mirror of
https://github.com/mpv-player/mpv
synced 2024-12-28 01:52:19 +00:00
2eb3f24dc1
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@4790 b3059339-0415-0410-9bf9-f77b7e298cf2
73 lines
2.2 KiB
C
73 lines
2.2 KiB
C
/*=============================================================================
|
|
//
|
|
// This software has been released under the terms of the GNU Public
|
|
// license. See http://www.gnu.org/copyleft/gpl.html for details.
|
|
//
|
|
// Copyright 2001 Anders Johansson ajh@atri.curtin.edu.au
|
|
//
|
|
//=============================================================================
|
|
*/
|
|
|
|
#ifndef __FIR_H__
|
|
#define __FIR_H__
|
|
|
|
/* Fixpoint 16 bit FIR filter. The filter is implemented both in C and
|
|
MMX assembly. The filter consists of the two inline functions updateq
|
|
and firn, update q is used for adding new data to the circular buffer
|
|
used by the filter firn. Limitations: max length of n = 16*4 and n
|
|
must be multiple of 4 (pad fiter with zeros for other lengths).
|
|
Sometimes it works with filters longer than 4*16 (the problem is
|
|
overshoot and the acumulated energy in the filter taps). */
|
|
|
|
#ifdef HAVE_MMX
|
|
inline int32_t firn(int16_t* x, int16_t* w, int16_t n)
|
|
{
|
|
register int32_t y; // Output
|
|
// Prologue
|
|
asm volatile(" pxor %mm1, %mm1;\n" ); // Clear buffer yt
|
|
// Main loop
|
|
while((n-=4)>=0){
|
|
asm volatile(
|
|
" movq (%1), %%mm0;\n" // Load x(n:n+4)
|
|
" pmaddwd (%0), %%mm0;\n" // yt(n:n+1)=sum(x(n:n+4).*w(n:n+4))
|
|
" psrld $16, %%mm0;\n" // yt(n:n+1)=yt(n:n+1)>>16
|
|
" paddd %%mm0, %%mm1;\n" // yt(n:n+1)=yt(n-2:n-1)+yt(n:n+1)
|
|
:: "r" (w), "r" (x));
|
|
w+=4; x+=4;
|
|
}
|
|
// Epilogue
|
|
asm volatile(
|
|
" movq %%mm1, %%mm0;\n"
|
|
" punpckhdq %%mm1, %%mm0;\n"
|
|
" paddd %%mm0, %%mm1;\n" //yt(n)=yt(n)+yt(n+1)
|
|
" movd %%mm1, %0 ;\n" //y=yt
|
|
" emms ;\n"
|
|
: "=&r" (y));
|
|
return y;
|
|
}
|
|
|
|
#else /* HAVE_MMX */
|
|
|
|
// Same thing as above but in C
|
|
inline int32_t firn(int16_t* x, int16_t* w, int16_t n)
|
|
{
|
|
register int32_t y=0;
|
|
while((n-=4) >=0)
|
|
y+=w[n]*x[n]+w[n+1]*x[n+1]+w[n+2]*x[n+2]+w[n+3]*x[n+3] >> 16;
|
|
return y;
|
|
}
|
|
|
|
#endif /* HAVE_MMX */
|
|
|
|
/* Add new data to circular queue designed to be used with a FIR
|
|
filter. xq is the circular queue, in pointing at the new sample, xi
|
|
current index for in xq and l the lenght of the filter */
|
|
inline uint16_t updateq(int16_t* xq, int16_t* in, uint16_t xi, uint16_t l)
|
|
{
|
|
xq[xi]=xq[xi+l]=*in;
|
|
return (--xi)&(l-1); \
|
|
}
|
|
|
|
#endif /* __FIR_H__ */
|
|
|