How do I get a full assembly code from c file?

Question

I\'m currently trying to figure out the way to produce equivalent assembly code from corresponding c source file. (pardon me for not being able to speak English fluently, I\'m n

Answer 1

_exp is the standard math library function double exp(double); apparently you're on a platform that prepends a leading underscore to C symbol names.

Given a .s that calls some library functions, build it the same way you would a .c file that calls library functions:

gcc foo.S -o foo  -lm

You'll get a dynamic executable by default.

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But if you really want all the code in one file with no external dependencies, you can link your .c into a static executable and disassemble that.

gcc -O3 -march=native foo.c -o foo -static -lm
objdump -drwC -Mintel foo > foo.s

There's no guarantee that the _exp implementation in libm.a (static library) is identical to the one you'd get in libm.so or libm.dll or whatever, because it's a different file. This is especially true for a function like memcpy where dynamic-linker tricks are often used to select an optimal version (for your CPU) at run-time.