00001 /*This file has been prepared for Doxygen automatic documentation generation.*/ 00015 /* Copyright (c) 2009 Atmel Corporation. All rights reserved. 00016 * 00017 * Redistribution and use in source and binary forms, with or without 00018 * modification, are permitted provided that the following conditions are met: 00019 * 00020 * 1. Redistributions of source code must retain the above copyright notice, this 00021 * list of conditions and the following disclaimer. 00022 * 00023 * 2. Redistributions in binary form must reproduce the above copyright notice, 00024 * this list of conditions and the following disclaimer in the documentation 00025 * and/or other materials provided with the distribution. 00026 * 00027 * 3. The name of Atmel may not be used to endorse or promote products derived 00028 * from this software without specific prior written permission. 00029 * 00030 * 4. This software may only be redistributed and used in connection with an Atmel 00031 * AVR product. 00032 * 00033 * THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED 00034 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 00035 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE 00036 * EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR 00037 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 00038 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 00039 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 00040 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 00041 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 00042 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE 00043 * 00044 */ 00045 00046 #include "dsp.h" 00047 00048 #if defined(FORCE_ALL_GENERICS) || \ 00049 defined(FORCE_GENERIC_OP16_LOG2) || \ 00050 !defined(TARGET_SPECIFIC_OP16_LOG2) 00051 00052 dsp16_t dsp16_op_log2(dsp16_t number) 00053 { 00054 S32 res; 00055 const S32 cst_ln2 = (S32) DSP_Q(32-DSP16_QB, DSP16_QB, 1./CST_LN_2); 00056 extern S32 dsp16_op_ln_raw(dsp16_t num); 00057 00058 res = dsp16_op_ln_raw(number); 00059 00060 if (res < ((S32) 0x80000000)/cst_ln2) 00061 return DSP_Q_MIN(DSP16_QA, DSP16_QB); 00062 00063 res = (res*cst_ln2) >> DSP16_QB; 00064 00065 if (res < ((S32) DSP_Q_MIN(DSP16_QA, DSP16_QB))) 00066 return (dsp16_t) DSP_Q_MIN(DSP16_QA, DSP16_QB); 00067 00068 return (dsp16_t) res; 00069 } 00070 00071 #endif 00072 00073 #if defined(FORCE_ALL_GENERICS) || \ 00074 defined(FORCE_GENERIC_OP32_LOG2) || \ 00075 !defined(TARGET_SPECIFIC_OP32_LOG2) 00076 00077 dsp32_t dsp32_op_log2(dsp32_t number) 00078 { 00079 S64 res; 00080 const S64 cst_ln2 = (S64) ((1./CST_LN_2)*(1LL << DSP32_QB)); 00081 extern S64 dsp32_op_ln_raw(dsp32_t num); 00082 00083 res = dsp32_op_ln_raw(number); 00084 00085 if (res < ((S64) -0x8000000000000000LL)/cst_ln2) 00086 return DSP_Q_MIN(DSP32_QA, DSP32_QB); 00087 00088 res = (res*cst_ln2) >> DSP32_QB; 00089 00090 if (res < ((S64) DSP_Q_MIN(DSP32_QA, DSP32_QB))) 00091 return (dsp32_t) DSP_Q_MIN(DSP32_QA, DSP32_QB); 00092 00093 return (dsp32_t) res; 00094 } 00095 00096 #endif