PowerPC: remove wrong truncl implementation for PowerPC64

The truncl assembly implementation (sysdeps/powerpc/powerpc64/fpu/s_truncl.S)
returns wrong results for some inputs where first double is a exact integer
and the precision is determined by second long double.

Checking on implementation comments and history, I am very confident the
assembly implementation was based on a version before commit
5c68d401698a58cf7da150d9cce769fa6679ba5f that fixes BZ#2423 (Errors in
long double (ldbl-128ibm) rounding functions in glibc-2.4).

By just removing the implementation and make the build select
sysdeps/ieee754/ldbl-128ibm/s_truncl.c instead it fixes tgammal
issues regarding wrong result sign.

diff --git a/ChangeLog b/ChangeLog
index 62ebe4b58467ccea684ff7fef2f7de4e02eefc2e..1b19405fd2a2460f15755c7093c57a5836baa5e0 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,11 @@
-2013-01-08  Adhemerval Zanella  <azanella@linux.vnet.ibm.com>
+2014-01-08  Adhemerval Zanella  <azanella@linux.vnet.ibm.com>
+
+       [BZ #16414]
+       * sysdeps/powerpc/powerpc64/fpu/s_truncl.S: Remove wrong
+       implementation.
+       * sysdeps/ieee754/ldbl-128ibm/s_truncl.c: Remove bogus comment.
+
+2014-01-08  Adhemerval Zanella  <azanella@linux.vnet.ibm.com>
 
        * sysdeps/powerpc/fpu/libm-test-ulps: Update.
 

diff --git a/NEWS b/NEWS
index 486e892c65c388b8b28a2583de484ea995f0b84f..4fe23146fc19840faa048b1df85e47f1497df222 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -24,7 +24,7 @@ Version 2.19
   16103, 16112, 16143, 16144, 16146, 16150, 16151, 16153, 16167, 16172,
   16195, 16214, 16245, 16271, 16274, 16283, 16289, 16293, 16314, 16316,
   16330, 16337, 16338, 16356, 16365, 16366, 16369, 16372, 16375, 16379,
-  16384, 16385, 16386, 16387, 16390, 16400, 16407, 16408.
+  16384, 16385, 16386, 16387, 16390, 16400, 16407, 16408, 16414.
 
 * Slovenian translations for glibc messages have been contributed by the
   Translation Project's Slovenian team of translators.

diff --git a/sysdeps/ieee754/ldbl-128ibm/s_truncl.c b/sysdeps/ieee754/ldbl-128ibm/s_truncl.c
index 490ad266d4e60d935462c8018bd8987508a0a744..aca3f3efc2eb569b9d0335dab78dab61c75a0777 100644 (file)
--- a/sysdeps/ieee754/ldbl-128ibm/s_truncl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_truncl.c
@@ -17,9 +17,6 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-/* This has been coded in assembler because GCC makes such a mess of it
-   when it's coded in C.  */
-
 #include <math.h>
 #include <math_ldbl_opt.h>
 #include <float.h>

diff --git a/sysdeps/powerpc/powerpc64/fpu/s_truncl.S b/sysdeps/powerpc/powerpc64/fpu/s_truncl.S
deleted file mode 100644 (file)
index e5a3008..0000000
--- a/sysdeps/powerpc/powerpc64/fpu/s_truncl.S
+++ /dev/null
@@ -1,120 +0,0 @@
-/* long double trunc function.
-   IBM extended format long double version.
-   Copyright (C) 2004-2014 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <http://www.gnu.org/licenses/>.  */
-
-#include <sysdep.h>
-#include <math_ldbl_opt.h>
-
-       .section        ".toc","aw"
-.LC0:  /* 2**52 */
-       .tc FD_43300000_0[TC],0x4330000000000000
-.LC1:  /* 0.5 */
-       .tc FD_3fe00000_0[TC],0x3fe0000000000000
-       .section        ".text"
-
-/* long double [fp1,fp2] truncl (long double x [fp1,fp2])  */
-
-ENTRY (__truncl)
-       mffs    fp11            /* Save current FPU rounding mode.  */
-       lfd     fp13,.LC0@toc(2)
-       fabs    fp0,fp1
-       fabs    fp9,fp2
-       fsub    fp12,fp13,fp13  /* generate 0.0  */
-       fcmpu   cr7,fp0,fp13    /* if (fabs(x) > TWO52)  */
-       fcmpu   cr6,fp1,fp12    /* if (x > 0.0)  */
-       bnl-    cr7,.L2
-       mtfsfi  7,1             /* Set rounding mode toward 0.  */
-       ble-    cr6,.L1
-       fneg    fp2,fp12
-       fadd    fp1,fp1,fp13    /* x+= TWO52;  */
-       fsub    fp1,fp1,fp13    /* x-= TWO52;  */
-       fabs    fp1,fp1         /* if (x == 0.0) x = 0.0;  */
-.L0:
-       mtfsf   0x01,fp11       /* restore previous rounding mode.  */
-       blr
-.L1:
-       fneg    fp2,fp12
-       bge-    cr6,.L0         /* if (x < 0.0)  */
-       fsub    fp1,fp1,fp13    /* x-= TWO52;  */
-       fadd    fp1,fp1,fp13    /* x+= TWO52;  */
-       fnabs   fp1,fp1         /* if (x == 0.0) x = -0.0;  */
-       mtfsf   0x01,fp11       /* restore previous rounding mode.  */
-       blr
-
-/* The high double is > TWO52 so we need to round the low double and
-   perhaps the high double.  In this case we have to round the low
-   double and handle any adjustment to the high double that may be
-   caused by rounding (up).  This is complicated by the fact that the
-   high double may already be rounded and the low double may have the
-   opposite sign to compensate.This gets a bit tricky so we use the
-   following algorithm:
-
-   tau = floor(x_high/TWO52);
-   x0 = x_high - tau;
-   x1 = x_low + tau;
-   r1 = rint(x1);
-   y_high = x0 + r1;
-   y_low = x0 - y_high + r1;
-   return y;  */
-.L2:
-       fcmpu   cr7,fp9,fp13    /* if (|x_low| > TWO52)  */
-       fcmpu   cr0,fp9,fp12    /* || (|x_low| == 0.0)  */
-       fcmpu   cr5,fp2,fp12    /* if (x_low > 0.0)  */
-       bgelr-  cr7             /*   return x;  */
-       beqlr-  cr0
-       mtfsfi  7,1             /* Set rounding mode toward 0.  */
-       fdiv    fp8,fp1,fp13    /* x_high/TWO52  */
-
-       bng-    cr6,.L6         /* if (x > 0.0)  */
-       fctidz  fp0,fp8
-       fcfid   fp8,fp0         /* tau = floor(x_high/TWO52);  */
-       fadd    fp8,fp8,fp8     /* tau++; Make tau even  */
-       bng     cr5,.L4         /* if (x_low > 0.0)  */
-       fmr     fp3,fp1
-       fmr     fp4,fp2
-       b       .L5
-.L4:                           /* if (x_low < 0.0)  */
-       fsub    fp3,fp1,fp8     /* x0 = x_high - tau;  */
-       fadd    fp4,fp2,fp8     /* x1 = x_low + tau;  */
-.L5:
-       fadd    fp5,fp4,fp13    /* r1 = r1 + TWO52;  */
-       fsub    fp5,fp5,fp13    /* r1 = r1 - TWO52;  */
-       b       .L9
-.L6:                           /* if (x < 0.0)  */
-       fctidz  fp0,fp8
-       fcfid   fp8,fp0         /* tau = floor(x_high/TWO52);  */
-       fadd    fp8,fp8,fp8     /* tau++; Make tau even  */
-       bnl     cr5,.L7         /* if (x_low < 0.0)  */
-       fmr     fp3,fp1
-       fmr     fp4,fp2
-       b       .L8
-.L7:                           /* if (x_low > 0.0)  */
-       fsub    fp3,fp1,fp8     /* x0 = x_high - tau;  */
-       fadd    fp4,fp2,fp8     /* x1 = x_low + tau;  */
-.L8:
-       fsub    fp5,fp4,fp13    /* r1-= TWO52;  */
-       fadd    fp5,fp5,fp13    /* r1+= TWO52;  */
-.L9:
-       mtfsf   0x01,fp11       /* restore previous rounding mode.  */
-       fadd    fp1,fp3,fp5     /* y_high = x0 + r1;  */
-       fsub    fp2,fp3,fp1     /* y_low = x0 - y_high + r1;  */
-       fadd    fp2,fp2,fp5
-       blr
-END (__truncl)
-
-long_double_symbol (libm, __truncl, truncl)