From 7b1c56e4834aa3b139fea39ded64a7e901be89a2 Mon Sep 17 00:00:00 2001 From: Wilco Dijkstra Date: Wed, 5 Aug 2015 15:03:08 +0100 Subject: Improve feenableexcept performance - avoid an unnecessary FPCR read in case the FPCR does not change. Also improve the logic of the return value. --- sysdeps/aarch64/fpu/feenablxcpt.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'sysdeps/aarch64') diff --git a/sysdeps/aarch64/fpu/feenablxcpt.c b/sysdeps/aarch64/fpu/feenablxcpt.c index 82ed0b6..a0f736c 100644 --- a/sysdeps/aarch64/fpu/feenablxcpt.c +++ b/sysdeps/aarch64/fpu/feenablxcpt.c @@ -24,24 +24,22 @@ feenableexcept (int excepts) { fpu_control_t fpcr; fpu_control_t fpcr_new; + fpu_control_t updated_fpcr; _FPU_GETCW (fpcr); excepts &= FE_ALL_EXCEPT; fpcr_new = fpcr | (excepts << FE_EXCEPT_SHIFT); if (fpcr != fpcr_new) - _FPU_SETCW (fpcr_new); - - /* Trapping exceptions are optional in AArch64 the relevant enable - bits in FPCR are RES0 hence the absence of support can be - detected by reading back the FPCR and comparing with the required - value. */ - if (excepts) { - fpu_control_t updated_fpcr; + _FPU_SETCW (fpcr_new); + /* Trapping exceptions are optional in AArch64; the relevant enable + bits in FPCR are RES0 hence the absence of support can be detected + by reading back the FPCR and comparing with the required value. */ _FPU_GETCW (updated_fpcr); - if (((updated_fpcr >> FE_EXCEPT_SHIFT) & excepts) != excepts) + + if (fpcr_new & ~updated_fpcr) return -1; } -- cgit v1.1