* How to write this insn define?
@ 2008-07-10 2:20 Ruan Beihong
2008-07-12 2:14 ` Ian Lance Taylor
0 siblings, 1 reply; 2+ messages in thread
From: Ruan Beihong @ 2008-07-10 2:20 UTC (permalink / raw)
To: gcc-help
There is a instruction:
mult rega,regb,regc
Lower 32-bit of sign-extended regb is multiplied by lower 32-bit of
sign-extended regc, and the lower 32-bit of product then sign-extends
to 64-bit and stores in rega.
How to write a (define_insn ) to describe this instruction?
Thanks.
James Ruan
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: How to write this insn define?
2008-07-10 2:20 How to write this insn define? Ruan Beihong
@ 2008-07-12 2:14 ` Ian Lance Taylor
0 siblings, 0 replies; 2+ messages in thread
From: Ian Lance Taylor @ 2008-07-12 2:14 UTC (permalink / raw)
To: Ruan Beihong; +Cc: gcc-help
"Ruan Beihong" <ruanbeihong@gmail.com> writes:
> There is a instruction:
> mult rega,regb,regc
> Lower 32-bit of sign-extended regb is multiplied by lower 32-bit of
> sign-extended regc, and the lower 32-bit of product then sign-extends
> to 64-bit and stores in rega.
> How to write a (define_insn ) to describe this instruction?
Something like this seems about right:
(set (match_operand:DI 0 "register_operand" "constraints")
(sign_extend:DI (mult:SI (match_operand:SI 1 "register_operand" "constraints")
(match_operand:SI 2 "register_operand" "constraints"))))
Ian
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2008-07-10 2:20 How to write this insn define? Ruan Beihong
2008-07-12 2:14 ` Ian Lance Taylor
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