rockbox/firmware/target/arm/samsung/yh920/lcd-as-yh920.S
Rafaël Carré 45c7498f59 FS#11335 by me: make ARM assembly functions thumb-friendly
We can't pop into pc on ARMv4t when using thumb: the T bit won't be
modified if we are returning to a thumb function
Code running on ARMv4t should use the new ldrpc / ldmpc macros instead
of ldr pc, [sp], #4 and ldm(cond) sp!, {regs, pc}
No modification on pure ARM builds and ARMv5+

Note: USE_THUMB is currently never defined, no targets can currently be
built with -mthumb, see FS#6734

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@26756 a1c6a512-1295-4272-9138-f99709370657
2010-06-11 04:41:36 +00:00

118 lines
2.9 KiB
ArmAsm

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2008 by Jens Arnold
* Modified from ipod/lcd-as-gray.S for YH920 by Rafaël Carré
*
* 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
/* Writes an array of pixels of specified width (in 8 bits unit)
*
* Arguments:
* r0 : pixels array
* r1 : number of pixels in 8 bits unit
*
* Register usage:
* r2 : LCD_CONTROL value / pixel value
* r3 : lcd bridge address
*/
.global lcd_write_data
.type lcd_write_data,%function
lcd_write_data:
ldr r3, =LCD1_BASE
.loop:
1:
ldr r2, [r3]
tst r2, #LCD1_BUSY_MASK
bne 1b
ldrb r2, [r0], #1
str r2, [r3, #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 - current block of phases
* r4 - current block of values
* r5 - lcd data accumulator
* r12 - phase signs mask
* lr - lcd bridge address
*/
lcd_grey_data:
stmfd sp!, {r4-r5, lr}
mov r12, #0x80
orr r12, r12, r12, lsl #8
orr r12, r12, r12, lsl #16
ldr lr, =LCD1_BASE
.greyloop:
ldr r3, [r1] /* Fetch 4 pixel phases */
ldr r4, [r0], #4 /* Fetch 4 pixel values */
mov r5, #0
tst r3, #0x80
orreq r5, r5, #0xc0
tst r3, #0x8000
orreq r5, r5, #0x30
tst r3, #0x800000
orreq r5, r5, #0x0c
tst r3, #0x80000000
orreq r5, r5, #0x03
bic r3, r3, r12
add r3, r3, r4
str r3, [r1], #4
1:
ldr r3, [lr]
tst r3, #LCD1_BUSY_MASK
bne 1b
str r5, [lr, #0x10]
subs r2, r2, #1
bne .greyloop
ldmpc regs=r4-r5
.size lcd_grey_data,.-lcd_grey_data