22 Jan
2005
22 Jan
'05
4:58 p.m.
Steve,
OK. I put your denormal-zeroing function w/SSE into the freeverb.cpp
code, and when compiling with the SSE option and calling
set_denormal_flags() in the activateFreeverb3 function (see below), I
get this error wherever asm is called:
freeverb/freeverb.cpp: In function `void set_denormal_flags()':
freeverb/freeverb.cpp:48: error: can't find a register in class `BREG'
while reloading `asm'
Do you have an idea of what might be wrong?
Here is where I put the call to your function. Does this make sense?
void
activateFreeverb3(LADSPA_Handle Instance) {
Freeverb3 * poFreeverb = (Freeverb3 *)Instance;
poFreeverb->mute();
/* call the Steve Harris denormal zeroing function w/SSE flag */
set_denormal_flags();
}
--Neil
PS: Maybe we should move this discussion to just linux-audio-dev for now
PPS: For reference, this is your function for zeroing denormals w/SSE
that I am using:
#ifdef __SSE__
#include <xmmintrin.h>
#endif
void set_denormal_flags()
{
unsigned long a, b, c, d;
#ifdef __SSE__
asm("cpuid": "=a" (a), "=b" (b), "=c" (c),
"=d" (d) : "a" (1));
if (d & 1<<25) { /* It has SSE support */
_MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_ON);
asm("cpuid": "=a" (a), "=b" (b), "=c"
(c), "=d" (d) : "a" (0));
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;
}
}
asm("cpuid": "=a" (a), "=b" (b), "=c"
(c), "=d" (d) : "a" (1));
if (d & 1<<26) { /* bit 26, SSE2 support */
_mm_setcsr(_mm_getcsr() | 0x40);
}
} else {
fprintf(stderr, "This code has been built with SSE support, but
your processor does not support\nthe SSE instruction set.\nexiting\n");
exit(1);
}
#endif
}
-------------Steve Harris wrote:---------------
For something like a reverb the best option is going to be to build with
SSE maths and call the function I posed here a week ago or so. There are
so many places where denormals can occur in reverbs that youre going to
burn a load of CPU trying to kill them.
OTOH I'm not sure how that function would interact with the host when
loaded as a plugin