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Problem in .md(Machine Description) file
- From: nitin jain <nitin_mbm at yahoo dot com>
- To: gcc-help at gcc dot gnu dot org
- Date: Fri, 22 Aug 2003 04:26:14 -0700 (PDT)
- Subject: Problem in .md(Machine Description) file
Hi,
I have to write a machine description file for a chip.
For that, i am trying to understand the structure and
systex of the machine description file of i386.
My problem is that why a 'define_insn' with a name
that start with '*' is used. Is it used for generating
RTL insn or for other purpose?
for example:
-------------------------------------------------
(define_insn "*cmphi_minus_1"
[(set (reg 17)
(compare (minus:HI (match_operand:HI 0
"nonimmediate_operand" "rm,r")
(match_operand:HI 1
"general_operand" "ri,mr"))
(const_int 0)))]
"ix86_match_ccmode (insn, CCGOCmode)"
"cmp{w}\t{%1, %0|%0, %1}"
[(set_attr "type" "icmp")
(set_attr "mode" "HI")])
--------------------------------------------------
If it is used to generate RTL insn then what is the
difference between this and 'define_insn' with name
that does not start with '*'.
Waitinf for a prompt reply.
Thanks in advance.
=====
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Nitin Jain,
H-8 ,Room No: 24
I.I.T.Bombay, Powai, Mumbai.
Mail-id: nitin-mbm@yahoo.com
nitinj@cse.iitb.ac.in
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