2 Copyright (C) 2012 Paul Davis
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 #include "libpbd-config.h"
22 #define _XOPEN_SOURCE 600
23 #include <cstring> // for memset
29 #include "pbd/error.h"
38 unsigned long cpuflags = 0;
42 #if defined(__MINGW64__) // Vkamyshniy: under __MINGW64__ the assembler code below is not compiled
46 #if !( (defined __x86_64__) || (defined __i386__) ) // !ARCH_X86
50 #ifndef _LP64 //USE_X86_64_ASM
59 : "%eax", "%ecx", "%edx"
64 /* asm notes: although we explicitly save&restore rbx, we must tell
65 gcc that ebx,rbx is clobbered so that it doesn't try to use it as an intermediate
66 register when storing rbx. gcc 4.3 didn't make this "mistake", but gcc 4.4
67 does, at least on x86_64.
78 : "%rax", "%rbx", "%rcx", "%rdx"
81 #endif /* USE_X86_64_ASM */
83 if (cpuflags & (1<<25)) {
84 _flags = Flags (_flags | (HasSSE|HasFlushToZero));
87 if (cpuflags & (1<<26)) {
88 _flags = Flags (_flags | HasSSE2);
91 if (cpuflags & (1 << 24)) {
95 /* DAZ wasn't available in the first version of SSE. Since
96 setting a reserved bit in MXCSR causes a general protection
97 fault, we need to be able to check the availability of this
98 feature without causing problems. To do this, one needs to
99 set up a 512-byte area of memory to save the SSE state to,
100 using fxsave, and then one needs to inspect bytes 28 through
101 31 for the MXCSR_MASK value. If bit 6 is set, DAZ is
102 supported, otherwise, it isn't.
105 #ifndef HAVE_POSIX_MEMALIGN
106 fxbuf = (char **) malloc (sizeof (char *));
108 *fxbuf = (char *) malloc (512);
111 posix_memalign ((void **) &fxbuf, 16, sizeof (char *));
113 posix_memalign ((void **) fxbuf, 16, 512);
117 memset (*fxbuf, 0, 512);
126 uint32_t mxcsr_mask = *((uint32_t*) &((*fxbuf)[28]));
128 /* if the mask is zero, set its default value (from intel specs) */
130 if (mxcsr_mask == 0) {
134 if (mxcsr_mask & (1<<6)) {
135 _flags = Flags (_flags | HasDenormalsAreZero);
148 #else // COMPILER_MSVC
149 const char* pbd_fpu = "pbd/msvc/fpu.cc takes precedence over this file";
150 #endif // COMPILER_MSVC