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[doc] Document clrsb optab and fix some inconsistencies. 

* doc/md.texi (clrsb): Document.
	(clz): Change reference to x into operand 1.
	(ctz): Likewise.
	(popcount): Likewise.

Co-Authored-By: James Greenhalgh <james.greenhalgh@arm.com>

From-SVN: r213557
This commit is contained in:
Kyrylo Tkachov 2014-08-04 10:06:28 +00:00 committed by Kyrylo Tkachov
parent 97334291c2
commit e7a45277aa
2 changed files with 23 additions and 7 deletions
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8
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@ -1,3 +1,11 @@
2014-08-04 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
James Greenhalgh <james.greenhalgh@arm.com>
* doc/md.texi (clrsb): Document.
(clz): Change reference to x into operand 1.
(ctz): Likewise.
(popcount): Likewise.
2014-08-04 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
PR target/61713

22
gcc/doc/md.texi
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@ -5316,10 +5316,18 @@ generating the instruction.
The @code{ffs} built-in function of C always uses the mode which
corresponds to the C data type @code{int}.
@cindex @code{clrsb@var{m}2} instruction pattern
@item @samp{clrsb@var{m}2}
Count leading redundant sign bits.
Store into operand 0 the number of redundant sign bits in operand 1, starting
at the most significant bit position.
A redundant sign bit is defined as any sign bit after the first. As such,
this count will be one less than the count of leading sign bits.
@cindex @code{clz@var{m}2} instruction pattern
@item @samp{clz@var{m}2}
Store into operand 0 the number of leading 0-bits in @var{x}, starting
at the most significant bit position. If @var{x} is 0, the
Store into operand 0 the number of leading 0-bits in operand 1, starting
at the most significant bit position. If operand 1 is 0, the
@code{CLZ_DEFINED_VALUE_AT_ZERO} (@pxref{Misc}) macro defines if
the result is undefined or has a useful value.
@var{m} is the mode of operand 0; operand 1's mode is
@ -5328,8 +5336,8 @@ operand to that mode before generating the instruction.
@cindex @code{ctz@var{m}2} instruction pattern
@item @samp{ctz@var{m}2}
Store into operand 0 the number of trailing 0-bits in @var{x}, starting
at the least significant bit position. If @var{x} is 0, the
Store into operand 0 the number of trailing 0-bits in operand 1, starting
at the least significant bit position. If operand 1 is 0, the
@code{CTZ_DEFINED_VALUE_AT_ZERO} (@pxref{Misc}) macro defines if
the result is undefined or has a useful value.
@var{m} is the mode of operand 0; operand 1's mode is
@ -5338,15 +5346,15 @@ operand to that mode before generating the instruction.
@cindex @code{popcount@var{m}2} instruction pattern
@item @samp{popcount@var{m}2}
Store into operand 0 the number of 1-bits in @var{x}. @var{m} is the
Store into operand 0 the number of 1-bits in operand 1. @var{m} is the
mode of operand 0; operand 1's mode is specified by the instruction
pattern, and the compiler will convert the operand to that mode before
generating the instruction.
@cindex @code{parity@var{m}2} instruction pattern
@item @samp{parity@var{m}2}
Store into operand 0 the parity of @var{x}, i.e.@: the number of 1-bits
in @var{x} modulo 2. @var{m} is the mode of operand 0; operand 1's mode
Store into operand 0 the parity of operand 1, i.e.@: the number of 1-bits
in operand 1 modulo 2. @var{m} is the mode of operand 0; operand 1's mode
is specified by the instruction pattern, and the compiler will convert
the operand to that mode before generating the instruction.