In
<ofd1484f42.6be3b89a-on85257b5c.007e856a-85257b5c.007f3...@tsys.tss.net>,
on 04/29/2013
at 07:09 PM, Kirk Talman <[email protected]> said:
>I was given at one point the Assembler source of the fast Fourier
>transform, which I wanted to port to the 360. I had to read the
>94 PoOp several times before I caught on that the EX instruction
>on the 94 ORed the register (can't remember which one but I
>remember only one 36-bit accumulator and 7 18-bit index registors)
>with the entire instruction.
No. In basic mode there were 3 15-bit index refisters and selected
index registers were OR'd together; in multiple tag mode there were
seven 15-bit index registers. In both cases the contents of the index
register were subtracted from the Y field. In the case of the XEC
instruction, that's the Y field of the XEC instruction, not of the
target instruction.
--
Shmuel (Seymour J.) Metz, SysProg and JOAT
Atid/2 <http://patriot.net/~shmuel>
We don't care. We don't have to care, we're Congress.
(S877: The Shut up and Eat Your spam act of 2003)
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