Actually the assembly code is the machine code, after compiling.
With the amxx compiler all i know is that you can get the asm of a sma.
Check the compiler parameters, it's there.
Perhaps there's a way to convert asm to amxx.
To convert from asm to sma seems kinda stupid. It's like writing a program in asm, convert it to c/c++ than back to asm when compiling.