296 lines
13 KiB
ArmAsm
296 lines
13 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: lcd-as-video.S 26756 2010-06-11 04:41:36Z funman $
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*
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* Copyright (C) 2010 by Andree Buschmann
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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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/****************************************************************************
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* #define FORCE_FIFO_WAIT
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*
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* This is not needed in YUV blitting when the LCD IF is fast enough. In this
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* case YUV-to-RGB conversion per pixel needs longer than the transfer of a
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* pixel via the LCD IF. For iPod nano 2G this is true if the LCD IF is
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* configured to use LCD_PHTIME = 0x00 (see lcd-nano2g.c).
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****************************************************************************/
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#include "config.h"
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.section .icode, "ax", %progbits
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/****************************************************************************
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* void lcd_write_line(const fb_data *addr,
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* int pixelcount,
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* const unsigned int lcd_base_addr);
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*
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* Writes pixelcount pixels from src-pointer (lcd_framebuffer) to LCD dataport.
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*/
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.align 2
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.global lcd_write_line
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.type lcd_write_line, %function
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/* r0 = addr, must be aligned */
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/* r1 = pixel count, must be even */
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lcd_write_line: /* r2 = LCD_BASE */
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stmfd sp!, {r4-r6, lr} /* save non-scratch registers */
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add r12, r2, #0x40 /* LCD_WDATA = LCD data port */
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.loop:
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ldmia r0!, {r3, r5} /* read 4 pixels (=8 byte) */
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/* wait for FIFO half full */
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.fifo_wait:
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ldr lr, [r2, #0x1C] /* while (LCD_STATUS & 0x08); */
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tst lr, #0x8
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bgt .fifo_wait
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mov r4, r3, asr #16 /* r3 = 1st pixel, r4 = 2nd pixel */
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mov r6, r5, asr #16 /* r5 = 3rd pixel, r6 = 4th pixel */
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stmia r12, {r3-r6} /* write pixels (lowest 16 bit used) */
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subs r1, r1, #4
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bgt .loop
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ldmpc regs=r4-r6
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/****************************************************************************
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* extern void lcd_write_yuv420_lines(unsigned char const * const src[3],
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* const unsigned LCD_BASE,
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* int width,
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* int stride);
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*
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* Conversion from Motion JPEG and MPEG Y'PbPr to RGB is:
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* |R| |1.164 0.000 1.596| |Y' - 16|
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* |G| = |1.164 -0.391 -0.813| |Pb - 128|
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* |B| |1.164 2.018 0.000| |Pr - 128|
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*
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* Scaled, normalized, rounded and tweaked to yield RGB 565:
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* |R| |74 0 101| |Y' - 16| >> 9
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* |G| = |74 -24 -51| |Cb - 128| >> 8
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* |B| |74 128 0| |Cr - 128| >> 9
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*
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* Converts two lines from YUV to RGB565 and writes to LCD at once. First loop
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* loads Cb/Cr, calculates the chroma offset and saves them to buffer. Within
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* the second loop these chroma offset are reloaded from buffer. Within each
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* loop two pixels are calculated and written to LCD.
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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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/* r0 = src = yuv_src */
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/* r1 = dst = LCD_BASE */
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/* r2 = width */
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/* r3 = stride */
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stmfd sp!, { r4-r10, lr } /* save non-scratch */
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ldmia r0, { r9, r10, r12 } /* r9 = yuv_src[0] = Y'_p */
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/* r10 = yuv_src[1] = Cb_p */
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/* r12 = yuv_src[2] = Cr_p */
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add r3, r9, r3 /* r3 = &ysrc[stride] */
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add r4, r2, r2, asr #1 /* chroma buffer lenght = width/2 *3 */
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mov r4, r4, asl #2 /* use words for str/ldm possibility */
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add r4, r4, #19 /* plus room for 4 additional words, */
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bic r4, r4, #3 /* rounded up to multiples of 4 byte */
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sub sp, sp, r4 /* and allocate on stack */
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stmia sp, {r1-r4} /* LCD_BASE, width, &ysrc[stride], stack_alloc */
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mov r7, r2 /* r7 = loop count */
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add r8, sp, #16 /* chroma buffer */
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add lr, r1, #0x40 /* LCD data port = LCD_BASE + 0x40 */
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/* 1st loop start */
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10: /* loop start */
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ldrb r0, [r10], #1 /* r0 = *usrc++ = *Cb_p++ */
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ldrb r1, [r12], #1 /* r1 = *vsrc++ = *Cr_p++ */
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sub r0, r0, #128 /* r0 = Cb-128 */
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sub r1, r1, #128 /* r1 = Cr-128 */
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add r2, r1, r1, asl #1 /* r2 = Cr*51 + Cb*24 */
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add r2, r2, r2, asl #4
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add r2, r2, r0, asl #3
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add r2, r2, r0, asl #4
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add r4, r1, r1, asl #2 /* r1 = Cr*101 */
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add r4, r4, r1, asl #5
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add r1, r4, r1, asl #6
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add r1, r1, #256 /* r1 = rv = (r1 + 256) >> 9 */
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mov r1, r1, asr #9
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rsb r2, r2, #128 /* r2 = guv = (-r2 + 128) >> 8 */
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mov r2, r2, asr #8
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add r0, r0, #2 /* r0 = bu = (Cb*128 + 256) >> 9 */
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mov r0, r0, asr #2
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stmia r8!, {r0-r2} /* store r0, r1 and r2 to chroma buffer */
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/* 1st loop, first pixel */
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ldrb r5, [r9], #1 /* r5 = *ysrc++ = *Y'_p++ */
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sub r5, r5, #16 /* r5 = (Y'-16) * 74 */
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add r3, r5, r5, asl #2
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add r5, r3, r5, asl #5
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add r6, r1, r5, asr #8 /* r6 = r = (Y >> 9) + rv */
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add r3, r2, r5, asr #7 /* r3 = g = (Y >> 8) + guv */
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add r4, r0, r5, asr #8 /* r4 = b = (Y >> 9) + bu */
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orr r5, r6, r4 /* check if clamping is needed... */
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orr r5, r5, r3, asr #1 /* ...at all */
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cmp r5, #31
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bls 15f /* -> no clamp */
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cmp r6, #31 /* clamp r */
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mvnhi r6, r6, asr #31
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andhi r6, r6, #31
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cmp r3, #63 /* clamp g */
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mvnhi r3, r3, asr #31
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andhi r3, r3, #63
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cmp r4, #31 /* clamp b */
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mvnhi r4, r4, asr #31
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andhi r4, r4, #31
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15: /* no clamp */
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/* calculate pixel_1 and save to r4 for later pixel packing */
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orr r4, r4, r3, lsl #5 /* pixel_1 = r<<11 | g<<5 | b */
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orr r4, r4, r6, lsl #11 /* r4 = pixel_1 */
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/* 1st loop, second pixel */
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ldrb r5, [r9], #1 /* r5 = *ysrc++ = *Y'_p++ */
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sub r5, r5, #16 /* r5 = (Y'-16) * 74 */
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add r3, r5, r5, asl #2
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add r5, r3, r5, asl #5
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add r6, r1, r5, asr #8 /* r6 = r = (Y >> 9) + rv */
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add r3, r2, r5, asr #7 /* r3 = g = (Y >> 8) + guv */
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add r5, r0, r5, asr #8 /* r5 = b = (Y >> 9) + bu */
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orr r0, r6, r5 /* check if clamping is needed... */
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orr r0, r0, r3, asr #1 /* ...at all */
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cmp r0, #31
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bls 15f /* -> no clamp */
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cmp r6, #31 /* clamp r */
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mvnhi r6, r6, asr #31
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andhi r6, r6, #31
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cmp r3, #63 /* clamp g */
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mvnhi r3, r3, asr #31
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andhi r3, r3, #63
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cmp r5, #31 /* clamp b */
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mvnhi r5, r5, asr #31
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andhi r5, r5, #31
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15: /* no clamp */
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/* calculate pixel_2 and pack with pixel_1 before writing */
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orr r5, r5, r3, lsl #5 /* pixel_2 = r<<11 | g<<5 | b */
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orr r5, r5, r6, lsl #11 /* r5 = pixel_2 */
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#ifdef FORCE_FIFO_WAIT
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/* wait for FIFO half full */
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.fifo_wait1:
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ldr r3, [lr, #-0x24] /* while (LCD_STATUS & 0x08); */
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tst r3, #0x8
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bgt .fifo_wait1
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#endif
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stmia lr, {r4,r5} /* write pixel_1 and pixel_2 */
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subs r7, r7, #2 /* check for loop end */
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bgt 10b /* back to beginning */
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/* 1st loop end */
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/* Reload several registers for pointer rewinding for next loop */
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add r8, sp, #16 /* chroma buffer */
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ldmia sp, { r1, r7, r9} /* r1 = LCD_BASE */
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/* r7 = loop count */
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/* r9 = &ysrc[stride] */
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/* 2nd loop start */
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20: /* loop start */
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/* restore r0 (bu), r1 (rv) and r2 (guv) from chroma buffer */
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ldmia r8!, {r0-r2}
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/* 2nd loop, first pixel */
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ldrb r5, [r9], #1 /* r5 = *ysrc++ = *Y'_p++ */
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sub r5, r5, #16 /* r5 = (Y'-16) * 74 */
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add r3, r5, r5, asl #2
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add r5, r3, r5, asl #5
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add r6, r1, r5, asr #8 /* r6 = r = (Y >> 9) + rv */
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add r3, r2, r5, asr #7 /* r3 = g = (Y >> 8) + guv */
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add r4, r0, r5, asr #8 /* r4 = b = (Y >> 9) + bu */
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orr r5, r6, r4 /* check if clamping is needed... */
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orr r5, r5, r3, asr #1 /* ...at all */
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cmp r5, #31
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bls 15f /* -> no clamp */
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cmp r6, #31 /* clamp r */
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mvnhi r6, r6, asr #31
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andhi r6, r6, #31
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cmp r3, #63 /* clamp g */
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mvnhi r3, r3, asr #31
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andhi r3, r3, #63
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cmp r4, #31 /* clamp b */
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mvnhi r4, r4, asr #31
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andhi r4, r4, #31
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15: /* no clamp */
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/* calculate pixel_1 and save to r4 for later pixel packing */
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orr r4, r4, r3, lsl #5 /* pixel_1 = r<<11 | g<<5 | b */
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orr r4, r4, r6, lsl #11 /* r4 = pixel_1 */
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/* 2nd loop, second pixel */
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ldrb r5, [r9], #1 /* r5 = *ysrc++ = *Y'_p++ */
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sub r5, r5, #16 /* r5 = (Y'-16) * 74 */
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add r3, r5, r5, asl #2
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add r5, r3, r5, asl #5
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add r6, r1, r5, asr #8 /* r6 = r = (Y >> 9) + rv */
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add r3, r2, r5, asr #7 /* r3 = g = (Y >> 8) + guv */
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add r5, r0, r5, asr #8 /* r5 = b = (Y >> 9) + bu */
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orr r0, r6, r5 /* check if clamping is needed... */
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orr r0, r0, r3, asr #1 /* ...at all */
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cmp r0, #31
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bls 15f /* -> no clamp */
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cmp r6, #31 /* clamp r */
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mvnhi r6, r6, asr #31
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andhi r6, r6, #31
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cmp r3, #63 /* clamp g */
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mvnhi r3, r3, asr #31
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andhi r3, r3, #63
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cmp r5, #31 /* clamp b */
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mvnhi r5, r5, asr #31
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andhi r5, r5, #31
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15: /* no clamp */
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/* calculate pixel_2 and pack with pixel_1 before writing */
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orr r5, r5, r3, lsl #5 /* pixel_2 = r<<11 | g<<5 | b */
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orr r5, r5, r6, lsl #11 /* r5 = pixel_2 */
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#ifdef FORCE_FIFO_WAIT
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/* wait for FIFO half full */
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.fifo_wait2:
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ldr r3, [lr, #-0x24] /* while (LCD_STATUS & 0x08); */
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tst r3, #0x8
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bgt .fifo_wait2
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#endif
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stmia lr, {r4,r5} /* write pixel_1 and pixel_2 */
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subs r7, r7, #2 /* check for loop end */
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bgt 20b /* back to beginning */
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/* 2nd loop end */
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ldr r3, [sp, #12]
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add sp, sp, r3 /* deallocate buffer */
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ldmpc regs=r4-r10 /* restore registers */
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.ltorg
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.size lcd_write_yuv420_lines, .-lcd_write_yuv420_lines
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