At 12:21 -0400 on 06/03/2012, Scott Ford wrote about Re: Base registers:
Robert, Thank you I appreciate the help been writing assembler a long time but not consistently every day. I have had to wear many function hats, sysprog vm,VSE,CICS,vtam ,tcpip, network engineer, etc. So I got rusty in assembler, I think everyone on here are very helpful..and it is appreciated. Scott ford www.identityforge.com
Some times you just run into a cute (or non-standard) trick with assembler. My favorite is the use of the TR command to do a patterned move (when the source and target are both under 256 bytes in length). You fill in the target area with offsets into the source and then TR the target using the source as the TR Table. This was a trick to flip the order of the bytes in a field (so it reads right to left) before MVCI was added to the instruction set. The major effort is in generating the offset mask in the first place. For the invert the order case you just assume the mask as: MASK DC 256AL1(MASK+255-*) 255,254,253,...,2,1,0
