ui32toa 模拟

; Prototype
;    eax ui32toa(unsigned int num, char *str, int base)
; Param
;    num: The unsigned 32-bit integer to be tranlated.
;    str: The address of a buffer where to save the ASCII result.
;    base: The basement of division.
; Function own the stack.
; Paramter push from left to right.
ui32toa    PROC NEAR32
    push    ebp
    mov    ebp, esp
    pushf
    push    ebx    ; Base of divisor
    push    edx
    push    esi
    push    edi

    mov    ebx, [ebp + 8]
    mov    esi, [ebp + 12]
    mov    edi, esi
    mov    eax, [ebp + 16]
    cld

    ; Add a null terminate character in the front of buffer.
    push    eax
    mov    eax, 0
    stosb    
    pop    eax

    ; Integer to ASCII.
while_ui32toa:
    mov    edx, 0
    div    ebx
    cmp    dl, 10        
    jb    below_10_ui32toa
    sub    dl, 10        ; dl > 10 => dl -= 10
    add    dl, 31h        ; Add 11h additional to hexidecimal character and so on.
below_10_ui32toa:
    add    dl, 30h        ; To ASCII.

    xchg    eax, edx
    stosb
    xchg    eax, edx
    cmp    eax, 0
    jne    while_ui32toa

    ; Reverse the ASCII string
    dec    edi
while_reverse_ui32toa:
    mov    al, [esi]
    xchg    al, [edi]
    mov    [esi], al
    inc    esi
    dec    edi
    cmp    esi, edi
    jb    while_reverse_ui32toa

exit_ui32toa:
    pop    edi
    pop    esi
    pop    edx
    pop    ebx
    popf
    pop    ebp
    ret    4
ui32toa    ENDP


; Prototype
;    eax i32toa(int num, char *str, int base)
; Param
;    num: The unsigned 32-bit integer to be tranlated.
;    str: The address of a buffer where to save the ASCII result.
;    base: The basement of division.
; Function own the stack.
; Paramter push from left to right.
i32toa    PROC NEAR32
    push    ebp
    mov    ebp, esp
    pushf
    push    ebx    ; Base of divisor
    push    edx
    push    esi
    push    edi

    mov    ebx, [ebp + 8]
    mov    esi, [ebp + 12]
    mov    edi, esi
    mov    eax, [ebp + 16]
    cld

    ; Add a null terminate character in the front of buffer.
    push    eax
    mov    eax, 0
    stosb    
    pop    eax

    ; Integer to ASCII.
while_i32toa:
    cdq
    idiv    ebx
    cmp    dl, 0
    jge    greater_0_i32toa    
    neg    dl        ; dl < 0 => dl = -dl
greater_0_i32toa:
    cmp    dl, 10        
    jl    less_10_i32toa
    sub    dl, 10        ; dl > 10 => dl -= 10
    add    dl, 31h        ; Add 11h additional to hexidecimal character and so on.
less_10_i32toa:
    add    dl, 30h        ; To ASCII.

    xchg    eax, edx
    stosb
    xchg    eax, edx
    cmp    eax, 0
    jne    while_i32toa

    ; Judge the sign
    mov    eax, [ebp + 16]
    cmp    eax, 0
    jge    positive_i32toa
    mov    al, '-'
    stosb
positive_i32toa:

    ; Reverse the ASCII string
    dec    edi
while_reverse_i32toa:
    mov    al, [esi]
    xchg    al, [edi]
    mov    [esi], al
    inc    esi
    dec    edi
    cmp    esi, edi
    jb    while_reverse_i32toa

exit_i32toa:
    pop    edi
    pop    esi
    pop    edx
    pop    ebx
    popf
    pop    ebp
    ret    4
i32toa    ENDP