Atoi

[HellOfMice]

A classic function revisited

Code Select Expand

;   __________________________________________________________________________________

                            ALIGN   16

;   *****************************************************************
;   *** All the registers are saved except: RAX RCX RDX R8 and R9 ***
;   *****************************************************************

;   Registers used: RDI, RAX, RBX, RCX, RDX, R10 and R11

Atoi                        PROC    USES RBX RDI R10 R11,__lpszNumericString:LPSTR PARMAREA = 4 * QWORD
                            mov     rdi,rcx

                            xor     eax,eax
                            xor     edx,edx                         ; Set initial total to 0
                            xor     ecx,ecx

                            mov     r11d,10                         ; No more than 10 characters: 123 456 789 012
                            mov     r10b,'0'                        ; Stock bounds into registers
                            mov     bl,'9'

                            ALIGN   16
Atoi_convert :
                            mov     al,BYTE PTR [rdi]               ; Get the current character

                            test    al,al                           ; Check for \0
                            jz      Atoi_done

                            cmp     al,r10b                         ; Anything less than 0 is invalid
                            jge     @F                              ; I try to use AL very often to reduce the code

                            jmp     Atoi_error

                            ALIGN   16
@@:
                            cmp     al,bl                           ; Anything greater than 9 is invalid
                            jle     @F

                            jmp     Atoi_error

                            ALIGN   16
@@ :
                            sub     al,r10b                         ; Convert from ASCII to decimal

                            mov     cl,dl
                            shl     edx,3                            ; * 8 ----> No multiplication
                            shl     ecx,1                            ; * 2
                            add     edx,ecx                         ; Multiply total by 10
                            add     edx,eax                         ; Add current digit to total

                            add     edi,1                           ; Get the address of the next character

                            sub     r11d,1                           ; SUB & ADD used rather than INC & DEC
                            jnz     Atoi_convert

                            ALIGN   16
Atoi_error :
                            mov  rax,-1                              ; Return -1 on error in RAX

                            ALIGN   16
Atoi_done :
                            mov     eax,edx  ; CWD more effiscient?

                            ret                                     ; Return total or error code
;   __________________________________________________________________________________
Atoi                        ENDP




If the Input String has more than 10 chacaracters, the function stops.Maybe there is no ending '\0'

[Vortex]

Here is another version from the Masm64 package :

Code Select Expand

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    .code

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atou_ex proc

  ; ------------------------------------------------
  ; Convert decimal string into UNSIGNED QWORD value
  ; ------------------------------------------------
  ; argument in RCX

    xor r11, r11
    movzx rax, BYTE PTR [rcx]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+1]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+2]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+3]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+4]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+5]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+6]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+7]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+8]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+9]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+10]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+11]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+12]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+13]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+14]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+15]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+16]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+17]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+18]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+19]
    test rax, rax
    jz quit

    lea r11, [r11+r11*4]
    lea r11, [rax+r11*2-48]
    movzx rax, BYTE PTR [rcx+20]
    test rax, rax
    jnz out_of_range

  quit:
    lea rax, [r11]      ; return value in EAX
    or rcx, -1          ; non zero in RCX for success
    ret

  out_of_range:
    xor rax, rax        ; zero return value on error
    xor rcx, rcx        ; zero in ECX is out of range error
    ret

atou_ex endp

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    end


[HellOfMice]

VORTEX, I should appreciate that you explain it in details


I have changed of keyboard this morning, now it has led every where and they exchanged 2 keys (END and DEL)! So excuse me if words are not well written. Made in China...

[John Z]

Hi Vortex,

MASM64??  Where to get this package?  I thought MASM32 was all there was...

John Z

[HellOfMice]

Hi John,


I think that there is a copyright on it. So you will not find it as a free compiler. Try to download windows SDK
I prefer POASM and you can use the debugger with it. The syntax is very close from MASM

[John Z]

Hi John,


I think that there is a copyright on it. So you will not find it as a free compiler. Try to download windows SDK
I prefer POASM and you can use the debugger with it. The syntax is very close from MASM

Thanks!

John Z

[Vortex]

Hi John,

You can get the Masm64 SDK from this thread :

https://masm32.com/board/index.php?topic=10880.0

Hi Philippe,

OK, I will try later to post here the explanation of the source code.

[HellOfMice]

Thank You Vortex, it seems too hard for me

[John Z]

Hi John,

You can get the Masm64 SDK from this thread :

https://masm32.com/board/index.php?topic=10880.0

Thanks very much Vortex!!  This might motivate me to take it up again....I'm certainly going to load and look.

John Z

[HellOfMice]

I cannot install the VLSX file. I stopped the antivirus but no result the file crash. I open the file with 7zip and extracted the X64 folder

[TimoVJL]

I cannot install the VLSX file..... I open the file with 7zip and extracted the X64 folder

A that packed file is just part of installation and update system, not something like msi.

[HellOfMice]

It has been extracted with 7zip

[TimoVJL]

And what you think, that i have missed ?
Just stay in in this actual topic about asm atoi 

[HellOfMice]

In four days it is Christmas
for thank you for the work made in this forum
I made you this (see below)


It is a sad year, Pelle has gone. I like what he did and found him very strong.
I hope he has no personal problem and a good health.
I will wish the same thing for the next year.


When I look at the biathlon on TV I often think to you.


A+


Philippe

[Vortex]

Hello,

With thanks to jj2007, member of the Masm Forum, you can try the new Masm64 package downloading also the Microsoft Masm 64-bit assembler :

Masm64 SDK installer: betatesters please

https://masm32.com/board/index.php?topic=12051.0

Direct link :

https://masm32.com/files/MASM64-SDKdev/Working/Installer/Masm64Sdk21set24.zip