rockbox/firmware/target/arm/lcd-as-memframe.S
Daniel Stenberg 2acc0ac542 Updated our source code header to explicitly mention that we are GPL v2 or
later. We still need to hunt down snippets used that are not. 1324 modified
files...
http://www.rockbox.org/mail/archive/rockbox-dev-archive-2008-06/0060.shtml


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@17847 a1c6a512-1295-4272-9138-f99709370657
2008-06-28 18:10:04 +00:00

589 lines
28 KiB
ArmAsm

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2007 by Michael Sevakis
*
* ARM code for memory framebuffer LCDs
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include "cpu.h"
/****************************************************************************
* void lcd_copy_buffer_rect(fb_data *dst, fb_data *src, int width,
* int height);
*/
.section .icode, "ax", %progbits
.align 2
.global lcd_copy_buffer_rect
.type lcd_copy_buffer_rect, %function
@ r0 = dst
@ r1 = src
@ r2 = width
@ r3 = height
lcd_copy_buffer_rect: @
stmfd sp!, { r4-r12, lr } @ save non-scratch regs
mov r5, r2 @ r5 = cached width
rsb r4, r2, #LCD_WIDTH @ r4 = LCD_WIDTH - width
10: @ copy line @
subs r2, r5, #1 @ r2 = width - 1
beq 40f @ finish line @ one halfword? skip to trailing copy
tst r0, #2 @ word aligned?
beq 20f @ rem copy @ yes? skip to word copy
ldrh r6, [r1], #2 @ copy leading halfword
subs r2, r2, #1 @
strh r6, [r0], #2 @
ble 40f @ finish line @ next line if lt or finish
@ trailing halfword if eq
20: @ rem copy @
add r14, r2, #1 @ get remaining width mod 16 after word
@ align (rw)
and r14, r14, #0xe @ r14 = 0 (16), 2, 4, 6, 8, 10, 12, 14
add pc, pc, r14, lsl #3 @ branch to 32-byte align
nop @
b 30f @ rw % 16 = 0 or 1? use octword loop
nop @
nop @
nop @
ldr r6, [r1], #4 @ rw % 16 = 2 or 3
subs r2, r2, #2 @
str r6, [r0], #4 @
b 25f @ copy up done @
ldmia r1!, { r6-r7 } @ rw % 16 = 4 or 5
subs r2, r2, #4 @
stmia r0!, { r6-r7 } @
b 25f @ copy up done @
ldmia r1!, { r6-r8 } @ rw % 16 = 6 or 7
subs r2, r2, #6 @
stmia r0!, { r6-r8 } @
b 25f @ copy up done @
ldmia r1!, { r6-r9 } @ rw % 16 = 8 or 9
subs r2, r2, #8 @
stmia r0!, { r6-r9 } @
b 25f @ copy up done @
ldmia r1!, { r6-r10 } @ rw % 16 = 10 or 11
subs r2, r2, #10 @
stmia r0!, { r6-r10 } @
b 25f @ copy up done @
ldmia r1!, { r6-r11 } @ rw % 16 = 12 or 13
subs r2, r2, #12 @
stmia r0!, { r6-r11 } @
b 25f @ copy up done @
ldmia r1!, { r6-r12 } @ rw % 16 = 14 or 15
subs r2, r2, #14 @
stmia r0!, { r6-r12 } @
25: @ copy up done @
ble 40f @ finish line @ no 32-byte segments remaining?
30: @ octword loop @ copy 16 pixels per loop
ldmia r1!, { r6-r12, r14 } @
subs r2, r2, #16 @
stmia r0!, { r6-r12, r14 } @
bgt 30b @ octword loop @
40: @ finish line @
ldreqh r6, [r1], #2 @ finish last halfword if eq ...
add r1, r1, r4, lsl #1 @
streqh r6, [r0], #2 @ ...
add r0, r0, r4, lsl #1 @
subs r3, r3, #1 @ next line
bgt 10b @ copy line @
ldmfd sp!, { r4-r12, pc } @ restore regs and return
.ltorg @ dump constant pool
.size lcd_copy_buffer_rect, .-lcd_copy_buffer_rect
/****************************************************************************
* void lcd_write_yuv_420_lines(fb_data *dst,
* unsigned char const * const src[3],
* int width,
* int stride);
*
* |R| |1.000000 -0.000001 1.402000| |Y'|
* |G| = |1.000000 -0.334136 -0.714136| |Pb|
* |B| |1.000000 1.772000 0.000000| |Pr|
* Scaled, normalized, rounded and tweaked to yield RGB 565:
* |R| |74 0 101| |Y' - 16| >> 9
* |G| = |74 -24 -51| |Cb - 128| >> 8
* |B| |74 128 0| |Cr - 128| >> 9
*
* Write four RGB565 pixels in the following order on each loop:
* 1 3 + > down
* 2 4 \/ left
*/
.section .icode, "ax", %progbits
.align 2
.global lcd_write_yuv420_lines
.type lcd_write_yuv420_lines, %function
lcd_write_yuv420_lines:
@ r0 = dst
@ r1 = yuv_src
@ r2 = width
@ r3 = stride
stmfd sp!, { r4-r12 } @ save non-scratch
ldmia r1, { r4, r5, r6 } @ r4 = yuv_src[0] = Y'_p
@ r5 = yuv_src[1] = Cb_p
@ r6 = yuv_src[2] = Cr_p
@ r1 = scratch
sub r3, r3, #1 @
10: @ loop line @
ldrb r7, [r4], #1 @ r7 = *Y'_p++;
ldrb r8, [r5], #1 @ r8 = *Cb_p++;
ldrb r9, [r6], #1 @ r9 = *Cr_p++;
@
sub r7, r7, #16 @ r7 = Y = (Y' - 16)*74
add r12, r7, r7, asl #2 @ actually (Y' - 16)*37 and shift right
add r7, r12, r7, asl #5 @ by one less when adding - same for all
@
sub r8, r8, #128 @ Cb -= 128
sub r9, r9, #128 @ Cr -= 128
@
add r10, r9, r9, asl #1 @ r10 = Cr*51 + Cb*24
add r10, r10, r10, asl #4 @
add r10, r10, r8, asl #3 @
add r10, r10, r8, asl #4 @
@
add r11, r9, r9, asl #2 @ r9 = Cr*101
add r11, r11, r9, asl #5 @
add r9, r11, r9, asl #6 @
@
add r8, r8, #2 @ r8 = bu = (Cb*128 + 128) >> 8
mov r8, r8, asr #2 @
add r9, r9, #256 @ r9 = rv = (r9 + 256) >> 9
mov r9, r9, asr #9 @
rsb r10, r10, #128 @ r10 = guv = (-r10 + 128) >> 8
mov r10, r10, asr #8 @
@ compute R, G, and B
add r1, r8, r7, asr #8 @ r1 = b = (Y >> 9) + bu
add r11, r9, r7, asr #8 @ r11 = r = (Y >> 9) + rv
add r7, r10, r7, asr #7 @ r7 = g = (Y >> 8) + guv
@
orr r12, r1, r11 @ check if clamping is needed...
orr r12, r12, r7, asr #1 @ ...at all
cmp r12, #31 @
bls 15f @ no clamp @
cmp r1, #31 @ clamp b
mvnhi r1, r1, asr #31 @
andhi r1, r1, #31 @
cmp r11, #31 @ clamp r
mvnhi r11, r11, asr #31 @
andhi r11, r11, #31 @
cmp r7, #63 @ clamp g
mvnhi r7, r7, asr #31 @
andhi r7, r7, #63 @
15: @ no clamp @
@
ldrb r12, [r4, r3] @ r12 = Y' = *(Y'_p + stride)
@
orr r1, r1, r7, lsl #5 @ r4 |= (g << 5)
orr r1, r1, r11, lsl #11 @ r4 = b | (r << 11)
#if LCD_WIDTH < 256
strh r1, [r0], #LCD_WIDTH @ store pixel
#else
strh r1, [r0] @
#endif
@
sub r7, r12, #16 @ r7 = Y = (Y' - 16)*74
add r12, r7, r7, asl #2 @
add r7, r12, r7, asl #5 @
@ compute R, G, and B
add r1, r8, r7, asr #8 @ r1 = b = (Y >> 9) + bu
add r11, r9, r7, asr #8 @ r11 = r = (Y >> 9) + rv
add r7, r10, r7, asr #7 @ r7 = g = (Y >> 8) + guv
@
orr r12, r1, r11 @ check if clamping is needed...
orr r12, r12, r7, asr #1 @ ...at all
cmp r12, #31 @
bls 15f @ no clamp @
cmp r1, #31 @ clamp b
mvnhi r1, r1, asr #31 @
andhi r1, r1, #31 @
cmp r11, #31 @ clamp r
mvnhi r11, r11, asr #31 @
andhi r11, r11, #31 @
cmp r7, #63 @ clamp g
mvnhi r7, r7, asr #31 @
andhi r7, r7, #63 @
15: @ no clamp @
@
ldrb r12, [r4], #1 @ r12 = Y' = *(Y'_p++)
@
orr r1, r1, r11, lsl #11 @ r1 = b | (r << 11)
orr r1, r1, r7, lsl #5 @ r1 |= (g << 5)
#if LCD_WIDTH < 256
strh r1, [r0, #-LCD_WIDTH-2] @ store pixel
#else
strh r1, [r0, #-2] @
add r0, r0, #LCD_WIDTH @
#endif
@
sub r7, r12, #16 @ r7 = Y = (Y' - 16)*74
add r12, r7, r7, asl #2 @
add r7, r12, r7, asl #5 @
@ compute R, G, and B
add r1, r8, r7, asr #8 @ r1 = b = (Y >> 9) + bu
add r11, r9, r7, asr #8 @ r11 = r = (Y >> 9) + rv
add r7, r10, r7, asr #7 @ r7 = g = (Y >> 8) + guv
@
orr r12, r1, r11 @ check if clamping is needed...
orr r12, r12, r7, asr #1 @ ...at all
cmp r12, #31 @
bls 15f @ no clamp @
cmp r1, #31 @ clamp b
mvnhi r1, r1, asr #31 @
andhi r1, r1, #31 @
cmp r11, #31 @ clamp r
mvnhi r11, r11, asr #31 @
andhi r11, r11, #31 @
cmp r7, #63 @ clamp g
mvnhi r7, r7, asr #31 @
andhi r7, r7, #63 @
15: @ no clamp @
@
ldrb r12, [r4, r3] @ r12 = Y' = *(Y'_p + stride)
@
orr r1, r1, r7, lsl #5 @ r1 = b | (g << 5)
orr r1, r1, r11, lsl #11 @ r1 |= (r << 11)
#if LCD_WIDTH < 256
strh r1, [r0, #LCD_WIDTH]! @ store pixel
#else
strh r1, [r0] @
#endif
@
sub r7, r12, #16 @ r7 = Y = (Y' - 16)*74
add r12, r7, r7, asl #2 @
add r7, r12, r7, asl #5 @
@ compute R, G, and B
add r1, r8, r7, asr #8 @ r1 = b = (Y >> 9) + bu
add r11, r9, r7, asr #8 @ r11 = r = (Y >> 9) + rv
add r7, r10, r7, asr #7 @ r7 = g = (Y >> 8) + guv
@
orr r12, r1, r11 @ check if clamping is needed...
orr r12, r12, r7, asr #1 @ ...at all
cmp r12, #31 @
bls 15f @ no clamp @
cmp r1, #31 @ clamp b
mvnhi r1, r1, asr #31 @
andhi r1, r1, #31 @
cmp r11, #31 @ clamp r
mvnhi r11, r11, asr #31 @
andhi r11, r11, #31 @
cmp r7, #63 @ clamp g
mvnhi r7, r7, asr #31 @
andhi r7, r7, #63 @
15: @ no clamp @
@
orr r12, r1, r11, lsl #11 @ r12 = b | (r << 11)
orr r12, r12, r7, lsl #5 @ r12 |= (g << 5)
strh r12, [r0, #-2] @ store pixel
#if LCD_WIDTH < 256
add r0, r0, #2*LCD_WIDTH @
#else
add r0, r0, #LCD_WIDTH @
#endif
@
subs r2, r2, #2 @ subtract block from width
bgt 10b @ loop line @
@
ldmfd sp!, { r4-r12 } @ restore registers and return
bx lr @
.ltorg @ dump constant pool
.size lcd_write_yuv420_lines, .-lcd_write_yuv420_lines
/****************************************************************************
* void lcd_write_yuv_420_lines_odither(fb_data *dst,
* unsigned char const * const src[3],
* int width,
* int stride,
* int x_screen,
* int y_screen);
*
* |R| |1.000000 -0.000001 1.402000| |Y'|
* |G| = |1.000000 -0.334136 -0.714136| |Pb|
* |B| |1.000000 1.772000 0.000000| |Pr|
* Red scaled at twice g & b but at same precision to place it in correct
* bit position after multiply and leave instruction count lower.
* |R| |258 0 408| |Y' - 16|
* |G| = |149 -49 -104| |Cb - 128|
* |B| |149 258 0| |Cr - 128|
*
* Write four RGB565 pixels in the following order on each loop:
* 1 3 + > down
* 2 4 \/ left
*
* Kernel pattern (raw|rotated|use order):
* 5 3 4 2 2 6 3 7 row0 row2 > down
* 1 7 0 6 | 4 0 5 1 | 2 4 6 0 3 5 7 1 col0 left
* 4 2 5 3 | 3 7 2 6 | 3 5 7 1 2 4 6 0 col2 \/
* 0 6 1 7 5 1 4 0
*/
.section .icode, "ax", %progbits
.align 2
.global lcd_write_yuv420_lines_odither
.type lcd_write_yuv420_lines_odither, %function
lcd_write_yuv420_lines_odither:
@ r0 = dst
@ r1 = yuv_src
@ r2 = width
@ r3 = stride
@ [sp] = x_screen
@ [sp+4] = y_screen
stmfd sp!, { r4-r12, lr } @ save non-scratch
ldmia r1, { r4, r5, r6 } @ r4 = yuv_src[0] = Y'_p
@ r5 = yuv_src[1] = Cb_p
@ r6 = yuv_src[2] = Cr_p
@
sub r3, r3, #1 @
add r1, sp, #40 @ Line up pattern and kernel quadrant
ldmia r1, { r12, r14 } @
eor r14, r14, r12 @
and r14, r14, #0x2 @
mov r14, r14, lsl #6 @ 0x00 or 0x80
10: @ loop line @
@
ldrb r7, [r4], #1 @ r7 = *Y'_p++;
ldrb r8, [r5], #1 @ r8 = *Cb_p++;
ldrb r9, [r6], #1 @ r9 = *Cr_p++;
@
eor r14, r14, #0x80 @ flip pattern quadrant
@
sub r7, r7, #16 @ r7 = Y = (Y' - 16)*149
add r12, r7, r7, asl #2 @
add r12, r12, r12, asl #4 @
add r7, r12, r7, asl #6 @
@
sub r8, r8, #128 @ Cb -= 128
sub r9, r9, #128 @ Cr -= 128
@
add r10, r8, r8, asl #4 @ r10 = guv = Cr*104 + Cb*49
add r10, r10, r8, asl #5 @
add r10, r10, r9, asl #3 @
add r10, r10, r9, asl #5 @
add r10, r10, r9, asl #6 @
@
mov r8, r8, asl #1 @ r8 = bu = Cb*258
add r8, r8, r8, asl #7 @
@
add r9, r9, r9, asl #1 @ r9 = rv = Cr*408
add r9, r9, r9, asl #4 @
mov r9, r9, asl #3 @
@
@ compute R, G, and B
add r1, r8, r7 @ r1 = b' = Y + bu
add r11, r9, r7, asl #1 @ r11 = r' = Y*2 + rv
rsb r7, r10, r7 @ r7 = g' = Y + guv
@
@ r8 = bu, r9 = rv, r10 = guv
@
sub r12, r1, r1, lsr #5 @ r1 = 31/32*b + b/256
add r1, r12, r1, lsr #8 @
@
sub r12, r11, r11, lsr #5 @ r11 = 31/32*r + r/256
add r11, r12, r11, lsr #8 @
@
sub r12, r7, r7, lsr #6 @ r7 = 63/64*g + g/256
add r7, r12, r7, lsr #8 @
@
add r12, r14, #0x100 @
@
add r1, r1, r12 @ b = r1 + delta
add r11, r11, r12, lsl #1 @ r = r11 + delta*2
add r7, r7, r12, lsr #1 @ g = r7 + delta/2
@
orr r12, r1, r11, asr #1 @ check if clamping is needed...
orr r12, r12, r7 @ ...at all
movs r12, r12, asr #15 @
beq 15f @ no clamp @
movs r12, r1, asr #15 @ clamp b
mvnne r1, r12, lsr #15 @
andne r1, r1, #0x7c00 @ mask b only if clamped
movs r12, r11, asr #16 @ clamp r
mvnne r11, r12, lsr #16 @
movs r12, r7, asr #15 @ clamp g
mvnne r7, r12, lsr #15 @
15: @ no clamp @
@
ldrb r12, [r4, r3] @ r12 = Y' = *(Y'_p + stride)
@
and r11, r11, #0xf800 @ pack pixel
and r7, r7, #0x7e00 @ r1 = pixel = (r & 0xf800) |
orr r11, r11, r7, lsr #4 @ ((g & 0x7e00) >> 4) |
orr r1, r11, r1, lsr #10 @ (b >> 10)
@
#if LCD_WIDTH < 256
strh r1, [r0], #LCD_WIDTH @ store pixel
#else
strh r1, [r0] @
#endif
@
sub r7, r12, #16 @ r7 = Y = (Y' - 16)*149
add r12, r7, r7, asl #2 @
add r12, r12, r12, asl #4 @
add r7, r12, r7, asl #6 @
@ compute R, G, and B
add r1, r8, r7 @ r1 = b' = Y + bu
add r11, r9, r7, asl #1 @ r11 = r' = Y*2 + rv
rsb r7, r10, r7 @ r7 = g' = Y + guv
@
sub r12, r1, r1, lsr #5 @ r1 = 31/32*b' + b'/256
add r1, r12, r1, lsr #8 @
@
sub r12, r11, r11, lsr #5 @ r11 = 31/32*r' + r'/256
add r11, r12, r11, lsr #8 @
@
sub r12, r7, r7, lsr #6 @ r7 = 63/64*g' + g'/256
add r7, r12, r7, lsr #8 @
@
add r12, r14, #0x200 @
@
add r1, r1, r12 @ b = r1 + delta
add r11, r11, r12, lsl #1 @ r = r11 + delta*2
add r7, r7, r12, lsr #1 @ g = r7 + delta/2
@
orr r12, r1, r11, asr #1 @ check if clamping is needed...
orr r12, r12, r7 @ ...at all
movs r12, r12, asr #15 @
beq 15f @ no clamp @
movs r12, r1, asr #15 @ clamp b
mvnne r1, r12, lsr #15 @
andne r1, r1, #0x7c00 @ mask b only if clamped
movs r12, r11, asr #16 @ clamp r
mvnne r11, r12, lsr #16 @
movs r12, r7, asr #15 @ clamp g
mvnne r7, r12, lsr #15 @
15: @ no clamp @
@
ldrb r12, [r4], #1 @ r12 = Y' = *(Y'_p++)
@
and r11, r11, #0xf800 @ pack pixel
and r7, r7, #0x7e00 @ r1 = pixel = (r & 0xf800) |
orr r11, r11, r7, lsr #4 @ ((g & 0x7e00) >> 4) |
orr r1, r11, r1, lsr #10 @ (b >> 10)
@
#if LCD_WIDTH < 256
strh r1, [r0, #-LCD_WIDTH-2] @ store pixel
#else
strh r1, [r0, #-2] @ store pixel
add r0, r0, #LCD_WIDTH @
#endif
@
sub r7, r12, #16 @ r7 = Y = (Y' - 16)*149
add r12, r7, r7, asl #2 @
add r12, r12, r12, asl #4 @
add r7, r12, r7, asl #6 @
@ compute R, G, and B
add r1, r8, r7 @ r1 = b' = Y + bu
add r11, r9, r7, asl #1 @ r11 = r' = Y*2 + rv
rsb r7, r10, r7 @ r7 = g' = Y + guv
@
@ r8 = bu, r9 = rv, r10 = guv
@
sub r12, r1, r1, lsr #5 @ r1 = 31/32*b' + b'/256
add r1, r12, r1, lsr #8 @
@
sub r12, r11, r11, lsr #5 @ r11 = 31/32*r' + r'/256
add r11, r12, r11, lsr #8 @
@
sub r12, r7, r7, lsr #6 @ r7 = 63/64*g' + g'/256
add r7, r12, r7, lsr #8 @
@
add r12, r14, #0x300 @
@
add r1, r1, r12 @ b = r1 + delta
add r11, r11, r12, lsl #1 @ r = r11 + delta*2
add r7, r7, r12, lsr #1 @ g = r7 + delta/2
@
orr r12, r1, r11, asr #1 @ check if clamping is needed...
orr r12, r12, r7 @ ...at all
movs r12, r12, asr #15 @
beq 15f @ no clamp @
movs r12, r1, asr #15 @ clamp b
mvnne r1, r12, lsr #15 @
andne r1, r1, #0x7c00 @ mask b only if clamped
movs r12, r11, asr #16 @ clamp r
mvnne r11, r12, lsr #16 @
movs r12, r7, asr #15 @ clamp g
mvnne r7, r12, lsr #15 @
15: @ no clamp @
@
ldrb r12, [r4, r3] @ r12 = Y' = *(Y'_p + stride)
@
and r11, r11, #0xf800 @ pack pixel
and r7, r7, #0x7e00 @ r1 = pixel = (r & 0xf800) |
orr r11, r11, r7, lsr #4 @ ((g & 0x7e00) >> 4) |
orr r1, r11, r1, lsr #10 @ (b >> 10)
@
#if LCD_WIDTH < 256
strh r1, [r0, #LCD_WIDTH]! @ store pixel
#else
strh r1, [r0] @
#endif
@
sub r7, r12, #16 @ r7 = Y = (Y' - 16)*149
add r12, r7, r7, asl #2 @
add r12, r12, r12, asl #4 @
add r7, r12, r7, asl #6 @
@ compute R, G, and B
add r1, r8, r7 @ r1 = b' = Y + bu
add r11, r9, r7, asl #1 @ r11 = r' = Y*2 + rv
rsb r7, r10, r7 @ r7 = g' = Y + guv
@
sub r12, r1, r1, lsr #5 @ r1 = 31/32*b + b/256
add r1, r12, r1, lsr #8 @
@
sub r12, r11, r11, lsr #5 @ r11 = 31/32*r + r/256
add r11, r12, r11, lsr #8 @
@
sub r12, r7, r7, lsr #6 @ r7 = 63/64*g + g/256
add r7, r12, r7, lsr #8 @
@
@ This element is zero - use r14 @
@
add r1, r1, r14 @ b = r1 + delta
add r11, r11, r14, lsl #1 @ r = r11 + delta*2
add r7, r7, r14, lsr #1 @ g = r7 + delta/2
@
orr r12, r1, r11, asr #1 @ check if clamping is needed...
orr r12, r12, r7 @ ...at all
movs r12, r12, asr #15 @
beq 15f @ no clamp @
movs r12, r1, asr #15 @ clamp b
mvnne r1, r12, lsr #15 @
andne r1, r1, #0x7c00 @ mask b only if clamped
movs r12, r11, asr #16 @ clamp r
mvnne r11, r12, lsr #16 @
movs r12, r7, asr #15 @ clamp g
mvnne r7, r12, lsr #15 @
15: @ no clamp @
@
and r11, r11, #0xf800 @ pack pixel
and r7, r7, #0x7e00 @ r1 = pixel = (r & 0xf800) |
orr r11, r11, r7, lsr #4 @ ((g & 0x7e00) >> 4) |
orr r1, r11, r1, lsr #10 @ (b >> 10)
@
strh r1, [r0, #-2] @ store pixel
#if LCD_WIDTH < 256
add r0, r0, #2*LCD_WIDTH @
#else
add r0, r0, #LCD_WIDTH @
#endif
@
subs r2, r2, #2 @ subtract block from width
bgt 10b @ loop line @
@
ldmfd sp!, { r4-r12, pc } @ restore registers and return
.ltorg @ dump constant pool
.size lcd_write_yuv420_lines_odither, .-lcd_write_yuv420_lines_odither