I seek for any lib or function to convert a string of assembly code to machine code, like the following:
char asmString[] = {\"mov eax,13H\"}; byte[] output;
Here is a project that can convert a string of assembly code (Intel or ARM) into its corresponding bytes.
https://github.com/bsmt/Assembler
It's written in Objective-C, but the source is there. I hope this helps.