how to call a function called 'add' in ml64

Question

Paul Moore 1

How can I write assembler code that

This is not a problem for masm32 as all functions are really called _func , ie _add

But x64 calling convention retains the function snames

nasm can do this but as far as I can see ml64 cannot

2 answers

Answer 1

Viorel 121.3K

Try to use the ALIAS directive:

.code

ALIAS <add> = <myAdd>

myAdd proc

    mov rax, rcx
    add rax, rdx

    ret

myAdd endp

end

extern "C" int add( int a, int b );

. . .

int x = add( 10, 20 ); // result: 30

Paul Moore 1 Reputation point

2025-04-23T20:19:09.6733333+00:00

thank you

I end up with add being a weak external, what does that mean

009 00000000 UNDEF notype WeakExternal | add

How about calling a function called add
Darran Rowe 1,541 Reputation points

2025-04-24T14:59:12.88+00:00
The way MASM parses files is pretty simple, this means that when it sees add then it will always be interpreted as an instruction. Any assembly instruction mnemonic will be recognised as an instruction.

The ALIAS directive is MASM's way of getting around this kind of issue by adding a second name to a function. So the WeakExternal is this second name, and it will be routed to the aliased function without issue. So this means that you have a function named add.

To give a full example.

//test.c #include <stdio.h> extern int add(int, int); int main() { int v = add(1, 2); printf("%d\n", v); return 0; }

//test64.asm _TEXT SEGMENT ALIAS <add> = <myadd> myadd PROC mov rax, rcx add rax, rdx ret myadd ENDP _TEXT ENDS END

For calling the add function. If you mean in assembly, then you would have to use the original function name. But yes, you can call this a weakness of MASM.
Paul Moore 1 Reputation point

2025-04-24T21:23:41.29+00:00

so its impossible for ml64 to call out to a function called 'add'

Answer 2

Anton Demetri 0

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