Assembly Language on Ubuntu
By Emma Martinez •
So I was currently studying about assembly language and I came across this awesome command on terminal, gcc -S filename.cpp, that produces the assembly code of a C++ source file.
But after I installed NASM and tried to link and compile the .S file (I also tried to use .asm by copy-pasting the code from the .s file), I only ended up facing errors in the terminal.
I am sure there were no errors in the C++ source file because its just a hello world program, but I know that I am missing something and Im hoping someone can point it out for me.
Here is the c++ source code:
#include <iostream>
using namespace std;
int main ()
{ cout<<"wtf"; return 0;
}Here is the .s file code:
.file "try1.cpp" .text .section .rodata .type _ZStL19piecewise_construct, @object .size _ZStL19piecewise_construct, 1
_ZStL19piecewise_construct: .zero 1 .local _ZStL8__ioinit .comm _ZStL8__ioinit,1,1
.LC0: .string "wtf" .text .globl main .type main, @function
main:
.LFB1493: .cfi_startproc pushq %rbp .cfi_def_cfa_offset 16 .cfi_offset 6, -16 movq %rsp, %rbp .cfi_def_cfa_register 6 leaq .LC0(%rip), %rsi leaq _ZSt4cout(%rip), %rdi call _ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc@PLT movl $0, %eax popq %rbp .cfi_def_cfa 7, 8 ret .cfi_endproc
.LFE1493: .size main, .-main .type _Z41__static_initialization_and_destruction_0ii, @function
_Z41__static_initialization_and_destruction_0ii: .LFB1977: .cfi_startproc pushq %rbp .cfi_def_cfa_offset 16 .cfi_offset 6, -16 movq %rsp, %rbp .cfi_def_cfa_register 6 subq $16, %rsp movl %edi, -4(%rbp) movl %esi, -8(%rbp) cmpl $1, -4(%rbp) jne .L5 cmpl $65535, -8(%rbp) jne .L5 leaq _ZStL8__ioinit(%rip), %rdi call _ZNSt8ios_base4InitC1Ev@PLT leaq __dso_handle(%rip), %rdx leaq _ZStL8__ioinit(%rip), %rsi movq _ZNSt8ios_base4InitD1Ev@GOTPCREL(%rip), %rax movq %rax, %rdi call __cxa_atexit@PLT
.L5: nop leave .cfi_def_cfa 7, 8 ret .cfi_endproc
.LFE1977: .size _Z41__static_initialization_and_destruction_0ii, .-_Z41__static_initialization_and_destruction_0ii .type _GLOBAL__sub_I_main, @function
_GLOBAL__sub_I_main:
.LFB1978: .cfi_startproc pushq %rbp .cfi_def_cfa_offset 16 .cfi_offset 6, -16 movq %rsp, %rbp .cfi_def_cfa_register 6 movl $65535, %esi movl $1, %edi call _Z41__static_initialization_and_destruction_0ii popq %rbp .cfi_def_cfa 7, 8 ret .cfi_endproc
.LFE1978: .size _GLOBAL__sub_I_main, .-_GLOBAL__sub_I_main .section .init_array,"aw" .align 8 .quad _GLOBAL__sub_I_main .hidden __dso_handle .ident "GCC: (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0" .section .note.GNU-stack,"",@progbitsHere is the error message from the terminal:
oliver@Nimitz:~$ nasm -f elf64 try1.asm
try1.asm:1: error: attempt to define a local label before any non-local labels
try1.asm:1: error: parser: instruction expected
try1.asm:2: warning: label alone on a line without a colon might be in error [-w+orphan-labels]
try1.asm:2: error: attempt to define a local label before any non-local labels
try1.asm:3: error: attempt to define a local label before any non-local labels
try1.asm:3: error: parser: instruction expected
try1.asm:4: error: attempt to define a local label before any non-local labels
try1.asm:4: error: parser: instruction expected
try1.asm:5: error: attempt to define a local label before any non-local labels
try1.asm:5: error: parser: instruction expected
try1.asm:7: error: parser: instruction expected
try1.asm:8: error: parser: instruction expected
try1.asm:9: error: parser: instruction expected
try1.asm:11: error: parser: instruction expected
try1.asm:12: warning: label alone on a line without a colon might be in error [-w+orphan-labels]
try1.asm:13: error: parser: instruction expected
try1.asm:14: error: parser: instruction expected
try1.asm:17: warning: label alone on a line without a colon might be in error [-w+orphan-labels]
try1.asm:18: error: parser: instruction expected
try1.asm:19: error: parser: instruction expected
try1.asm:20: error: parser: instruction expected
try1.asm:21: error: expression syntax error
try1.asm:22: error: parser: instruction expected
try1.asm:23: error: parser: instruction expected
try1.asm:24: error: symbol `leaq' redefined
try1.asm:24: error: parser: instruction expected
try1.asm:26: error: parser: instruction expected
try1.asm:27: error: parser: instruction expected
try1.asm:28: error: parser: instruction expected
try1.asm:30: warning: label alone on a line without a colon might be in error [-w+orphan-labels]
try1.asm:32: error: parser: instruction expected
try1.asm:33: error: parser: instruction expected
try1.asm:36: warning: label alone on a line without a colon might be in error [-w+orphan-labels]
try1.asm:37: error: symbol `pushq' redefined
try1.asm:37: error: parser: instruction expected
try1.asm:38: error: parser: instruction expected
try1.asm:39: error: parser: instruction expected
try1.asm:40: error: expression syntax error
try1.asm:41: error: parser: instruction expected
try1.asm:42: error: parser: instruction expected
try1.asm:43: error: symbol `movl' redefined
try1.asm:43: error: parser: instruction expected
try1.asm:44: error: symbol `movl' redefined
try1.asm:44: error: parser: instruction expected
try1.asm:45: error: parser: instruction expected
try1.asm:47: error: symbol `cmpl' redefined
try1.asm:47: error: parser: instruction expected
try1.asm:49: error: symbol `leaq' redefined
try1.asm:49: error: parser: instruction expected
try1.asm:51: error: symbol `leaq' redefined
try1.asm:51: error: parser: instruction expected
try1.asm:52: error: symbol `leaq' redefined
try1.asm:52: error: parser: instruction expected
try1.asm:53: error: comma, colon, decorator or end of line expected after operand
try1.asm:53: error: expression syntax error
try1.asm:54: error: expression syntax error
try1.asm:59: error: parser: instruction expected
try1.asm:61: warning: label alone on a line without a colon might be in error [-w+orphan-labels]
try1.asm:63: error: parser: instruction expected
try1.asm:64: error: parser: instruction expected
try1.asm:67: warning: label alone on a line without a colon might be in error [-w+orphan-labels]
try1.asm:68: error: symbol `pushq' redefined
try1.asm:68: error: parser: instruction expected
try1.asm:69: error: parser: instruction expected
try1.asm:70: error: parser: instruction expected
try1.asm:71: error: expression syntax error
try1.asm:72: error: parser: instruction expected
try1.asm:73: error: symbol `movl' redefined
try1.asm:73: error: parser: instruction expected
try1.asm:74: error: symbol `movl' redefined
try1.asm:74: error: parser: instruction expected
try1.asm:76: error: symbol `popq' redefined
try1.asm:76: error: parser: instruction expected
try1.asm:77: error: parser: instruction expected
try1.asm:79: warning: label alone on a line without a colon might be in error [-w+orphan-labels]
try1.asm:81: error: parser: instruction expected
try1.asm:82: error: parser: instruction expected
try1.asm:83: error: parser: instruction expected
try1.asm:84: error: parser: instruction expected
try1.asm:85: error: parser: instruction expected
try1.asm:86: error: parser: instruction expected
try1.asm:87: error: symbol `.section' redefined
try1.asm:87: error: parser: instruction expected
oliver@Nimitz:~$ 
