How to generate a nasm compilable assembly code from c source code on Linux?

If you're lazy: https://github.com/diogovk/c2nasm

There I have a script that does Babken Vardanyan's suggestion automatically.

I find it's a better approach to disassemble the object files rather than use assembly code generated by gcc.

First, generate an object file from your source code:
```
gcc -fno-asynchronous-unwind-tables -O2 -s -c -o main.o main.c
```
-fno-asynchronous-unwind-tables: do not generate unnecessary sections like .eh_frame

-O2 optimizes so the asm isn't horrible. Optionally use -Os (size over speed) or -O3 (full optimization including auto-vectorization). Also you can tune for a CPU and and use extensions it supports with -march=native or -march=haswell or -march=znver1 (Zen)

-s: make smaller executable (strip)

-c -o main.o: compile but don't link, generate an object file called main.o
Use objconv to generate nasm code:
```
objconv -fnasm main.o
```
The result will be stored in main.asm.
The result will be very close to Nasm syntax. However you might need to make some minor tweaks to eliminiate warnings/errors. Simply try to compile it with Nasm
```
nasm -f elf32 main.asm
```
and fix the errors/warnings by hand. For example:
- remove the align=N and execute/noexecute words from .SECTION lines.
- remove the text : function from global declarations
- remove the default rel line
- remove empty sections if you wish etc
Link the resulting main.o which generated by Nasm in step 3 using gcc:
```
gcc main.o
```
You can also link it using ld but it's much harder.

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