This chapter goes through some programming snippets and examples to give a feeling about how the instructions work.
To left justify the number, one can take advantage of the sign flag which will be set when the leftmost bit is set. To avoid an infinite loop, one need to test the input value in X for zero. The following code snippet performs a left justify:
TST X ; set sign and zero flags according to X
FS? 00 ; zero?
GTO 00 ; yes, done
LBL 01 ; no, loop to left justify
FS? 01 ; negative?
GTO 00 ; yes, done
SL 01 ; shift left, setting flags
GTO 01
LBL 00