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Re: insns for register-move between general and floating
- From: Falk Hueffner <falk at debian dot org>
- To: Greg McGary <greg at mcgary dot org>
- Cc: gcc at gcc dot gnu dot org
- Date: Wed, 22 Mar 2006 14:32:21 +0100
- Subject: Re: insns for register-move between general and floating
- References: <email@example.com>
Greg McGary <firstname.lastname@example.org> writes:
> I'm working on a port that has instructions to move bits between
> 64-bit floating-point and 64-bit general-purpose regs. I say "bits"
> because there's no conversion between float and int: the bit pattern
> is unaltered. Therefore, it's possible to use scratch FPRs for
> spilling GPRs & vice-versa, and float<->int conversions need not go
> through memory.
> Among all the knobs to turn regarding register classes, reload
> classes, and modes+constraints on movM, floatMN2, fixMN2 patterns,
> I need some advice on how to do this properly.
The Alpha port supports the "itof" and "ftoi" instructions, which do
exactly that. So you might want to look there.