1/* 2 * Copyright (C) 2004-2010 NXP Software 3 * Copyright (C) 2010 The Android Open Source Project 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18#include "LVM_Types.h" 19#include "LVM_Macros.h" 20#include "ScalarArithmetic.h" 21 22/*-------------------------------------------------------------------------*/ 23/* FUNCTION: */ 24/* LVM_Polynomial */ 25/* */ 26/* DESCRIPTION: */ 27/* This function performs polynomial expansion */ 28/* Y = (A0 + A1*X + A2*X2 + A3*X3 + �.. + AN*xN) << AN+1 */ 29/* */ 30/* LVM_INT32 LVM_Polynomial(LVM_UINT16 N, */ 31/* LVM_INT32 *pCoefficients, */ 32/* LVM_INT32 X) */ 33/* */ 34/* PARAMETERS: */ 35/* */ 36/* N is the polynomial order */ 37/* pCoefficients is the ptr to polynomial coefficients A0,A1.. in Q.31 */ 38/* X is the input variable */ 39/* */ 40/* RETURNS: */ 41/* The result of the polynomial expansion in Q1.31 format */ 42/*-------------------------------------------------------------------------*/ 43#ifdef BUILD_FLOAT 44LVM_FLOAT LVM_Polynomial(LVM_UINT16 N, 45 LVM_FLOAT *pCoefficients, 46 LVM_FLOAT X) 47{ 48 LVM_INT32 i; 49 LVM_FLOAT Y,A,XTemp,Temp,sign; 50 51 Y = *pCoefficients; /* Y=A0*/ 52 pCoefficients++; 53 54 if(X == -1.0f) 55 { 56 Temp = -1; 57 sign = Temp; 58 for(i = 1; i <= N; i++) 59 { 60 Y += ((*pCoefficients) * sign); 61 pCoefficients++; 62 sign *= Temp; 63 } 64 65 66 } 67 else 68 { 69 XTemp = X; 70 for(i = N-1; i >= 0; i--) 71 { 72 A = *pCoefficients; 73 pCoefficients++; 74 75 Temp = A * XTemp; 76 Y += Temp; 77 78 Temp = XTemp * X; 79 XTemp = Temp; 80 } 81 } 82 return Y; 83} 84#else 85LVM_INT32 LVM_Polynomial(LVM_UINT16 N, 86 LVM_INT32 *pCoefficients, 87 LVM_INT32 X) 88{ 89 LVM_INT32 i; 90 LVM_INT32 Y,A,XTemp,Temp,sign; 91 92 Y=*pCoefficients; /* Y=A0*/ 93 pCoefficients++; 94 95 if((LVM_UINT32)X==0x80000000) 96 { 97 Temp=-1; 98 sign=Temp; 99 for(i=1;i<=N;i++) 100 { 101 Y+=((*pCoefficients)*sign); 102 pCoefficients++; 103 sign*=Temp; 104 } 105 106 107 } 108 else 109 { 110 XTemp=X; 111 for(i=N-1;i>=0;i--) 112 { 113 A=*pCoefficients; 114 pCoefficients++; 115 116 MUL32x32INTO32(A,XTemp,Temp,31) 117 Y+=Temp; 118 119 MUL32x32INTO32(XTemp,X,Temp,31) 120 XTemp=Temp; 121 } 122 } 123 A=*pCoefficients; 124 pCoefficients++; 125 126 if(A<0) 127 { 128 A=Abs_32(A); 129 Y=Y>>A; 130 } 131 else 132 { 133 Y = Y<<A; 134 } 135 return Y; 136} 137#endif 138