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/*
SuperCollider real time audio synthesis system
Copyright (c) 2002 James McCartney. All rights reserved.
http://www.audiosynth.com

This program 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 2 of the License, or
(at your option) any later version.

This program 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.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/

/*
* SC_Carbon.cpp
* SC3synth
*
* Created by James McCartney on Sat Mar 15 2003.
* Copyright (c) 2003 __MyCompanyName__. All rights reserved.
*
*/

#include <stdlib.h>
#include <string.h>
#include "SC_World.h"

// Return true if CPU has vector unit.
bool sc_HasVectorUnit();

// Return true if vector unit is present and should be used.
// Vectorisation can be turned off by exporting SC_NOVEC in the
// process environment.
bool sc_UseVectorUnit();

// Set denormal FTZ mode on CPUs that need/support it.
void sc_SetDenormalFlags();

bool sc_UseVectorUnit()
{
if (sc_HasVectorUnit()) {
const char* novec = getenv("SC_NOVEC");
return !novec || (strcmp(novec, "0") == 0);
}
return false;
}

#if defined(__APPLE__) && !defined(SC_IPHONE)
# include <Carbon/Carbon.h>
#include <TargetConditionals.h>

bool sc_HasVectorUnit()
{
SInt32 response;
Gestalt(gestaltPowerPCProcessorFeatures, &response);
//printf("HasAltivec %p %d\n", response, response & (1<<gestaltPowerPCHasVectorInstructions));
return response & (1<<gestaltPowerPCHasVectorInstructions);
}

#ifdef __SSE__
#include <xmmintrin.h>

void sc_SetDenormalFlags()
{
// all Macs have SSE
_MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_ON);
_mm_setcsr(_mm_getcsr() | 0x40);
}

#else

void sc_SetDenormalFlags()
{
}

#endif

#elif defined(__linux__) && defined(__ALTIVEC__)
# include <stdio.h>
# include <string.h>
# include <unistd.h>
# include <signal.h>
# include <setjmp.h>

// kernel independent altivec detection
// contributed by niklas werner
// borrowed from mplayer, who borrowed from libmpeg2
// <sk>

static sigjmp_buf sigIllJmpBuf;
static volatile sig_atomic_t sigIllCanJump = 0;
static sighandler_t sigIllOldHandler = SIG_DFL;

static void sigIllHandler(int sig)
{
if (!sigIllCanJump) {
signal(sig, sigIllOldHandler);
raise(sig);
}
sigIllCanJump = 0;
siglongjmp(sigIllJmpBuf, 1);
}

bool sc_HasVectorUnit()
{
sigIllOldHandler = signal(SIGILL, sigIllHandler);

if (sigsetjmp(sigIllJmpBuf, 1)) {
signal(SIGILL, sigIllOldHandler);
} else {
sigIllCanJump = 1;
asm volatile ("mtspr 256, %0\n\t"
"vand %%v0, %%v0, %%v0"
:
: "r" (-1));
signal(SIGILL, sigIllOldHandler);
return true;
}
return false;
}

void sc_SetDenormalFlags()
{
}
#elif (defined(__linux__) || defined(__FreeBSD__)) && defined(__SSE__)
# include <xmmintrin.h>

// cpuid function that works with -fPIC from `minor' at http://red-bean.com
// http://svn.red-bean.com/repos/minor/trunk/gc/barriers-ia-32.c
// http://svn.red-bean.com/repos/minor/trunk/gc/barriers-amd64.c
// <sk>

# if defined(__i386__)
/* If the current processor supports the CPUID instruction, execute
one, with REQUEST in %eax, and set *EAX, *EBX, *ECX, and *EDX to
the values the 'cpuid' stored in those registers. Return true if
the current processor supports CPUID, false otherwise. */
static bool cpuid(
uint32_t request,
uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx)
{
uint32_t pre_change, post_change;
const uint32_t id_flag = 0x200000;

/* This is pretty much the standard way to detect whether the CPUID
instruction is supported, as recommended in the Intel
documentation: try to change the ID bit in the EFLAGS register.
If we can change it, then the CPUID instruction is
implemented. */
asm ("pushfl\n\t" /* Save %eflags to restore later. */
"pushfl\n\t" /* Push second copy, for manipulation. */
"popl %1\n\t" /* Pop it into post_change. */
"movl %1,%0\n\t" /* Save present value in pre_change. */
"xorl %2,%1\n\t" /* Tweak bit in post_change. */
"pushl %1\n\t" /* Push tweaked copy... */
"popfl\n\t" /* ... and pop it into %eflags. */
"pushfl\n\t" /* Did it change? Push new %eflags... */
"popl %1\n\t" /* ... and pop it into post_change. */
"popfl" /* Restore original value of %eflags. */
: "=&r" (pre_change), "=&r" (post_change)
: "ir" (id_flag));

/* If the bit changed, then we support the CPUID instruction. */
if ((pre_change ^ post_change) & id_flag)
    {
/* The IA-32 ABI specifies that, in position-independent code,
%ebx holds the address of the global offset table. GCC seems
to be unable to handle asms in PIC with result operands that
live in %ebx. For example:

$ cat pic-ebx-asm.c
int
foo (void)
{
int i;

asm ("" : "=b" (i));

return i;
}
$ gcc -c -fPIC pic-ebx-asm.c
pic-ebx-asm.c: In function `foo':
pic-ebx-asm.c:6: error: can't find a register in class `BREG'
while reloading `asm'
$

But the CPUID instruction leaves results in %ebx, so we have
to use it.

To work around this, we save %ebx in %esi, restore %ebx after
we've done the 'cpuid', and return %ebx's value in %esi.
Thus the interesting constraint / operand pair '"=S" (*ebx)'.

We include "memory" in the clobber list, because this is a
synchronizing instruction; the caller may be expecting other
processors' writes to become visible here. */
asm volatile ("mov %%ebx, %%esi\n\t" /* Save %ebx. */
"cpuid\n\t"
"xchgl %%ebx, %%esi" /* Restore %ebx. */
: "=a" (*eax), "=S" (*ebx), "=c" (*ecx), "=d" (*edx)
: "0" (request)
: "memory");

return true;
    }
else
return false;
}
# elif defined(__x86_64__)
/* Execute a CPUID instruction with REQUEST in %eax, and set *EAX,
*EBX, *ECX, and *EDX to the values the 'cpuid' stored in those
registers. */
static bool cpuid(
uint32_t request,
uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx)
{
/* We include "memory" in the clobber list, because this is a
synchronizing instruction; the caller may be expecting other
processors' writes to become visible here. */
asm volatile ("cpuid\n\t"
: "=a" (*eax), "=b" (*ebx), "=c" (*ecx), "=d" (*edx)
: "0" (request)
: "memory");
return true;
}
# else
# error Unknown SSE CPU
# endif

bool sc_HasVectorUnit()
{
// SSE detection from steve harris
// http://www.ecs.soton.ac.uk/~swh/denormal-finder/
// <sk>
uint32_t a, b, c, d;
if (cpuid(1, &a, &b, &c, &d)) {
// SSE support
return d & 1<<25;
}
return false;
}

void sc_SetDenormalFlags()
{
// SSE denormal setup from steve harris
// http://www.ecs.soton.ac.uk/~swh/denormal-finder/
// <sk>
uint32_t a, b, c, d;

if (sc_HasVectorUnit()) {
// FTZ flag (flush to zero)
_MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_ON);

cpuid(0, &a, &b, &c, &d);
if (b == 0x756e6547) { /* It's an Intel */
int stepping, model, family, extfamily;

family = (a >> 8) & 0xf;
extfamily = (a >> 20) & 0xff;
model = (a >> 4) & 0xf;
stepping = a & 0xf;
if (family == 15 && extfamily == 0 && model == 0 && stepping < 7) {
return;
}
}

cpuid(1, &a, &b, &c, &d);
if (d & 1<<26) { /* bit 26, SSE2 support */
// DAZ flag (disable denormals)
_mm_setcsr(_mm_getcsr() | 0x40);
}
    }
}
#else
bool sc_HasVectorUnit()
{
return false;
}
void sc_SetDenormalFlags()
{
}
#endif
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