count by sevens

Print every multiple of seven from 7 up to and including 70, one per line.

The starter holds the first multiple and the limit in callee-saved registers. Write the loop: print, step by seven, and keep going while the counter has not passed the limit. Since printf is a function call, it is free to clobber the caller-saved registers; that is exactly why the loop state lives in x19callee-saved register (x19-x28): a routine must restore it before it returns. and x20callee-saved register (x19-x28): a routine must restore it before it returns..

what is checked

• ten lines, 7 through 70
• the program exits cleanly
• a comparison drives the loop