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Re: ARCH_rtx_costs
Hi, Eric. Thanks for reply.
> http://gcc.gnu.org/onlinedocs/gccint/Costs.html#Costs
Yes I refer to it.
> Has most of the cost information you need, looking at a similar existing
> port could help. What you want to remember in particular is that it's a
> set of relative costs. For example, if your "fast" instruction is an
> add, e.g. add $2, $3, $4, and takes one cycle and a multiply takes 12
> cycles then you'd want to have a MULT cost COST_N_INSNS (12).
So COST_N_INSNS doesn't mean real cycles but relative cycles, does it?
That is, COST_N_INSNS (1) doesn't mean one cycle.
If I don't know about cycle cost, I need to ask people who develop an
architecture.
Is my understanding correct?
Regards,
Shinpei Kato