Looking for Prompt-475

Eric Smith spacewar at gmail.com
Thu Nov 3 19:15:56 CDT 2016


On Thu, Nov 3, 2016 at 8:42 AM, dwight <dkelvey at hotmail.com> wrote:

> The UPP had a bug that was never fixed. The level for the
> [...]
> The problem was in an app note. Their solution was to put
> a few NOPs at the start of the code. It worked most of the time.
>

Wow!  I noticed the NOPs when I disassembled the code, but had no idea why
it was there.

The first >NINE< microinstructions in the iAPX 432 GDP Release 1.0
microcode ROM (in the 43201 chip) are all "reset processor", which doesn't
affect the micro program counter, but resets much of the other hardware in
both the 43201 and 43202 chips.  I wonder whether there might have been
similar issues.


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