2acc0ac542
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
246 lines
7.4 KiB
ArmAsm
246 lines
7.4 KiB
ArmAsm
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2006 by Jens Arnold
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "config.h"
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#include "cpu.h"
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.section .icode, "ax", @progbits
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/* lcd_write_yuv420_lines()
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*
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* See http://en.wikipedia.org/wiki/YCbCr
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* ITU-R BT.601 (formerly CCIR 601):
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* |Y'| | 0.299000 0.587000 0.114000| |R|
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* |Pb| = |-0.168736 -0.331264 0.500000| |G| or 0.564334*(B - Y')
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* |Pr| | 0.500000 -0.418688 0.081312| |B| or 0.713267*(R - Y')
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* Scaled, normalized and rounded:
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* |Y'| | 65 129 25| |R| + 16 : 16->235
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* |Cb| = |-38 -74 112| |G| + 128 : 16->240
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* |Cr| |112 -94 -18| |B| + 128 : 16->240
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*
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* The inverse:
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* |R| |1.000000 0.000000 1.402000| |Y'|
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* |G| = |1.000000 -0.334136 -0.714136| |Pb|
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* |B| |1.000000 1.772000 0.000000| |Pr|
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* Scaled, normalized, rounded and tweaked to yield RGB565:
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* |R| |19611723 0 26881894| |Y' - 16| >> 27
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* |G| = |19611723 -6406711 -13692816| |Cb - 128| >> 26
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* |B| |19611723 33976259 0| |Cr - 128| >> 27
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*
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* Needs EMAC set to saturated, signed integer mode.
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*
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* register usage:
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* %a0 - LCD data port
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* %a1 - Y pointer
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* %a2 - C pointer
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* %a3 - C width
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* %a4 - Y end address
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* %a5 - Y factor
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* %a6 - BU factor
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* %d0 - scratch
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* %d1 - B, previous Y \ alternating
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* %d2 - U / B, previous Y /
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* %d3 - V / G
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* %d4 - R / output pixel
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* %d5 - GU factor
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* %d6 - GV factor
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* %d7 - RGB signed -> unsigned conversion mask
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*/
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.align 2
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.global lcd_write_yuv420_lines
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.type lcd_write_yuv420_lines, @function
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lcd_write_yuv420_lines:
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lea.l (-44, %sp), %sp /* free up some registers */
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movem.l %d2-%d7/%a2-%a6, (%sp)
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lea.l 0xf0000002, %a0 /* LCD data port */
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movem.l (44+4, %sp), %a1-%a3 /* Y data, C data, C width */
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lea.l (%a1, %a3*2), %a4 /* Y end address */
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move.l #19611723, %a5 /* y factor */
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move.l #33976259, %a6 /* bu factor */
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move.l #-6406711, %d5 /* gu factor */
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move.l #-13692816, %d6 /* gv factor */
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move.l #0x8410, %d7 /* bitmask for signed->unsigned conversion
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* of R, G and B within RGB565 at once */
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/* chroma for first 2x2 pixel block */
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clr.l %d3 /* load v component */
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move.b (%a2, %a3), %d3
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clr.l %d2 /* load u component */
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move.b (%a2)+, %d2
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moveq.l #-128, %d0
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add.l %d0, %d2
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add.l %d0, %d3
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mac.l %a6, %d2, %acc0 /* bu */
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mac.l %d5, %d2, %acc1 /* gu */
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mac.l %d6, %d3, %acc1 /* gv */
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move.l #26881894, %d0 /* rv factor */
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mac.l %d0, %d3, %acc2 /* rv */
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/* luma for very first pixel (top left) */
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clr.l %d1
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move.b (%a1, %a3*2), %d1
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moveq.l #-126, %d0
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add.l %d1, %d0 /* y' (-0.5 ... +0.5) */
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mac.l %a5, %d0, %acc0
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mac.l %a5, %d0, %acc1
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mac.l %a5, %d0, %acc2
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bra.b .yuv_line_entry
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.yuv_line_loop:
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/* chroma for 2x2 pixel block */
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clr.l %d3 /* load v component */
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move.b (%a2, %a3), %d3
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clr.l %d2 /* load u component */
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move.b (%a2)+, %d2
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moveq.l #-128, %d0
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add.l %d0, %d2
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add.l %d0, %d3
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mac.l %a6, %d2, %acc0 /* bu */
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mac.l %d5, %d2, %acc1 /* gu */
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mac.l %d6, %d3, %acc1 /* gv */
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move.l #26881894, %d0 /* rv factor */
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mac.l %d0, %d3, %acc2 /* rv */
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/* luma for first pixel (top left) */
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clr.l %d1
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move.b (%a1, %a3*2), %d1
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moveq.l #-126, %d0
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add.l %d1, %d0 /* y' (-0.5 ... +0.5) */
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mac.l %a5, %d0, %acc0
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mac.l %a5, %d0, %acc1
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mac.l %a5, %d0, %acc2
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move.w %d4, (%a0)
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/* LCD write is delayed one pixel to use it for filling the EMAC latency */
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/* convert to RGB565, pack and output */
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.yuv_line_entry:
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moveq.l #27, %d0
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move.l %acc0, %d2
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move.l %acc1, %d3
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move.l %acc2, %d4
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lsr.l %d0, %d2
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lsr.l %d0, %d4
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moveq.l #26, %d0
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lsr.l %d0, %d3
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lsl.l #6, %d4
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or.l %d3, %d4
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lsl.l #5, %d4
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or.l %d2, %d4
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eor.l %d7, %d4
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/* luma for second pixel (bottom left) as delta from the first */
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clr.l %d2
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move.b (%a1)+, %d2
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move.l %d2, %d0
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sub.l %d1, %d0
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mac.l %a5, %d0, %acc0
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mac.l %a5, %d0, %acc1
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mac.l %a5, %d0, %acc2
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move.w %d4, (%a0)
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/* LCD write is delayed one pixel to use it for filling the EMAC latency */
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/* convert to RGB565, pack and output */
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moveq.l #27, %d0
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move.l %acc0, %d1
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move.l %acc1, %d3
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move.l %acc2, %d4
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lsr.l %d0, %d1
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lsr.l %d0, %d4
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moveq.l #26, %d0
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lsr.l %d0, %d3
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lsl.l #6, %d4
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or.l %d3, %d4
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lsl.l #5, %d4
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or.l %d1, %d4
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eor.l %d7, %d4
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/* luma for third pixel (top right) as delta from the second */
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clr.l %d1
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move.b (%a1, %a3*2), %d1
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move.l %d1, %d0
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sub.l %d2, %d0
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mac.l %a5, %d0, %acc0
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mac.l %a5, %d0, %acc1
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mac.l %a5, %d0, %acc2
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move.w %d4, (%a0)
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/* LCD write is delayed one pixel to use it for filling the EMAC latency */
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/* convert to RGB565, pack and output */
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moveq.l #27, %d0
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move.l %acc0, %d2
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move.l %acc1, %d3
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move.l %acc2, %d4
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lsr.l %d0, %d2
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lsr.l %d0, %d4
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moveq.l #26, %d0
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lsr.l %d0, %d3
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lsl.l #6, %d4
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or.l %d3, %d4
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lsl.l #5, %d4
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or.l %d2, %d4
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eor.l %d7, %d4
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/* luma for fourth pixel (bottom right) as delta from the third */
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clr.l %d2
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move.b (%a1)+, %d2
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move.l %d2, %d0
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sub.l %d1, %d0
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mac.l %a5, %d0, %acc0
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mac.l %a5, %d0, %acc1
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mac.l %a5, %d0, %acc2
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move.w %d4, (%a0)
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/* LCD write is delayed one pixel to use it for filling the EMAC latency */
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/* convert to RGB565, pack and output */
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moveq.l #27, %d0
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movclr.l %acc0, %d1
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movclr.l %acc1, %d3
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movclr.l %acc2, %d4
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lsr.l %d0, %d1
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lsr.l %d0, %d4
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moveq.l #26, %d0
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lsr.l %d0, %d3
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lsl.l #6, %d4
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or.l %d3, %d4
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lsl.l #5, %d4
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or.l %d1, %d4
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eor.l %d7, %d4
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cmp.l %a1, %a4 /* run %a1 up to end of line */
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bhi.w .yuv_line_loop
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move.w %d4, (%a0) /* write (very) last pixel */
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movem.l (%sp), %d2-%d7/%a2-%a6
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lea.l (44, %sp), %sp /* restore registers */
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rts
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.yuv_end:
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.size lcd_write_yuv420_lines, .yuv_end - lcd_write_yuv420_lines
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