| /* |
| * Copyright (C) 2005-2013 Free Software Foundation, Inc. |
| * |
| * This file is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License as published by the |
| * Free Software Foundation; either version 3, or (at your option) any |
| * later version. |
| * |
| * This file 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 |
| * General Public License for more details. |
| * |
| * Under Section 7 of GPL version 3, you are granted additional |
| * permissions described in the GCC Runtime Library Exception, version |
| * 3.1, as published by the Free Software Foundation. |
| * |
| * You should have received a copy of the GNU General Public License and |
| * a copy of the GCC Runtime Library Exception along with this program; |
| * see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| * <http://www.gnu.org/licenses/>. |
| */ |
| |
| #define MXCSR_DAZ (1 << 6) /* Enable denormals are zero mode */ |
| #define MXCSR_FTZ (1 << 15) /* Enable flush to zero mode */ |
| |
| #ifndef __x86_64__ |
| /* All 64-bit targets have SSE and DAZ; |
| only check them explicitly for 32-bit ones. */ |
| #include "cpuid.h" |
| #endif |
| |
| #if !defined __x86_64__ && defined __sun__ && defined __svr4__ |
| #include <signal.h> |
| #include <ucontext.h> |
| |
| static volatile sig_atomic_t sigill_caught; |
| |
| static void |
| sigill_hdlr (int sig __attribute((unused)), |
| siginfo_t *sip __attribute__((unused)), |
| ucontext_t *ucp) |
| { |
| sigill_caught = 1; |
| /* Set PC to the instruction after the faulting one to skip over it, |
| otherwise we enter an infinite loop. 3 is the size of the movaps |
| instruction. */ |
| ucp->uc_mcontext.gregs[EIP] += 3; |
| setcontext (ucp); |
| } |
| #endif |
| |
| static void __attribute__((constructor)) |
| #ifndef __x86_64__ |
| /* The i386 ABI only requires 4-byte stack alignment, so this is necessary |
| to make sure the fxsave struct gets correct alignment. |
| See PR27537 and PR28621. */ |
| __attribute__ ((force_align_arg_pointer)) |
| #endif |
| set_fast_math (void) |
| { |
| #ifndef __x86_64__ |
| unsigned int eax, ebx, ecx, edx; |
| |
| if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx)) |
| return; |
| |
| if (edx & bit_SSE) |
| { |
| unsigned int mxcsr; |
| |
| #if defined __sun__ && defined __svr4__ |
| /* Solaris 2 before Solaris 9 4/04 cannot execute SSE instructions even |
| if the CPU supports them. Programs receive SIGILL instead, so check |
| for that at runtime. */ |
| struct sigaction act, oact; |
| |
| act.sa_handler = sigill_hdlr; |
| sigemptyset (&act.sa_mask); |
| /* Need to set SA_SIGINFO so a ucontext_t * is passed to the handler. */ |
| act.sa_flags = SA_SIGINFO; |
| sigaction (SIGILL, &act, &oact); |
| |
| /* We need a single SSE instruction here so the handler can safely skip |
| over it. */ |
| __asm__ volatile ("movaps %xmm0,%xmm0"); |
| |
| sigaction (SIGILL, &oact, NULL); |
| |
| if (sigill_caught) |
| return; |
| #endif /* __sun__ && __svr4__ */ |
| |
| if (edx & bit_FXSAVE) |
| { |
| /* Check if DAZ is available. */ |
| struct |
| { |
| unsigned short cwd; |
| unsigned short swd; |
| unsigned short twd; |
| unsigned short fop; |
| unsigned int fip; |
| unsigned int fcs; |
| unsigned int foo; |
| unsigned int fos; |
| unsigned int mxcsr; |
| unsigned int mxcsr_mask; |
| unsigned int st_space[32]; |
| unsigned int xmm_space[32]; |
| unsigned int padding[56]; |
| } __attribute__ ((aligned (16))) fxsave; |
| |
| /* This is necessary since some implementations of FXSAVE |
| do not modify reserved areas within the image. */ |
| fxsave.mxcsr_mask = 0; |
| |
| __builtin_ia32_fxsave (&fxsave); |
| |
| mxcsr = fxsave.mxcsr; |
| |
| if (fxsave.mxcsr_mask & MXCSR_DAZ) |
| mxcsr |= MXCSR_DAZ; |
| } |
| else |
| mxcsr = __builtin_ia32_stmxcsr (); |
| |
| mxcsr |= MXCSR_FTZ; |
| __builtin_ia32_ldmxcsr (mxcsr); |
| } |
| #else |
| unsigned int mxcsr = __builtin_ia32_stmxcsr (); |
| mxcsr |= MXCSR_DAZ | MXCSR_FTZ; |
| __builtin_ia32_ldmxcsr (mxcsr); |
| #endif |
| } |