On Thu, 29 Jun 2006 16:14:40 -0400, Bruce Black <[EMAIL PROTECTED]> wrote:
> >BTW, for those who don't know, millicode consists of the silicon >instructions from the normal zSeries instruction set, plus some >'millicode-only" silicon instructions, so executing a millicoded >instruction is more or less like executing a subroutine in the >instruction processor. The Amdahl 580 series had the same sort of thing, but they called it macrocode. It made it easy to implement new instructions. An interrupt would cause a switch to "System state" and macrocode would decide what to do with it. Macrocode, combined with increased addressability and some novel channel architecture made it relatively simple to implement XA. MDF was implemented with a lot of special registers and macrocode to perform the necessary setup. Too bad I didn't keep my copy of the ALTA POO when I left the company... Tom Marchant ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
