Just a few more multiplication instructions, and we will move forward in the alphabet from “M”. MHY is a companion instruction to MFY. These two instructions share the same instruction format: RXY-a. Remember that “Y”-type instructions can reach farther from the base address, both forward and backward. You can find a writeup here.
Review an Instruction: MHY
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Hilarious!
The ‘Y’ indexing affords extended addressability whilst (potentially) overflowing base register addressing.
Note to self – write, exclusively, re-entrant code and mind the constants in the CSECT