s = real_raa_init(r->layers - 1);
        r = *s;
        posn = l.rem;
    }

    r->u.l.data[posn] = value;

    return result;
}

#define SAA_MAXLEN 8192

struct SAA *saa_init(long elem_len)
{
    struct SAA *s;

    if (elem_len > SAA_MAXLEN)
        nasm_malloc_error(ERR_PANIC | ERR_NOFILE,
                          "SAA with huge elements");

    s = nasm_malloc(sizeof(struct SAA));
    s->posn = s->start = 0L;
    s->elem_len = elem_len;
    s->length = SAA_MAXLEN - (SAA_MAXLEN % elem_len);
    s->data = nasm_malloc(s->length);
    s->next = NULL;
    s->end = s;

    return s;
}

void saa_free(struct SAA *s)
{
    struct SAA *t;

    while (s) {
        t = s->next;
        nasm_free(s->data);
        nasm_free(s);
        s = t;
    }
}

void *saa_wstruct(struct SAA *s)
{
    void *p;

    if (s->end->length - s->end->posn < s->elem_len) {
        s->end->next = nasm_malloc(sizeof(struct SAA));
        s->end->next->start = s->end->start + s->end->posn;
        s->end = s->end->next;
        s->end->length = s->length;
        s->end->next = NULL;
        s->end->posn = 0L;
        s->end->data = nasm_malloc(s->length);
    }

    p = s->end->data + s->end->posn;
    s->end->posn += s->elem_len;
    return p;
}

void saa_wbytes(struct SAA *s, const void *data, long len)
{
    const char *d = data;

    while (len > 0) {
        long l = s->end->length - s->end->posn;
        if (l > len)
            l = len;
        if (l > 0) {
            if (d) {
                memcpy(s->end->data + s->end->posn, d, l);
                d += l;
            } else
                memset(s->end->data + s->end->posn, 0, l);
            s->end->posn += l;
            len -= l;
        }
        if (len > 0) {
            s->end->next = nasm_malloc(sizeof(struct SAA));
            s->end->next->start = s->end->start + s->end->posn;
            s->end = s->end->next;
            s->end->length = s->length;
            s->end->next = NULL;
            s->end->posn = 0L;
            s->end->data = nasm_malloc(s->length);
        }
    }
}

void saa_rewind(struct SAA *s)
{
    s->rptr = s;
    s->rpos = 0L;
}

void *saa_rstruct(struct SAA *s)
{
    void *p;

    if (!s->rptr)
        return NULL;

    if (s->rptr->posn - s->rpos < s->elem_len) {
        s->rptr = s->rptr->next;
        if (!s->rptr)
            return NULL;        /* end of array */
        s->rpos = 0L;
    }

    p = s->rptr->data + s->rpos;
    s->rpos += s->elem_len;
    return p;
}

void *saa_rbytes(struct SAA *s, long *len)
{
    void *p;

    if (!s->rptr)
        return NULL;

    p = s->rptr->data + s->rpos;
    *len = s->rptr->posn - s->rpos;
    s->rptr = s->rptr->next;
    s->rpos = 0L;
    return p;
}

void saa_rnbytes(struct SAA *s, void *data, long len)
{
    char *d = data;

    while (len > 0) {
        long l;

        if (!s->rptr)
            return;

        l = s->rptr->posn - s->rpos;
        if (l > len)
            l = len;
        if (l > 0) {
            memcpy(d, s->rptr->data + s->rpos, l);
            d += l;
            s->rpos += l;
            len -= l;
        }
        if (len > 0) {
            s->rptr = s->rptr->next;
            s->rpos = 0L;
        }
    }
}

void saa_fread(struct SAA *s, long posn, void *data, long len)
{
    struct SAA *p;
    long pos;
    char *cdata = data;

    if (!s->rptr || posn < s->rptr->start)
        saa_rewind(s);
    p = s->rptr;
    while (posn >= p->start + p->posn) {
        p = p->next;
        if (!p)
            return;             /* what else can we do?! */
    }

    pos = posn - p->start;
    while (len) {
        long l = p->posn - pos;
        if (l > len)
            l = len;
        memcpy(cdata, p->data + pos, l);
        len -= l;
        cdata += l;
        p = p->next;
        if (!p)
            return;
        pos = 0L;
    }
    s->rptr = p;
}

void saa_fwrite(struct SAA *s, long posn, void *data, long len)
{
    struct SAA *p;
    long pos;
    char *cdata = data;

    if (!s->rptr || posn < s->rptr->start)
        saa_rewind(s);
    p = s->rptr;
    while (posn >= p->start + p->posn) {
        p = p->next;
        if (!p)
            return;             /* what else can we do?! */
    }

    pos = posn - p->start;
    while (len) {
        long l = p->posn - pos;
        if (l > len)
            l = len;
        memcpy(p->data + pos, cdata, l);
        len -= l;
        cdata += l;
        p = p->next;
        if (!p)
            return;
        pos = 0L;
    }
    s->rptr = p;
}

void saa_fpwrite(struct SAA *s, FILE * fp)
{
    char *data;
    long len;

    saa_rewind(s);
    while ((data = saa_rbytes(s, &len)))
        fwrite(data, 1, len, fp);
}

/*
 * Register, instruction, condition-code and prefix keywords used
 * by the scanner.
 */
#include "names.c"
static const char *special_names[] = {
    "byte", "dword", "far", "long", "near", "nosplit", "qword",
    "short", "strict", "to", "tword", "word"
};
static const char *prefix_names[] = {
    "a16", "a32", "lock", "o16", "o32", "rep", "repe", "repne",
    "repnz", "repz", "times"
};

/*
 * Standard scanner routine used by parser.c and some output
 * formats. It keeps a succession of temporary-storage strings in
 * stdscan_tempstorage, which can be cleared using stdscan_reset.
 */
static char **stdscan_tempstorage = NULL;
static int stdscan_tempsize = 0, stdscan_templen = 0;
#define STDSCAN_TEMP_DELTA 256

static void stdscan_pop(void)
{
    nasm_free(stdscan_tempstorage[--stdscan_templen]);
}

void stdscan_reset(void)
{
    while (stdscan_templen > 0)
        stdscan_pop();
}

/*
 * Unimportant cleanup is done to avoid confusing people who are trying
 * to debug real memory leaks
 */
void nasmlib_cleanup(void)
{
    stdscan_reset();
    nasm_free(stdscan_tempstorage);
}

static char *stdscan_copy(char *p, int len)
{
    char *text;

    text = nasm_malloc(len + 1);
    strncpy(text, p, len);
    text[len] = '\0';

    if (stdscan_templen >= stdscan_tempsize) {
        stdscan_tempsize += STDSCAN_TEMP_DELTA;
        stdscan_tempstorage = nasm_realloc(stdscan_tempstorage,
                                           stdscan_tempsize *
                                           sizeof(char *));
    }
    stdscan_tempstorage[stdscan_templen++] = text;

    return text;
}

char *stdscan_bufptr = NULL;
int stdscan(void *private_data, struct tokenval *tv)
{
    char ourcopy[MAX_KEYWORD + 1], *r, *s;

    (void)private_data;         /* Don't warn that this parameter is unused */

    while (isspace(*stdscan_bufptr))
        stdscan_bufptr++;
    if (!*stdscan_bufptr)
        return tv->t_type = 0;

    /* we have a token; either an id, a number or a char */
    if (isidstart(*stdscan_bufptr) ||
        (*stdscan_bufptr == '$' && isidstart(stdscan_bufptr[1]))) {
        /* now we've got an identifier */
        int i;
        int is_sym = FALSE;

        if (*stdscan_bufptr == '$') {
            is_sym = TRUE;
            stdscan_bufptr++;
        }

        r = stdscan_bufptr++;
        /* read the entire buffer to advance the buffer pointer but... */
        while (isidchar(*stdscan_bufptr))
            stdscan_bufptr++;

        /* ... copy only up to IDLEN_MAX-1 characters */
        tv->t_charptr = stdscan_copy(r, stdscan_bufptr - r < IDLEN_MAX ?
                                     stdscan_bufptr - r : IDLEN_MAX - 1);

        if (is_sym || stdscan_bufptr - r > MAX_KEYWORD)
            return tv->t_type = TOKEN_ID;       /* bypass all other checks */

        for (s = tv->t_charptr, r = ourcopy; *s; s++)
            *r++ = tolower(*s);
        *r = '\0';
        /* right, so we have an identifier sitting in temp storage. now,
         * is it actually a register or instruction name, or what? */
        if ((tv->t_integer = bsi(ourcopy, reg_names,
                                 elements(reg_names))) >= 0) {
            tv->t_integer += EXPR_REG_START;
            return tv->t_type = TOKEN_REG;
        } else if ((tv->t_integer = bsi(ourcopy, insn_names,
                                        elements(insn_names))) >= 0) {
            return tv->t_type = TOKEN_INSN;
        }
        for (i = 0; i < elements(icn); i++)
            if (!strncmp(ourcopy, icn[i], strlen(icn[i]))) {
                char *p = ourcopy + strlen(icn[i]);
                tv->t_integer = ico[i];
                if ((tv->t_inttwo = bsi(p, conditions,
                                        elements(conditions))) >= 0)
                    return tv->t_type = TOKEN_INSN;
            }
        if ((tv->t_integer = bsi(ourcopy, prefix_names,
                                 elements(prefix_names))) >= 0) {
            tv->t_integer += PREFIX_ENUM_START;
            return tv->t_type = TOKEN_PREFIX;
        }
        if ((tv->t_integer = bsi(ourcopy, special_names,
                                 elements(special_names))) >= 0)
            return tv->t_type = TOKEN_SPECIAL;
        if (!nasm_stricmp(ourcopy, "seg"))
            return tv->t_type = TOKEN_SEG;
        if (!nasm_stricmp(ourcopy, "wrt"))
            return tv->t_type = TOKEN_WRT;
        return tv->t_type = TOKEN_ID;
    } else if (*stdscan_bufptr == '$' && !isnumchar(stdscan_bufptr[1])) {
        /*
         * It's a $ sign with no following hex number; this must
         * mean it's a Here token ($), evaluating to the current
         * assembly location, or a Base token ($$), evaluating to
         * the base of the current segment.
         */
        stdscan_bufptr++;
        if (*stdscan_bufptr == '$') {
            stdscan_bufptr++;
            return tv->t_type = TOKEN_BASE;
        }
        return tv->t_type = TOKEN_HERE;
    } else if (isnumstart(*stdscan_bufptr)) {   /* now we've got a number */
        int rn_error;

        r = stdscan_bufptr++;
        while (isnumchar(*stdscan_bufptr))
            stdscan_bufptr++;

        if (*stdscan_bufptr == '.') {
            /*
             * a floating point constant
             */
            stdscan_bufptr++;
            while (isnumchar(*stdscan_bufptr) ||
                   ((stdscan_bufptr[-1] == 'e'
                     || stdscan_bufptr[-1] == 'E')
                    && (*stdscan_bufptr == '-' || *stdscan_bufptr == '+'))) {
                stdscan_bufptr++;
            }
            tv->t_charptr = stdscan_copy(r, stdscan_bufptr - r);
            return tv->t_type = TOKEN_FLOAT;
        }
        r = stdscan_copy(r, stdscan_bufptr - r);
        tv->t_integer = readnum(r, &rn_error);
        stdscan_pop();
        if (rn_error)
            return tv->t_type = TOKEN_ERRNUM;   /* some malformation occurred */
        tv->t_charptr = NULL;
        return tv->t_type = TOKEN_NUM;
    } else if (*stdscan_bufptr == '\'' || *stdscan_bufptr == '"') {     /* a char constant */
        char quote = *stdscan_bufptr++, *r;
        int rn_warn;
        r = tv->t_charptr = stdscan_bufptr;
        while (*stdscan_bufptr && *stdscan_bufptr != quote)
            stdscan_bufptr++;
        tv->t_inttwo = stdscan_bufptr - r;      /* store full version */
        if (!*stdscan_bufptr)
            return tv->t_type = TOKEN_ERRNUM;   /* unmatched quotes */
        stdscan_bufptr++;       /* skip over final quote */
        tv->t_integer = readstrnum(r, tv->t_inttwo, &rn_warn);
        /* FIXME: rn_warn is not checked! */
        return tv->t_type = TOKEN_NUM;
    } else if (*stdscan_bufptr == ';') {        /* a comment has happened - stay */
        return tv->t_type = 0;
    } else if (stdscan_bufptr[0] == '>' && stdscan_bufptr[1] == '>') {
        stdscan_bufptr += 2;
        return tv->t_type = TOKEN_SHR;
    } else if (stdscan_bufptr[0] == '<' && stdscan_bufptr[1] == '<') {
        stdscan_bufptr += 2;
        return tv->t_type = TOKEN_SHL;
    } else if (stdscan_bufptr[0] == '/' && stdscan_bufptr[1] == '/') {
        stdscan_bufptr += 2;
        return tv->t_type = TOKEN_SDIV;
    } else if (stdscan_bufptr[0] == '%' && stdscan_bufptr[1] == '%') {
        stdscan_bufptr += 2;
        return tv->t_type = TOKEN_SMOD;
    } else if (stdscan_bufptr[0] == '=' && stdscan_bufptr[1] == '=') {
        stdscan_bufptr += 2;
        return tv->t_type = TOKEN_EQ;
    } else if (stdscan_bufptr[0] == '<' && stdscan_bufptr[1] == '>') {
        stdscan_bufptr += 2;
        return tv->t_type = TOKEN_NE;
    } else if (stdscan_bufptr[0] == '!' && stdscan_bufptr[1] == '=') {
        stdscan_bufptr += 2;
        return tv->t_type = TOKEN_NE;
    } else if (stdscan_bufptr[0] == '<' && stdscan_bufptr[1] == '=') {
        stdscan_bufptr += 2;
        return tv->t_type = TOKEN_LE;
    } else if (stdscan_bufptr[0] == '>' && stdscan_bufptr[1] == '=') {
        stdscan_bufptr += 2;
        return tv->t_type = TOKEN_GE;
    } else if (stdscan_bufptr[0] == '&' && stdscan_bufptr[1] == '&') {
        stdscan_bufptr += 2;
        return tv->t_type = TOKEN_DBL_AND;
    } else if (stdscan_bufptr[0] == '^' && stdscan_bufptr[1] == '^') {
        stdscan_bufptr += 2;
        return tv->t_type = TOKEN_DBL_XOR;
    } else if (stdscan_bufptr[0] == '|' && stdscan_bufptr[1] == '|') {
        stdscan_bufptr += 2;
        return tv->t_type = TOKEN_DBL_OR;
    } else                      /* just an ordinary char */
        return tv->t_type = (unsigned char)(*stdscan_bufptr++);
}

/*
 * Return TRUE if the argument is a simple scalar. (Or a far-
 * absolute, which counts.)
 */
int is_simple(expr * vect)
{
    while (vect->type && !vect->value)
        vect++;
    if (!vect->type)
        return 1;
    if (vect->type != EXPR_SIMPLE)
        return 0;
    do {
        vect++;
    } while (vect->type && !vect->value);
    if (vect->type && vect->type < EXPR_SEGBASE + SEG_ABS)
        return 0;
    return 1;
}

/*
 * Return TRUE if the argument is a simple scalar, _NOT_ a far-
 * absolute.
 */
int is_really_simple(expr * vect)
{
    while (vect->type && !vect->value)
        vect++;
    if (!vect->type)
        return 1;
    if (vect->type != EXPR_SIMPLE)
        return 0;
    do {
        vect++;
    } while (vect->type && !vect->value);
    if (vect->type)
        return 0;
    return 1;
}

/*
 * Return TRUE if the argument is relocatable (i.e. a simple
 * scalar, plus at most one segment-base, plus possibly a WRT).
 */
int is_reloc(expr * vect)
{
    while (vect->type && !vect->value)  /* skip initial value-0 terms */
        vect++;
    if (!vect->type)            /* trivially return TRUE if nothing */
        return 1;               /* is present apart from value-0s */
    if (vect->type < EXPR_SIMPLE)       /* FALSE if a register is present */
        return 0;
    if (vect->type == EXPR_SIMPLE) {    /* skip over a pure number term... */
        do {
            vect++;
        } while (vect->type && !vect->value);
        if (!vect->type)        /* ...returning TRUE if that's all */
            return 1;
    }
    if (vect->type == EXPR_WRT) {       /* skip over a WRT term... */
        do {
            vect++;
        } while (vect->type && !vect->value);
        if (!vect->type)        /* ...returning TRUE if that's all */
            return 1;
    }
    if (vect->value != 0 && vect->value != 1)
        return 0;               /* segment base multiplier non-unity */
    do {                        /* skip over _one_ seg-base term... */
        vect++;
    } while (vect->type && !vect->value);
    if (!vect->type)            /* ...returning TRUE if that's all */
        return 1;
    return 0;                   /* And return FALSE if there's more */
}

/*
 * Return TRUE if the argument contains an `unknown' part.
 */
int is_unknown(expr * vect)
{
    while (vect->type && vect->type < EXPR_UNKNOWN)
        vect++;
    return (vect->type == EXPR_UNKNOWN);
}

/*
 * Return TRUE if the argument contains nothing but an `unknown'
 * part.
 */
int is_just_unknown(expr * vect)
{
    while (vect->type && !vect->value)
        vect++;
    return (vect->type == EXPR_UNKNOWN);
}

/*
 * Return the scalar part of a relocatable vector. (Including
 * simple scalar vectors - those qualify as relocatable.)
 */
long reloc_value(expr * vect)
{
    while (vect->type && !vect->value)
        vect++;
    if (!vect->type)
        return 0;
    if (vect->type == EXPR_SIMPLE)
        return vect->value;
    else
        return 0;
}

/*
 * Return the segment number of a relocatable vector, or NO_SEG for
 * simple scalars.
 */
long reloc_seg(expr * vect)
{
    while (vect->type && (vect->type == EXPR_WRT || !vect->value))
        vect++;
    if (vect->type == EXPR_SIMPLE) {
        do {
            vect++;
        } while (vect->type && (vect->type == EXPR_WRT || !vect->value));
    }
    if (!vect->type)
        return NO_SEG;
    else
        return vect->type - EXPR_SEGBASE;
}

/*
 * Return the WRT segment number of a relocatable vector, or NO_SEG
 * if no WRT part is present.
 */
long reloc_wrt(expr * vect)
{
    while (vect->type && vect->type < EXPR_WRT)
        vect++;
    if (vect->type == EXPR_WRT) {
        return vect->value;
    } else
        return NO_SEG;
}

/*
 * Binary search.
 */
int bsi(char *string, const char **array, int size)
{
    int i = -1, j = size;       /* always, i < index < j */
    while (j - i >= 2) {
        int k = (i + j) / 2;
        int l = strcmp(string, array[k]);
        if (l < 0)              /* it's in the first half */
            j = k;
        else if (l > 0)         /* it's in the second half */
            i = k;
        else                    /* we've got it :) */
            return k;
    }
    return -1;                  /* we haven't got it :( */
}

static char *file_name = NULL;
static long line_number = 0;

char *src_set_fname(char *newname)
{
    char *oldname = file_name;
    file_name = newname;
    return oldname;
}

long src_set_linnum(long newline)
{
    long oldline = line_number;
    line_number = newline;
    return oldline;
}

long src_get_linnum(void)
{
    return line_number;
}

int src_get(long *xline, char **xname)
{
    if (!file_name || !*xname || strcmp(*xname, file_name)) {
        nasm_free(*xname);
        *xname = file_name ? nasm_strdup(file_name) : NULL;
        *xline = line_number;
        return -2;
    }
    if (*xline != line_number) {
        long tmp = line_number - *xline;
        *xline = line_number;
        return tmp;
    }
    return 0;
}

void nasm_quote(char **str)
{
    int ln = strlen(*str);
    char q = (*str)[0];
    char *p;
    if (ln > 1 && (*str)[ln - 1] == q && (q == '"' || q == '\''))
        return;
    q = '"';
    if (strchr(*str, q))
        q = '\'';
    p = nasm_malloc(ln + 3);
    strcpy(p + 1, *str);
    nasm_free(*str);
    p[ln + 1] = p[0] = q;
    p[ln + 2] = 0;
    *str = p;
}

char *nasm_strcat(char *one, char *two)
{
    char *rslt;
    int l1 = strlen(one);
    rslt = nasm_malloc(l1 + strlen(two) + 1);
    strcpy(rslt, one);
    strcpy(rslt + l1, two);
    return rslt;
}

void null_debug_init(struct ofmt *of, void *id, FILE * fp, efunc error)
{
}
void null_debug_linenum(const char *filename, long linenumber, long segto)
{
}
void null_debug_deflabel(char *name, long segment, long offset,
                         int is_global, char *special)
{
}
void null_debug_routine(const char *directive, const char *params)
{
}
void null_debug_typevalue(long type)
{
}
void null_debug_output(int type, void *param)
{
}
void null_debug_cleanup(void)
{
}

struct dfmt null_debug_form = {
    "Null debug format",
    "null",
    null_debug_init,
    null_debug_linenum,
    null_debug_deflabel,
    null_debug_routine,
    null_debug_typevalue,
    null_debug_output,
    null_debug_cleanup
};

struct dfmt *null_debug_arr[2] = { &null_debug_form, NULL };