rockbox/firmware/target/arm/bits-armv6.S
Michael Sevakis f728559bf9 Make atomic bit modification functions return previous value.
Change-Id: I19a94cf946735e1d9e51c3207cd82198fd4dfc1a
2017-10-30 21:43:15 -04:00

78 lines
2.5 KiB
ArmAsm

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2010 by Michael Sevakis
*
* 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.
*
****************************************************************************/
/***************************************************************************
* uint32_t bitmod32(volatile uint32_t *addr, uint32_t bits, uint32_t mask)
*/
.section .text.bitmod32, "ax", %progbits
.align 2
.global bitmod32
.type bitmod32, %function
bitmod32:
mov r3, r0
mrs r12, cpsr
cpsid if
ldr r0, [r3]
and r1, r1, r2 @ Only allow mod of bits in 'mask'
bic r2, r0, r2 @ Clear mask bits
orr r1, r2, r1 @ Set according to 'bits'
str r1, [r3]
msr cpsr_c, r12
bx lr
.size bitmod32, .-bitmod32
/***************************************************************************
* uint32_t bitset32(volatile uint32_t *addr, uint32_t mask)
*/
.section .text.bitset32, "ax", %progbits
.align 2
.global bitset32
.type bitset32, %function
bitset32:
mov r2, r0
mrs r12, cpsr
cpsid if
ldr r0, [r2]
orr r1, r0, r1
str r1, [r2]
msr cpsr_c, r12
bx lr
.size bitset32, .-bitset32
/***************************************************************************
* uint32_t bitclr32(volatile uint32_t *addr, uint32_t mask)
*/
.section .text.bitclr32, "ax", %progbits
.align 2
.global bitclr32
.type bitclr32, %function
bitclr32:
mov r2, r0
mrs r12, cpsr
cpsid if
ldr r0, [r2]
bic r1, r0, r1
str r1, [r2]
msr cpsr_c, r12
bx lr
.size bitclr32, .-bitclr32