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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
    
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    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
    
    
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    /* ********************************************************************* */
    
    /*      HP100 Version 55 */
    
    /* $Log$
    
     * Revision 1.15  2004/06/26 03:50:14  markster
     * Merge source cleanups (bug #1911)
    
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     *
    
     * 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
     *
    
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     * 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_ */