Question

So I have a simple C program that loops through the args passed to main then returns:

#include <stdio.h>

int main(int argc, char *argv[])
{
    int i;
    for(i = 0; i < argc; ++i) {
        fprintf(stdout, "%s\n", argv[i]);
    }
    return 0;
}

I wanted to see how gcc wrote out the assembly in NASM format. I was looking over the output in the .asm file and noticed that the syntax was TASM. Below is the make file and the output from gcc. Am I doing something wrong or is it that gcc does not output true NASM syntax?

all: main

main: main.o
        ld -o main main.o

main.o : main.c
        gcc -S -masm=intel -o main.asm main.c
        nasm -f elf -g -F stabs main.asm -l main.lst

AND

    .file   "main.c"
    .intel_syntax noprefix
    .section    .rodata
.LC0:
    .string "%s\n"
    .text
.globl main
    .type   main, @function
main:
    push    ebp
    mov ebp, esp
    and esp, -16
    sub esp, 32
    mov DWORD PTR [esp+28], 0
    jmp .L2
.L3:
    mov eax, DWORD PTR [esp+28]
    sal eax, 2
    add eax, DWORD PTR [ebp+12]
    mov ecx, DWORD PTR [eax]
    mov edx, OFFSET FLAT:.LC0
    mov eax, DWORD PTR stdout
    mov DWORD PTR [esp+8], ecx
    mov DWORD PTR [esp+4], edx
    mov DWORD PTR [esp], eax
    call    fprintf
    add DWORD PTR [esp+28], 1
.L2:
    mov eax, DWORD PTR [esp+28]
    cmp eax, DWORD PTR [ebp+8]
    jl  .L3
    mov eax, 0
    leave
    ret
    .size   main, .-main
    .ident  "GCC: (GNU) 4.5.1 20100924 (Red Hat 4.5.1-4)"
    .section    .note.GNU-stack,"",@progbits

The errors on the command line are:

[mehoggan@fedora sandbox-print_args]$ make
gcc -S -masm=intel -o main.asm main.c
nasm -f elf -g -F stabs main.asm -l main.lst
main.asm:1: error: attempt to define a local label before any non-local labels
main.asm:1: error: parser: instruction expected
main.asm:2: error: attempt to define a local label before any non-local labels
main.asm:2: error: parser: instruction expected
main.asm:3: error: attempt to define a local label before any non-local labels
main.asm:3: error: parser: instruction expected
main.asm:4: error: attempt to define a local label before any non-local labels
main.asm:5: error: attempt to define a local label before any non-local labels
main.asm:5: error: parser: instruction expected
main.asm:6: error: attempt to define a local label before any non-local labels
main.asm:7: error: attempt to define a local label before any non-local labels
main.asm:7: error: parser: instruction expected
main.asm:8: error: attempt to define a local label before any non-local labels
main.asm:8: error: parser: instruction expected
main.asm:14: error: comma, colon or end of line expected
main.asm:17: error: comma, colon or end of line expected
main.asm:19: error: comma, colon or end of line expected
main.asm:20: error: comma, colon or end of line expected
main.asm:21: error: comma, colon or end of line expected
main.asm:22: error: comma, colon or end of line expected
main.asm:23: error: comma, colon or end of line expected
main.asm:24: error: comma, colon or end of line expected
main.asm:25: error: comma, colon or end of line expected
main.asm:27: error: comma, colon or end of line expected
main.asm:29: error: comma, colon or end of line expected
main.asm:30: error: comma, colon or end of line expected
main.asm:35: error: parser: instruction expected
main.asm:36: error: parser: instruction expected
main.asm:37: error: parser: instruction expected
make: *** [main.o] Error 1

What lead me to believe that this is TASM syntax was information posted at this link:
http://rs1.szif.hu/~tomcat/win32/intro.txt

TASM coders usually have lexical difficulties with NASM because it
lacks the “ptr” keyword used extensively in TASM.

TASM uses this:

mov al, byte ptr [ds:si] or mov ax, word ptr [ds:si] or mov eax,
dword ptr [ds:si]

For NASM This simply translates into:

mov al, byte [ds:si] or mov ax, word [ds:si] or mov eax, dword
[ds:si]

NASM allows these size keywords in many places, and thus gives you a
lot of control over the generated opcodes in a unifrom way, for
example These are all valid:

push dword 123 jmp [ds: word 1234] ; these both specify the size
of the offset jmp [ds: dword 1234] ; for tricky code when
interfacing 32bit and
; 16bit segments

it can get pretty hairy, but the important thing to remember is you
can have all the control you need, when you want it.

Answer 1

Intel syntax means Intel syntax, not NASM syntax. MASM and TASM syntaxes are based on Intel Syntax, NASM syntax gets inspiration from Intel syntax, but it is different.

What gcc outputs is actually gas syntax using Intel syntax for individual instructions, (Assembler directives, labels et al. use gas-specific syntax)