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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id:$
*
* Copyright (C) 2010-2011 by Andree Buschmann
*
* Generic asm helper function used by YUV blitting.
*
* 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"
/****************************************************************************
* #define FORCE_FIFO_WAIT
*
* This is not needed in YUV blitting when the LCD IF is fast enough. In this
* case YUV-to-RGB conversion per pixel needs longer than the transfer of a
* pixel via the LCD IF.
****************************************************************************/
#include "config.h"
/* Set FIFO wait for both iPod Color and iPod nano1G until we know for which
* devices we can switch this off. */
#define FORCE_FIFO_WAIT
.section .icode, "ax", %progbits
/****************************************************************************
* extern void lcd_write_yuv420_lines(unsigned char const * const src[3],
* const unsigned LCD_BASE,
* int width,
* int stride);
*
* Conversion from Motion JPEG and MPEG Y'PbPr to RGB is:
* |R| |1.164 0.000 1.596| |Y' - 16|
* |G| = |1.164 -0.391 -0.813| |Pb - 128|
* |B| |1.164 2.018 0.000| |Pr - 128|
*
* 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
*
* Converts two lines from YUV to RGB565 and writes to LCD at once. First loop
* loads Cb/Cr, calculates the chroma offset and saves them to buffer. Within
* the second loop these chroma offset are reloaded from buffer. Within each
* loop two pixels are calculated and written to LCD.
*/
.align 2
.global lcd_write_yuv420_lines
.type lcd_write_yuv420_lines, %function
lcd_write_yuv420_lines:
/* r0 = src = yuv_src */
/* r1 = dst = LCD_BASE */
/* r2 = width */
/* r3 = stride */
stmfd sp!, { r4-r10, lr } /* save non-scratch */
ldmia r0, { r9, r10, r12 } /* r9 = yuv_src[0] = Y'_p */
/* r10 = yuv_src[1] = Cb_p */
/* r12 = yuv_src[2] = Cr_p */
add r3, r9, r3 /* r3 = &ysrc[stride] */
add r4, r2, r2, asr #1 /* chroma buffer lenght = width/2 *3 */
mov r4, r4, asl #2 /* use words for str/ldm possibility */
add r4, r4, #19 /* plus room for 4 additional words, */
bic r4, r4, #3 /* rounded up to multiples of 4 byte */
sub sp, sp, r4 /* and allocate on stack */
stmia sp, {r1-r4} /* LCD_BASE, width, &ysrc[stride], stack_alloc */
mov r7, r2 /* r7 = loop count */
add r8, sp, #16 /* chroma buffer */
add lr, r1, #0x100 /* LCD data port = LCD2_BASE + 0x100 */
/* 1st loop start */
10: /* loop start */
ldrb r0, [r10], #1 /* r0 = *usrc++ = *Cb_p++ */
ldrb r1, [r12], #1 /* r1 = *vsrc++ = *Cr_p++ */
sub r0, r0, #128 /* r0 = Cb-128 */
sub r1, r1, #128 /* r1 = Cr-128 */
add r2, r1, r1, asl #1 /* r2 = Cr*51 + Cb*24 */
add r2, r2, r2, asl #4
add r2, r2, r0, asl #3
add r2, r2, r0, asl #4
add r4, r1, r1, asl #2 /* r1 = Cr*101 */
add r4, r4, r1, asl #5
add r1, r4, r1, asl #6
add r1, r1, #256 /* r1 = rv = (r1 + 256) >> 9 */
mov r1, r1, asr #9
rsb r2, r2, #128 /* r2 = guv = (-r2 + 128) >> 8 */
mov r2, r2, asr #8
add r0, r0, #2 /* r0 = bu = (Cb*128 + 256) >> 9 */
mov r0, r0, asr #2
stmia r8!, {r0-r2} /* store r0, r1 and r2 to chroma buffer */
/* 1st loop, first pixel */
ldrb r5, [r9], #1 /* r5 = *ysrc++ = *Y'_p++ */
sub r5, r5, #16 /* r5 = (Y'-16) * 74 */
add r3, r5, r5, asl #2
add r5, r3, r5, asl #5
add r6, r1, r5, asr #8 /* r6 = r = (Y >> 9) + rv */
add r3, r2, r5, asr #7 /* r3 = g = (Y >> 8) + guv */
add r4, r0, r5, asr #8 /* r4 = b = (Y >> 9) + bu */
orr r5, r6, r4 /* check if clamping is needed... */
orr r5, r5, r3, asr #1 /* ...at all */
cmp r5, #31
bls 15f /* -> no clamp */
cmp r6, #31 /* clamp r */
mvnhi r6, r6, asr #31
andhi r6, r6, #31
cmp r3, #63 /* clamp g */
mvnhi r3, r3, asr #31
andhi r3, r3, #63
cmp r4, #31 /* clamp b */
mvnhi r4, r4, asr #31
andhi r4, r4, #31
15: /* no clamp */
/* calculate pixel_1 and save to r4 for later pixel packing */
orr r4, r4, r3, lsl #5 /* pixel_1 = r<<11 | g<<5 | b */
orr r4, r4, r6, lsl #11 /* r4 = pixel_1 */
/* 1st loop, second pixel */
ldrb r5, [r9], #1 /* r5 = *ysrc++ = *Y'_p++ */
sub r5, r5, #16 /* r5 = (Y'-16) * 74 */
add r3, r5, r5, asl #2
add r5, r3, r5, asl #5
add r6, r1, r5, asr #8 /* r6 = r = (Y >> 9) + rv */
add r3, r2, r5, asr #7 /* r3 = g = (Y >> 8) + guv */
add r5, r0, r5, asr #8 /* r5 = b = (Y >> 9) + bu */
orr r0, r6, r5 /* check if clamping is needed... */
orr r0, r0, r3, asr #1 /* ...at all */
cmp r0, #31
bls 15f /* -> no clamp */
cmp r6, #31 /* clamp r */
mvnhi r6, r6, asr #31
andhi r6, r6, #31
cmp r3, #63 /* clamp g */
mvnhi r3, r3, asr #31
andhi r3, r3, #63
cmp r5, #31 /* clamp b */
mvnhi r5, r5, asr #31
andhi r5, r5, #31
15: /* no clamp */
/* calculate pixel_2 and pack with pixel_1 before writing */
orr r5, r5, r3, lsl #5 /* pixel_2 = r<<11 | g<<5 | b */
orr r5, r5, r6, lsl #11 /* r5 = pixel_2 */
#ifdef FORCE_FIFO_WAIT
/* wait for FIFO half full */
.fifo_wait1:
ldr r3, [lr, #-0xE0] /* while !(LCD2_BLOCK_CTRL & 0x1000000); */
tst r3, #0x1000000
beq .fifo_wait1
#endif
mov r3, r4, lsl #8 /* swap pixel_1 */
and r3, r3, #0xff00
add r4, r3, r4, lsr #8
orr r4, r4, r5, lsl #24 /* swap pixel_2 and pack with pixel_1 */
mov r5, r5, lsr #8
orr r4, r4, r5, lsl #16
str r4, [lr] /* write pixel_1 and pixel_2 */
subs r7, r7, #2 /* check for loop end */
bgt 10b /* back to beginning */
/* 1st loop end */
/* Reload several registers for pointer rewinding for next loop */
add r8, sp, #16 /* chroma buffer */
ldmia sp, { r1, r7, r9} /* r1 = LCD_BASE */
/* r7 = loop count */
/* r9 = &ysrc[stride] */
/* 2nd loop start */
20: /* loop start */
/* restore r0 (bu), r1 (rv) and r2 (guv) from chroma buffer */
ldmia r8!, {r0-r2}
/* 2nd loop, first pixel */
ldrb r5, [r9], #1 /* r5 = *ysrc++ = *Y'_p++ */
sub r5, r5, #16 /* r5 = (Y'-16) * 74 */
add r3, r5, r5, asl #2
add r5, r3, r5, asl #5
add r6, r1, r5, asr #8 /* r6 = r = (Y >> 9) + rv */
add r3, r2, r5, asr #7 /* r3 = g = (Y >> 8) + guv */
add r4, r0, r5, asr #8 /* r4 = b = (Y >> 9) + bu */
orr r5, r6, r4 /* check if clamping is needed... */
orr r5, r5, r3, asr #1 /* ...at all */
cmp r5, #31
bls 15f /* -> no clamp */
cmp r6, #31 /* clamp r */
mvnhi r6, r6, asr #31
andhi r6, r6, #31
cmp r3, #63 /* clamp g */
mvnhi r3, r3, asr #31
andhi r3, r3, #63
cmp r4, #31 /* clamp b */
mvnhi r4, r4, asr #31
andhi r4, r4, #31
15: /* no clamp */
/* calculate pixel_1 and save to r4 for later pixel packing */
orr r4, r4, r3, lsl #5 /* pixel_1 = r<<11 | g<<5 | b */
orr r4, r4, r6, lsl #11 /* r4 = pixel_1 */
/* 2nd loop, second pixel */
ldrb r5, [r9], #1 /* r5 = *ysrc++ = *Y'_p++ */
sub r5, r5, #16 /* r5 = (Y'-16) * 74 */
add r3, r5, r5, asl #2
add r5, r3, r5, asl #5
add r6, r1, r5, asr #8 /* r6 = r = (Y >> 9) + rv */
add r3, r2, r5, asr #7 /* r3 = g = (Y >> 8) + guv */
add r5, r0, r5, asr #8 /* r5 = b = (Y >> 9) + bu */
orr r0, r6, r5 /* check if clamping is needed... */
orr r0, r0, r3, asr #1 /* ...at all */
cmp r0, #31
bls 15f /* -> no clamp */
cmp r6, #31 /* clamp r */
mvnhi r6, r6, asr #31
andhi r6, r6, #31
cmp r3, #63 /* clamp g */
mvnhi r3, r3, asr #31
andhi r3, r3, #63
cmp r5, #31 /* clamp b */
mvnhi r5, r5, asr #31
andhi r5, r5, #31
15: /* no clamp */
/* calculate pixel_2 and pack with pixel_1 before writing */
orr r5, r5, r3, lsl #5 /* pixel_2 = r<<11 | g<<5 | b */
orr r5, r5, r6, lsl #11 /* r5 = pixel_2 */
#ifdef FORCE_FIFO_WAIT
/* wait for FIFO half full */
.fifo_wait2:
ldr r3, [lr, #-0xE0] /* while !(LCD2_BLOCK_CTRL & 0x1000000); */
tst r3, #0x1000000
beq .fifo_wait2
#endif
mov r3, r4, lsl #8 /* swap pixel_1 */
and r3, r3, #0xff00
add r4, r3, r4, lsr #8
orr r4, r4, r5, lsl #24 /* swap pixel_2 and pack with pixel_1 */
mov r5, r5, lsr #8
orr r4, r4, r5, lsl #16
str r4, [lr] /* write pixel_1 and pixel_2 */
subs r7, r7, #2 /* check for loop end */
bgt 20b /* back to beginning */
/* 2nd loop end */
ldr r3, [sp, #12]
add sp, sp, r3 /* deallocate buffer */
ldmpc regs=r4-r10 /* restore registers */
.ltorg
.size lcd_write_yuv420_lines, .-lcd_write_yuv420_lines
|
