* instruction codes - novice questions
@ 2000-03-29 4:00 Dragos Badea
2000-03-29 8:56 ` Jeffrey A Law
0 siblings, 1 reply; 2+ messages in thread
From: Dragos Badea @ 2000-03-29 4:00 UTC (permalink / raw)
To: gcc
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Â
Hi!
Â
1. Here it is part of after-flow-pass
dump.
Â
(insn 9 6 11 (set (reg:SI
22 )
(mem/f:SI (plus:SI (reg:SI 6
%ebp)
(const_int -8 [0xfffffff8])) 0)) 48
{movsi+2} (nil)
(nil))
Â
Could you tell me please, when
were
48 {movsi+2}
fields added and which is their
meaning (what is +2 ?).
Â
2.Are the instructions scheduled by
sched.c in a 1-1 relation to asm output instructions (without taking into
account the afterwards effect of peephole optimizations) ?
Â
Â
 Thank you very much.
 Adrian
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: instruction codes - novice questions
2000-03-29 4:00 instruction codes - novice questions Dragos Badea
@ 2000-03-29 8:56 ` Jeffrey A Law
0 siblings, 0 replies; 2+ messages in thread
From: Jeffrey A Law @ 2000-03-29 8:56 UTC (permalink / raw)
To: Dragos Badea; +Cc: gcc
In message < 001c01bf9976$c0b6cf60$3725558d@cs.pub.ro >you write:
>
> 1. Here it is part of after-flow-pass dump.=20
>
> (insn 9 6 11 (set (reg:SI 22)
> (mem/f:SI (plus:SI (reg:SI 6 %ebp)
> (const_int -8 [0xfffffff8])) 0)) 48 {movsi+2} (nil)
> (nil))
>
> Could you tell me please, when were
> 48 {movsi+2}=20
> fields added and which is their meaning (what is +2 ?).
The insn matched pattern #48 in the backend. To find pattern #48 in the
backend, first find the "movsi" pattern, then go forward two patterns (movsi+2)
> 2.Are the instructions scheduled by sched.c in a 1-1 relation to asm =
> output instructions (without taking into account the afterwards effect =
> of peephole optimizations) ?
The scheduler schedules insns; the relation of insns to assembly instructions
depends entirely on how many assembly instructions are emitted by your
patterns in the md file.
ie, if each pattern in the md file emitted a single assembly instruction,
then there would be a 1:1 relation, if each pattern emitted 5 assembly
instructions then there would be a 1:5 relation. It all depends on how
you write your machine description. We recommend you try to emit only
a single instruction in each pattern in your md file.
jeff
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2000-03-29 4:00 instruction codes - novice questions Dragos Badea
2000-03-29 8:56 ` Jeffrey A Law
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