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Re: flow patch for condexec


On Wed, Feb 21, 2001 at 09:04:53PM -0500, Michael Meissner wrote:
> ... having undefined makes nested IF-THEN statements easier.

Not really.  "Undefined" is a horrible model.

>    3)	CR2 = TEST2	if (CR1)
>    4)	CR2 = CR2 & CR1
> In instruction #3, CR2 gets undefined if CR1 is false or undefined.

Much better is ia64's .unc tests.  E.g.

	(p5) cmp.lt.unc p6, p7 = r5, r6

performs

	p6 <= p5 & (r5 < r6)
	p7 <= p5 & ! (r5 < r6)

A definite "and" is better, imo, than a mushy "undefined".


r~


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