string.h

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#ifndef STRING_H
#define STRING_H
 
#include "types.h"
 
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wreturn-type"
bool strcmp(int str1, int str2) {
    asm("L%=:\n"
        "   mov al, [si+bx]\n"
        "   cmp al, [di+bx]\n"
        "   jne neq%=\n"
        "   cmp al,0\n"
        "   je eq%=\n"
        "   inc bx\n"
        "jmp L%=\n"
        "eq%=:\n"
        "   mov ax, 1\n"
        "   jmp end%=\n"
        "neq%=:\n"
        "   mov ax, 0\n"
        "end%=:"
        ::"b"(0), "S"(str1), "D"(str2));
}
 
size_t strlen(const char *str) {
    asm("xor eax,eax\n"
        "L%=:\n"
        "   cmp BYTE ptr [si+bx], 0\n"
        "   je end%=\n"
        "   inc bx\n"
        "   jmp L%=\n"
        "end%=:\n"
        "   mov eax, ebx"::"b"(0), "S"(str));
}
 
#pragma GCC diagnostic pop
 
const char * strchr ( const char * str, int character ) {
    while(*str != 0) {
        if(*str == character)
            return str;
        str++;
    }
    return NULL;
}
 
const uint32_t pows[] = {1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000};
int stoi(const char *str) {
    int num = 0;
    size_t size = strlen(str) - 1;
    for(size_t i = (str[0] == '-' ? 1 : 0); str[i] != 0; i++)
        num += pows[size - i] * (str[i] - '0');
 
    return (str[0] == '-') ? -num : num;
}
 
int memset(int ptr, int value, size_t count) {
    asm("L%=:\n\
        mov [bx],dx\n\
        inc bx\n\
        loop L%="
        ::"b"(ptr), "c"(count), "d"(value));
    return ptr;
}
 
char * strcpy ( char * destination, const char * source ) {
    //copy all characters, including null
    int i = 0;
    do {
        destination[i] = source[i];
        i++;
    } while(source[i - 1] != 0);
    return destination;
}
 
int strncpy (int destination, int source, size_t num ) {
    asm("L%=:\n"
        "   mov al, byte ptr [si+bx]\n"
        "   mov byte ptr [di+bx], al\n"
        "   cmp al,0\n"
        "   je after%=\n"
        "   inc bx\n"
        "loop L%=\n"
        "after%=:"
        ::"D"(destination), "S"(source), "b"(0), "c"(num));
    return destination;
}
 
#endif