ref: 11b9b14691609e53a65f04c076d4191c78d115c6
dir: /vp8/encoder/arm/neon/fastquantizeb_neon.asm/
;
; Copyright (c) 2011 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 |vp8_fast_quantize_b_neon|
INCLUDE asm_enc_offsets.asm
ARM
REQUIRE8
PRESERVE8
AREA ||.text||, CODE, READONLY, ALIGN=4
;void vp8_fast_quantize_b_c(BLOCK *b, BLOCKD *d)
|vp8_fast_quantize_b_neon| PROC
stmfd sp!, {r4-r7}
ldr r3, [r0, #vp8_block_coeff]
ldr r4, [r0, #vp8_block_quant_fast]
ldr r5, [r0, #vp8_block_round]
vld1.16 {q0, q1}, [r3@128] ; load z
vorr.s16 q14, q0, q1 ; check if all zero (step 1)
ldr r6, [r1, #vp8_blockd_qcoeff]
ldr r7, [r1, #vp8_blockd_dqcoeff]
vorr.s16 d28, d28, d29 ; check if all zero (step 2)
vabs.s16 q12, q0 ; calculate x = abs(z)
vabs.s16 q13, q1
;right shift 15 to get sign, all 0 if it is positive, all 1 if it is negative
vshr.s16 q2, q0, #15 ; sz
vmov r2, r3, d28 ; check if all zero (step 3)
vshr.s16 q3, q1, #15
vld1.s16 {q14, q15}, [r5@128]; load round_ptr [0-15]
vld1.s16 {q8, q9}, [r4@128] ; load quant_ptr [0-15]
vadd.s16 q12, q14 ; x + Round
vadd.s16 q13, q15
ldr r0, _inv_zig_zag_ ; load ptr of inverse zigzag table
vqdmulh.s16 q12, q8 ; y = ((Round+abs(z)) * Quant) >> 16
vqdmulh.s16 q13, q9
vld1.16 {q10, q11}, [r0@128]; load inverse scan order
vceq.s16 q8, q8 ; set q8 to all 1
ldr r4, [r1, #vp8_blockd_dequant]
vshr.s16 q12, #1 ; right shift 1 after vqdmulh
vshr.s16 q13, #1
orr r2, r2, r3 ; check if all zero (step 4)
cmp r2, #0 ; check if all zero (step 5)
beq zero_output ; check if all zero (step 6)
;modify data to have its original sign
veor.s16 q12, q2 ; y^sz
veor.s16 q13, q3
vsub.s16 q12, q2 ; x1=(y^sz)-sz = (y^sz)-(-1) (2's complement)
vsub.s16 q13, q3
vld1.s16 {q2, q3}, [r4@128] ; load dequant_ptr[i]
vtst.16 q14, q12, q8 ; now find eob
vtst.16 q15, q13, q8 ; non-zero element is set to all 1
vst1.s16 {q12, q13}, [r6@128]; store: qcoeff = x1
vand q10, q10, q14 ; get all valid numbers from scan array
vand q11, q11, q15
vmax.u16 q0, q10, q11 ; find maximum value in q0, q1
vmax.u16 d0, d0, d1
vmovl.u16 q0, d0
vmul.s16 q2, q12 ; x * Dequant
vmul.s16 q3, q13
vmax.u32 d0, d0, d1
vpmax.u32 d0, d0, d0
vst1.s16 {q2, q3}, [r7@128] ; store dqcoeff = x * Dequant
vmov.32 r0, d0[0] ; this instruction takes 1+13 cycles
; if we have vfp, we could use
; vstr s0, [r1, #vp8_blockd_eob]
str r0, [r1, #vp8_blockd_eob]
ldmfd sp!, {r4-r7}
bx lr
zero_output
str r2, [r1, #vp8_blockd_eob]
vst1.s16 {q0, q1}, [r6@128] ; qcoeff = 0
vst1.s16 {q0, q1}, [r7@128] ; dqcoeff = 0
ldmfd sp!, {r4-r7}
bx lr
ENDP
; default inverse zigzag table is defined in vp8/common/entropy.c
_inv_zig_zag_
DCD inv_zig_zag
ALIGN 16 ; enable use of @128 bit aligned loads
inv_zig_zag
DCW 0x0001, 0x0002, 0x0006, 0x0007
DCW 0x0003, 0x0005, 0x0008, 0x000d
DCW 0x0004, 0x0009, 0x000c, 0x000e
DCW 0x000a, 0x000b, 0x000f, 0x0010
END