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# commit da13146da10360436941e843834c90a9aef5fd7a
# Author: Alan Modra <amodra@gmail.com>
# Date: Sat Aug 17 18:30:23 2013 +0930
#
# PowerPC floating point little-endian [10 of 15]
# http://sourceware.org/ml/libc-alpha/2013-07/msg00201.html
#
# These two functions oddly test x+1>0 when a double x is >= 0.0, and
# similarly when x is negative. I don't see the point of that since the
# test should always be true. I also don't see any need to convert x+1
# to integer rather than simply using xr+1. Note that the standard
# allows these functions to return any value when the input is outside
# the range of long long, but it's not too hard to prevent xr+1
# overflowing so that's what I've done.
#
# (With rounding mode FE_UPWARD, x+1 can be a lot more than what you
# might naively expect, but perhaps that situation was covered by the
# x - xrf < 1.0 test.)
#
# * sysdeps/powerpc/fpu/s_llround.c (__llround): Rewrite.
# * sysdeps/powerpc/fpu/s_llroundf.c (__llroundf): Rewrite.
#
---
# sysdeps/powerpc/fpu/s_llround.c | 33 ++++++++++++++++-----------------
# sysdeps/powerpc/fpu/s_llroundf.c | 33 ++++++++++++++++-----------------
# 2 files changed, 32 insertions(+), 34 deletions(-)
#
--- a/sysdeps/powerpc/fpu/s_llround.c
+++ b/sysdeps/powerpc/fpu/s_llround.c
@@ -19,29 +19,28 @@
#include <math.h>
#include <math_ldbl_opt.h>
-/* I think that what this routine is supposed to do is round a value
- to the nearest integer, with values exactly on the boundary rounded
- away from zero. */
-/* This routine relies on (long long)x, when x is out of range of a long long,
- clipping to MAX_LLONG or MIN_LLONG. */
+/* Round to the nearest integer, with values exactly on a 0.5 boundary
+ rounded away from zero, regardless of the current rounding mode.
+ If (long long)x, when x is out of range of a long long, clips at
+ LLONG_MAX or LLONG_MIN, then this implementation also clips. */
long long int
__llround (double x)
{
- double xrf;
- long long int xr;
- xr = (long long int) x;
- xrf = (double) xr;
+ long long xr = (long long) x;
+ double xrf = (double) xr;
+
if (x >= 0.0)
- if (x - xrf >= 0.5 && x - xrf < 1.0 && x+1 > 0)
- return x+1;
- else
- return x;
+ {
+ if (x - xrf >= 0.5)
+ xr += (long long) ((unsigned long long) xr + 1) > 0;
+ }
else
- if (xrf - x >= 0.5 && xrf - x < 1.0 && x-1 < 0)
- return x-1;
- else
- return x;
+ {
+ if (xrf - x >= 0.5)
+ xr -= (long long) ((unsigned long long) xr - 1) < 0;
+ }
+ return xr;
}
weak_alias (__llround, llround)
#ifdef NO_LONG_DOUBLE
--- a/sysdeps/powerpc/fpu/s_llroundf.c
+++ b/sysdeps/powerpc/fpu/s_llroundf.c
@@ -18,28 +18,27 @@
#include <math.h>
-/* I think that what this routine is supposed to do is round a value
- to the nearest integer, with values exactly on the boundary rounded
- away from zero. */
-/* This routine relies on (long long)x, when x is out of range of a long long,
- clipping to MAX_LLONG or MIN_LLONG. */
+/* Round to the nearest integer, with values exactly on a 0.5 boundary
+ rounded away from zero, regardless of the current rounding mode.
+ If (long long)x, when x is out of range of a long long, clips at
+ LLONG_MAX or LLONG_MIN, then this implementation also clips. */
long long int
__llroundf (float x)
{
- float xrf;
- long long int xr;
- xr = (long long int) x;
- xrf = (float) xr;
+ long long xr = (long long) x;
+ float xrf = (float) xr;
+
if (x >= 0.0)
- if (x - xrf >= 0.5 && x - xrf < 1.0 && x+1 > 0)
- return x+1;
- else
- return x;
+ {
+ if (x - xrf >= 0.5)
+ xr += (long long) ((unsigned long long) xr + 1) > 0;
+ }
else
- if (xrf - x >= 0.5 && xrf - x < 1.0 && x-1 < 0)
- return x-1;
- else
- return x;
+ {
+ if (xrf - x >= 0.5)
+ xr -= (long long) ((unsigned long long) xr - 1) < 0;
+ }
+ return xr;
}
weak_alias (__llroundf, llroundf)
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