1@ 2@ Copyright (c) 2012 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@ This file contains the function WebRtcSpl_FilterARFastQ12(), optimized for 12@ ARMv7 platform. The description header can be found in 13@ signal_processing_library.h 14@ 15@ Output is bit-exact with the generic C code as in filter_ar_fast_q12.c, and 16@ the reference C code at end of this file. 17 18@ Assumptions: 19@ (1) data_length > 0 20@ (2) coefficients_length > 1 21 22@ Register usage: 23@ 24@ r0: &data_in[i] 25@ r1: &data_out[i], for result ouput 26@ r2: &coefficients[0] 27@ r3: coefficients_length 28@ r4: Iteration counter for the outer loop. 29@ r5: data_out[j] as multiplication inputs 30@ r6: Calculated value for output data_out[]; interation counter for inner loop 31@ r7: Partial sum of a filtering multiplication results 32@ r8: Partial sum of a filtering multiplication results 33@ r9: &data_out[], for filtering input; data_in[i] 34@ r10: coefficients[j] 35@ r11: Scratch 36@ r12: &coefficients[j] 37 38#include "webrtc/system_wrappers/interface/asm_defines.h" 39 40GLOBAL_FUNCTION WebRtcSpl_FilterARFastQ12 41.align 2 42DEFINE_FUNCTION WebRtcSpl_FilterARFastQ12 43 push {r4-r11} 44 45 ldrsh r12, [sp, #32] @ data_length 46 subs r4, r12, #1 47 beq ODD_LENGTH @ jump if data_length == 1 48 49LOOP_LENGTH: 50 add r12, r2, r3, lsl #1 51 sub r12, #4 @ &coefficients[coefficients_length - 2] 52 sub r9, r1, r3, lsl #1 53 add r9, #2 @ &data_out[i - coefficients_length + 1] 54 ldr r5, [r9], #4 @ data_out[i - coefficients_length + {1,2}] 55 56 mov r7, #0 @ sum1 57 mov r8, #0 @ sum2 58 subs r6, r3, #3 @ Iteration counter for inner loop. 59 beq ODD_A_LENGTH @ branch if coefficients_length == 3 60 blt POST_LOOP_A_LENGTH @ branch if coefficients_length == 2 61 62LOOP_A_LENGTH: 63 ldr r10, [r12], #-4 @ coefficients[j - 1], coefficients[j] 64 subs r6, #2 65 smlatt r8, r10, r5, r8 @ sum2 += coefficients[j] * data_out[i - j + 1]; 66 smlatb r7, r10, r5, r7 @ sum1 += coefficients[j] * data_out[i - j]; 67 smlabt r7, r10, r5, r7 @ coefficients[j - 1] * data_out[i - j + 1]; 68 ldr r5, [r9], #4 @ data_out[i - j + 2], data_out[i - j + 3] 69 smlabb r8, r10, r5, r8 @ coefficients[j - 1] * data_out[i - j + 2]; 70 bgt LOOP_A_LENGTH 71 blt POST_LOOP_A_LENGTH 72 73ODD_A_LENGTH: 74 ldrsh r10, [r12, #2] @ Filter coefficients coefficients[2] 75 sub r12, #2 @ &coefficients[0] 76 smlabb r7, r10, r5, r7 @ sum1 += coefficients[2] * data_out[i - 2]; 77 smlabt r8, r10, r5, r8 @ sum2 += coefficients[2] * data_out[i - 1]; 78 ldr r5, [r9, #-2] @ data_out[i - 1], data_out[i] 79 80POST_LOOP_A_LENGTH: 81 ldr r10, [r12] @ coefficients[0], coefficients[1] 82 smlatb r7, r10, r5, r7 @ sum1 += coefficients[1] * data_out[i - 1]; 83 84 ldr r9, [r0], #4 @ data_in[i], data_in[i + 1] 85 smulbb r6, r10, r9 @ output1 = coefficients[0] * data_in[i]; 86 sub r6, r7 @ output1 -= sum1; 87 88 sbfx r11, r6, #12, #16 89 ssat r7, #16, r6, asr #12 90 cmp r7, r11 91 addeq r6, r6, #2048 92 ssat r6, #16, r6, asr #12 93 strh r6, [r1], #2 @ Store data_out[i] 94 95 smlatb r8, r10, r6, r8 @ sum2 += coefficients[1] * data_out[i]; 96 smulbt r6, r10, r9 @ output2 = coefficients[0] * data_in[i + 1]; 97 sub r6, r8 @ output1 -= sum1; 98 99 sbfx r11, r6, #12, #16 100 ssat r7, #16, r6, asr #12 101 cmp r7, r11 102 addeq r6, r6, #2048 103 ssat r6, #16, r6, asr #12 104 strh r6, [r1], #2 @ Store data_out[i + 1] 105 106 subs r4, #2 107 bgt LOOP_LENGTH 108 blt END @ For even data_length, it's done. Jump to END. 109 110@ Process i = data_length -1, for the case of an odd length. 111ODD_LENGTH: 112 add r12, r2, r3, lsl #1 113 sub r12, #4 @ &coefficients[coefficients_length - 2] 114 sub r9, r1, r3, lsl #1 115 add r9, #2 @ &data_out[i - coefficients_length + 1] 116 mov r7, #0 @ sum1 117 mov r8, #0 @ sum1 118 subs r6, r3, #2 @ inner loop counter 119 beq EVEN_A_LENGTH @ branch if coefficients_length == 2 120 121LOOP2_A_LENGTH: 122 ldr r10, [r12], #-4 @ coefficients[j - 1], coefficients[j] 123 ldr r5, [r9], #4 @ data_out[i - j], data_out[i - j + 1] 124 subs r6, #2 125 smlatb r7, r10, r5, r7 @ sum1 += coefficients[j] * data_out[i - j]; 126 smlabt r8, r10, r5, r8 @ coefficients[j - 1] * data_out[i - j + 1]; 127 bgt LOOP2_A_LENGTH 128 addlt r12, #2 129 blt POST_LOOP2_A_LENGTH 130 131EVEN_A_LENGTH: 132 ldrsh r10, [r12, #2] @ Filter coefficients coefficients[1] 133 ldrsh r5, [r9] @ data_out[i - 1] 134 smlabb r7, r10, r5, r7 @ sum1 += coefficients[1] * data_out[i - 1]; 135 136POST_LOOP2_A_LENGTH: 137 ldrsh r10, [r12] @ Filter coefficients coefficients[0] 138 ldrsh r9, [r0] @ data_in[i] 139 smulbb r6, r10, r9 @ output1 = coefficients[0] * data_in[i]; 140 sub r6, r7 @ output1 -= sum1; 141 sub r6, r8 @ output1 -= sum1; 142 sbfx r8, r6, #12, #16 143 ssat r7, #16, r6, asr #12 144 cmp r7, r8 145 addeq r6, r6, #2048 146 ssat r6, #16, r6, asr #12 147 strh r6, [r1] @ Store the data_out[i] 148 149END: 150 pop {r4-r11} 151 bx lr 152 153@Reference C code: 154@ 155@void WebRtcSpl_FilterARFastQ12(int16_t* data_in, 156@ int16_t* data_out, 157@ int16_t* __restrict coefficients, 158@ int coefficients_length, 159@ int data_length) { 160@ int i = 0; 161@ int j = 0; 162@ 163@ for (i = 0; i < data_length - 1; i += 2) { 164@ int32_t output1 = 0; 165@ int32_t sum1 = 0; 166@ int32_t output2 = 0; 167@ int32_t sum2 = 0; 168@ 169@ for (j = coefficients_length - 1; j > 2; j -= 2) { 170@ sum1 += coefficients[j] * data_out[i - j]; 171@ sum1 += coefficients[j - 1] * data_out[i - j + 1]; 172@ sum2 += coefficients[j] * data_out[i - j + 1]; 173@ sum2 += coefficients[j - 1] * data_out[i - j + 2]; 174@ } 175@ 176@ if (j == 2) { 177@ sum1 += coefficients[2] * data_out[i - 2]; 178@ sum2 += coefficients[2] * data_out[i - 1]; 179@ } 180@ 181@ sum1 += coefficients[1] * data_out[i - 1]; 182@ output1 = coefficients[0] * data_in[i]; 183@ output1 -= sum1; 184@ // Saturate and store the output. 185@ output1 = WEBRTC_SPL_SAT(134215679, output1, -134217728); 186@ data_out[i] = (int16_t)((output1 + 2048) >> 12); 187@ 188@ sum2 += coefficients[1] * data_out[i]; 189@ output2 = coefficients[0] * data_in[i + 1]; 190@ output2 -= sum2; 191@ // Saturate and store the output. 192@ output2 = WEBRTC_SPL_SAT(134215679, output2, -134217728); 193@ data_out[i + 1] = (int16_t)((output2 + 2048) >> 12); 194@ } 195@ 196@ if (i == data_length - 1) { 197@ int32_t output1 = 0; 198@ int32_t sum1 = 0; 199@ 200@ for (j = coefficients_length - 1; j > 1; j -= 2) { 201@ sum1 += coefficients[j] * data_out[i - j]; 202@ sum1 += coefficients[j - 1] * data_out[i - j + 1]; 203@ } 204@ 205@ if (j == 1) { 206@ sum1 += coefficients[1] * data_out[i - 1]; 207@ } 208@ 209@ output1 = coefficients[0] * data_in[i]; 210@ output1 -= sum1; 211@ // Saturate and store the output. 212@ output1 = WEBRTC_SPL_SAT(134215679, output1, -134217728); 213@ data_out[i] = (int16_t)((output1 + 2048) >> 12); 214@ } 215@} 216