30 July 2015

Tip: How to create short jmp

When doing some assembler I noticed an important optimization setting for jumps. To force the compiler to generate short jumps (short jmp, short jz, short jnz) the Branch optimization setting must be >= 1.


A short jump requires 2 bytes of opcode instructions. Otherwise a jump takes 6 bytes. Short jumps are only generates when the target is within 127 bytes offset, of course.