#NUP lab4 (x_pasrev)

// labnup4.cpp: определяет точку входа для консольного приложения.
//
//pasrev - аналог strrev для pascal-строк
#include "string.h"
#include "stdafx.h"

#if defined(__GNUC__)
char *x_pasrev(char *str) {
    unsigned char len = str[0];
    if (len < 2) return str;
    unsigned char *beg = str + 1, *end = str + len, i;
    for (i = 0; i < len / 2; i++) {
        asm("movb (%0), %%al\n\t"
            "movsb\n\t"
            "movb %%al, -1(%1)\n\t"
            "sub $2, %0\n\t" : "+D"(end), "+S"(beg) : : "al");
    }
    return str;
}
#else
char *x_pasrev(char *str) {
    unsigned char len = str[0];
    if (len < 2) return str;
    unsigned char *beg = str + 1, *end = str + len, i;
    for (i = 0; i < len / 2; i++) {
        __asm {
            mov esi, beg
            mov edi, end

            mov al, [edi]
            movsb
            mov [esi - 1], al
            sub edi, 2

            mov beg, esi
            mov end, edi
        }
    }
    return str;
}
#endif

int main()
{
    int i;
    char pastr1[9] = { 8, 'D', 'E', 'S', 'S', 'E', 'R', 'T', 'S'};
    printf("in :%d ", pastr1[0]);
    for (i = 1; i < pastr1[0] + 1; i++) printf("%c", pastr1[i]);
    char *pastr2 = x_pasrev(pastr1);
    printf("\nout:%d ", pastr2[0]);
    for (i = 1; i < pastr2[0] + 1; i++) printf("%c", pastr2[i]);


    char pastr3[5] = { 4, 'E', 'V', 'I', 'L' };
    printf("\nin :%d ", pastr3[0]);
    for (i = 1; i < pastr3[0] + 1; i++) printf("%c", pastr3[i]);
    char *pastr4 = x_pasrev(pastr3);
    printf("\nout:%d ", pastr4[0]);
    for (i = 1; i < pastr4[0] + 1; i++) printf("%c", pastr4[i]);

    getchar();
    return 0;
}