From patchwork Sun Jul 10 11:39:50 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aurelien Jarno X-Patchwork-Id: 13720 Received: (qmail 125541 invoked by alias); 10 Jul 2016 11:40:14 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 125356 invoked by uid 89); 10 Jul 2016 11:40:05 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.2 required=5.0 tests=BAYES_00, KAM_LAZY_DOMAIN_SECURITY, RP_MATCHES_RCVD autolearn=ham version=3.3.2 spammy=2711, 0.0000, Hx-languages-length:2926, 00000 X-HELO: hall.aurel32.net From: Aurelien Jarno To: libc-alpha@sourceware.org Cc: Aurelien Jarno Subject: [PATCH v2 4/4] alpha: fix trunc for big input values Date: Sun, 10 Jul 2016 13:39:50 +0200 Message-Id: <1468150790-18080-5-git-send-email-aurelien@aurel32.net> In-Reply-To: <1468150790-18080-1-git-send-email-aurelien@aurel32.net> References: <1468150790-18080-1-git-send-email-aurelien@aurel32.net> The alpha specific version of trunc and truncf always add and subtract 0x1.0p23 or 0x1.0p52 even for big values. This causes this kind of errors in the testsuite: Failure: Test: trunc_towardzero (0x1p107) Result: is: 1.6225927682921334e+32 0x1.fffffffffffffp+106 should be: 1.6225927682921336e+32 0x1.0000000000000p+107 difference: 1.8014398509481984e+16 0x1.0000000000000p+54 ulp : 0.5000 max.ulp : 0.0000 Change this by returning the input value when its absolute value is greater than 0x1.0p23 or 0x1.0p52. NaN have to go through the add and subtract operations to get possibly silenced. Finally remove the code to handle inexact exception, trunc should never generate such an exception. Changelog: * sysdeps/alpha/fpu/s_trunc.c (__trunc): Return the input value when its absolute value is greater than 0x1.0p52. [_IEEE_FP_INEXACT] Remove. * sysdeps/alpha/fpu/s_truncf.c (__truncf): Return the input value when its absolute value is greater than 0x1.0p23. [_IEEE_FP_INEXACT] Remove. --- ChangeLog | 6 ++++++ sysdeps/alpha/fpu/s_trunc.c | 7 +++---- sysdeps/alpha/fpu/s_truncf.c | 7 +++---- 3 files changed, 12 insertions(+), 8 deletions(-) v1 -> v2: - use isgreaterequal instead of checking for nan and doing a comparison diff --git a/ChangeLog b/ChangeLog index c7dbf18..2168d31 100644 --- a/ChangeLog +++ b/ChangeLog @@ -11,6 +11,12 @@ * sysdeps/alpha/fpu/s_rint.c (__rint): Add argument with itself when it is a NaN. * sysdeps/alpha/fpu/s_rintf.c (__rintf): Likewise. + * sysdeps/alpha/fpu/s_trunc.c (__trunc): Return the input value + when its absolute value is greater than 0x1.0p52. + [_IEEE_FP_INEXACT] Remove. + * sysdeps/alpha/fpu/s_truncf.c (__truncf): Return the input value + when its absolute value is greater than 0x1.0p23. + [_IEEE_FP_INEXACT] Remove. 2016-07-08 Adhemerval Zanella diff --git a/sysdeps/alpha/fpu/s_trunc.c b/sysdeps/alpha/fpu/s_trunc.c index 16cb114..4b986a6 100644 --- a/sysdeps/alpha/fpu/s_trunc.c +++ b/sysdeps/alpha/fpu/s_trunc.c @@ -28,12 +28,11 @@ __trunc (double x) double two52 = copysign (0x1.0p52, x); double r, tmp; + if (isgreaterequal (fabs (x), 0x1.0p52)) + return x; + __asm ( -#ifdef _IEEE_FP_INEXACT - "addt/suic %2, %3, %1\n\tsubt/suic %1, %3, %0" -#else "addt/suc %2, %3, %1\n\tsubt/suc %1, %3, %0" -#endif : "=&f"(r), "=&f"(tmp) : "f"(x), "f"(two52)); diff --git a/sysdeps/alpha/fpu/s_truncf.c b/sysdeps/alpha/fpu/s_truncf.c index 2290f28..3e93356 100644 --- a/sysdeps/alpha/fpu/s_truncf.c +++ b/sysdeps/alpha/fpu/s_truncf.c @@ -27,12 +27,11 @@ __truncf (float x) float two23 = copysignf (0x1.0p23, x); float r, tmp; + if (isgreaterequal (fabsf (x), 0x1.0p23)) + return x; + __asm ( -#ifdef _IEEE_FP_INEXACT - "adds/suic %2, %3, %1\n\tsubs/suic %1, %3, %0" -#else "adds/suc %2, %3, %1\n\tsubs/suc %1, %3, %0" -#endif : "=&f"(r), "=&f"(tmp) : "f"(x), "f"(two23));