String search, Int to String and String to int

String search, Int to String and String to int
This was used in an old proyect by me... don't have time anymore so I want to share it...


macro strsearch text,char,register
{
    push ebx
    xor register,register ;set esi to 0
    mov ebx,text   ;copy caption to edx
    @@:
    cmp byte [ebx],char ;compare if current char is 0
    je @f    ;if equal then goto forward
    inc register  ;not equal so inc esi and ebx
    inc ebx
    jmp @b   ;keep with the loop until 0 is found
    @@:
    pop ebx
}

;Converts an int into a null terminated string
macro itoa int,destination
{
local .loop
xor esi,esi



mov eax,[int]
mov edi,destination

push eax
mov ebx,10

@@:;calculate the number of digits
xor edx,edx
div ebx
inc esi
cmp eax,0
jne @b

add edi,esi;-1
dec edi
mov [edi+1],byte 0 ;0 ended strings!

mov ecx,esi ;number of loops
mov ebx,10
pop eax
.loop:
xor edx,edx ;se necesita para la division
div ebx ;eax=number divided by ten. edx=modulo
add edx,'0' ;"0" is added to convert number to ascii char (0 + "0" = "0", 1+"0"="1", 5+"0"=5 etc.)
mov [edi],dl ;move the char to the string
dec edi ;continue with another char
loop .loop
;alternative way;
;cmp edi,destination
;jne .loop
 }

 ;Converts a string into an integer
macro atoi string,destination
{
xor eax,eax
mov esi,string

mov ebx,10 ;we'll be multiplying by 10
.digitloop:
mul ebx ;shift eax by one decimal digit left (eg. multuiply by 10)
;or dx,dx             ;check if edx was affected... then overflow
;jz .overflow
movzx ecx,byte [esi]  ;mov byte[si] to CL and zero CH
inc esi
or ecx,ecx ;end if 0 found
jz .done
sub ecx,'0' ;convert from ascii digit to digit
add eax,ecx
jmp .digitloop
.done:
xor edx,edx
div ebx
mov [destination],eax
}

better version of strsearch (strchr)


macro strsearch text,char,register 
{
   mov edi, text
   mov ecx,255        ;text's len ist max 255 char
   mov al,char
   cld
   repne scasb

   mov register,255
   sub register,ecx
}

for a "strlen" function, you can simply remplace char by 0 and dec register:


macro strlen string, register
{
   mov edi,text
   mov ecx,255
   mov al,0
   cld
   repne scasb

   mov register,255
   sub  register,ecx
  dec register
}

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