It’s not possible to program the board that way, or at least I'm not aware of any method for this. The following threads might be of your interest since they discuss similar topics; however, it’s not possible to program the board through assembly code:
- Compiler for Compiling only in Assembly code?
- Assembly in Intel Galileo (you received a similar response to mine in this thread)
actually it is possible to use an assembler code to play with gpio pins.
Please let me some time to make a public code example.
So, an example is here: https://github.com/xbolshe/galileo-sources/tree/master/blink_asm
This is an assembler application. It is not so hard to copy it into a C program as assembly inline code.