36 lines
711 B
ArmAsm
Executable file
36 lines
711 B
ArmAsm
Executable file
! strncmp() Author: Kees J. Bot
|
|
! 1 Jan 1994
|
|
.sect .text; .sect .rom; .sect .data; .sect .bss
|
|
|
|
! int strncmp(const char *s1, const char *s2, size_t ecx)
|
|
! Compare two strings.
|
|
!
|
|
.sect .text
|
|
.define __strncmp
|
|
.align 16
|
|
__strncmp:
|
|
push ebp
|
|
mov ebp, esp
|
|
push esi
|
|
push edi
|
|
test ecx, ecx ! Max length is zero?
|
|
je done
|
|
mov esi, 8(ebp) ! esi = string s1
|
|
mov edi, 12(ebp) ! edi = string s2
|
|
cld
|
|
compare:
|
|
cmpsb ! Compare two bytes
|
|
jne done
|
|
cmpb -1(esi), 0 ! End of string?
|
|
je done
|
|
dec ecx ! Length limit reached?
|
|
jne compare
|
|
done: seta al ! al = (s1 > s2)
|
|
setb ah ! ah = (s1 < s2)
|
|
subb al, ah
|
|
movsxb eax, al ! eax = (s1 > s2) - (s1 < s2), i.e. -1, 0, 1
|
|
pop edi
|
|
pop esi
|
|
pop ebp
|
|
ret
|