Both of those will be flagged and the result won't be what you're expecting. USING just informs the assembler of how to convert a relocatable expression into a base and displacement; it doesn;t change the architecture.
I can't e-mail a list from work due to network security but maybe someone else will be willing to do it, Or is everybody locked down these days? -- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 עַם יִשְׂרָאֵל חַי נֵ֣צַח יִשְׂרָאֵ֔ל לֹ֥א יְשַׁקֵּ֖ר ________________________________________ From: IBM Mainframe Assembler List <[email protected]> on behalf of Tony Harminc <[email protected]> Sent: Wednesday, February 11, 2026 12:27 AM To: [email protected] <[email protected]> Subject: Re: Move data to a location prior to a given (based) address External Message: Use Caution On Tue, 10 Feb 2026 at 23:21, Seymour J Metz <[email protected]> wrote: > You can't have a negative displacement on an RS or RX instruction. It's a > 12 bit unsigned field, padded with zeros on the left. Sure - 12-bit displacements are unsigned, and addressing arithmetic using them is unsigned. But the assembler can help you by allowing specification of a negative number if there is a suitable USING in effect. Off the top of my head, something like LHI R5,-1024 USING -1024,R5 LA R1,-123(R1) Subtract 123 from R1 Tony H.
