forked from KolibriOS/kolibrios
47 lines
1.3 KiB
ArmAsm
47 lines
1.3 KiB
ArmAsm
# strchr() Author: Kees J. Bot 1 Jan 1994
|
|
|
|
# char *strchr(const char *s, int c)
|
|
# Look for a character in a string.
|
|
|
|
.intel_syntax
|
|
|
|
.globl _strchr
|
|
|
|
.text
|
|
.align 16
|
|
_strchr:
|
|
push ebp
|
|
mov ebp, esp
|
|
push edi
|
|
cld
|
|
mov edi, [ebp+8] # edi = string
|
|
mov edx, 16 # Look at small chunks of the string
|
|
next:
|
|
shl edx, 1 # Chunks become bigger each time
|
|
mov ecx, edx
|
|
xorb al, al # Look for the zero at the end
|
|
repne scasb
|
|
|
|
pushf # Remember the flags
|
|
sub ecx, edx
|
|
neg ecx # Some or all of the chunk
|
|
sub edi, ecx # Step back
|
|
movb al, [ebp+12] # The character to look for
|
|
repne scasb
|
|
je found
|
|
|
|
popf # Did we find the end of string earlier?
|
|
|
|
jne next # No, try again
|
|
|
|
xor eax, eax # Return NULL
|
|
pop edi
|
|
pop ebp
|
|
ret
|
|
found:
|
|
pop eax # Get rid of those flags
|
|
lea eax, [edi-1] # Address of byte found
|
|
pop edi
|
|
pop ebp
|
|
ret
|