subroutine int2asc

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C.H.R

Joined: 28 Jul 2017
Posts: 5
Location: Colombia

C.H.R 20 Dec 2017, 22:00

Thank you very much Ville
Im sorry, I dont understood the part of ( until that no left part integer in rax)

I wrote the following:

Code:

int2asc:    ; function to convert int to ascii
    push    rbp  ; args in: integer(RDI), ptr buffer(RSI)
    mov rbp, rsp
    sub rbp, 0x10
    
    xor rax, rax
    xchg rdi, rsi
    
    mov rcx, 0
    mov r15, 10
    mov rax, rsi
  np:
    div r15
    add dl, 48
    mov byte[rdi], dl
    inc rdi
    dec rax
    cmp rax, 0
    jnz np
    
    leave
    ret

Say me what's wrong here.

Much obliged.
Nice day.

20 Dec 2017, 22:00

CandyMan

Joined: 04 Sep 2009
Posts: 413
Location: film "CandyMan" directed through Bernard Rose OR Candy Shop

CandyMan 21 Dec 2017, 11:51

Code:

int2asc:    ; function to convert int to ascii ; args in: integer(RDI), ptr buffer(RSI)
        xchg    rdi,rsi
        mov     rax,rsi
        mov     r15d,10
np:
        xor     edx,edx
        div     r15
        add     dl,48
        mov     [rdi],dl
        inc     rdi

        or      rax,rax
        jnz     np
        ret

stack frame and "dec rax" is unnecessary

_________________
smaller is better

21 Dec 2017, 11:51

C.H.R

Joined: 28 Jul 2017
Posts: 5
Location: Colombia

C.H.R 21 Dec 2017, 21:56

Thanks CandyMan. I will test it inmediatly. Thanks for the push.

21 Dec 2017, 21:56

tthsqe

Joined: 20 May 2009
Posts: 767

tthsqe 22 Dec 2017, 06:12

It looks like CandyMan reads the digits backwards or has quite a unique system.

Code:

PrintUnsignedInteger:
        ; in: rax unsigned integer
        ; io: rdi string
                mov   ecx, 10
                mov   r8, rsp
        .l1:    xor   edx, edx
                div   rcx
               push   rdx
               test   rax, rax
                jnz   .l1
        .l2:    pop   rax
                add   al, '0'
              stosb
                cmp   rsp, r8
                 jb   .l2
                ret

22 Dec 2017, 06:12

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20304
Location: In your JS exploiting you and your system

revolution 22 Dec 2017, 08:41

tthsqe wrote:

It looks like CandyMan reads the digits backwards or has quite a unique system.

It's called little endian. Most spoken and written natural languages use big endian base-10, but I wonder if that is really the best choice?

22 Dec 2017, 08:41

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