On Thu, 9 Nov 2023 12:54:36 -0500, Dave Clark <[email protected]> wrote:
>"IBM Mainframe Assembler List" <[email protected]> wrote on >11/09/2023 12:33:58 PM: >> Principles is your friend! > > Yes, I will be doing some reading. But a few quick answers are >helpful. > Please do. It isn't that hard to look up one instruction (BRC) and read the half page or so that documents it. > > OK, so the "normal" relative jump is the signed, 16-bit variety >mentioned (15-bit relative target with left-most bit as the direction). >How is that +/- 65K? Wouldn't that be +/- 32K? As clearly documented in the POO it is +/- 32K halfwords. >Or are there actually >three varieties -- 16-bit, 32-bit, and the "even longer ones" you hinted >at? The relative long instructions with a 32-bit relative offset allows for plus/minus 4GB from the PSW address. You want even longer than that? -- Tom Marchant
