kvisc/ka/str/strcmp.k

; The OS/K Team licenses this file to you under the MIT license.
; See the LICENSE file in the project root for more information.

;
; int strcmp(const char *str1, const char *str2)
;
; Returns:
;    0 if the contents of both strings are equal
;    1 if the first character that does not match has a greater value in str1 than in str2
;   -1 if the first character that does not match has a lower value in str1 than in str2
;

strcmp:
    cmp b[ax0], b[ax1]
    jmp.nz .1

    test b[ax0], b[ax0]
    jmp.z .1

    inc ax0
    inc ax1
    jmp strcmp

.1:
    mov rax, b[ax0]
    sub rax, b[ax1]
    sgn rax, rax
    ret

;
; int strncmp(const char *str1, const char *str2, int maxn)
;
strncmp:
    mov rcx, ax2

.0:
    cmp b[ax0], b[ax1]
    jmp.nz .1

    test b[ax0], b[ax0]
    jmp.z .1

    inc ax0
    inc ax1
    loop .0

.1:
    mov rax, b[ax0]
    sub rax, b[ax1]
    sgn rax, rax
    ret