| ; |
| ; Copyright (c) 2010 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 |idct_dequant_full_2x_neon| |
| ARM |
| REQUIRE8 |
| PRESERVE8 |
| |
| AREA ||.text||, CODE, READONLY, ALIGN=2 |
| ;void idct_dequant_full_2x_neon(short *q, short *dq, |
| ; unsigned char *dst, int stride); |
| ; r0 *q, |
| ; r1 *dq, |
| ; r2 *dst |
| ; r3 stride |
| |idct_dequant_full_2x_neon| PROC |
| vld1.16 {q0, q1}, [r1] ; dq (same l/r) |
| vld1.16 {q2, q3}, [r0] ; l q |
| add r0, r0, #32 |
| vld1.16 {q4, q5}, [r0] ; r q |
| add r12, r2, #4 |
| |
| ; interleave the predictors |
| vld1.32 {d28[0]}, [r2], r3 ; l pre |
| vld1.32 {d28[1]}, [r12], r3 ; r pre |
| vld1.32 {d29[0]}, [r2], r3 |
| vld1.32 {d29[1]}, [r12], r3 |
| vld1.32 {d30[0]}, [r2], r3 |
| vld1.32 {d30[1]}, [r12], r3 |
| vld1.32 {d31[0]}, [r2], r3 |
| vld1.32 {d31[1]}, [r12] |
| |
| adr r1, cospi8sqrt2minus1 ; pointer to the first constant |
| |
| ; dequant: q[i] = q[i] * dq[i] |
| vmul.i16 q2, q2, q0 |
| vmul.i16 q3, q3, q1 |
| vmul.i16 q4, q4, q0 |
| vmul.i16 q5, q5, q1 |
| |
| vld1.16 {d0}, [r1] |
| |
| ; q2: l0r0 q3: l8r8 |
| ; q4: l4r4 q5: l12r12 |
| vswp d5, d8 |
| vswp d7, d10 |
| |
| ; _CONSTANTS_ * 4,12 >> 16 |
| ; q6: 4 * sinpi : c1/temp1 |
| ; q7: 12 * sinpi : d1/temp2 |
| ; q8: 4 * cospi |
| ; q9: 12 * cospi |
| vqdmulh.s16 q6, q4, d0[2] ; sinpi8sqrt2 |
| vqdmulh.s16 q7, q5, d0[2] |
| vqdmulh.s16 q8, q4, d0[0] ; cospi8sqrt2minus1 |
| vqdmulh.s16 q9, q5, d0[0] |
| |
| vqadd.s16 q10, q2, q3 ; a1 = 0 + 8 |
| vqsub.s16 q11, q2, q3 ; b1 = 0 - 8 |
| |
| ; vqdmulh only accepts signed values. this was a problem because |
| ; our constant had the high bit set, and was treated as a negative value. |
| ; vqdmulh also doubles the value before it shifts by 16. we need to |
| ; compensate for this. in the case of sinpi8sqrt2, the lowest bit is 0, |
| ; so we can shift the constant without losing precision. this avoids |
| ; shift again afterward, but also avoids the sign issue. win win! |
| ; for cospi8sqrt2minus1 the lowest bit is 1, so we lose precision if we |
| ; pre-shift it |
| vshr.s16 q8, q8, #1 |
| vshr.s16 q9, q9, #1 |
| |
| ; q4: 4 + 4 * cospi : d1/temp1 |
| ; q5: 12 + 12 * cospi : c1/temp2 |
| vqadd.s16 q4, q4, q8 |
| vqadd.s16 q5, q5, q9 |
| |
| ; c1 = temp1 - temp2 |
| ; d1 = temp1 + temp2 |
| vqsub.s16 q2, q6, q5 |
| vqadd.s16 q3, q4, q7 |
| |
| ; [0]: a1+d1 |
| ; [1]: b1+c1 |
| ; [2]: b1-c1 |
| ; [3]: a1-d1 |
| vqadd.s16 q4, q10, q3 |
| vqadd.s16 q5, q11, q2 |
| vqsub.s16 q6, q11, q2 |
| vqsub.s16 q7, q10, q3 |
| |
| ; rotate |
| vtrn.32 q4, q6 |
| vtrn.32 q5, q7 |
| vtrn.16 q4, q5 |
| vtrn.16 q6, q7 |
| ; idct loop 2 |
| ; q4: l 0, 4, 8,12 r 0, 4, 8,12 |
| ; q5: l 1, 5, 9,13 r 1, 5, 9,13 |
| ; q6: l 2, 6,10,14 r 2, 6,10,14 |
| ; q7: l 3, 7,11,15 r 3, 7,11,15 |
| |
| ; q8: 1 * sinpi : c1/temp1 |
| ; q9: 3 * sinpi : d1/temp2 |
| ; q10: 1 * cospi |
| ; q11: 3 * cospi |
| vqdmulh.s16 q8, q5, d0[2] ; sinpi8sqrt2 |
| vqdmulh.s16 q9, q7, d0[2] |
| vqdmulh.s16 q10, q5, d0[0] ; cospi8sqrt2minus1 |
| vqdmulh.s16 q11, q7, d0[0] |
| |
| vqadd.s16 q2, q4, q6 ; a1 = 0 + 2 |
| vqsub.s16 q3, q4, q6 ; b1 = 0 - 2 |
| |
| ; see note on shifting above |
| vshr.s16 q10, q10, #1 |
| vshr.s16 q11, q11, #1 |
| |
| ; q10: 1 + 1 * cospi : d1/temp1 |
| ; q11: 3 + 3 * cospi : c1/temp2 |
| vqadd.s16 q10, q5, q10 |
| vqadd.s16 q11, q7, q11 |
| |
| ; q8: c1 = temp1 - temp2 |
| ; q9: d1 = temp1 + temp2 |
| vqsub.s16 q8, q8, q11 |
| vqadd.s16 q9, q10, q9 |
| |
| ; a1+d1 |
| ; b1+c1 |
| ; b1-c1 |
| ; a1-d1 |
| vqadd.s16 q4, q2, q9 |
| vqadd.s16 q5, q3, q8 |
| vqsub.s16 q6, q3, q8 |
| vqsub.s16 q7, q2, q9 |
| |
| ; +4 >> 3 (rounding) |
| vrshr.s16 q4, q4, #3 ; lo |
| vrshr.s16 q5, q5, #3 |
| vrshr.s16 q6, q6, #3 ; hi |
| vrshr.s16 q7, q7, #3 |
| |
| vtrn.32 q4, q6 |
| vtrn.32 q5, q7 |
| vtrn.16 q4, q5 |
| vtrn.16 q6, q7 |
| |
| ; adding pre |
| ; input is still packed. pre was read interleaved |
| vaddw.u8 q4, q4, d28 |
| vaddw.u8 q5, q5, d29 |
| vaddw.u8 q6, q6, d30 |
| vaddw.u8 q7, q7, d31 |
| |
| vmov.i16 q14, #0 |
| vmov q15, q14 |
| vst1.16 {q14, q15}, [r0] ; write over high input |
| sub r0, r0, #32 |
| vst1.16 {q14, q15}, [r0] ; write over low input |
| |
| sub r2, r2, r3, lsl #2 ; dst - 4*stride |
| add r1, r2, #4 ; hi |
| |
| ;saturate and narrow |
| vqmovun.s16 d0, q4 ; lo |
| vqmovun.s16 d1, q5 |
| vqmovun.s16 d2, q6 ; hi |
| vqmovun.s16 d3, q7 |
| |
| vst1.32 {d0[0]}, [r2], r3 ; lo |
| vst1.32 {d0[1]}, [r1], r3 ; hi |
| vst1.32 {d1[0]}, [r2], r3 |
| vst1.32 {d1[1]}, [r1], r3 |
| vst1.32 {d2[0]}, [r2], r3 |
| vst1.32 {d2[1]}, [r1], r3 |
| vst1.32 {d3[0]}, [r2] |
| vst1.32 {d3[1]}, [r1] |
| |
| bx lr |
| |
| ENDP ; |idct_dequant_full_2x_neon| |
| |
| ; Constant Pool |
| cospi8sqrt2minus1 DCD 0x4e7b |
| ; because the lowest bit in 0x8a8c is 0, we can pre-shift this |
| sinpi8sqrt2 DCD 0x4546 |
| |
| END |
