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author | Adhemerval Zanella <azanella@linux.vnet.ibm.com> | 2014-03-14 07:35:43 -0500 |
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committer | Adhemerval Zanella <azanella@linux.vnet.ibm.com> | 2014-03-14 12:54:47 -0500 |
commit | 374f7f61214967bb4e2257695aeeeecc2a77f369 (patch) | |
tree | 5fdfc34f3a435a8df5823508a51e5bb3e726a300 /sysdeps | |
parent | 4655c291d1808c35b7c54236ae62be7a3aaa0a2d (diff) | |
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PowerPC: remove wrong ceill implementation for PowerPC64
The ceill assembly implementation (sysdeps/powerpc/powerpc64/fpu/s_ceill.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_ceill.c instead fixes the failing math.
Fixes BZ#16701.
Diffstat (limited to 'sysdeps')
-rw-r--r-- | sysdeps/powerpc/powerpc64/fpu/s_ceill.S | 132 |
1 files changed, 0 insertions, 132 deletions
diff --git a/sysdeps/powerpc/powerpc64/fpu/s_ceill.S b/sysdeps/powerpc/powerpc64/fpu/s_ceill.S deleted file mode 100644 index 42a73affcd..0000000000 --- a/sysdeps/powerpc/powerpc64/fpu/s_ceill.S +++ /dev/null @@ -1,132 +0,0 @@ -/* s_ceill.S 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 - - .section ".text" - -/* long double [fp1,fp2] ceill (long double x [fp1,fp2]) - IEEE 1003.1 ceil function. - - PowerPC64 long double uses the IBM extended format which is - represented two 64-floating point double values. The values are - non-overlapping giving an effective precision of 106 bits. The first - double contains the high order bits of mantissa and is always ceiled - to represent a normal ceiling of long double to double. Since the - long double value is sum of the high and low values, the low double - normally has the opposite sign to compensate for the this ceiling. - - For long double there are two cases: - 1) |x| < 2**52, all the integer bits are in the high double. - ceil the high double and set the low double to -0.0. - 2) |x| >= 2**52, ceiling involves both doubles. - See the comment before label .L2 for details. - */ - -ENTRY (__ceill) - 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 7,2 /* Set rounding mode toward +inf. */ - fneg fp2,fp12 - ble- cr6,.L1 - fadd fp1,fp1,fp13 /* x+= TWO52; */ - fsub fp1,fp1,fp13 /* x-= TWO52; */ - fabs fp1,fp1 /* if (x == 0.0) */ -.L0: - mtfsf 0x01,fp11 /* restore previous rounding mode. */ - blr /* x = 0.0; */ -.L1: - bge- cr6,.L0 /* if (x < 0.0) */ - fsub fp1,fp1,fp13 /* x-= TWO52; */ - fadd fp1,fp1,fp13 /* x+= TWO52; */ - fcmpu cr5,fp1,fp12 /* if (x > 0.0) */ - mtfsf 0x01,fp11 /* restore previous rounding mode. */ - fnabs fp1,fp1 /* if (x == 0.0) */ - blr /* x = -0.0; */ - -/* 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 7,2 /* Set rounding mode toward +inf. */ - 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); */ - 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); */ - 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 (__ceill) - -long_double_symbol (libm, __ceill, ceill) |