nasm.c

nasm早期的源代码,比较简单是学习汇编和编译原理的好例子

    if (!*p)
        return 0;

    q = p++;

    while (*p && *p != ';') {
        if (!isspace(*p))
            return 0;
        p++;
    }
    q[1] = '\0';

    *directive = p = buf + 1;
    while (*buf && *buf != ' ' && *buf != ']' && *buf != '\t')
        buf++;
    if (*buf == ']') {
        *buf = '\0';
        *value = buf;
    } else {
        *buf++ = '\0';
        while (isspace(*buf))
            buf++;              /* beppu - skip leading whitespace */
        *value = buf;
        while (*buf != ']')
            buf++;
        *buf++ = '\0';
    }

    return bsii(*directive, directives, elements(directives));
}

/**
 * gnu style error reporting
 * This function prints an error message to error_file in the
 * style used by GNU. An example would be:
 * file.asm:50: error: blah blah blah
 * where file.asm is the name of the file, 50 is the line number on 
 * which the error occurs (or is detected) and "error:" is one of
 * the possible optional diagnostics -- it can be "error" or "warning"
 * or something else.  Finally the line terminates with the actual 
 * error message.
 * 
 * @param severity the severity of the warning or error 
 * @param fmt the printf style format string
 */
static void report_error_gnu(int severity, const char *fmt, ...)
{
    va_list ap;

    if (is_suppressed_warning(severity))
        return;

    if (severity & ERR_NOFILE)
        fputs("nasm: ", error_file);
    else {
        char *currentfile = NULL;
        int32_t lineno = 0;
        src_get(&lineno, &currentfile);
        fprintf(error_file, "%s:%"PRId32": ", currentfile, lineno);
        nasm_free(currentfile);
    }
    va_start(ap, fmt);
    report_error_common(severity, fmt, ap);
    va_end(ap);
}

/**
 * MS style error reporting
 * This function prints an error message to error_file in the
 * style used by Visual C and some other Microsoft tools. An example 
 * would be:
 * file.asm(50) : error: blah blah blah
 * where file.asm is the name of the file, 50 is the line number on 
 * which the error occurs (or is detected) and "error:" is one of
 * the possible optional diagnostics -- it can be "error" or "warning"
 * or something else.  Finally the line terminates with the actual 
 * error message.
 * 
 * @param severity the severity of the warning or error 
 * @param fmt the printf style format string
 */
static void report_error_vc(int severity, const char *fmt, ...)
{
    va_list ap;

    if (is_suppressed_warning(severity))
        return;

    if (severity & ERR_NOFILE)
        fputs("nasm: ", error_file);
    else {
        char *currentfile = NULL;
        int32_t lineno = 0;
        src_get(&lineno, &currentfile);
        fprintf(error_file, "%s(%"PRId32") : ", currentfile, lineno);
        nasm_free(currentfile);
    }
    va_start(ap, fmt);
    report_error_common(severity, fmt, ap);
    va_end(ap);
}

/**
 * check for supressed warning
 * checks for suppressed warning or pass one only warning and we're 
 * not in pass 1
 *
 * @param severity the severity of the warning or error
 * @return true if we should abort error/warning printing
 */
static int is_suppressed_warning(int severity)
{
    /*
     * See if it's a suppressed warning.
     */
    return ((severity & ERR_MASK) == ERR_WARNING &&
            (severity & ERR_WARN_MASK) != 0 &&
            suppressed[(severity & ERR_WARN_MASK) >> ERR_WARN_SHR]) ||
        /*
         * See if it's a pass-one only warning and we're not in pass one.
         */
        ((severity & ERR_PASS1) && pass0 == 2);
}

/**
 * common error reporting
 * This is the common back end of the error reporting schemes currently
 * implemented.  It prints the nature of the warning and then the 
 * specific error message to error_file and may or may not return.  It
 * doesn't return if the error severity is a "panic" or "debug" type.
 * 
 * @param severity the severity of the warning or error 
 * @param fmt the printf style format string
 */
static void report_error_common(int severity, const char *fmt,
                                va_list args)
{
    switch (severity & ERR_MASK) {
    case ERR_WARNING:
        fputs("warning: ", error_file);
        break;
    case ERR_NONFATAL:
        fputs("error: ", error_file);
        break;
    case ERR_FATAL:
        fputs("fatal: ", error_file);
        break;
    case ERR_PANIC:
        fputs("panic: ", error_file);
        break;
    case ERR_DEBUG:
        fputs("debug: ", error_file);
        break;
    }

    vfprintf(error_file, fmt, args);
    fputc('\n', error_file);

    if (severity & ERR_USAGE)
        want_usage = true;

    switch (severity & ERR_MASK) {
    case ERR_WARNING:
    case ERR_DEBUG:
        /* no further action, by definition */
        break;
    case ERR_NONFATAL:
        /* hack enables listing(!) on errors */
        terminate_after_phase = true;
        break;
    case ERR_FATAL:
        if (ofile) {
            fclose(ofile);
            remove(outname);
        }
        if (want_usage)
            usage();
        exit(1);                /* instantly die */
        break;                  /* placate silly compilers */
    case ERR_PANIC:
        fflush(NULL);
        /*	abort();	*//* halt, catch fire, and dump core */
        exit(3);
        break;
    }
}

static void usage(void)
{
    fputs("type `nasm -h' for help\n", error_file);
}

static void register_output_formats(void)
{
    ofmt = ofmt_register(report_error);
}

#define BUF_DELTA 512

static FILE *no_pp_fp;
static efunc no_pp_err;
static ListGen *no_pp_list;
static int32_t no_pp_lineinc;

static void no_pp_reset(char *file, int pass, efunc error, evalfunc eval,
                        ListGen * listgen)
{
    src_set_fname(nasm_strdup(file));
    src_set_linnum(0);
    no_pp_lineinc = 1;
    no_pp_err = error;
    no_pp_fp = fopen(file, "r");
    if (!no_pp_fp)
        no_pp_err(ERR_FATAL | ERR_NOFILE,
                  "unable to open input file `%s'", file);
    no_pp_list = listgen;
    (void)pass;                 /* placate compilers */
    (void)eval;                 /* placate compilers */
}

static char *no_pp_getline(void)
{
    char *buffer, *p, *q;
    int bufsize;

    bufsize = BUF_DELTA;
    buffer = nasm_malloc(BUF_DELTA);
    src_set_linnum(src_get_linnum() + no_pp_lineinc);

    while (1) {                 /* Loop to handle %line */

        p = buffer;
        while (1) {             /* Loop to handle long lines */
            q = fgets(p, bufsize - (p - buffer), no_pp_fp);
            if (!q)
                break;
            p += strlen(p);
            if (p > buffer && p[-1] == '\n')
                break;
            if (p - buffer > bufsize - 10) {
                int offset;
                offset = p - buffer;
                bufsize += BUF_DELTA;
                buffer = nasm_realloc(buffer, bufsize);
                p = buffer + offset;
            }
        }

        if (!q && p == buffer) {
            nasm_free(buffer);
            return NULL;
        }

        /*
         * Play safe: remove CRs, LFs and any spurious ^Zs, if any of
         * them are present at the end of the line.
         */
        buffer[strcspn(buffer, "\r\n\032")] = '\0';

        if (!nasm_strnicmp(buffer, "%line", 5)) {
            int32_t ln;
            int li;
            char *nm = nasm_malloc(strlen(buffer));
            if (sscanf(buffer + 5, "%"PRId32"+%d %s", &ln, &li, nm) == 3) {
                nasm_free(src_set_fname(nm));
                src_set_linnum(ln);
                no_pp_lineinc = li;
                continue;
            }
            nasm_free(nm);
        }
        break;
    }

    no_pp_list->line(LIST_READ, buffer);

    return buffer;
}

static void no_pp_cleanup(int pass)
{
    (void)pass;                     /* placate GCC */
    fclose(no_pp_fp);
}

static uint32_t get_cpu(char *value)
{
    if (!strcmp(value, "8086"))
        return IF_8086;
    if (!strcmp(value, "186"))
        return IF_186;
    if (!strcmp(value, "286"))
        return IF_286;
    if (!strcmp(value, "386"))
        return IF_386;
    if (!strcmp(value, "486"))
        return IF_486;
    if (!strcmp(value, "586") || !nasm_stricmp(value, "pentium"))
        return IF_PENT;
    if (!strcmp(value, "686") ||
        !nasm_stricmp(value, "ppro") ||
        !nasm_stricmp(value, "pentiumpro") || !nasm_stricmp(value, "p2"))
        return IF_P6;
    if (!nasm_stricmp(value, "p3") || !nasm_stricmp(value, "katmai"))
        return IF_KATMAI;
    if (!nasm_stricmp(value, "p4") ||   /* is this right? -- jrc */
        !nasm_stricmp(value, "willamette"))
        return IF_WILLAMETTE;
    if (!nasm_stricmp(value, "prescott"))
        return IF_PRESCOTT;
    if (!nasm_stricmp(value, "x64") ||
        !nasm_stricmp(value, "x86-64"))
        return IF_X86_64;
    if (!nasm_stricmp(value, "ia64") ||
        !nasm_stricmp(value, "ia-64") ||
        !nasm_stricmp(value, "itanium") ||
        !nasm_stricmp(value, "itanic") || !nasm_stricmp(value, "merced"))
        return IF_IA64;

    report_error(pass0 < 2 ? ERR_NONFATAL : ERR_FATAL,
                 "unknown 'cpu' type");

    return IF_PLEVEL;           /* the maximum level */
}

static int get_bits(char *value)
{
    int i;

    if ((i = atoi(value)) == 16)
        return i;               /* set for a 16-bit segment */
    else if (i == 32) {
        if (cpu < IF_386) {
            report_error(ERR_NONFATAL,
                         "cannot specify 32-bit segment on processor below a 386");
            i = 16;
        }
    } else if (i == 64) {
        if (cpu < IF_X86_64) {
            report_error(ERR_NONFATAL,
                         "cannot specify 64-bit segment on processor below an x86-64");
            i = 16;
        }
        if (i != maxbits) {
            report_error(ERR_NONFATAL,
                         "%s output format does not support 64-bit code",
                         ofmt->shortname);
            i = 16;
        }
    } else {
        report_error(pass0 < 2 ? ERR_NONFATAL : ERR_FATAL,
                     "`%s' is not a valid segment size; must be 16, 32 or 64",
                     value);
        i = 16;
    }
    return i;
}

/* end of nasm.c */