ref: 3a4002b94d3b6ea589fb3b087e95a220c5f2b36c
dir: /vp8/encoder/arm/armv6/vp8_short_fdct4x4_armv6.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_short_fdct4x4_armv6|
ARM
REQUIRE8
PRESERVE8
AREA |.text|, CODE, READONLY
; void vp8_short_fdct4x4_c(short *input, short *output, int pitch)
|vp8_short_fdct4x4_armv6| PROC
stmfd sp!, {r4 - r12, lr}
; PART 1
; coeffs 0-3
ldrd r4, r5, [r0] ; [i1 | i0] [i3 | i2]
ldr r10, c7500
ldr r11, c14500
ldr r12, c0x22a453a0 ; [2217*4 | 5352*4]
ldr lr, c0x00080008
ror r5, r5, #16 ; [i2 | i3]
qadd16 r6, r4, r5 ; [i1+i2 | i0+i3] = [b1 | a1] without shift
qsub16 r7, r4, r5 ; [i1-i2 | i0-i3] = [c1 | d1] without shift
add r0, r0, r2 ; update input pointer
qadd16 r7, r7, r7 ; 2*[c1|d1] --> we can use smlad and smlsd
; with 2217*4 and 5352*4 without losing the
; sign bit (overflow)
smuad r4, r6, lr ; o0 = (i1+i2)*8 + (i0+i3)*8
smusd r5, r6, lr ; o2 = (i1+i2)*8 - (i0+i3)*8
smlad r6, r7, r12, r11 ; o1 = (c1 * 2217 + d1 * 5352 + 14500)
smlsdx r7, r7, r12, r10 ; o3 = (d1 * 2217 - c1 * 5352 + 7500)
ldrd r8, r9, [r0] ; [i5 | i4] [i7 | i6]
pkhbt r3, r4, r6, lsl #4 ; [o1 | o0], keep in register for PART 2
pkhbt r6, r5, r7, lsl #4 ; [o3 | o2]
str r6, [r1, #4]
; coeffs 4-7
ror r9, r9, #16 ; [i6 | i7]
qadd16 r6, r8, r9 ; [i5+i6 | i4+i7] = [b1 | a1] without shift
qsub16 r7, r8, r9 ; [i5-i6 | i4-i7] = [c1 | d1] without shift
add r0, r0, r2 ; update input pointer
qadd16 r7, r7, r7 ; 2x[c1|d1] --> we can use smlad and smlsd
; with 2217*4 and 5352*4 without losing the
; sign bit (overflow)
smuad r9, r6, lr ; o4 = (i5+i6)*8 + (i4+i7)*8
smusd r8, r6, lr ; o6 = (i5+i6)*8 - (i4+i7)*8
smlad r6, r7, r12, r11 ; o5 = (c1 * 2217 + d1 * 5352 + 14500)
smlsdx r7, r7, r12, r10 ; o7 = (d1 * 2217 - c1 * 5352 + 7500)
ldrd r4, r5, [r0] ; [i9 | i8] [i11 | i10]
pkhbt r9, r9, r6, lsl #4 ; [o5 | o4], keep in register for PART 2
pkhbt r6, r8, r7, lsl #4 ; [o7 | o6]
str r6, [r1, #12]
; coeffs 8-11
ror r5, r5, #16 ; [i10 | i11]
qadd16 r6, r4, r5 ; [i9+i10 | i8+i11]=[b1 | a1] without shift
qsub16 r7, r4, r5 ; [i9-i10 | i8-i11]=[c1 | d1] without shift
add r0, r0, r2 ; update input pointer
qadd16 r7, r7, r7 ; 2x[c1|d1] --> we can use smlad and smlsd
; with 2217*4 and 5352*4 without losing the
; sign bit (overflow)
smuad r2, r6, lr ; o8 = (i9+i10)*8 + (i8+i11)*8
smusd r8, r6, lr ; o10 = (i9+i10)*8 - (i8+i11)*8
smlad r6, r7, r12, r11 ; o9 = (c1 * 2217 + d1 * 5352 + 14500)
smlsdx r7, r7, r12, r10 ; o11 = (d1 * 2217 - c1 * 5352 + 7500)
ldrd r4, r5, [r0] ; [i13 | i12] [i15 | i14]
pkhbt r2, r2, r6, lsl #4 ; [o9 | o8], keep in register for PART 2
pkhbt r6, r8, r7, lsl #4 ; [o11 | o10]
str r6, [r1, #20]
; coeffs 12-15
ror r5, r5, #16 ; [i14 | i15]
qadd16 r6, r4, r5 ; [i13+i14 | i12+i15]=[b1|a1] without shift
qsub16 r7, r4, r5 ; [i13-i14 | i12-i15]=[c1|d1] without shift
qadd16 r7, r7, r7 ; 2x[c1|d1] --> we can use smlad and smlsd
; with 2217*4 and 5352*4 without losing the
; sign bit (overflow)
smuad r4, r6, lr ; o12 = (i13+i14)*8 + (i12+i15)*8
smusd r5, r6, lr ; o14 = (i13+i14)*8 - (i12+i15)*8
smlad r6, r7, r12, r11 ; o13 = (c1 * 2217 + d1 * 5352 + 14500)
smlsdx r7, r7, r12, r10 ; o15 = (d1 * 2217 - c1 * 5352 + 7500)
pkhbt r0, r4, r6, lsl #4 ; [o13 | o12], keep in register for PART 2
pkhbt r6, r5, r7, lsl #4 ; [o15 | o14]
str r6, [r1, #28]
; PART 2 -------------------------------------------------
ldr r11, c12000
ldr r10, c51000
ldr lr, c0x00070007
qadd16 r4, r3, r0 ; a1 = [i1+i13 | i0+i12]
qadd16 r5, r9, r2 ; b1 = [i5+i9 | i4+i8]
qsub16 r6, r9, r2 ; c1 = [i5-i9 | i4-i8]
qsub16 r7, r3, r0 ; d1 = [i1-i13 | i0-i12]
qadd16 r4, r4, lr ; a1 + 7
add r0, r11, #0x10000 ; add (d!=0)
qadd16 r2, r4, r5 ; a1 + b1 + 7
qsub16 r3, r4, r5 ; a1 - b1 + 7
ldr r12, c0x08a914e8 ; [2217 | 5352]
lsl r8, r2, #16 ; prepare bottom halfword for scaling
asr r2, r2, #4 ; scale top halfword
lsl r9, r3, #16 ; prepare bottom halfword for scaling
asr r3, r3, #4 ; scale top halfword
pkhtb r4, r2, r8, asr #20 ; pack and scale bottom halfword
pkhtb r5, r3, r9, asr #20 ; pack and scale bottom halfword
smulbt r2, r6, r12 ; [ ------ | c1*2217]
str r4, [r1, #0] ; [ o1 | o0]
smultt r3, r6, r12 ; [c1*2217 | ------ ]
str r5, [r1, #16] ; [ o9 | o8]
smlabb r8, r7, r12, r2 ; [ ------ | d1*5352]
smlatb r9, r7, r12, r3 ; [d1*5352 | ------ ]
smulbb r2, r6, r12 ; [ ------ | c1*5352]
smultb r3, r6, r12 ; [c1*5352 | ------ ]
lsls r6, r7, #16 ; d1 != 0 ?
addeq r8, r8, r11 ; c1_b*2217+d1_b*5352+12000 + (d==0)
addne r8, r8, r0 ; c1_b*2217+d1_b*5352+12000 + (d!=0)
asrs r6, r7, #16
addeq r9, r9, r11 ; c1_t*2217+d1_t*5352+12000 + (d==0)
addne r9, r9, r0 ; c1_t*2217+d1_t*5352+12000 + (d!=0)
smlabt r4, r7, r12, r10 ; [ ------ | d1*2217] + 51000
smlatt r5, r7, r12, r10 ; [d1*2217 | ------ ] + 51000
pkhtb r9, r9, r8, asr #16
sub r4, r4, r2
sub r5, r5, r3
ldr r3, [r1, #4] ; [i3 | i2]
pkhtb r5, r5, r4, asr #16 ; [o13|o12]
str r9, [r1, #8] ; [o5 | 04]
ldr r9, [r1, #12] ; [i7 | i6]
ldr r8, [r1, #28] ; [i15|i14]
ldr r2, [r1, #20] ; [i11|i10]
str r5, [r1, #24] ; [o13|o12]
qadd16 r4, r3, r8 ; a1 = [i3+i15 | i2+i14]
qadd16 r5, r9, r2 ; b1 = [i7+i11 | i6+i10]
qadd16 r4, r4, lr ; a1 + 7
qsub16 r6, r9, r2 ; c1 = [i7-i11 | i6-i10]
qadd16 r2, r4, r5 ; a1 + b1 + 7
qsub16 r7, r3, r8 ; d1 = [i3-i15 | i2-i14]
qsub16 r3, r4, r5 ; a1 - b1 + 7
lsl r8, r2, #16 ; prepare bottom halfword for scaling
asr r2, r2, #4 ; scale top halfword
lsl r9, r3, #16 ; prepare bottom halfword for scaling
asr r3, r3, #4 ; scale top halfword
pkhtb r4, r2, r8, asr #20 ; pack and scale bottom halfword
pkhtb r5, r3, r9, asr #20 ; pack and scale bottom halfword
smulbt r2, r6, r12 ; [ ------ | c1*2217]
str r4, [r1, #4] ; [ o3 | o2]
smultt r3, r6, r12 ; [c1*2217 | ------ ]
str r5, [r1, #20] ; [ o11 | o10]
smlabb r8, r7, r12, r2 ; [ ------ | d1*5352]
smlatb r9, r7, r12, r3 ; [d1*5352 | ------ ]
smulbb r2, r6, r12 ; [ ------ | c1*5352]
smultb r3, r6, r12 ; [c1*5352 | ------ ]
lsls r6, r7, #16 ; d1 != 0 ?
addeq r8, r8, r11 ; c1_b*2217+d1_b*5352+12000 + (d==0)
addne r8, r8, r0 ; c1_b*2217+d1_b*5352+12000 + (d!=0)
asrs r6, r7, #16
addeq r9, r9, r11 ; c1_t*2217+d1_t*5352+12000 + (d==0)
addne r9, r9, r0 ; c1_t*2217+d1_t*5352+12000 + (d!=0)
smlabt r4, r7, r12, r10 ; [ ------ | d1*2217] + 51000
smlatt r5, r7, r12, r10 ; [d1*2217 | ------ ] + 51000
pkhtb r9, r9, r8, asr #16
sub r4, r4, r2
sub r5, r5, r3
str r9, [r1, #12] ; [o7 | o6]
pkhtb r5, r5, r4, asr #16 ; [o15|o14]
str r5, [r1, #28] ; [o15|o14]
ldmfd sp!, {r4 - r12, pc}
ENDP
; Used constants
c7500
DCD 7500
c14500
DCD 14500
c0x22a453a0
DCD 0x22a453a0
c0x00080008
DCD 0x00080008
c12000
DCD 12000
c51000
DCD 51000
c0x00070007
DCD 0x00070007
c0x08a914e8
DCD 0x08a914e8
END