Inline Asmebly with C (Trying to use nasm syntax)

[Israel]

Ok, some of you probably know what this code does, that's has nothing to do with this. I've been translating some AT&T syntax over to nasm with no problem. But suddenly with this code I've had a problem. Here is the C code with AT&T syntax:

Code: Select all

#include <stdio.h>
unsigned long get_sp(void){
   __asm__("movl %esp, %eax");
}
int main(){
   printf("Stack Pointer (ESP): 0x%x\n", get_sp());
}

That works fine. But when I try to put in as nasm syntax like this:

Code: Select all

#include <stdio.h>
unsigned long get_sp(void){
   __asm__("mov eax, esp");
}
int main(){
   printf("Stack Pointer (ESP): 0x%x\n", get_sp());
}

I get this error from the compiler:

Code: Select all

$ gcc -o get_nasm get_nasm.c
get_nasm.c: Assembler messages:
get_nasm.c:3: Error: too many memory references for `mov'


Does C not allow inline-assembly in nasm syntax? Or am I missing something in the code. I'm quite new to Assembly so I won't be surprised.

[mischief]

gcc uses gas ('as' from binutils) as it's assembler, and gas takes AT&T syntax. read the manpage for more info :p

[tgoe]

Code: Select all

#include <stdio.h>
unsigned long get_sp(void){
   __asm__(".intel_syntax noprefix\n mov eax, esp");
}
int main(){
   printf("Stack Pointer (ESP): 0x%x\n", get_sp());
}


Code: Select all

$ gcc asm.c -masm=intel


Not sure if that is the right way to do things but it compiles and runs.

[Israel]

Works for me. But I had to use:

Code: Select all

gcc -o get_nasm get_nasm.c -masm=intel

Or I wouldn't get an executable

Thanks, I was about to give up and start going with AT&T.