Some of you may recall that I urged caution in a response to Edward Jaffe's post about the use of unsigned arithmetic. (His specific interest was in establishing mnemonics for the jumps employed with unsigned binary-integer values.)
This morning, in the course of writing a BXLEG instruction in a code skeleton, I had a minor epiphany. BXH and BXLE use signed four-byte binary-integer arithmetic, and BXHG and BXL:EG of course use signed eight-byte binary-integer arithmetic. Unsigned quantities are thus not immediately usable with indexed branching instructions. For the uses EJ contemplates, this is, I imagine, unimportant. For some of the computational work I do it is a severe limitation. I should have, but did not, mention this in my original post. John Gilmore, Ashland, MA 01721 - USA ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
