C++ to assembly conversion

[Kaishain]

Hello,

I'm looking for a way of getting an assembly version of my programs. For example, I have the below (small) program called average.c:

#include <stdio.h>
float average(float x, float y);
int main() {
        float a, b, c;
        a = 1;
        b = 3;
        c = average(a, b);
        printf("The average of %f and %f is %f.\n", a, b, c);
}
float average(float x, float y) {
        float z;
        z = (x + y) / 2; /* The average */
        return z;
}

I want to convert this to an assembly version, something like the following:

0x08048390 <main+32>: sub   $0x8,%esp
0x08048393 <main+35>: pushl 0xfffffff8(%ebp)
0x08048396 <main+38>: pushl 0xfffffffc(%ebp)

At the moment, I'm using the command 'gcc -S average.c', but it is only giving me the following type of assembly:

main:
        pushl   %ebp
        movl    %esp, %ebp
        subl    $24, %esp
        andl    $-16, %esp
        movl    $0, %eax

Does anyone know of a way to convert my C file to an assembly file that contains all the memory addresses, etc., as per the second piece of code above?


Thanks,
K

[G_Morgan]

Assembly usually uses relocatable code so won't hard code addresses. It deals with symbolic addresses rather than actual addresses. You won't get addresses until the loader has got the program running.

[Kaishain]

Thanks for the reply!

When I run the program through GDB, I can type in, say, "main+52" and it comes up with some debugging information including the memory address of that piece of code.

Is there a way of doing something similar, but to all of the code at once? I don't want to have to type "main+1", "main+2", etc. all the way through the program as it'd just take forever...


Thanks again,
K

[G_Morgan]

Sorry I don't know, I don't use GDB. I find unit testing to be far quicker and more effective than traditional debuggers.

[Kaishain]

I'll keep looking then. There must be a way of showing all the memory locations of pieces of code during run-time. Thanks for your replies anyway!

[axneer]

code might be like this--
for main function

pushl	%ebp
	movl	%esp, %ebp
	subl	$40, %esp
	movl	$0x3f800000, %eax
	movl	%eax, -4(%ebp)
	movl	$0x40400000, %eax
	movl	%eax, -8(%ebp)
	movl	-8(%ebp), %eax
	movl	%eax, 4(%esp)
	movl	-4(%ebp), %eax
	movl	%eax, (%esp)
	call	_average
	fstps	-12(%ebp)
	flds	-12(%ebp)
	fstpl	20(%esp)
	flds	-8(%ebp)
	fstpl	12(%esp)
	flds	-4(%ebp)
	fstpl	4(%esp)
	movl	$LC2, (%esp)
	call	_printf
	leave
	ret

for average function

LC1:
	.long	1073741824
	
pushl	%ebp
	movl	%esp, %ebp
	subl	$8, %esp
	flds	8(%ebp)
	fadds	12(%ebp)
	flds	LC1
	fdivrp	%st, %st(1)
	fstps	-4(%ebp)
	movl	-4(%ebp), %eax
	movl	%eax, -8(%ebp)
	flds	-8(%ebp)
	leave
	ret