ref: 0259778a0f3b2911473e6146d3861618e2454219
dir: /vpx_dsp/arm/idct4x4_add_neon.asm/
; ; Copyright (c) 2013 The WebM project authors. All Rights Reserved. ; ; Use of this source code is governed by a BSD-style license ; that can be found in the LICENSE file in the root of the source ; tree. An additional intellectual property rights grant can be found ; in the file PATENTS. All contributing project authors may ; be found in the AUTHORS file in the root of the source tree. ; EXPORT |vpx_idct4x4_16_add_neon| ARM REQUIRE8 PRESERVE8 AREA ||.text||, CODE, READONLY, ALIGN=2 INCLUDE vpx_dsp/arm/idct_neon.asm.S AREA Block, CODE, READONLY ; name this block of code ;void vpx_idct4x4_16_add_neon(int16_t *input, uint8_t *dest, int stride) ; ; r0 int16_t input ; r1 uint8_t *dest ; r2 int stride) |vpx_idct4x4_16_add_neon| PROC ; The 2D transform is done with two passes which are actually pretty ; similar. We first transform the rows. This is done by transposing ; the inputs, doing an SIMD column transform (the columns are the ; transposed rows) and then transpose the results (so that it goes back ; in normal/row positions). Then, we transform the columns by doing ; another SIMD column transform. ; So, two passes of a transpose followed by a column transform. ; load the inputs into q8-q9, d16-d19 LOAD_TRAN_LOW_TO_S16 d16, d17, d18, d19, r0 ; generate scalar constants ; cospi_8_64 = 15137 movw r0, #0x3b21 ; cospi_16_64 = 11585 movw r3, #0x2d41 ; cospi_24_64 = 6270 movw r12, #0x187e ; transpose the input data ; 00 01 02 03 d16 ; 10 11 12 13 d17 ; 20 21 22 23 d18 ; 30 31 32 33 d19 vtrn.16 d16, d17 vtrn.16 d18, d19 ; generate constant vectors vdup.16 d20, r0 ; replicate cospi_8_64 vdup.16 d21, r3 ; replicate cospi_16_64 ; 00 10 02 12 d16 ; 01 11 03 13 d17 ; 20 30 22 32 d18 ; 21 31 23 33 d19 vtrn.32 q8, q9 ; 00 10 20 30 d16 ; 01 11 21 31 d17 ; 02 12 22 32 d18 ; 03 13 23 33 d19 vdup.16 d22, r12 ; replicate cospi_24_64 ; do the transform on transposed rows ; stage 1 vmull.s16 q15, d17, d22 ; input[1] * cospi_24_64 vmull.s16 q1, d17, d20 ; input[1] * cospi_8_64 ; (input[0] + input[2]) * cospi_16_64; ; (input[0] - input[2]) * cospi_16_64; vmull.s16 q8, d16, d21 vmull.s16 q14, d18, d21 vadd.s32 q13, q8, q14 vsub.s32 q14, q8, q14 ; input[1] * cospi_24_64 - input[3] * cospi_8_64; ; input[1] * cospi_8_64 + input[3] * cospi_24_64; vmlsl.s16 q15, d19, d20 vmlal.s16 q1, d19, d22 ; dct_const_round_shift vrshrn.s32 d26, q13, #14 vrshrn.s32 d27, q14, #14 vrshrn.s32 d29, q15, #14 vrshrn.s32 d28, q1, #14 ; stage 2 ; output[0] = step[0] + step[3]; ; output[1] = step[1] + step[2]; ; output[3] = step[0] - step[3]; ; output[2] = step[1] - step[2]; vadd.s16 q8, q13, q14 vsub.s16 q9, q13, q14 vswp d18, d19 ; transpose the results ; 00 01 02 03 d16 ; 10 11 12 13 d17 ; 20 21 22 23 d18 ; 30 31 32 33 d19 vtrn.16 d16, d17 vtrn.16 d18, d19 ; 00 10 02 12 d16 ; 01 11 03 13 d17 ; 20 30 22 32 d18 ; 21 31 23 33 d19 vtrn.32 q8, q9 ; 00 10 20 30 d16 ; 01 11 21 31 d17 ; 02 12 22 32 d18 ; 03 13 23 33 d19 ; do the transform on columns ; stage 1 vadd.s16 d23, d16, d18 ; (input[0] + input[2]) vsub.s16 d24, d16, d18 ; (input[0] - input[2]) vmull.s16 q15, d17, d22 ; input[1] * cospi_24_64 vmull.s16 q1, d17, d20 ; input[1] * cospi_8_64 ; (input[0] + input[2]) * cospi_16_64; ; (input[0] - input[2]) * cospi_16_64; vmull.s16 q13, d23, d21 vmull.s16 q14, d24, d21 ; input[1] * cospi_24_64 - input[3] * cospi_8_64; ; input[1] * cospi_8_64 + input[3] * cospi_24_64; vmlsl.s16 q15, d19, d20 vmlal.s16 q1, d19, d22 ; dct_const_round_shift vrshrn.s32 d26, q13, #14 vrshrn.s32 d27, q14, #14 vrshrn.s32 d29, q15, #14 vrshrn.s32 d28, q1, #14 ; stage 2 ; output[0] = step[0] + step[3]; ; output[1] = step[1] + step[2]; ; output[3] = step[0] - step[3]; ; output[2] = step[1] - step[2]; vadd.s16 q8, q13, q14 vsub.s16 q9, q13, q14 ; The results are in two registers, one of them being swapped. This will ; be taken care of by loading the 'dest' value in a swapped fashion and ; also storing them in the same swapped fashion. ; temp_out[0, 1] = d16, d17 = q8 ; temp_out[2, 3] = d19, d18 = q9 swapped ; ROUND_POWER_OF_TWO(temp_out[j], 4) vrshr.s16 q8, q8, #4 vrshr.s16 q9, q9, #4 vld1.32 {d26[0]}, [r1], r2 vld1.32 {d26[1]}, [r1], r2 vld1.32 {d27[1]}, [r1], r2 vld1.32 {d27[0]}, [r1] ; no post-increment ; ROUND_POWER_OF_TWO(temp_out[j], 4) + dest[j * stride + i] vaddw.u8 q8, q8, d26 vaddw.u8 q9, q9, d27 ; clip_pixel vqmovun.s16 d26, q8 vqmovun.s16 d27, q9 ; do the stores in reverse order with negative post-increment, by changing ; the sign of the stride rsb r2, r2, #0 vst1.32 {d27[0]}, [r1], r2 vst1.32 {d27[1]}, [r1], r2 vst1.32 {d26[1]}, [r1], r2 vst1.32 {d26[0]}, [r1] ; no post-increment bx lr ENDP ; |vpx_idct4x4_16_add_neon| END