On Fri, 2003-10-17 at 02:09, Juan Linietsky wrote:
> Benno Sennoner and I were discussing today on IRC about
> the usual fixed point vs floating point (regarding to some resampling code)
Attached is some quick-and-dirty hack written tired and drunk at friday
night...
--
Jussi Laako <[EMAIL PROTECTED]>
#define BUFF_LENGTH 8192
#define BUFF_MIX 2048 //somewhat regular audio chunk size?
volatile float src_buff[BUFF_LENGTH]; //src float buffer
volatile float dst_buff[BUFF_LENGTH]; //dst float buffer
static void resample()
{
float advance_f=0.3;
float volume_f=0.2; // 1/5 of max volume
volatile float *src_ptr=src_buff;
volatile float *dst_ptr=dst_buff;
asm volatile (
"pushal\n\t"
"movl %0, %%eax\n\t"
"movl %1, %%ebx\n\t"
"movl $2048, %%ecx\n\t"
"pxor %%mm0, %%mm0\n\t"
"movd %2, %%mm2\n\t"
"movd %3, %%mm3\n\t"
"resampleloop:\n\t"
"pf2id %%mm0, %%mm1\n\t"
"movd %%mm1, %%edx\n\t"
"shll $2, %%edx\n\t"
"addl %%eax, %%edx\n\t"
"movq (%%edx), %%mm4\n\t"
"pswapd %%mm4, %%mm5\n\t"
"pi2fd %%mm1, %%mm6\n\t"
"pfsubr %%mm4, %%mm5\n\t"
"pfsubr %%mm0, %%mm6\n\t"
"pfmul %%mm5, %%mm6\n\t"
"pfadd %%mm6, %%mm4\n\t"
"pfmul %%mm2, %%mm4\n\t"
"movd (%%ebx), %%mm7\n\t"
"pfadd %%mm4, %%mm7\n\t"
"movd %%mm7, (%%ebx)\n\t"
"addl $4, %%ebx\n\t"
"pfadd %%mm3, %%mm0\n\t"
"decl %%ecx\n\t"
"jnz resampleloop\n\t"
"femms\n\t"
"popal\n\t"
:
: "m" (src_ptr),
"m" (dst_ptr),
"m" (volume_f),
"m" (advance_f)
: "eax", "ebx", "ecx", "edx",
"mm0", "mm1", "mm2", "mm3", "mm4", "mm5", "mm6", "mm7",
"memory");
/*while (todo--) {
pos=float_to_int(counter);
//pos=todo>>2;
res=src_ptr[pos];
res_next=src_ptr[pos+1];
counter+=advance_f;
//this line works perfect, since res and res_next contain 16 bits values
res+= (res_next-res) * (counter-(float)pos);
res*=volume_f; //thanks to the volume, now the value goes into the higher 16 bits
*dst_ptr++ +=res;
}*/
}
#define TEST_REPEAT 100000
int main() {
//fill it with some data
int i;
for (i=0;i<BUFF_LENGTH;i++) {
src_buff[i]=i;
dst_buff[i]=i;
}
for (i=0;i<TEST_REPEAT;i++) {
resample();
}
return 0;
}
