On Sat, 20 Feb 2016 10:46:05 -0600, Paul Gilmartin wrote: >On Sat, 20 Feb 2016 06:54:56 -0600, Bill Woodger wrote: > >>Indeed, there's a bit in the PSW indicating whether it is running in ASCII >>or EBCDIC, isn't there? :-) >> >Used to be. I doubt that it's still functional. Did COBOL ever exploit it?
Bit 12. As Charles noted, it was only used for the setting of the sign and/or zone nibble in decimal numbers in pack decimal arithmetic, as well as UNPACK, CVD, EDIT and EDMK. When set to 1, it indicated ASCII mode. I don't know what you mean about Cobol exploiting it. Bit 12 was removed for the initial system/370 models. It was required to be zero in those models. When virtual memory was added to System/370, setting it to 1 enabled EC mode, which changed the format of the PSW and enabled Dynamic Address Translation. Extended Architecture removed BC mode, so that bit 12 was always one. z/Architecture again changed bit 12. It is now always zero, and the PSW is now 128 bits (16 bytes) LPSWE loads the PSW from 16 bytes in memory, and bit 12 of that storage area must be 0, or specification error occurs. LPSW still loads the PSW from an 8 byte area in storage that looks mostly like an ESA PSW, and bit 12 of that storage area must be set to 1. -- Tom Marchant ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
