andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license |
| 5 | * that can be found in the LICENSE file in the root of the source |
| 6 | * tree. An additional intellectual property rights grant can be found |
| 7 | * in the file PATENTS. All contributing project authors may |
| 8 | * be found in the AUTHORS file in the root of the source tree. |
| 9 | */ |
| 10 | |
| 11 | |
| 12 | /* |
| 13 | * This file contains implementations of the divisions |
| 14 | * WebRtcSpl_DivU32U16() |
| 15 | * WebRtcSpl_DivW32W16() |
| 16 | * WebRtcSpl_DivW32W16ResW16() |
| 17 | * WebRtcSpl_DivResultInQ31() |
| 18 | * WebRtcSpl_DivW32HiLow() |
| 19 | * |
| 20 | * The description header can be found in signal_processing_library.h |
| 21 | * |
| 22 | */ |
| 23 | |
pbos@webrtc.org | abf0cd8 | 2013-05-27 09:49:58 +0000 | [diff] [blame] | 24 | #include "webrtc/common_audio/signal_processing/include/signal_processing_library.h" |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 25 | |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 26 | uint32_t WebRtcSpl_DivU32U16(uint32_t num, uint16_t den) |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 27 | { |
| 28 | // Guard against division with 0 |
| 29 | if (den != 0) |
| 30 | { |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 31 | return (uint32_t)(num / den); |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 32 | } else |
| 33 | { |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 34 | return (uint32_t)0xFFFFFFFF; |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 35 | } |
| 36 | } |
| 37 | |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 38 | int32_t WebRtcSpl_DivW32W16(int32_t num, int16_t den) |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 39 | { |
| 40 | // Guard against division with 0 |
| 41 | if (den != 0) |
| 42 | { |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 43 | return (int32_t)(num / den); |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 44 | } else |
| 45 | { |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 46 | return (int32_t)0x7FFFFFFF; |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 47 | } |
| 48 | } |
| 49 | |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 50 | int16_t WebRtcSpl_DivW32W16ResW16(int32_t num, int16_t den) |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 51 | { |
| 52 | // Guard against division with 0 |
| 53 | if (den != 0) |
| 54 | { |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 55 | return (int16_t)(num / den); |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 56 | } else |
| 57 | { |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 58 | return (int16_t)0x7FFF; |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 59 | } |
| 60 | } |
| 61 | |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 62 | int32_t WebRtcSpl_DivResultInQ31(int32_t num, int32_t den) |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 63 | { |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 64 | int32_t L_num = num; |
| 65 | int32_t L_den = den; |
| 66 | int32_t div = 0; |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 67 | int k = 31; |
| 68 | int change_sign = 0; |
| 69 | |
| 70 | if (num == 0) |
| 71 | return 0; |
| 72 | |
| 73 | if (num < 0) |
| 74 | { |
| 75 | change_sign++; |
| 76 | L_num = -num; |
| 77 | } |
| 78 | if (den < 0) |
| 79 | { |
| 80 | change_sign++; |
| 81 | L_den = -den; |
| 82 | } |
| 83 | while (k--) |
| 84 | { |
| 85 | div <<= 1; |
| 86 | L_num <<= 1; |
| 87 | if (L_num >= L_den) |
| 88 | { |
| 89 | L_num -= L_den; |
| 90 | div++; |
| 91 | } |
| 92 | } |
| 93 | if (change_sign == 1) |
| 94 | { |
| 95 | div = -div; |
| 96 | } |
| 97 | return div; |
| 98 | } |
| 99 | |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 100 | int32_t WebRtcSpl_DivW32HiLow(int32_t num, int16_t den_hi, int16_t den_low) |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 101 | { |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 102 | int16_t approx, tmp_hi, tmp_low, num_hi, num_low; |
| 103 | int32_t tmpW32; |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 104 | |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 105 | approx = (int16_t)WebRtcSpl_DivW32W16((int32_t)0x1FFFFFFF, den_hi); |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 106 | // result in Q14 (Note: 3FFFFFFF = 0.5 in Q30) |
| 107 | |
| 108 | // tmpW32 = 1/den = approx * (2.0 - den * approx) (in Q30) |
| 109 | tmpW32 = (WEBRTC_SPL_MUL_16_16(den_hi, approx) << 1) |
| 110 | + ((WEBRTC_SPL_MUL_16_16(den_low, approx) >> 15) << 1); |
| 111 | // tmpW32 = den * approx |
| 112 | |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 113 | tmpW32 = (int32_t)0x7fffffffL - tmpW32; // result in Q30 (tmpW32 = 2.0-(den*approx)) |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 114 | |
| 115 | // Store tmpW32 in hi and low format |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 116 | tmp_hi = (int16_t)WEBRTC_SPL_RSHIFT_W32(tmpW32, 16); |
| 117 | tmp_low = (int16_t)WEBRTC_SPL_RSHIFT_W32((tmpW32 |
| 118 | - WEBRTC_SPL_LSHIFT_W32((int32_t)tmp_hi, 16)), 1); |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 119 | |
| 120 | // tmpW32 = 1/den in Q29 |
| 121 | tmpW32 = ((WEBRTC_SPL_MUL_16_16(tmp_hi, approx) + (WEBRTC_SPL_MUL_16_16(tmp_low, approx) |
| 122 | >> 15)) << 1); |
| 123 | |
| 124 | // 1/den in hi and low format |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 125 | tmp_hi = (int16_t)WEBRTC_SPL_RSHIFT_W32(tmpW32, 16); |
| 126 | tmp_low = (int16_t)WEBRTC_SPL_RSHIFT_W32((tmpW32 |
| 127 | - WEBRTC_SPL_LSHIFT_W32((int32_t)tmp_hi, 16)), 1); |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 128 | |
| 129 | // Store num in hi and low format |
pbos@webrtc.org | 1727dc7 | 2013-04-09 16:40:28 +0000 | [diff] [blame] | 130 | num_hi = (int16_t)WEBRTC_SPL_RSHIFT_W32(num, 16); |
| 131 | num_low = (int16_t)WEBRTC_SPL_RSHIFT_W32((num |
| 132 | - WEBRTC_SPL_LSHIFT_W32((int32_t)num_hi, 16)), 1); |
andrew@webrtc.org | a7b57da | 2012-10-22 18:19:23 +0000 | [diff] [blame] | 133 | |
| 134 | // num * (1/den) by 32 bit multiplication (result in Q28) |
| 135 | |
| 136 | tmpW32 = (WEBRTC_SPL_MUL_16_16(num_hi, tmp_hi) + (WEBRTC_SPL_MUL_16_16(num_hi, tmp_low) |
| 137 | >> 15) + (WEBRTC_SPL_MUL_16_16(num_low, tmp_hi) >> 15)); |
| 138 | |
| 139 | // Put result in Q31 (convert from Q28) |
| 140 | tmpW32 = WEBRTC_SPL_LSHIFT_W32(tmpW32, 3); |
| 141 | |
| 142 | return tmpW32; |
| 143 | } |