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insns for register-move between general and floating
- From: Greg McGary <greg at mcgary dot org>
- To: gcc at gcc dot gnu dot org
- Cc: greg at mcgary dot org
- Date: 21 Mar 2006 17:41:03 -0700
- Subject: insns for register-move between general and floating
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.
Thanks!
Greg