Re: [mips patch rfa] slight tweak to vr5400 "mul" opcode

[cgd at broadcom dot com]

At Sat, 5 Apr 2003 00:11:30 +0000 (UTC), "Eric Christopher" wrote:
> > any reason the following patch shouldn't be applied?
> 
> Yup. For the 5432 only 3 operand is correct. Don't ask me, I didn't
> write the spec.

Err, really?

I ask because, upon seeing your msg, i just found and downloaded a
5432 spec (i'd previously been looking at a 5464 spec 8-) from:

	http://www.necelam.com/docs/files/1375_V2.pdf

On page 484, where it describes the MUL instruction, it gives no such
restriction...

Do you mean that "only the 3-operand form is described in the
instruction description?"  OK, that's true, but the same is true for
say, mips32/mips64, and it's really lame for:

	mul	foo, bar

to expand into the "original" instructions if

	mul foo, bar, baz

does the expected thing and there's no restriction that foo != bar...

-- 
Chris Demetriou                                            Broadcom Corporation
Principal Design Engineer                     Broadband Processor Business Unit
  Any opinions expressed in this message are mine, not necessarily Broadcom's.