*updating* 8088's

Roy J. Tellason rtellason at verizon.net
Wed Nov 21 12:07:24 CST 2007


On Tuesday 20 November 2007 21:00, Jim Leonard wrote:
> The only thing I can think of that might substantiate this claim is when
> you were working with 32-bit registers in 16-bit DOS.  Each instruction
> needed a 66h or 67h prefix opcode to indicate 32-bit.  This was wasteful
> on a 386sx because the 16-bit memory interface ate more time fetching
> the additional opcodes than you were saving by using 32-bit registers
> (!).

This is one of the things that's always bugged me about those "extra" z80 
instructions...

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin




More information about the cctalk mailing list