1 /* ------------------------------------------------------------------ 2 * Copyright (C) 1998-2009 PacketVideo 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either 13 * express or implied. 14 * See the License for the specific language governing permissions 15 * and limitations under the License. 16 * ------------------------------------------------------------------- 17 */ 18 /* 19 ------------------------------------------------------------------------------ 20 21 PacketVideo Corp. 22 MP3 Decoder Library 23 24 Filename: pvmp3_dct6.cpp 25 26 Date: 09/21/2007 27 28 ------------------------------------------------------------------------------ 29 REVISION HISTORY 30 31 32 Description: 33 34 ------------------------------------------------------------------------------ 35 INPUT AND OUTPUT DEFINITIONS 36 37 Input 38 Int32 vec[] vector of 6 32-bit integers 39 Returns 40 Int32 vec[] dct computation in-place 41 42 43 ------------------------------------------------------------------------------ 44 FUNCTION DESCRIPTION 45 46 Returns the dct of length 6 of the input vector 47 48 ------------------------------------------------------------------------------ 49 REQUIREMENTS 50 51 52 ------------------------------------------------------------------------------ 53 REFERENCES 54 55 ------------------------------------------------------------------------------ 56 PSEUDO-CODE 57 58 ------------------------------------------------------------------------------ 59 */ 60 61 62 /*---------------------------------------------------------------------------- 63 ; INCLUDES 64 ----------------------------------------------------------------------------*/ 65 66 #include "pvmp3_audio_type_defs.h" 67 #include "pv_mp3dec_fxd_op.h" 68 #include "pvmp3_mdct_6.h" 69 70 71 /*---------------------------------------------------------------------------- 72 ; MACROS 73 ; Define module specific macros here 74 ----------------------------------------------------------------------------*/ 75 76 77 /*---------------------------------------------------------------------------- 78 ; DEFINES 79 ; Include all pre-processor statements here. Include conditional 80 ; compile variables also. 81 ----------------------------------------------------------------------------*/ 82 #define Qfmt30(a) (Int32)(a*((Int32)1<<30) + (a>=0?0.5F:-0.5F)) 83 84 #define cos_pi_6 Qfmt30( 0.86602540378444f) 85 #define cos_2_pi_6 Qfmt30( 0.5f) 86 #define cos_7_pi_12 Qfmt30( -0.25881904510252f) 87 #define cos_3_pi_12 Qfmt30( 0.70710678118655f) 88 #define cos_11_pi_12 Qfmt30( -0.96592582628907f) 89 90 /*---------------------------------------------------------------------------- 91 ; LOCAL FUNCTION DEFINITIONS 92 ; Function Prototype declaration 93 ----------------------------------------------------------------------------*/ 94 95 /*---------------------------------------------------------------------------- 96 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS 97 ; Variable declaration - defined here and used outside this module 98 ----------------------------------------------------------------------------*/ 99 100 /*---------------------------------------------------------------------------- 101 ; EXTERNAL FUNCTION REFERENCES 102 ; Declare functions defined elsewhere and referenced in this module 103 ----------------------------------------------------------------------------*/ 104 105 /*---------------------------------------------------------------------------- 106 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES 107 ; Declare variables used in this module but defined elsewhere 108 ----------------------------------------------------------------------------*/ 109 110 /*---------------------------------------------------------------------------- 111 ; FUNCTION CODE 112 ----------------------------------------------------------------------------*/ 113 114 void pvmp3_dct_6(int32 vec[]) 115 { 116 117 Int32 tmp0; 118 Int32 tmp1; 119 Int32 tmp2; 120 Int32 tmp3; 121 Int32 tmp4; 122 Int32 tmp5; 123 124 125 /* split input vector */ 126 127 tmp0 = vec[5] + vec[0]; 128 tmp5 = vec[5] - vec[0]; 129 tmp1 = vec[4] + vec[1]; 130 tmp4 = vec[4] - vec[1]; 131 tmp2 = vec[3] + vec[2]; 132 tmp3 = vec[3] - vec[2]; 133 134 vec[0] = tmp0 + tmp2 ; 135 vec[2] = fxp_mul32_Q30(tmp0 - tmp2, cos_pi_6); 136 vec[4] = (vec[0] >> 1) - tmp1; 137 vec[0] += tmp1; 138 139 tmp0 = fxp_mul32_Q30(tmp3, cos_7_pi_12); 140 tmp0 = fxp_mac32_Q30(tmp4, -cos_3_pi_12, tmp0); 141 vec[1] = fxp_mac32_Q30(tmp5, cos_11_pi_12, tmp0); 142 143 vec[3] = fxp_mul32_Q30((tmp3 + tmp4 - tmp5), cos_3_pi_12); 144 tmp0 = fxp_mul32_Q30(tmp3, cos_11_pi_12); 145 tmp0 = fxp_mac32_Q30(tmp4, cos_3_pi_12, tmp0); 146 vec[5] = fxp_mac32_Q30(tmp5, cos_7_pi_12, tmp0); 147 148 } 149 150 151 152 153
