Micro Five system (PC Clone system)
cclist at sydex.com
Tue Dec 4 00:00:13 CST 2007
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.
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