rockbox/firmware/target/arm/olympus/mrobe-100/lcd-as-mr100.S
Jens Arnold 47d4c4739b ARM asm LCD and ATA driver functions: Don't save r12 as it is a scratch reg. Saves a bit of stack and execution time.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21795 a1c6a512-1295-4272-9138-f99709370657
2009-07-11 23:43:44 +00:00

116 lines
2.9 KiB
ArmAsm

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2008 by Jens Arnold
*
* 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"
.text
.align 2
.global lcd_write_data
.type lcd_write_data,%function
lcd_write_data:
ldr r12, =LCD1_BASE
.loop:
ldrb r2, [r0], #1
1:
ldr r3, [r12]
tst r3, #LCD1_BUSY_MASK
bne 1b
str r2, [r12, #0x10]
subs r1, r1, #1
bne .loop
bx lr
.size lcd_write_data,.-lcd_write_data
.global lcd_grey_data
.type lcd_grey_data,%function
/* A high performance function to write grey phase data to the display,
* one or multiple pixels.
*
* Arguments:
* r0 - pixel value data address
* r1 - pixel phase data address
* r2 - pixel block count
*
* Register usage:
* r3/r4 - current block of phases
* r5/r6 - current block of values
* r7 - lcd data accumulator
* r12 - phase signs mask
* lr - lcd bridge address
*/
lcd_grey_data:
stmfd sp!, {r4-r7, lr}
mov r12, #0x80
orr r12, r12, r12, lsl #8
orr r12, r12, r12, lsl #16
ldr lr, =LCD1_BASE
.greyloop:
ldmia r1, {r3-r4} /* Fetch 8 pixel phases */
ldmia r0!, {r5-r6} /* Fetch 8 pixel values */
mov r7, #0xff
tst r3, #0x80
biceq r7, r7, #0x80
tst r3, #0x8000
biceq r7, r7, #0x40
tst r3, #0x800000
biceq r7, r7, #0x20
tst r3, #0x80000000
biceq r7, r7, #0x10
bic r3, r3, r12
add r3, r3, r5
tst r4, #0x80
biceq r7, r7, #0x08
tst r4, #0x8000
biceq r7, r7, #0x04
tst r4, #0x800000
biceq r7, r7, #0x02
tst r4, #0x80000000
biceq r7, r7, #0x01
bic r4, r4, r12
add r4, r4, r6
stmia r1!, {r3-r4}
1:
ldr r5, [lr]
tst r5, #LCD1_BUSY_MASK
bne 1b
str r7, [lr, #0x10]
subs r2, r2, #1
bne .greyloop
ldmfd sp!, {r4-r7, pc}
.size lcd_grey_data,.-lcd_grey_data