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/*
$Log$
Revision 1.15 2004/06/26 03:50:14 markster
Merge source cleanups (bug #1911)
Revision 1.14 2003/02/12 13:59:15 matteo
mer feb 12 14:56:57 CET 2003
Revision 1.1.1.1 2003/02/12 13:59:15 matteo
mer feb 12 14:56:57 CET 2003
Revision 1.2 2000/01/05 08:20:39 markster
Some OSS fixes and a few lpc changes to make it actually work
* Revision 1.2 1996/08/20 20:28:05 jaf
* Removed all static local variables that were SAVE'd in the Fortran
* code, and put them in struct lpc10_encoder_state that is passed as an
* argument.
*
* Removed init function, since all initialization is now done in
* init_lpc10_encoder_state().
*
* Revision 1.1 1996/08/19 22:32:04 jaf
* Initial revision
*
*/
/* -- translated by f2c (version 19951025).
You must link the resulting object file with the libraries:
-lf2c -lm (in that order)
*/
#include "f2c.h"
#ifdef P_R_O_T_O_T_Y_P_E_S
extern int hp100_(real *speech, integer *start, integer *end,
struct lpc10_encoder_state *st);
extern int inithp100_(void);
#endif
/* ********************************************************************* */
/* HP100 Version 55 */
/* $Log$
* Revision 1.15 2004/06/26 03:50:14 markster
* Merge source cleanups (bug #1911)
*
* Revision 1.14 2003/02/12 13:59:15 matteo
* mer feb 12 14:56:57 CET 2003
*
* Revision 1.1.1.1 2003/02/12 13:59:15 matteo
* mer feb 12 14:56:57 CET 2003
*
* Revision 1.2 2000/01/05 08:20:39 markster
* Some OSS fixes and a few lpc changes to make it actually work
*
* Revision 1.2 1996/08/20 20:28:05 jaf
* Removed all static local variables that were SAVE'd in the Fortran
* code, and put them in struct lpc10_encoder_state that is passed as an
* argument.
*
* Removed init function, since all initialization is now done in
* init_lpc10_encoder_state().
*
* Revision 1.1 1996/08/19 22:32:04 jaf
* Initial revision
* */
/* Revision 1.6 1996/03/15 16:45:25 jaf */
/* Rearranged a few comments. */
/* Revision 1.5 1996/03/14 23:20:54 jaf */
/* Added comments about when INITHP100 should be used. */
/* Revision 1.4 1996/03/14 23:08:08 jaf */
/* Added an entry named INITHP100 that initializes the local state of */
/* subroutine HP100. */
/* Revision 1.3 1996/03/14 22:09:20 jaf */
/* Comments added explaining which of the local variables of this */
/* subroutine need to be saved from one invocation to the next, and which */
/* do not. */
/* Revision 1.2 1996/02/12 15:05:54 jaf */
/* Added lots of comments explaining why I changed one line, which was a */
/* declaration with initializations. */
/* Revision 1.1 1996/02/07 14:47:12 jaf */
/* Initial revision */
/* ********************************************************************* */
/* 100 Hz High Pass Filter */
/* Jan 92 - corrected typo (1.937148 to 1.935715), */
/* rounded coefficients to 7 places, */
/* corrected and merged gain (.97466**4), */
/* merged numerator into first two sections. */
/* Input: */
/* start, end - Range of samples to filter */
/* Input/Output: */
/* speech(end) - Speech data. */
/* Indices start through end are read and modified. */
/* This subroutine maintains local state from one call to the next. If */
/* you want to switch to using a new audio stream for this filter, or */
/* reinitialize its state for any other reason, call the ENTRY */
/* INITHP100. */
/* Subroutine */ int hp100_(real *speech, integer *start, integer *end,
struct lpc10_encoder_state *st)
{
/* Temporary local copies of variables in lpc10_encoder_state.
I've only created these because it might cause the loop below
to execute a bit faster to access local variables, rather than
variables in the lpc10_encoder_state structure. It is just a
guess that it will be faster. */
real z11;
real z21;
real z12;
real z22;
/* System generated locals */
integer i__1;
/* Local variables */
integer i__;
real si, err;
/* Arguments */
/* Local variables that need not be saved */
/* Local state */
/* Parameter adjustments */
if (speech) {
--speech;
}
/* Function Body */
z11 = st->z11;
z21 = st->z21;
z12 = st->z12;
z22 = st->z22;
i__1 = *end;
for (i__ = *start; i__ <= i__1; ++i__) {
si = speech[i__];
err = si + z11 * 1.859076f - z21 * .8648249f;
si = err - z11 * 2.f + z21;
z21 = z11;
z11 = err;
err = si + z12 * 1.935715f - z22 * .9417004f;
si = err - z12 * 2.f + z22;
z22 = z12;
z12 = err;
speech[i__] = si * .902428f;
}
st->z11 = z11;
st->z21 = z21;
st->z12 = z12;
st->z22 = z22;
return 0;
} /* hp100_ */
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