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
28 #ifdef PLATFORM_WINDOWS
33 #include "pbd/error.h"
42 unsigned long cpuflags = 0;
46 #if !( (defined __x86_64__) || (defined __i386__) ) // !ARCH_X86
50 #ifdef PLATFORM_WINDOWS
52 #ifndef USE_X86_64_ASM
53 /* no 32 bit version of assembler for windows */
56 // Get CPU flags using Microsoft function
57 // It works for both 64 and 32 bit systems
58 // no need to use assembler for getting info from register, this function does this for us
61 cpuflags = cpuInfo[3];
66 #ifndef _LP64 /* *nix; 32 bit version. This odd macro constant is required because we need something that identifies this as a 32 bit
67 build on Linux and on OS X. Anything that serves this purpose will do, but this is the best thing we've identified
79 : "%eax", "%ecx", "%edx"
82 #else /* *nix; 64 bit version */
84 /* asm notes: although we explicitly save&restore rbx, we must tell
85 gcc that ebx,rbx is clobbered so that it doesn't try to use it as an intermediate
86 register when storing rbx. gcc 4.3 didn't make this "mistake", but gcc 4.4
87 does, at least on x86_64.
98 : "%rax", "%rbx", "%rcx", "%rdx"
101 #endif /* USE_X86_64_ASM */
102 #endif /* PLATFORM_WINDOWS */
104 if (cpuflags & (1<<25)) {
105 _flags = Flags (_flags | (HasSSE|HasFlushToZero));
108 if (cpuflags & (1<<26)) {
109 _flags = Flags (_flags | HasSSE2);
112 if (cpuflags & (1 << 24)) {
116 /* DAZ wasn't available in the first version of SSE. Since
117 setting a reserved bit in MXCSR causes a general protection
118 fault, we need to be able to check the availability of this
119 feature without causing problems. To do this, one needs to
120 set up a 512-byte area of memory to save the SSE state to,
121 using fxsave, and then one needs to inspect bytes 28 through
122 31 for the MXCSR_MASK value. If bit 6 is set, DAZ is
123 supported, otherwise, it isn't.
126 #ifndef HAVE_POSIX_MEMALIGN
127 fxbuf = (char **) malloc (sizeof (char *));
129 *fxbuf = (char *) malloc (512);
132 (void) posix_memalign ((void **) &fxbuf, 16, sizeof (char *));
134 (void) posix_memalign ((void **) fxbuf, 16, 512);
138 memset (*fxbuf, 0, 512);
154 uint32_t mxcsr_mask = *((uint32_t*) &((*fxbuf)[28]));
156 /* if the mask is zero, set its default value (from intel specs) */
158 if (mxcsr_mask == 0) {
162 if (mxcsr_mask & (1<<6)) {
163 _flags = Flags (_flags | HasDenormalsAreZero);