Date   : Sat, 20 Nov 1982 0730-:00PST
From   : BILLW@Sri-Kl
Subject: Re: GODBOUT/COMPUPRO questions...

The 8087 is a co-processor.  When the 8086 want to do floating point
operations, it uses the various ESC opcodes.  The 8087 reads this
from the bus, and by watching the status lines of the 8086, is able to
determine when tey are executed.  It then can read an operand from the
bus (which the 8086 fetches and discards durring the ESC operation).
I dont know wgether the 8087 can also control the bus itself, but I
assume it must (otherwise  it would take several ESC instructions
to load a full floating point number...)  All this means that there
is little chance of getting at the 8087 from another processor.

Presumably, the 8087 will only run at 5MHz because is is not as far
along the learning curve as the 8086.  The first 8086s were 5Mhz too.
Due to the above outlined tight coupling between the 86 and 87, they
must both run at the same clock speed.

BillW