CODEWITHSUNDEEP
cubuntunasm
zepolar
zepolar

Reputation: 41

How can i call a assembly function from another assembly file?

Actually, I'm using NASM for my scholar project. The idea is to build one static library for Math Operations.

I've been able to build separate functions in different asm files. Example:

But I have an third asm file that it must call the 2 functions: add_vectorial and sub_vectorial for to do some calculus.

I've read that i must to use the call word for calling my external function. But I don't have idea how can i pass the parameter??

Example of my code:

extern add_vectorial

global operation:    ;for linux

operation:
            ;Initialize a stack frame
            push    ebp
            mov     ebp, esp
            ;Loading the arguments values
            mov     ebx, [ebp+8]    ; ebx='d'
            mov     ecx, [ebp+12]   ; ecx='v1'
            mov     edx, [ebp+16]   ; edx='v2'
            mov     eax, [ebp+20]   ; eax = rt

            ;Initial the xmm4 registry with zero.
            xorps   xmm4, xmm4
.body:

            ;Here, How can i pass the parameters to my asm external function?
            call   add_vectorial

.done:
            ;Restore the call's stack frame pointer
            leave                   ; mov esp,ebp / pop ebp 
            ret                     ; return from function

Upvotes: 2

Views: 6166

Answers (3)

zepolar
zepolar

Reputation: 41

Thanks guys for your support... Finally I found a one solution to my problem... I leave my solution..

%macro call_fun1  4
pushad             ;I put this
push %4
push %3
push %2
push %1
call sub_vectorial
add  esp, 16   ;4p*4bytes
popad             ;I put this
%endmacro

Upvotes: 2

zepolar
zepolar

Reputation: 41

I've created a macro for calling my external functions, passing the parameter like in C.

%macro call_fun1  4
push %4
push %3
push %2
push %1
call sub_vectorial
add  ebp, 16   ;4p*4bytes
%endmacro

Only when i integrate this code with my main asm file, give me the follow error: Program received signal SIGSEGV, Segmentation fault.

For this reason i made one unit test of my function, but the function work fine.

The error only is to give when i integrate with the rest of my code.

Upvotes: 0

bodangly
bodangly

Reputation: 2624

You can either pass the parameters by pushing them onto the stack before you execute the call statement, or by inserting them into registers first.

Upvotes: 0

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