FASM x86 - strlen and strcmp implementation
I wrote my own implementation of strlen and strcmp from C in x86 FASM and I would like to know is there anything that should be changed/removed/added.
strlen needs string in eax and its returning length of that string into ebx
strlen:
mov ebx,0
strlen_loop:
cmp byte [eax+ebx],0
je strlen_end
inc ebx
jmp strlen_loop
strlen_end:
inc ebx
ret
strcmp needs two strings (one in eax, second in ebx) and its returning 0 if strings are equal or 1/-1 if they are not into ecx.
strcmp:
mov ecx,0
strcmp_loop:
mov byte dl,[eax+ecx]
mov byte dh,[ebx+ecx]
inc ecx
cmp dl,0
je strcmp_end_0
cmp byte dl,dh
je strcmp_loop
jl strcmp_end_1
jg strcmp_end_2
strcmp_end_0:
cmp dh,0
jne strcmp_end_1
ret
strcmp_end_1:
mov ecx,1
ret
strcmp_end_2:
mov ecx,-1
ret
x86
asked 4 mins ago
DeBos
12
add a comment |
I wrote my own implementation of strlen and strcmp from C in x86 FASM and I would like to know is there anything that should be changed/removed/added.
strlen needs string in eax and its returning length of that string into ebx
strlen:
mov ebx,0
strlen_loop:
cmp byte [eax+ebx],0
je strlen_end
inc ebx
jmp strlen_loop
strlen_end:
inc ebx
ret
strcmp needs two strings (one in eax, second in ebx) and its returning 0 if strings are equal or 1/-1 if they are not into ecx.
strcmp:
mov ecx,0
strcmp_loop:
mov byte dl,[eax+ecx]
mov byte dh,[ebx+ecx]
inc ecx
cmp dl,0
je strcmp_end_0
cmp byte dl,dh
je strcmp_loop
jl strcmp_end_1
jg strcmp_end_2
strcmp_end_0:
cmp dh,0
jne strcmp_end_1
ret
strcmp_end_1:
mov ecx,1
ret
strcmp_end_2:
mov ecx,-1
ret
x86
asked 4 mins ago
DeBos
12
add a comment |
I wrote my own implementation of strlen and strcmp from C in x86 FASM and I would like to know is there anything that should be changed/removed/added.
strlen needs string in eax and its returning length of that string into ebx
strlen:
mov ebx,0
strlen_loop:
cmp byte [eax+ebx],0
je strlen_end
inc ebx
jmp strlen_loop
strlen_end:
inc ebx
ret
strcmp needs two strings (one in eax, second in ebx) and its returning 0 if strings are equal or 1/-1 if they are not into ecx.
strcmp:
mov ecx,0
strcmp_loop:
mov byte dl,[eax+ecx]
mov byte dh,[ebx+ecx]
inc ecx
cmp dl,0
je strcmp_end_0
cmp byte dl,dh
je strcmp_loop
jl strcmp_end_1
jg strcmp_end_2
strcmp_end_0:
cmp dh,0
jne strcmp_end_1
ret
strcmp_end_1:
mov ecx,1
ret
strcmp_end_2:
mov ecx,-1
ret
x86
asked 4 mins ago
DeBos
12
I wrote my own implementation of strlen and strcmp from C in x86 FASM and I would like to know is there anything that should be changed/removed/added.
strlen needs string in eax and its returning length of that string into ebx
strlen:
mov ebx,0
strlen_loop:
cmp byte [eax+ebx],0
je strlen_end
inc ebx
jmp strlen_loop
strlen_end:
inc ebx
ret
strcmp needs two strings (one in eax, second in ebx) and its returning 0 if strings are equal or 1/-1 if they are not into ecx.
strcmp:
mov ecx,0
strcmp_loop:
mov byte dl,[eax+ecx]
mov byte dh,[ebx+ecx]
inc ecx
cmp dl,0
je strcmp_end_0
cmp byte dl,dh
je strcmp_loop
jl strcmp_end_1
jg strcmp_end_2
strcmp_end_0:
cmp dh,0
jne strcmp_end_1
ret
strcmp_end_1:
mov ecx,1
ret
strcmp_end_2:
mov ecx,-1
ret
x86
x86
asked 4 mins ago
DeBos
12
asked 4 mins ago
DeBos
12
asked 4 mins ago
DeBos
12
asked 4 mins ago
DeBos
12
asked 4 mins ago
DeBos
12
12
add a comment |
add a comment |
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