9 Oct
1998
9 Oct
'98
6:58 a.m.
"Hans Franke" <franke(a)sbs.de> wrote:
Yes, but as a rule, mainframes and most minis catch
undefined
opcodes in a special exeption.
That's only a 'rule' for recent machines. Most of the early ones didn't.
When IBM was developing the 1401 emulation for the 360/30, they discovered
that many customers were in fact using and dependent on undefined behaviors
of the 1401. They had to emulate a lot of things that were never documented.
References:
_The Mythical Man Month_ by Brooks,
_Computer Architecture: Concepts and Evolution_ by Brooks and Blaauw,
_IBM's 360 and Early 370 Systems_ by Pugh, Johnson, and Palmer
Eric