Messages in this thread | | | Date | Thu, 20 Dec 2007 19:30:36 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [patch 14/24] Immediate Values - x86 Optimization |
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Mathieu Desnoyers wrote: > > Argh.. Rusty asked to have a simplified version first, and then to > implement the "more complex" one on top of it. However, in order to get > the reentrancy I need for the markers, I need the complex version of the > immediate values. Therefore, you find, in this patchset, the simple > version first, and then, the more complex one implemented on top. > > About this patch header, the initial idea was to use the "Q" and "R" > constraints, but, as stated just below, the "q" and "r" constraints are > used instead to make sure the REX prefixed opcodes for 1, 2, and 4 bytes > immediate values are never used. So the complete header follows the > source code, it's just that this paragraph could be clearer. >
Then you have it backwards. "Q" and "R" avoid REX prefixes, "q" and "r" DO NOT.
-hpa
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