u-boot/arch/arm/include/asm/macro.h

/*
 * include/asm-arm/macro.h
 *
 * Copyright (C) 2009 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#ifndef __ASM_ARM_MACRO_H__
#define __ASM_ARM_MACRO_H__
#ifdef __ASSEMBLY__

/*
 * These macros provide a convenient way to write 8, 16 and 32 bit data
 * to any address.
 * Registers r4 and r5 are used, any data in these registers are
 * overwritten by the macros.
 * The macros are valid for any ARM architecture, they do not implement
 * any memory barriers so caution is recommended when using these when the
 * caches are enabled or on a multi-core system.
 */

.macro	write32, addr, data
	ldr	r4, =\addr
	ldr	r5, =\data
	str	r5, [r4]
.endm

.macro	write16, addr, data
	ldr	r4, =\addr
	ldrh	r5, =\data
	strh	r5, [r4]
.endm

.macro	write8, addr, data
	ldr	r4, =\addr
	ldrb	r5, =\data
	strb	r5, [r4]
.endm

/*
 * This macro generates a loop that can be used for delays in the code.
 * Register r4 is used, any data in this register is overwritten by the
 * macro.
 * The macro is valid for any ARM architeture. The actual time spent in the
 * loop will vary from CPU to CPU though.
 */

.macro	wait_timer, time
	ldr	r4, =\time
1:
	nop
	subs	r4, r4, #1
	bcs	1b
.endm

#endif /* __ASSEMBLY__ */
#endif /* __ASM_ARM_MACRO_H__ */