3 Dec
2007
3 Dec
'07
10 p.m.
On 3 Dec 2007 at 20:58, jim s wrote:
Initially intel had added such instructions to the
dies and then enabled
them when they produced what were called bondout parts for their In
Circuit Emulators, or ICE products. when they came out with the 286 and
built their ICE they didn't disable it on the production parts.
The significance of LOADALL was that it offered a way to load not only
the registers that one normally could modify with architectural
instructions, but it could also modify others, some of which happened to
be the registers that were computed and were the actual memory pointer
registers for certain memory operations.
LOADALL was probably one of the the worst-kept secret in the 80286
world (Intel did document it in a memo that soon made the rounds).
Most 386 and 486 BIOSes even emulate the 286 LOADALL (the 386 and 486
and P's have a different version of the instruction). I think it
finally went official in a DDJ article.
I hadn't realized that Micro Five was part of the brouhaha.
Cheers,
Chuck