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 some minimum and maximum functions, optimized for 12 @ ARM Neon platform. The description header can be found in 13 @ signal_processing_library.h 14 @ 15 @ The reference C code is in file min_max_operations.c. Code here is basically 16 @ a loop unrolling by 8 with Neon instructions. Bit-exact. 17 18 #include "webrtc/system_wrappers/interface/asm_defines.h" 19 20 GLOBAL_FUNCTION WebRtcSpl_MaxAbsValueW16Neon 21 GLOBAL_FUNCTION WebRtcSpl_MaxAbsValueW32Neon 22 GLOBAL_FUNCTION WebRtcSpl_MaxValueW16Neon 23 GLOBAL_FUNCTION WebRtcSpl_MaxValueW32Neon 24 GLOBAL_FUNCTION WebRtcSpl_MinValueW16Neon 25 GLOBAL_FUNCTION WebRtcSpl_MinValueW32Neon 26 27 .align 2 28 @ int16_t WebRtcSpl_MaxAbsValueW16Neon(const int16_t* vector, int length); 29 DEFINE_FUNCTION WebRtcSpl_MaxAbsValueW16Neon 30 mov r2, #-1 @ Initialize the return value. 31 cmp r0, #0 32 beq END_MAX_ABS_VALUE_W16 33 cmp r1, #0 34 ble END_MAX_ABS_VALUE_W16 35 36 cmp r1, #8 37 blt LOOP_MAX_ABS_VALUE_W16 38 39 vmov.i16 q12, #0 40 sub r1, #8 @ Counter for loops 41 42 LOOP_UNROLLED_BY_8_MAX_ABS_VALUE_W16: 43 vld1.16 {q13}, [r0]! 44 subs r1, #8 45 vabs.s16 q13, q13 @ Note vabs doesn't change the value of -32768. 46 vmax.u16 q12, q13 @ Use u16 so we don't lose the value -32768. 47 bge LOOP_UNROLLED_BY_8_MAX_ABS_VALUE_W16 48 49 @ Find the maximum value in the Neon registers and move it to r2. 50 vmax.u16 d24, d25 51 vpmax.u16 d24, d24, d24 52 vpmax.u16 d24, d24, d24 53 adds r1, #8 54 vmov.u16 r2, d24[0] 55 beq END_MAX_ABS_VALUE_W16 56 57 LOOP_MAX_ABS_VALUE_W16: 58 ldrsh r3, [r0], #2 59 eor r12, r3, r3, asr #31 @ eor and then sub, to get absolute value. 60 sub r12, r12, r3, asr #31 61 cmp r2, r12 62 movlt r2, r12 63 subs r1, #1 64 bne LOOP_MAX_ABS_VALUE_W16 65 66 END_MAX_ABS_VALUE_W16: 67 cmp r2, #0x8000 @ Guard against the case for -32768. 68 subeq r2, #1 69 mov r0, r2 70 bx lr 71 72 73 74 @ int32_t WebRtcSpl_MaxAbsValueW32Neon(const int32_t* vector, int length); 75 DEFINE_FUNCTION WebRtcSpl_MaxAbsValueW32Neon 76 cmp r0, #0 77 moveq r0, #-1 78 beq EXIT @ Return -1 for a NULL pointer. 79 cmp r1, #0 @ length 80 movle r0, #-1 81 ble EXIT @ Return -1 if length <= 0. 82 83 vmov.i32 q11, #0 84 vmov.i32 q12, #0 85 cmp r1, #8 86 blt LOOP_MAX_ABS_VALUE_W32 87 88 sub r1, #8 @ Counter for loops 89 90 LOOP_UNROLLED_BY_8_MAX_ABS_VALUE_W32: 91 vld1.32 {q13, q14}, [r0]! 92 subs r1, #8 @ Counter for loops 93 vabs.s32 q13, q13 @ vabs doesn't change the value of 0x80000000. 94 vabs.s32 q14, q14 95 vmax.u32 q11, q13 @ Use u32 so we don't lose the value 0x80000000. 96 vmax.u32 q12, q14 97 bge LOOP_UNROLLED_BY_8_MAX_ABS_VALUE_W32 98 99 @ Find the maximum value in the Neon registers and move it to r2. 100 vmax.u32 q12, q11 101 vmax.u32 d24, d25 102 vpmax.u32 d24, d24, d24 103 adds r1, #8 104 vmov.u32 r2, d24[0] 105 beq END_MAX_ABS_VALUE_W32 106 107 LOOP_MAX_ABS_VALUE_W32: 108 ldr r3, [r0], #4 109 eor r12, r3, r3, asr #31 @ eor and then sub, to get absolute value. 110 sub r12, r12, r3, asr #31 111 cmp r2, r12 112 movcc r2, r12 113 subs r1, #1 114 bne LOOP_MAX_ABS_VALUE_W32 115 116 END_MAX_ABS_VALUE_W32: 117 mvn r0, #0x80000000 @ Guard against the case for 0x80000000. 118 cmp r2, r0 119 movcc r0, r2 120 121 EXIT: 122 bx lr 123 124 @ int16_t WebRtcSpl_MaxValueW16Neon(const int16_t* vector, int length); 125 DEFINE_FUNCTION WebRtcSpl_MaxValueW16Neon 126 mov r2, #0x8000 @ Initialize the return value. 127 cmp r0, #0 128 beq END_MAX_VALUE_W16 129 cmp r1, #0 130 ble END_MAX_VALUE_W16 131 132 vmov.i16 q12, #0x8000 133 cmp r1, #8 134 blt LOOP_MAX_VALUE_W16 135 136 sub r1, #8 @ Counter for loops 137 138 LOOP_UNROLLED_BY_8_MAX_VALUE_W16: 139 vld1.16 {q13}, [r0]! 140 subs r1, #8 141 vmax.s16 q12, q13 142 bge LOOP_UNROLLED_BY_8_MAX_VALUE_W16 143 144 @ Find the maximum value in the Neon registers and move it to r2. 145 vmax.s16 d24, d25 146 vpmax.s16 d24, d24, d24 147 vpmax.s16 d24, d24, d24 148 adds r1, #8 149 vmov.u16 r2, d24[0] 150 beq END_MAX_VALUE_W16 151 152 LOOP_MAX_VALUE_W16: 153 ldrsh r3, [r0], #2 154 cmp r2, r3 155 movlt r2, r3 156 subs r1, #1 157 bne LOOP_MAX_VALUE_W16 158 159 END_MAX_VALUE_W16: 160 mov r0, r2 161 bx lr 162 163 @ int32_t WebRtcSpl_MaxValueW32Neon(const int32_t* vector, int length); 164 DEFINE_FUNCTION WebRtcSpl_MaxValueW32Neon 165 mov r2, #0x80000000 @ Initialize the return value. 166 cmp r0, #0 167 beq END_MAX_VALUE_W32 168 cmp r1, #0 169 ble END_MAX_VALUE_W32 170 171 vmov.i32 q11, #0x80000000 172 vmov.i32 q12, #0x80000000 173 cmp r1, #8 174 blt LOOP_MAX_VALUE_W32 175 176 sub r1, #8 @ Counter for loops 177 178 LOOP_UNROLLED_BY_8_MAX_VALUE_W32: 179 vld1.32 {q13, q14}, [r0]! 180 subs r1, #8 181 vmax.s32 q11, q13 182 vmax.s32 q12, q14 183 bge LOOP_UNROLLED_BY_8_MAX_VALUE_W32 184 185 @ Find the maximum value in the Neon registers and move it to r2. 186 vmax.s32 q12, q11 187 vpmax.s32 d24, d24, d25 188 vpmax.s32 d24, d24, d24 189 adds r1, #8 190 vmov.s32 r2, d24[0] 191 beq END_MAX_VALUE_W32 192 193 LOOP_MAX_VALUE_W32: 194 ldr r3, [r0], #4 195 cmp r2, r3 196 movlt r2, r3 197 subs r1, #1 198 bne LOOP_MAX_VALUE_W32 199 200 END_MAX_VALUE_W32: 201 mov r0, r2 202 bx lr 203 204 @ int16_t WebRtcSpl_MinValueW16Neon(const int16_t* vector, int length); 205 DEFINE_FUNCTION WebRtcSpl_MinValueW16Neon 206 movw r2, #0x7FFF @ Initialize the return value. 207 cmp r0, #0 208 beq END_MIN_VALUE_W16 209 cmp r1, #0 210 ble END_MIN_VALUE_W16 211 212 vmov.i16 q12, #0x7FFF 213 cmp r1, #8 214 blt LOOP_MIN_VALUE_W16 215 216 sub r1, #8 @ Counter for loops 217 218 LOOP_UNROLLED_BY_8_MIN_VALUE_W16: 219 vld1.16 {q13}, [r0]! 220 subs r1, #8 221 vmin.s16 q12, q13 222 bge LOOP_UNROLLED_BY_8_MIN_VALUE_W16 223 224 @ Find the maximum value in the Neon registers and move it to r2. 225 vmin.s16 d24, d25 226 vpmin.s16 d24, d24, d24 227 vpmin.s16 d24, d24, d24 228 adds r1, #8 229 vmov.s16 r2, d24[0] 230 sxth r2, r2 231 beq END_MIN_VALUE_W16 232 233 LOOP_MIN_VALUE_W16: 234 ldrsh r3, [r0], #2 235 cmp r2, r3 236 movge r2, r3 237 subs r1, #1 238 bne LOOP_MIN_VALUE_W16 239 240 END_MIN_VALUE_W16: 241 mov r0, r2 242 bx lr 243 244 @ int32_t WebRtcSpl_MinValueW32Neon(const int32_t* vector, int length); 245 DEFINE_FUNCTION WebRtcSpl_MinValueW32Neon 246 mov r2, #0x7FFFFFFF @ Initialize the return value. 247 cmp r0, #0 248 beq END_MIN_VALUE_W32 249 cmp r1, #0 250 ble END_MIN_VALUE_W32 251 252 vdup.32 q11, r2 253 vdup.32 q12, r2 254 cmp r1, #8 255 blt LOOP_MIN_VALUE_W32 256 257 sub r1, #8 @ Counter for loops 258 259 LOOP_UNROLLED_BY_8_MIN_VALUE_W32: 260 vld1.32 {q13, q14}, [r0]! 261 subs r1, #8 262 vmin.s32 q11, q13 263 vmin.s32 q12, q14 264 bge LOOP_UNROLLED_BY_8_MIN_VALUE_W32 265 266 @ Find the maximum value in the Neon registers and move it to r2. 267 vmin.s32 q12, q11 268 vpmin.s32 d24, d24, d25 269 vpmin.s32 d24, d24, d24 270 adds r1, #8 271 vmov.s32 r2, d24[0] 272 beq END_MIN_VALUE_W32 273 274 LOOP_MIN_VALUE_W32: 275 ldr r3, [r0], #4 276 cmp r2, r3 277 movge r2, r3 278 subs r1, #1 279 bne LOOP_MIN_VALUE_W32 280 281 END_MIN_VALUE_W32: 282 mov r0, r2 283 bx lr 284
