In article <[email protected]> you wrote: > On Thu, 29 Nov 2012 04:29:25 -0800, Lloyd Fuller wrote: > > > >The latter can also run into issues in AMODE 64. The index register is > >always > >32 bits, not 24, 31, or 64 depending upon AMODE. Waste the extra > >nano-second, > >use the comma. It is meaningful. > > > I hadn't known that; I'm behind in my reading; thanks. Is it sign-extended, > or unsigned?
> (The worst case was the 6502, which ignored carries out of the low half > of the address, at least sometimes.) > -- gil As others have already pointed out, this isn't true. The full 64 bits are always used in the addition and any overflow is ignored. The AMODE determines the memory address to be used, ignoring (when 24 or 31 bit) the high order bits. -- Don Poitras - SAS Development - SAS Institute Inc. - SAS Campus Drive [email protected] (919) 531-5637 Cary, NC 27513 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
