On Mon, 20 Oct 2008 20:31:08 -0500, W. Kevin Kelley wrote: >On Mon, 20 Oct 2008 15:00:48 -0500, Paul Gilmartin ><[EMAIL PROTECTED]> wrote: > >>I thought 31-bit was for compatibility with existing exploitation >>of the sign bit; ... > >Nope, it was the use of a X'80' in the high-order byte of a fullword to >terminate a variable-length parameter list (of fullwords). > "Nope"? Where do you perceive us to be in disagreement?
Of course, with the transition from 370 to XA, the bit could no longer be set with MVI; OI was required. This almost certainly provoked an interminable thread on ASSEMBLER-LIST concerning the performance impact. I'd hardly be surprised, though, if OI on XA ran faster than MVI on 370. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
