cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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dsp_biquad.h (977B)

      1/* SPDX-License-Identifier: GPL-2.0-or-later */
      2/*
      3 * SpanDSP - a series of DSP components for telephony
      4 *
      5 * biquad.h - General telephony bi-quad section routines (currently this just
      6 *            handles canonic/type 2 form)
      7 *
      8 * Written by Steve Underwood <steveu@coppice.org>
      9 *
     10 * Copyright (C) 2001 Steve Underwood
     11 *
     12 * All rights reserved.
     13 */
     14
     15struct biquad2_state {
     16	int32_t gain;
     17	int32_t a1;
     18	int32_t a2;
     19	int32_t b1;
     20	int32_t b2;
     21
     22	int32_t z1;
     23	int32_t z2;
     24};
     25
     26static inline void biquad2_init(struct biquad2_state *bq,
     27				int32_t gain, int32_t a1, int32_t a2, int32_t b1, int32_t b2)
     28{
     29	bq->gain = gain;
     30	bq->a1 = a1;
     31	bq->a2 = a2;
     32	bq->b1 = b1;
     33	bq->b2 = b2;
     34
     35	bq->z1 = 0;
     36	bq->z2 = 0;
     37}
     38
     39static inline int16_t biquad2(struct biquad2_state *bq, int16_t sample)
     40{
     41	int32_t y;
     42	int32_t z0;
     43
     44	z0 = sample * bq->gain + bq->z1 * bq->a1 + bq->z2 * bq->a2;
     45	y = z0 + bq->z1 * bq->b1 + bq->z2 * bq->b2;
     46
     47	bq->z2 = bq->z1;
     48	bq->z1 = z0 >> 15;
     49	y >>= 15;
     50	return  y;
     51}