Assembly & C Code

gcd.asm:


segment data

segment bss

segment text
    global gcd
gcd:
    push ebp
    mov  ebp,esp
    mov  eax,[ebp+8]        ; x
    mov  ebx,[ebp+12]       ; y
looptop:
    cmp  eax,0              ; if (x == 0) we're done
    je   goback
    cmp  eax,ebx            ; make certain x is the larger number
    jge  modulo
    xchg eax,ebx            ; swap x and y
modulo:
    cdq                    ; set up for division
    idiv ebx               ; divide edxeax by eb
    mov  eax,edx           ; the remainder is in edx
    jmp  looptop

goback:
    mov  eax,ebx           ; return y
    mov  esp,ebp
    pop  ebp
    ret



gcdargs.asm:


segment .data

segment .bss

segment .text
    global gcdargs
gcdargs:
    push ebp
    mov  ebp,esp
looptop:
    mov  eax,[ebp+8]
    cmp  eax,0              ; if (x == 0) we're done
    je   goback
    mov  ebx,[ebp+12]
    cmp  eax,ebx            ; make certain x is the larger number
    jge  modulo
    mov  eax,[ebp+8]
    xchg eax,[ebp+12]
    mov  [ebp+8],eax
modulo:
    mov  ebx,[ebp+12]
    mov  eax,[ebp+8]
    cdq                    ; set up for division
    idiv ebx               ; divide edxeax by ebx
    mov  [ebp+8],edx           ; the remainder is in edx
    jmp  looptop

goback:
    mov  eax,[ebp+12]           ; return y
    mov  esp,ebp
    pop  ebp
    ret



gcdlocal.asm:


segment .data

segment .bss

segment .text
    global gcdlocal
gcdlocal:
    push ebp
    mov  ebp,esp
    sub  esp,8              ; room for local variables
    mov  eax,[ebp+8]        ; x
    mov  [ebp-4],eax
    mov  eax,[ebp+12]       ; y
    mov  [ebp-8],eax
looptop:
    mov  eax,[ebp-4]
    cmp  eax,0              ; if (x == 0) we're done
    je   goback
    cmp  eax,[ebp-8]        ; make certain x is the larger number
    jge  modulo
    xchg eax,[ebp-8]
    mov  [ebp-4],eax
modulo:
    mov  ebx,[ebp-8]
    mov  eax,[ebp-4]
    cdq                    ; set up for division
    idiv ebx               ; divide edxeax by ebx
    mov  [ebp-4],edx       ; the remainder is in edx
    jmp  looptop

goback:
    mov  eax,[ebp-8]           ; return y
    mov  esp,ebp
    pop  ebp
    ret



gcdmem.asm:


segment .data

segment .bss
x:    resd  1
y:    resd  1
segment .text
    global gcdmem
gcdmem:
    push ebp
    mov  ebp,esp
    mov  eax,[ebp+8]        ; x
    mov  [x],eax
    mov  eax,[ebp+12]       ; y
    mov  [y],eax
looptop:
    mov  eax,[x]
    cmp  eax,0              ; if (x == 0) we're done
    je   goback
    mov  ebx,[y]
    cmp  eax,ebx            ; make certain x is the larger number
    jge  modulo
    mov  [x],ebx
    mov  [y],eax
modulo:
    mov  ebx,[y]
    mov  eax,[x]
    cdq                    ; set up for division
    idiv ebx               ; divide edxeax by ebx
    mov  [x],edx           ; the remainder is in edx
    jmp  looptop

goback:
    mov  eax,[y]           ; return y
    mov  esp,ebp
    pop  ebp
    ret

--------------------------------------
mainline.c:


#include <stdio.h>

int gcd(int a,int b);

int main()
{
    int result;
    int a;
    int b;

    a = 46;
    b = 90;
    printf("%d and %d have a gcd of %d\n",a,b,gcd(a,b));

    a = 9863;
    b = 41272;
    printf("%d and %d have a gcd of %d\n",a,b,gcd(a,b));
}



mainlineargs.c:



#include <stdio.h>

int gcdargs(int a,int b);

int main()
{
    int result;
    int a;
    int b;

    a = 46;
    b = 90;
    printf("%d and %d have a gcd of %d\n",a,b,gcdargs(a,b));

    a = 9863;
    b = 41272;
    printf("%d and %d have a gcd of %d\n",a,b,gcdargs(a,b));
}

mainlinelocal.c:



#include <stdio.h>

int gcdlocal(int a,int b);

int main()
{
    int result;
    int a;
    int b;

    a = 46;
    b = 90;
    printf("%d and %d have a gcd of %d\n",a,b,gcdlocal(a,b));

    a = 9863;
    b = 41272;
    printf("%d and %d have a gcd of %d\n",a,b,gcdlocal(a,b));
}


mainlinemem.c:


#include <stdio.h>

int gcdmem(int a,int b);

int main()
{
    int result;
    int a;
    int b;

    a = 46;
    b = 90;
    printf("%d and %d have a gcd of %d\n",a,b,gcdmem(a,b));

    a = 9863;
    b = 41272;
    printf("%d and %d have a gcd of %d\n",a,b,gcdmem(a,b));
}