Audio: DRC: Use fast exponent functions

The exp_fixed() function is replaced by fast sofm_exp_fixed()
and sofm_db2lin() functions. It saves 40 MCPS, from 123 to 83 MCPS
in a test run in TGL platform.

Signed-off-by: shastry <malladi.sastry@intel.com>

Author: ShriramShastry

src/audio/drc/Kconfig

@@ -4,7 +4,7 @@ config COMP_DRC
 	bool "Dynamic Range Compressor component"
 	select CORDIC_FIXED
 	select NUMBERS_NORM
-	select MATH_DECIBELS
+	select MATH_EXP
 	select COMP_BLOB
 	default n
 	help

src/audio/drc/drc_generic.c

@@ -6,7 +6,7 @@
 
 #include <sof/audio/component.h>
 #include <sof/audio/format.h>
-#include <sof/math/decibels.h>
+#include <sof/math/exp_fcn.h>
 #include <sof/math/numbers.h>
 #include <stdint.h>
 
@@ -36,7 +36,7 @@ static int32_t knee_curveK(const struct sof_drc_params *p, int32_t x)
 	 *	 beta = -expf(k * linear_threshold) / k
 	 *	 gamma = -k * x
 	 */
-	knee_exp_gamma = exp_fixed(Q_MULTSR_32X32((int64_t)x, -p->K, 31, 20, 27)); /* Q12.20 */
+	knee_exp_gamma = sofm_exp_fixed(Q_MULTSR_32X32((int64_t)x, -p->K, 31, 20, 27)); /* Q12.20 */
 	return p->knee_alpha + Q_MULTSR_32X32((int64_t)p->knee_beta, knee_exp_gamma, 24, 20, 24);
 }
 
@@ -66,8 +66,10 @@ static int32_t volume_gain(const struct sof_drc_params *p, int32_t x)
 		 * => y/x = ratio_base * x^(s - 1)
 		 * => y/x = ratio_base * e^(log(x) * (s - 1))
 		 */
-		exp_knee = exp_fixed(Q_MULTSR_32X32((int64_t)drc_log_fixed(Q_SHIFT_RND(x, 31, 26)),
-						    (p->slope - ONE_Q30), 26, 30, 27)); /* Q12.20 */
+		exp_knee = sofm_exp_fixed(Q_MULTSR_32X32((int64_t)
+						drc_log_fixed(Q_SHIFT_RND(x, 31, 26)),
+						(p->slope - ONE_Q30),
+						26, 30, 27)); /* Q12.20 */
 		y = Q_MULTSR_32X32((int64_t)p->ratio_base, exp_knee, 30, 20, 30);
 	}
 
@@ -149,7 +151,7 @@ void drc_update_detector_average(struct drc_state *state,
 						       p->sat_release_frames_inv_neg,
 						       21, 30, 24); /* Q8.24 */
 				sat_release_rate =
-					db2lin_fixed(db_per_frame) - ONE_Q20; /* Q12.20 */
+					sofm_db2lin_fixed(db_per_frame) - ONE_Q20; /* Q12.20 */
 				detector_average += Q_MULTSR_32X32((int64_t)gain_diff,
 								   sat_release_rate, 30, 20, 30);
 			}
@@ -226,7 +228,7 @@ void drc_update_envelope(struct drc_state *state, const struct sof_drc_params *p
 		/* db_per_frame = kSpacingDb / release_frames */
 		db_per_frame = drc_inv_fixed(release_frames, 12, 30); /* Q2.30 */
 		db_per_frame = Q_MULTSR_32X32((int64_t)db_per_frame, p->kSpacingDb, 30, 0, 24);
-		envelope_rate = db2lin_fixed(db_per_frame); /* Q12.20 */
+		envelope_rate = sofm_db2lin_fixed(db_per_frame); /* Q12.20 */
 	} else {
 		int32_t sat32;
 		/* Attack mode - compression_diff_db should be positive dB */

src/audio/drc/drc_hifi3.c

@@ -6,7 +6,7 @@
 
 #include <sof/audio/component.h>
 #include <sof/audio/format.h>
-#include <sof/math/decibels.h>
+#include <sof/math/exp_fcn.h>
 #include <sof/math/numbers.h>
 #include <stdint.h>
 
@@ -42,7 +42,7 @@ static int32_t knee_curveK(const struct sof_drc_params *p, int32_t x)
 	 *	 gamma = -k * x
 	 */
 	gamma = drc_mult_lshift(x, -p->K, drc_get_lshift(31, 20, 27));
-	knee_exp_gamma = exp_fixed(gamma);
+	knee_exp_gamma = sofm_exp_fixed(gamma);
 	knee_curve_k = drc_mult_lshift(p->knee_beta, knee_exp_gamma, drc_get_lshift(24, 20, 24));
 	knee_curve_k = AE_ADD32(knee_curve_k, p->knee_alpha);
 	return knee_curve_k;
@@ -78,7 +78,7 @@ static int32_t volume_gain(const struct sof_drc_params *p, int32_t x)
 		tmp = AE_SRAI32R(x, 5); /* Q1.31 -> Q5.26 */
 		tmp = drc_log_fixed(tmp); /* Q6.26 */
 		tmp2 = AE_SUB32(p->slope, ONE_Q30); /* Q2.30 */
-		exp_knee = exp_fixed(drc_mult_lshift(tmp, tmp2, drc_get_lshift(26, 30, 27)));
+		exp_knee = sofm_exp_fixed(drc_mult_lshift(tmp, tmp2, drc_get_lshift(26, 30, 27)));
 		y = drc_mult_lshift(p->ratio_base, exp_knee, drc_get_lshift(30, 20, 30));
 	}
 
@@ -159,7 +159,8 @@ void drc_update_detector_average(struct drc_state *state,
 				db_per_frame = drc_mult_lshift(drc_lin2db_fixed(gain),
 							       p->sat_release_frames_inv_neg,
 							       drc_get_lshift(21, 30, 24));
-				sat_release_rate = AE_SUB32(db2lin_fixed(db_per_frame), ONE_Q20);
+				sat_release_rate = AE_SUB32(sofm_db2lin_fixed(db_per_frame),
+							    ONE_Q20);
 				tmp = drc_mult_lshift(gain_diff, sat_release_rate,
 						      drc_get_lshift(30, 20, 30));
 			}
@@ -254,7 +255,7 @@ void drc_update_envelope(struct drc_state *state, const struct sof_drc_params *p
 		tmp = p->kSpacingDb << 16; /* Q16.16 */
 		lshift = drc_get_lshift(30, 16, 24);
 		db_per_frame = drc_mult_lshift(db_per_frame, tmp, lshift); /* Q8.24 */
-		envelope_rate = db2lin_fixed(db_per_frame); /* Q12.20 */
+		envelope_rate = sofm_db2lin_fixed(db_per_frame); /* Q12.20 */
 	} else {
 		/* Attack mode - compression_diff_db should be positive dB */
 

src/audio/drc/drc_hifi4.c

@@ -6,7 +6,7 @@
 
 #include <sof/audio/component.h>
 #include <sof/audio/format.h>
-#include <sof/math/decibels.h>
+#include <sof/math/exp_fcn.h>
 #include <sof/math/numbers.h>
 #include <stdint.h>
 
@@ -65,7 +65,7 @@ static int32_t knee_curveK(const struct sof_drc_params *p, int32_t x)
 	 *	 gamma = -k * x
 	 */
 	gamma = drc_mult_lshift(x, -p->K, LSHIFT_QX31_QY20_QZ27);
-	knee_exp_gamma = exp_fixed(gamma);
+	knee_exp_gamma = sofm_exp_fixed(gamma);
 	knee_curve_k = drc_mult_lshift(p->knee_beta, knee_exp_gamma, LSHIFT_QX24_QY20_QZ24);
 	knee_curve_k = AE_ADD32(knee_curve_k, p->knee_alpha);
 	return knee_curve_k;
@@ -101,7 +101,7 @@ static int32_t volume_gain(const struct sof_drc_params *p, int32_t x)
 		tmp = AE_SRAI32R(x, 5); /* Q1.31 -> Q5.26 */
 		tmp = drc_log_fixed(tmp); /* Q6.26 */
 		tmp2 = AE_SUB32(p->slope, ONE_Q30); /* Q2.30 */
-		exp_knee = exp_fixed(drc_mult_lshift(tmp, tmp2, LSHIFT_QX26_QY30_QZ27));
+		exp_knee = sofm_exp_fixed(drc_mult_lshift(tmp, tmp2, LSHIFT_QX26_QY30_QZ27));
 		y = drc_mult_lshift(p->ratio_base, exp_knee, LSHIFT_QX30_QY20_QZ30);
 	}
 
@@ -185,7 +185,8 @@ void drc_update_detector_average(struct drc_state *state,
 				db_per_frame = drc_mult_lshift(drc_lin2db_fixed(gain),
 							       p->sat_release_frames_inv_neg,
 							       LSHIFT_QX21_QY30_QZ24);
-				sat_release_rate = AE_SUB32(db2lin_fixed(db_per_frame), ONE_Q20);
+				sat_release_rate = AE_SUB32(sofm_db2lin_fixed(db_per_frame),
+							    ONE_Q20);
 				tmp = drc_mult_lshift(gain_diff, sat_release_rate,
 						      LSHIFT_QX30_QY20_QZ30);
 			}
@@ -278,7 +279,7 @@ void drc_update_envelope(struct drc_state *state, const struct sof_drc_params *p
 		tmp = p->kSpacingDb << 16; /* Q16.16 */
 		/* Q8.24 */
 		db_per_frame = drc_mult_lshift(db_per_frame, tmp, LSHIFT_QX30_QY16_QZ24);
-		envelope_rate = db2lin_fixed(db_per_frame); /* Q12.20 */
+		envelope_rate = sofm_db2lin_fixed(db_per_frame); /* Q12.20 */
 	} else {
 		/* Attack mode - compression_diff_db should be positive dB */
 

src/audio/drc/drc_math_generic.c

@@ -6,6 +6,7 @@
 
 #include <sof/audio/format.h>
 #include <sof/math/decibels.h>
+#include <sof/math/exp_fcn.h>
 #include <sof/math/numbers.h>
 #include <sof/math/trig.h>
 
@@ -234,7 +235,7 @@ inline int32_t drc_pow_fixed(int32_t x, int32_t y)
 		return 0;
 
 	/* x^y = expf(y * log(x)) */
-	return exp_fixed(q_mult(y, drc_log_fixed(x), 30, 26, 27));
+	return sofm_exp_fixed(q_mult(y, drc_log_fixed(x), 30, 26, 27));
 }
 
 #undef q_multq