AAC Encoder low delay quality

* AAC-Encoder

   - Revise bit distribution for lowdelay configuration to improve encoder
     audio quality.
   - Adjust lowdelay bitreservoir for low bitreservoir configuration.
     Modified file(s):
        libAACenc\src\aacEnc_ram.cpp
        libAACenc\src\aacenc.cpp
        libAACenc\src\aacenc_lib.cpp
        libAACenc\src\aacenc_tns.cpp
        libAACenc\src\adj_thr.cpp
        libAACenc\src\adj_thr.h
        libAACenc\src\block_switch.cpp
        libAACenc\src\block_switch.h
        libAACenc\src\interface.h
        libAACenc\src\psy_main.cpp
        libAACenc\src\qc_data.h
        libAACenc\src\qc_main.cpp

* FDK-Library

   - Increase the accuracy in CalcInvLdData() calculation which improves the
     encoder audio quality.
     Modified file(s):
        libFDK\src\fixpoint_math.cpp

Bug 9428126

Change-Id: I302d7f4c3aeccf79e1b85f20e18a31e6e2b10544

libAACenc/src/aacEnc_ram.cpp

@@ -95,7 +95,7 @@ amm-info@iis.fraunhofer.de
 
 #include "aacEnc_ram.h"
 
-  C_ALLOC_MEM (AACdynamic_RAM, FIXP_DBL, AAC_ENC_DYN_RAM_SIZE/sizeof(FIXP_DBL))
+  C_AALLOC_MEM (AACdynamic_RAM, FIXP_DBL, AAC_ENC_DYN_RAM_SIZE/sizeof(FIXP_DBL))
 
 /*
   Static memory areas, must not be overwritten in other sections of the decoder !
@@ -175,7 +175,7 @@ C_ALLOC_MEM (Ram_aacEnc_BitCntrState, BITCNTR_STATE, 1)
 */
 
 C_ALLOC_MEM2 (Ram_aacEnc_QCout, QC_OUT, 1, (1))
-C_ALLOC_MEM2 (Ram_aacEnc_QCelement, QC_OUT_ELEMENT, 1, (1)*(6))
+C_ALLOC_MEM2 (Ram_aacEnc_QCelement, QC_OUT_ELEMENT, (1), (6))
   QC_OUT_CHANNEL *GetRam_aacEnc_QCchannel (int n, UCHAR* dynamic_RAM) {
       FDK_ASSERT(dynamic_RAM!=0);
       return ((QC_OUT_CHANNEL*) (dynamic_RAM + P_BUF_0 + n*sizeof(QC_OUT_CHANNEL)));

libAACenc/src/aacenc.cpp

@@ -578,6 +578,8 @@ AAC_ENCODER_ERROR FDKaacEnc_Initialize(HANDLE_AAC_ENC      hAacEnc,
       qcInit.minBits         = (config->minBitsPerFrame!=-1) ? fixMax(qcInit.minBits, config->minBitsPerFrame) : qcInit.minBits;
   }
 
+  qcInit.sampleRate          = config->sampleRate;
+  qcInit.advancedBitsToPe    = isLowDelay(config->audioObjectType) ? 1 : 0 ;
   qcInit.nSubFrames          = config->nSubFrames;
   qcInit.padding.paddingRest = config->sampleRate;
 

libAACenc/src/aacenc_lib.cpp

@@ -98,7 +98,7 @@ amm-info@iis.fraunhofer.de
 /* Encoder library info */
 #define AACENCODER_LIB_VL0 3
 #define AACENCODER_LIB_VL1 4
-#define AACENCODER_LIB_VL2 7
+#define AACENCODER_LIB_VL2 8
 #define AACENCODER_LIB_TITLE "AAC Encoder"
 #define AACENCODER_LIB_BUILD_DATE __DATE__
 #define AACENCODER_LIB_BUILD_TIME __TIME__
@@ -689,7 +689,7 @@ AACENC_ERROR FDKaacEnc_AdjustEncSettings(HANDLE_AACENCODER hAacEncoder,
           hAacConfig->bitrateMode = 0;
         }
         if (config->userBitrateMode==0) {
-          hAacConfig->bitreservoir = 50*config->nChannels; /* default, reduced bitreservoir */
+          hAacConfig->bitreservoir = 100*config->nChannels; /* default, reduced bitreservoir */
         }
         if (hAacConfig->bitrateMode!=0) {
           return AACENC_INVALID_CONFIG;

libAACenc/src/aacenc_tns.cpp

@@ -83,7 +83,7 @@ amm-info@iis.fraunhofer.de
 
 /******************************** MPEG Audio Encoder **************************
 
-   Initial author:       Alex Groeschel
+   Initial author:       Alex Groeschel, Tobias Chalupka
    contents/description: Temporal noise shaping
 
 ******************************************************************************/

libAACenc/src/adj_thr.h

@@ -98,13 +98,14 @@ amm-info@iis.fraunhofer.de
 #include "interface.h"
 
 
-
-void FDKaacEnc_peCalculation(PE_DATA *peData,
+void FDKaacEnc_peCalculation(
+        PE_DATA *peData,
         PSY_OUT_CHANNEL* psyOutChannel[(2)],
         QC_OUT_CHANNEL* qcOutChannel[(2)],
         struct TOOLSINFO *toolsInfo,
         ATS_ELEMENT* adjThrStateElement,
-                             const INT nChannels);
+        const INT nChannels
+        );
 
 INT  FDKaacEnc_AdjThrNew(ADJ_THR_STATE** phAdjThr,
                          INT             nElements);
@@ -112,7 +113,11 @@ INT  FDKaacEnc_AdjThrNew(ADJ_THR_STATE** phAdjThr,
 void FDKaacEnc_AdjThrInit(ADJ_THR_STATE *hAdjThr,
                 const INT peMean,
                 ELEMENT_BITS* elBits[(6)],
+                INT invQuant,
                 INT nElements,
+                INT nChannelsEff,
+                INT sampleRate,
+                INT advancedBitsToPe,
                 FIXP_DBL vbrQualFactor);
  
 
@@ -128,7 +133,7 @@ void FDKaacEnc_DistributeBits(ADJ_THR_STATE *adjThrState,
     const INT         bitresBits,
     const INT         maxBitresBits,
     const FIXP_DBL    maxBitFac,
-    const INT         bitDistributenMode);
+    const INT         bitDistributionMode);
 
 void FDKaacEnc_AdjustThresholds(ATS_ELEMENT* AdjThrStateElement[(6)],
     QC_OUT_ELEMENT*   qcElement[(6)],

libAACenc/src/block_switch.cpp

@@ -83,7 +83,7 @@ amm-info@iis.fraunhofer.de
 
 /*****************************  MPEG-4 AAC Encoder  **************************
 
-   Author(s):   M. Werner
+   Author(s):   M. Werner, Tobias Chalupka
    Description: Block switching
 
 ******************************************************************************/
@@ -100,9 +100,11 @@ amm-info@iis.fraunhofer.de
 
 static FIXP_DBL FDKaacEnc_GetWindowEnergy(const FIXP_DBL in[], const INT blSwWndIdx);
 
-static void FDKaacEnc_CalcWindowEnergy( BLOCK_SWITCHING_CONTROL *RESTRICT blockSwitchingControl,
-                              INT                      windowLen);
-
+static void FDKaacEnc_CalcWindowEnergy(
+        BLOCK_SWITCHING_CONTROL *RESTRICT blockSwitchingControl,
+        INT                      windowLen,
+        const INT_PCM           *pTimeSignal
+        );
 
 /****************** Constants *****************************/
 /*                                                LONG         START        SHORT         STOP         LOWOV                  */
@@ -145,20 +147,9 @@ static const FIXP_DBL minAttackNrg = (FL2FXCONST_DBL(1e+6f*NORM_PCM_ENERGY)>>BLO
 
 /**************** internal function prototypes ***********/
 
-static INT FDKaacEnc_GetWindowIndex(INT blockSwWindowIndex);
-
-static FIXP_DBL FDKaacEnc_GetWindowEnergy(const FIXP_DBL in[], const INT shortWndIdx);
-
-static void FDKaacEnc_CalcWindowEnergy( BLOCK_SWITCHING_CONTROL *RESTRICT blockSwitchingControl,
-                                        INT windowLen);
-
-
-
 /****************** Routines ****************************/
 void FDKaacEnc_InitBlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, INT isLowDelay)
 {
-  /* note: the pointer to timeSignal can be zeroed here, because it is initialized for every call
-           to FDKaacEnc_BlockSwitching anew */
   FDKmemclear (blockSwitchingControl, sizeof(BLOCK_SWITCHING_CONTROL));
 
   if (isLowDelay)
@@ -214,7 +205,7 @@ static const INT chgWndSqLkAhd[2][2][N_BLOCKTYPES] =
   /*attack   */   {START_WINDOW,  SHORT_WINDOW,  SHORT_WINDOW,  START_WINDOW, WRONG_WINDOW, WRONG_WINDOW} }  /* attack      */
 };
 
-int FDKaacEnc_BlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, const INT granuleLength, const int isLFE)
+int FDKaacEnc_BlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, const INT granuleLength, const int isLFE, const INT_PCM *pTimeSignal)
 {
     UINT i;
     FIXP_DBL enM1, enMax;
@@ -263,7 +254,7 @@ int FDKaacEnc_BlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, con
 
 
     /* Calculate unfiltered and filtered energies in subwindows and combine to segments */
-    FDKaacEnc_CalcWindowEnergy(blockSwitchingControl, granuleLength>>(nBlockSwitchWindows==4? 2:3 ));
+    FDKaacEnc_CalcWindowEnergy(blockSwitchingControl, granuleLength>>(nBlockSwitchWindows==4? 2:3 ), pTimeSignal);
 
     /* now calculate if there is an attack */
 
@@ -335,8 +326,7 @@ static FIXP_DBL FDKaacEnc_GetWindowEnergy(const FIXP_DBL in[], const INT blSwWnd
 
 }
 
-
-static void FDKaacEnc_CalcWindowEnergy(BLOCK_SWITCHING_CONTROL *RESTRICT blockSwitchingControl, INT windowLen)
+static void FDKaacEnc_CalcWindowEnergy(BLOCK_SWITCHING_CONTROL *RESTRICT blockSwitchingControl, INT windowLen, const INT_PCM *pTimeSignal)
 {
     INT  i;
     UINT w;
@@ -344,8 +334,6 @@ static void FDKaacEnc_CalcWindowEnergy(BLOCK_SWITCHING_CONTROL *RESTRICT blockSw
     FIXP_SGL hiPassCoeff0 = hiPassCoeff[0];
     FIXP_SGL hiPassCoeff1 = hiPassCoeff[1];
 
-    INT_PCM *timeSignal = blockSwitchingControl->timeSignal;
-
     /* sum up scalarproduct of timesignal as windowed Energies */
     for (w=0; w < blockSwitchingControl->nBlockSwitchWindows; w++) {
 
@@ -361,9 +349,9 @@ static void FDKaacEnc_CalcWindowEnergy(BLOCK_SWITCHING_CONTROL *RESTRICT blockSw
             FIXP_DBL tempUnfiltered, tempFiltred, t1, t2;
             /* tempUnfiltered is scaled with 1 to prevent overflows during calculation of tempFiltred */
 #if SAMPLE_BITS == DFRACT_BITS
-            tempUnfiltered = (FIXP_DBL) *timeSignal++ >> 1;
+            tempUnfiltered = (FIXP_DBL) *pTimeSignal++ >> 1;
 #else
-            tempUnfiltered = (FIXP_DBL) *timeSignal++ << (DFRACT_BITS-SAMPLE_BITS-1);
+            tempUnfiltered = (FIXP_DBL) *pTimeSignal++ << (DFRACT_BITS-SAMPLE_BITS-1);
 #endif
             t1 = fMultDiv2(hiPassCoeff1, tempUnfiltered-temp_iirState0);
             t2 = fMultDiv2(hiPassCoeff0, temp_iirState1);

libAACenc/src/block_switch.h

@@ -107,7 +107,6 @@ amm-info@iis.fraunhofer.de
 
 /****************** Structures ***************************/
 typedef struct{
-  INT_PCM *timeSignal;
   INT   lastWindowSequence;
   INT   windowShape;
   INT   lastWindowShape;
@@ -136,7 +135,7 @@ typedef struct{
 
 void FDKaacEnc_InitBlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, INT isLowDelay);
 
-int FDKaacEnc_BlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, const INT granuleLength, const int isLFE);
+int FDKaacEnc_BlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, const INT granuleLength, const int isLFE, const INT_PCM *pTimeSignal);
 
 int FDKaacEnc_SyncBlockSwitching(
       BLOCK_SWITCHING_CONTROL *blockSwitchingControlLeft,

libAACenc/src/interface.h

@@ -92,6 +92,7 @@ amm-info@iis.fraunhofer.de
 #define _INTERFACE_H
 
 #include "common_fix.h"
+#include "FDK_audio.h"
 
 #include "psy_data.h"
 #include "aacenc_tns.h"
@@ -160,4 +161,9 @@ typedef struct {
 
 }PSY_OUT;
 
+inline int isLowDelay( AUDIO_OBJECT_TYPE aot )
+{
+  return (aot==AOT_ER_AAC_LD || aot==AOT_ER_AAC_ELD);
+}
+
 #endif /* _INTERFACE_H */

libAACenc/src/psy_main.cpp

@@ -116,11 +116,6 @@ static const FIXP_DBL fadeOutFactor[FADE_OUT_LEN] = {1840644096, 1533870080, 122
 /* forward definitions */
 
 
-static inline int isLowDelay( AUDIO_OBJECT_TYPE aot )
-{
-  return (aot==AOT_ER_AAC_LD || aot==AOT_ER_AAC_ELD);
-}
-
 /*****************************************************************************
 
     functionname: FDKaacEnc_PsyNew
@@ -513,28 +508,28 @@ AAC_ENCODER_ERROR FDKaacEnc_psyMain(INT                 channels,
 
       for(ch = 0; ch < channels; ch++)
       {
-          C_ALLOC_SCRATCH_START(timeSignal, INT_PCM, (1024));
-          psyStatic[ch]->blockSwitchingControl.timeSignal = timeSignal;
+          C_ALLOC_SCRATCH_START(pTimeSignal, INT_PCM, (1024))
 
           /* deinterleave input data and use for block switching */
-          FDKaacEnc_deinterleaveInputBuffer( psyStatic[ch]->blockSwitchingControl.timeSignal,
+          FDKaacEnc_deinterleaveInputBuffer( pTimeSignal,
                                             &pInput[chIdx[ch]],
                                              psyConf->granuleLength,
                                              totalChannels);
 
 
           FDKaacEnc_BlockSwitching (&psyStatic[ch]->blockSwitchingControl,
-                                     psyConf->granuleLength
-                                    ,psyStatic[ch]->isLFE
+                                     psyConf->granuleLength,
+                                     psyStatic[ch]->isLFE,
+                                     pTimeSignal
                                    );
 
 
             /* fill up internal input buffer, to 2xframelength samples */
             FDKmemcpy(psyStatic[ch]->psyInputBuffer+blockSwitchingOffset,
-                      psyStatic[ch]->blockSwitchingControl.timeSignal,
+                      pTimeSignal,
                       (2*psyConf->granuleLength-blockSwitchingOffset)*sizeof(INT_PCM));
 
-            C_ALLOC_SCRATCH_END(timeSignal, INT_PCM, (1024));
+            C_ALLOC_SCRATCH_END(pTimeSignal, INT_PCM, (1024))
       }
 
       /* synch left and right block type */

libAACenc/src/qc_data.h

@@ -143,6 +143,8 @@ struct QC_INIT{
   INT maxBits;     /* maximum number of bits in reservoir  */
   INT averageBits; /* average number of bits we should use */
   INT bitRes;
+  INT sampleRate;       /* output sample rate                   */
+  INT advancedBitsToPe; /* if set, calc bits2PE factor depending on samplerate */
   INT staticBits;  /* Bits per frame consumed by transport layers. */
   QCDATA_BR_MODE bitrateMode;
   INT meanPe;
@@ -252,7 +254,7 @@ typedef struct
   INT minBitsPerFrame;   /* minimal allowd bits per fram, superframing - DRM */
   INT nElements;
   QCDATA_BR_MODE bitrateMode;
-  INT bitDistributenMode; /* 0: full bitreservoir, 1: reduced bitreservoir, 2: disabled bitreservoir */
+  INT bitDistributionMode; /* 0: full bitreservoir, 1: reduced bitreservoir, 2: disabled bitreservoir */
   INT bitResTot;
   INT bitResTotMax;
   INT maxIterations;      /* Maximum number of allowed iterations before FDKaacEnc_crashRecovery() is applied. */

libAACenc/src/qc_main.cpp

@@ -382,10 +382,10 @@ AAC_ENCODER_ERROR FDKaacEnc_QCInit(QC_STATE *hQC,
   if ( isConstantBitrateMode(hQC->bitrateMode) ) {
     INT bitresPerChannel = (hQC->bitResTotMax / init->channelMapping->nChannelsEff);
     /* 0: full bitreservoir, 1: reduced bitreservoir, 2: disabled bitreservoir */
-    hQC->bitDistributenMode = (bitresPerChannel>50) ? 0 : (bitresPerChannel>0) ? 1 : 2;
+    hQC->bitDistributionMode = (bitresPerChannel>100) ? 0 : (bitresPerChannel>0) ? 1 : 2;
   }
   else {
-    hQC->bitDistributenMode = 0; /* full bitreservoir */
+    hQC->bitDistributionMode = 0; /* full bitreservoir */
   }
 
 
@@ -420,11 +420,17 @@ AAC_ENCODER_ERROR FDKaacEnc_QCInit(QC_STATE *hQC,
       break;
   }
 
-  FDKaacEnc_AdjThrInit(hQC->hAdjThr,
+  FDKaacEnc_AdjThrInit(
+        hQC->hAdjThr,
         init->meanPe,
         hQC->elementBits,                 /* or channelBitrates, was: channelBitrate */
+        hQC->invQuant,
         init->channelMapping->nElements,
-             hQC->vbrQualFactor);
+        init->channelMapping->nChannelsEff,
+        init->sampleRate,                 /* output sample rate */
+        init->advancedBitsToPe,           /* if set, calc bits2PE factor depending on samplerate */
+        hQC->vbrQualFactor
+        );
 
   return AAC_ENC_OK;
 }
@@ -655,7 +661,7 @@ static AAC_ENCODER_ERROR FDKaacEnc_prepareBitDistribution(QC_STATE*            h
                                          hQC->elementBits[i]->bitResLevelEl,
                                          hQC->elementBits[i]->maxBitResBitsEl,
                                          hQC->maxBitFac,
-                                         hQC->bitDistributenMode);
+                                         hQC->bitDistributionMode);
 
                 *totalAvailableBits += hQC->elementBits[i]->bitResLevelEl;
         /* get total corrected granted PE */

libFDK/src/FDK_core.cpp

@@ -93,7 +93,7 @@ amm-info@iis.fraunhofer.de
 /* FDK tools library info */
 #define FDK_TOOLS_LIB_VL0 2
 #define FDK_TOOLS_LIB_VL1 3
-#define FDK_TOOLS_LIB_VL2 1
+#define FDK_TOOLS_LIB_VL2 2
 #define FDK_TOOLS_LIB_TITLE "FDK Tools"
 #define FDK_TOOLS_LIB_BUILD_DATE __DATE__
 #define FDK_TOOLS_LIB_BUILD_TIME __TIME__

libFDK/src/fixpoint_math.cpp

@@ -242,30 +242,72 @@ FIXP_DBL mul_dbl_sgl_rnd (const FIXP_DBL op1, const FIXP_SGL op2)
 
 *****************************************************************************/
 LNK_SECTION_CODE_L1
-FIXP_DBL CalcInvLdData(FIXP_DBL op)
+/* This table is used for lookup 2^x with   */
+/* x in range [0...1.0[ in steps of 1/32 */
+LNK_SECTION_DATA_L1 static const UINT exp2_tab_long[32]={
+0x40000000,0x4166C34C,0x42D561B4,0x444C0740,
+0x45CAE0F2,0x47521CC6,0x48E1E9BA,0x4A7A77D4,
+0x4C1BF829,0x4DC69CDD,0x4F7A9930,0x51382182,
+0x52FF6B55,0x54D0AD5A,0x56AC1F75,0x5891FAC1,
+0x5A82799A,0x5C7DD7A4,0x5E8451D0,0x60962665,
+0x62B39509,0x64DCDEC3,0x6712460B,0x69540EC9,
+0x6BA27E65,0x6DFDDBCC,0x70666F76,0x72DC8374,
+0x75606374,0x77F25CCE,0x7A92BE8B,0x7D41D96E
+// 0x80000000
+};
+
+/* This table is used for lookup 2^x with   */
+/* x in range [0...1/32[ in steps of 1/1024 */
+LNK_SECTION_DATA_L1 static const UINT exp2w_tab_long[32]={
+0x40000000,0x400B1818,0x4016321B,0x40214E0C,
+0x402C6BE9,0x40378BB4,0x4042AD6D,0x404DD113,
+0x4058F6A8,0x40641E2B,0x406F479E,0x407A7300,
+0x4085A051,0x4090CF92,0x409C00C4,0x40A733E6,
+0x40B268FA,0x40BD9FFF,0x40C8D8F5,0x40D413DD,
+0x40DF50B8,0x40EA8F86,0x40F5D046,0x410112FA,
+0x410C57A2,0x41179E3D,0x4122E6CD,0x412E3152,
+0x41397DCC,0x4144CC3B,0x41501CA0,0x415B6EFB,
+// 0x4166C34C,
+};
+/* This table is used for lookup 2^x with   */
+/* x in range [0...1/1024[ in steps of 1/32768 */
+LNK_SECTION_DATA_L1 static const UINT exp2x_tab_long[32]={
+0x40000000,0x400058B9,0x4000B173,0x40010A2D,
+0x400162E8,0x4001BBA3,0x4002145F,0x40026D1B,
+0x4002C5D8,0x40031E95,0x40037752,0x4003D011,
+0x400428CF,0x4004818E,0x4004DA4E,0x4005330E,
+0x40058BCE,0x4005E48F,0x40063D51,0x40069613,
+0x4006EED5,0x40074798,0x4007A05B,0x4007F91F,
+0x400851E4,0x4008AAA8,0x4009036E,0x40095C33,
+0x4009B4FA,0x400A0DC0,0x400A6688,0x400ABF4F,
+//0x400B1818
+};
+
+LNK_SECTION_CODE_L1 FIXP_DBL CalcInvLdData(FIXP_DBL x)
 {
-  FIXP_DBL result_m;
+  int set_zero = (x <  FL2FXCONST_DBL(-31.0/64.0))? 0 : 1;
+  int set_max  = (x >= FL2FXCONST_DBL( 31.0/64.0)) | (x == FL2FXCONST_DBL(0.0));
 
-  if ( op == FL2FXCONST_DBL(0.0f) ) {
-    result_m = (FIXP_DBL)MAXVAL_DBL;
-  }
-  else if ( op < FL2FXCONST_DBL(0.0f) ) {
-    result_m = f2Pow(op, LD_DATA_SHIFT);
-  }
-  else {
-    int result_e;
+  FIXP_SGL frac = (FIXP_SGL)(LONG)(x & 0x3FF);
+  UINT index3 = (UINT)(LONG)(x >> 10) & 0x1F;
+  UINT index2 = (UINT)(LONG)(x >> 15) & 0x1F; 
+  UINT index1 = (UINT)(LONG)(x >> 20) & 0x1F;
+  int exp  = (x >  FL2FXCONST_DBL(0.0f)) ? (31 - (int)(x>>25)) : (int)(-(x>>25));
 
-    result_m = f2Pow(op, LD_DATA_SHIFT, &result_e);
-    result_e = fixMin(fixMax(result_e+1-(DFRACT_BITS-1), -(DFRACT_BITS-1)), (DFRACT_BITS-1)); /* rounding and saturation */
+  UINT lookup1 = exp2_tab_long[index1]*set_zero;
+  UINT lookup2 = exp2w_tab_long[index2];
+  UINT lookup3 = exp2x_tab_long[index3];
+  UINT lookup3f = lookup3 + (UINT)(LONG)fMultDiv2((FIXP_DBL)(0x0016302F),(FIXP_SGL)frac);
   
-    if ( (result_e>0) && ( result_m > (((FIXP_DBL)MAXVAL_DBL)>>result_e) ) ) {
-      result_m = (FIXP_DBL)MAXVAL_DBL; /* saturate to max representable value */
-    }
-    else {
-      result_m = (scaleValue(result_m, result_e)+(FIXP_DBL)1)>>1; /* descale result + rounding */
-    }
-  }
-  return result_m;
+  UINT lookup12 = (UINT)(LONG)fMult((FIXP_DBL)lookup1,  (FIXP_DBL) lookup2);
+  UINT lookup   = (UINT)(LONG)fMult((FIXP_DBL)lookup12, (FIXP_DBL) lookup3f);
+
+  FIXP_DBL retVal = (lookup<<3) >> exp;
+
+  if (set_max)
+    retVal=FL2FXCONST_DBL(1.0f);
+
+  return retVal;
 }