60 lines
1.4 KiB
C
60 lines
1.4 KiB
C
#ifndef M_PI
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#define M_PI 3.14159265358979323846264338327
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#endif
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#ifndef M_LN2
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#define M_LN2 0.69314718055994530942
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#endif
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/* ln(2)/2 */
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#define LN_2_2 0.3465735902799726547086
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#define SQR(x) ((x)*(x))
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#define DB2LIN(x) ((x) > -90 ? pow(10, (x) * 0.05) : 0)
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/* branchless, supposedly kills denormals when l=1 u=1 */
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#define CLIP(v,l,u) (fabs(v-l)+(l+u)-fabs(v-u))*0.5;
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/* branches, but smaller and generic with no side effects */
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#define LIMIT(v,l,u) ((v)<(l)?(l):((v)>(u)?(u):(v)))
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/* frequency to rads/sec (angular frequency) */
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#define ANGULAR(fc, fs) (2 * M_PI / (fs) * (fc))
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#define ANGULAR_LIM(fc, fs) (2 * M_PI / (fs) * LIMIT((fc), 1, (fs)/2))
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/* http://musicdsp.org/showone.php?id=51 */
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/* http://musicdsp.org/files/denormal.pdf */
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#ifdef BIQUAD_DOUBLE
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typedef double bq_t;
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#define IS_DENORMAL(f) (((*(uint64_t *)&f)&0x7FF0000000000000)==0)
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#else
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typedef float bq_t;
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#define IS_DENORMAL(f) (((*(uint32_t *)&f)&0x7F800000)==0)
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#endif
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typedef struct {
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bq_t a1, a2, b0, b1, b2, x1, x2, y1, y2;
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} biquad;
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typedef struct {
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double b0, b1, b2, a0, a1, a2;
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} biquad_interim;
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void
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biquad_init(biquad *bq);
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biquad_interim
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peaking(double cw, double Gf, double g);
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biquad_interim
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highpass(double cw, double g);
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biquad_interim
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orfanidi(double w0, double Gf, double g);
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void
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biquad_gen(biquad *bq, int type, double fc, double gain, double bw, double fs);
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bq_t
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biquad_run(biquad *bq, bq_t x);
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