Since virtual storage is now so much less expensive and so much more available than storage [1] was 50 years ago, why not be really extravagant and use one whole byte per store? If the byte contains 0, then the store number is not valid, or something like that, and if the byte contains anything other than 0, then the store number is valid. This should result in much simpler code to access this table. Bill Fairchild Nolensville, TN [1] In those days, there was no virtual or real storage available on IBM's mainframes. There was only "storage".
----- Original Message ----- From: "Gerhard Postpischil" <[email protected]> To: [email protected] Sent: Tuesday, February 18, 2014 4:42:04 PM Subject: Re: assembler On 2/18/2014 2:42 PM, John Gilmore wrote: > continued > > uence 0, 1, 2, . . . > > by dividing by eight to obtain the bytes offset as quotient and the > bit offset, in the sequence 0, 1, 2, 3, 4, 5, 6, 7 as remainder. > > I neither see nor feel between my toes any mud. > > There is of course no objection to using a <bit count> derived as > <byte count> x 8, for bullet-proofing and the like, but the > fundamental storage quantity is the byte count. You seem to be deliberately confounding the issue. There is no efficient way of testing the validity of a bit number using only bytes. Let me simplify this for you - when the OP has 62 stores, then the allocation obviously is for a minimum of 8 bytes, but the value for checking validity of a bit is 62, not 8, and not 8*8. Gerhard Postpischil Bradford, Vermont ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
