CODEWITHSUNDEEP
assemblyx86nasm
LubosD
LubosD

Reputation: 840

Position independent code in NASM (32bit)

How can I simply call an external symbol in a library function written in 32bit x86 assembler? This works under x86-64 (NASM):

extern ExternSymbol

MyFunc:
    ...
    call ExternSymbol WRT ..plt

The same code compiled for 32bit x86 jumps to address 0x0.

Upvotes: 2

Views: 2335

Answers (1)

Jester
Jester

Reputation: 58762

You must be doing something wrong, as it works for me like this:

$ cat >libfoo.c
int foo() { return 42; }
$ gcc -m32 -shared -o libfoo.so libfoo.c
$ cat >main.asm
[bits 32]
extern foo
global _start
_start:
call foo wrt ..plt
mov ebx, eax
mov eax, 1
int 80h
$ nasm -f elf32 main.asm
$ gcc -nostdlib -m32 -L. -lfoo main.o
$ LD_LIBRARY_PATH=. ./a.out
$ echo $?
42

Upvotes: 2

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