On Sat, 20 Feb 2016 21:26:11 -0600, Tom Marchant wrote: > >In the -6 edition at >http://bitsavers.trailing-edge.com/pdf/ibm/360/princOps/A22-6821-6_360PrincOpsJan67.pdf > >on page 149, in Appendix F, it shows how the 7-bit ASCII is manipulated >to come up with the 8-bit USASCII-8. I won't try to replicate the figure here, >but it shows that the high bit, bit 7, is repeated between bits 5 and 6. So, >for >example, the 011 for the high three bits of numbers in the 7 bit code becomes >0101 in USASCII-8. And the 100 0001 for "A" becomes 1010 0001. > Might the objective have been to protect the EBCDIC control codes at 0x00-0x3F? Then one could just put an ASCII ball in the 3215 or an ASCII train in the 1403 and the commands would still work. Also, that maps the ASCII blank to the EBCDIC blank, perhaps a boon to hardware that treats 0x40 specially.
Bit 7? Bit 6? Bit 1? Big-endian? Little-endian? 0-bias? 1-bias? Whatever. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
