John McKown wrote: <begin extract> Or, amusingly to me, if you have a MACRO of the same name in your MACLIB, the macro will be expanded rather than the opcode use. So, if you wanted to, you could create a lot of macros to implement instruction-equivalents. Then use of a specific opcode would either generate the code for the opcode if the MACHINE level is high enough, or use the macro definition if the opcode does not exist at that MACHINE level. </end extract>
This is, I think, an intelligent, imaginative design. It has served IBM well in the past. There have, for example, been machines that did not implement certain floating-point divides; and in these circumstances a macro has been supplied to close the gap produced by such an omissis. It could also be used by ISVs. FLOGR is not, for example available on all of the mainframes currently in use, but its availability changes the rules for bit-map processing in a fundamental way. Shipping a FLOGR macro with a product that notionally uses the FLOGR instruction would eliminate the need, felt by some ISVs, to avoid it (and other instructions of that ilk). 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
