diff options
Diffstat (limited to 'arm-fm-22k/lib_src/eas_pan.c')
| -rw-r--r-- | arm-fm-22k/lib_src/eas_pan.c | 172 |
1 files changed, 86 insertions, 86 deletions
diff --git a/arm-fm-22k/lib_src/eas_pan.c b/arm-fm-22k/lib_src/eas_pan.c index 373d90e..ae4c69d 100644 --- a/arm-fm-22k/lib_src/eas_pan.c +++ b/arm-fm-22k/lib_src/eas_pan.c @@ -1,16 +1,16 @@ -/*----------------------------------------------------------------------------
- *
- * File:
- * eas_pan.c
- *
- * Contents and purpose:
- * Calculates left and right gain multipliers based on a pan value from -63 to +63
- *
- * NOTES:
- * The _CMX_PARSER and _MFI_PARSER preprocessor symbols determine
- * whether the parser works for those particular file formats.
- *
- * Copyright Sonic Network Inc. 2005
+/*---------------------------------------------------------------------------- + * + * File: + * eas_pan.c + * + * Contents and purpose: + * Calculates left and right gain multipliers based on a pan value from -63 to +63 + * + * NOTES: + * The _CMX_PARSER and _MFI_PARSER preprocessor symbols determine + * whether the parser works for those particular file formats. + * + * Copyright Sonic Network Inc. 2005 * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -23,76 +23,76 @@ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. - *
- *----------------------------------------------------------------------------
- * Revision Control:
- * $Revision: 82 $
- * $Date: 2006-07-10 11:45:19 -0700 (Mon, 10 Jul 2006) $
- *----------------------------------------------------------------------------
-*/
-
-#include "eas_pan.h"
-#include "eas_math.h"
-
-/*----------------------------------------------------------------------------
- * EAS_CalcPanControl()
- *----------------------------------------------------------------------------
- * Purpose:
- * Assign the left and right gain values corresponding to the given pan value.
- *
- * This routine uses sin/cos approximations for an equal power curve:
- *
- * sin(x) = (2-4*c)*x^2 + c + x
- * cos(x) = (2-4*c)*x^2 + c - x
- *
- * where c = 1/sqrt(2)
- * using the a0 + x*(a1 + x*a2) approach
- *
- * Inputs:
- * pan - pan value (-63 to + 63)
- *
- * Outputs:
- * pGainLeft linear gain multiplier for left channel (15-bit fraction)
- * pGainRight linear gain multiplier for left channel (15-bit fraction)
- *
- * Side Effects:
- *----------------------------------------------------------------------------
-*/
-void EAS_CalcPanControl (EAS_INT pan, EAS_I16 *pGainLeft, EAS_I16 *pGainRight)
-{
- EAS_INT temp;
- EAS_INT netAngle;
-
- /* impose hard limit */
- if (pan < -63)
- netAngle = -63;
- else if (pan > 63)
- netAngle = 63;
- else
- netAngle = pan;
-
- /*lint -e{701} <avoid multiply for performance reasons>*/
- netAngle = netAngle << 8;
-
- /* calculate sin */
- temp = EG1_ONE + FMUL_15x15(COEFF_PAN_G2, netAngle);
- temp = COEFF_PAN_G0 + FMUL_15x15(temp, netAngle);
-
- if (temp > SYNTH_FULL_SCALE_EG1_GAIN)
- temp = SYNTH_FULL_SCALE_EG1_GAIN;
- else if (temp < 0)
- temp = 0;
-
- *pGainRight = (EAS_I16) temp;
-
- /* calculate cos */
- temp = -EG1_ONE + FMUL_15x15(COEFF_PAN_G2, netAngle);
- temp = COEFF_PAN_G0 + FMUL_15x15(temp, netAngle);
- if (temp > SYNTH_FULL_SCALE_EG1_GAIN)
- temp = SYNTH_FULL_SCALE_EG1_GAIN;
- else if (temp < 0)
- temp = 0;
-
- *pGainLeft = (EAS_I16) temp;
-}
-
+ * + *---------------------------------------------------------------------------- + * Revision Control: + * $Revision: 82 $ + * $Date: 2006-07-10 11:45:19 -0700 (Mon, 10 Jul 2006) $ + *---------------------------------------------------------------------------- +*/ + +#include "eas_pan.h" +#include "eas_math.h" + +/*---------------------------------------------------------------------------- + * EAS_CalcPanControl() + *---------------------------------------------------------------------------- + * Purpose: + * Assign the left and right gain values corresponding to the given pan value. + * + * This routine uses sin/cos approximations for an equal power curve: + * + * sin(x) = (2-4*c)*x^2 + c + x + * cos(x) = (2-4*c)*x^2 + c - x + * + * where c = 1/sqrt(2) + * using the a0 + x*(a1 + x*a2) approach + * + * Inputs: + * pan - pan value (-63 to + 63) + * + * Outputs: + * pGainLeft linear gain multiplier for left channel (15-bit fraction) + * pGainRight linear gain multiplier for left channel (15-bit fraction) + * + * Side Effects: + *---------------------------------------------------------------------------- +*/ +void EAS_CalcPanControl (EAS_INT pan, EAS_I16 *pGainLeft, EAS_I16 *pGainRight) +{ + EAS_INT temp; + EAS_INT netAngle; + + /* impose hard limit */ + if (pan < -63) + netAngle = -63; + else if (pan > 63) + netAngle = 63; + else + netAngle = pan; + + /*lint -e{701} <avoid multiply for performance reasons>*/ + netAngle = netAngle << 8; + + /* calculate sin */ + temp = EG1_ONE + FMUL_15x15(COEFF_PAN_G2, netAngle); + temp = COEFF_PAN_G0 + FMUL_15x15(temp, netAngle); + + if (temp > SYNTH_FULL_SCALE_EG1_GAIN) + temp = SYNTH_FULL_SCALE_EG1_GAIN; + else if (temp < 0) + temp = 0; + + *pGainRight = (EAS_I16) temp; + + /* calculate cos */ + temp = -EG1_ONE + FMUL_15x15(COEFF_PAN_G2, netAngle); + temp = COEFF_PAN_G0 + FMUL_15x15(temp, netAngle); + if (temp > SYNTH_FULL_SCALE_EG1_GAIN) + temp = SYNTH_FULL_SCALE_EG1_GAIN; + else if (temp < 0) + temp = 0; + + *pGainLeft = (EAS_I16) temp; +} + |