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rtl.texi (Arithmetic): Rewrite entries for PLUS, SS_PLUS, US_PLUS, LO_SUM, MINUS, SS_MINUS, US_MINUS. 

* doc/rtl.texi (Arithmetic): Rewrite entries for PLUS,
	SS_PLUS, US_PLUS, LO_SUM, MINUS, SS_MINUS, US_MINUS.

From-SVN: r76735
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Zack Weinberg 2004-01-27 18:03:17 +00:00 committed by Zack Weinberg
parent 52ad4d7b53
commit 60ffd2fe09
2 changed files with 40 additions and 33 deletions
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@ -1,3 +1,8 @@
2004-01-27 Zack Weinberg <zack@codesourcery.com>
* doc/rtl.texi (Arithmetic): Rewrite entries for PLUS,
SS_PLUS, US_PLUS, LO_SUM, MINUS, SS_MINUS, US_MINUS.
2004-01-27 Zack Weinberg <zack@codesourcery.com>
PR 7198

68
gcc/doc/rtl.texi
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@ -1749,51 +1749,53 @@ second operand.
@table @code
@findex plus
@cindex RTL addition
@findex ss_plus
@findex us_plus
@cindex RTL sum
@cindex RTL addition
@cindex RTL addition with signed saturation
@cindex RTL addition with unsigned saturation
@item (plus:@var{m} @var{x} @var{y})
Represents the sum of the values represented by @var{x} and @var{y}
carried out in machine mode @var{m}.
@itemx (ss_plus:@var{m} @var{x} @var{y})
@itemx (us_plus:@var{m} @var{x} @var{y})
These three expressions all represent the sum of the values
represented by @var{x} and @var{y} carried out in machine mode
@var{m}. They differ in their behavior on overflow of integer modes.
@code{plus} wraps round modulo the width of @var{m}; @code{ss_plus}
saturates at the maximum signed value representable in @var{m};
@code{us_plus} saturates at the maximum unsigned value.
@c ??? What happens on overflow of floating point modes?
@findex lo_sum
@item (lo_sum:@var{m} @var{x} @var{y})
Like @code{plus}, except that it represents that sum of @var{x} and the
low-order bits of @var{y}. The number of low order bits is
machine-dependent but is normally the number of bits in a @code{Pmode}
item minus the number of bits set by the @code{high} code
(@pxref{Constants}).
This expression represents the sum of @var{x} and the low-order bits
of @var{y}. It is used with @code{high} (@pxref{Constants}) to
represent the typical two-instruction sequence used in RISC machines
to reference a global memory location.
The number of low order bits is machine-dependent but is
normally the number of bits in a @code{Pmode} item minus the number of
bits set by @code{high}.
@var{m} should be @code{Pmode}.
@findex minus
@cindex RTL subtraction
@cindex RTL difference
@item (minus:@var{m} @var{x} @var{y})
Like @code{plus} but represents subtraction.
@findex ss_plus
@cindex RTL addition with signed saturation
@item (ss_plus:@var{m} @var{x} @var{y})
Like @code{plus}, but using signed saturation in case of an overflow.
@findex us_plus
@cindex RTL addition with unsigned saturation
@item (us_plus:@var{m} @var{x} @var{y})
Like @code{plus}, but using unsigned saturation in case of an overflow.
@findex ss_minus
@cindex RTL addition with signed saturation
@item (ss_minus:@var{m} @var{x} @var{y})
Like @code{minus}, but using signed saturation in case of an overflow.
@findex us_minus
@cindex RTL addition with unsigned saturation
@item (us_minus:@var{m} @var{x} @var{y})
@cindex RTL difference
@cindex RTL subtraction
@cindex RTL subtraction with signed saturation
@cindex RTL subtraction with unsigned saturation
@item (minus:@var{m} @var{x} @var{y})
@itemx (ss_minus:@var{m} @var{x} @var{y})
@itemx (us_minus:@var{m} @var{x} @var{y})
Like @code{minus}, but using unsigned saturation in case of an overflow.
These three expressions represent the result of subtracting @var{y}
from @var{x}, carried out in mode @var{M}. Behavior on overflow is
the same as for the three variants of @code{plus} (see above).
@findex compare
@cindex RTL comparison