asm/rdstrnum.c

/* ----------------------------------------------------------------------- *
 *   
 *   Copyright 1996-2016 The NASM Authors - All Rights Reserved
 *   See the file AUTHORS included with the NASM distribution for
 *   the specific copyright holders.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following
 *   conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * 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 COPYRIGHT HOLDERS AND
 *     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 COPYRIGHT OWNER OR
 *     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.
 *
 * ----------------------------------------------------------------------- */

/*
 * rdstrnum.c
 *
 * This converts a NASM string to an integer, used when a string
 * is used in an integer constant context.  This is a binary conversion,
 * not a conversion from a numeric constant in text form.
 */

#include "compiler.h"
#include "nasmlib.h"
#include "nasm.h"

int64_t readstrnum(char *str, int length, bool *warn)
{
    int64_t charconst = 0;
    int i;

    *warn = false;

    str += length;
    if (globalbits == 64) {
        for (i = 0; i < length; i++) {
            if (charconst & UINT64_C(0xFF00000000000000))
                *warn = true;
            charconst = (charconst << 8) + (uint8_t)*--str;
        }
    } else {
        for (i = 0; i < length; i++) {
            if (charconst & 0xFF000000UL)
                *warn = true;
            charconst = (charconst << 8) + (uint8_t)*--str;
        }
    }
    return charconst;
}