日記/2010/07/15/文字列をスタック上にPUSHするコードの自動生成, NASM用

#include <stdio.h>
#include <string.h>
 
int main(int argc, char *argv[])
{
    int len, d;
    int i, j, k;
    char *src;
    char cbuf[4];
    char *offset_label = "OFFSET";
    
    if (2 > argc) {
        fprintf(stderr, "usage: %s push_string <offset_label>\n", argv[0]);
        return 1;
    }
    
    src = argv[1];
    len = strlen(src);
    if (3 == argc) {
        offset_label = argv[2];
    }
    printf("; '%s', 0 (%d = 0x%X bytes)\n", src, len + 1, len + 1);
    printf("%%define %s ebp - 0000h\n", offset_label);
    d = len / 4;
    if (len % 4) {
        d++;
    }
    
    for (i = 0, j = 0, k = 0; i < d; i++) {
        cbuf[0] = src[j++];
        cbuf[1] = (j > len) ? 0 : src[j++];
        cbuf[2] = (j > len) ? 0 : src[j++];
        cbuf[3] = (j > len) ? 0 : src[j++];
        printf("mov eax, 0%02X%02X%02X%02Xh\n", 
            cbuf[3], cbuf[2], cbuf[1], cbuf[0]);
        printf("mov dword[%s + 0%Xh], eax\n", offset_label, k);
        k += 4;
    }
    return 0;
}