view target-utils/libbase/osmodelay.S @ 529:30bec872824a

doc/Target-utils: flash-boot-test documented
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 16 Jun 2019 18:42:44 +0000
parents e7502631a0f9
children
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/*
 * This assembly module provides a replica of OsmocomBB's bogo-millisecond
 * delay_ms() function.  It is literally a copy of what OsmocomBB's delay_ms()
 * compiles to with their gcc version and their optimization settings, as seen
 * by doing arm-elf-objdump on their lib/delay.o.
 *
 * This hack is intended for those cases where we have to copy OsmocomBB's
 * black magic voodoo operations with no ability to understand what is actually
 * needed, such as SPCA552E initialization on the Pirelli DP-L10.
 */

	.text
	.code	32
	.globl	osmo_delay_ms
osmo_delay_ms:
	mov     r3, #0
	sub     sp, sp, #4
	str     r3, [sp]
	ldr     r3, =1300
	mul     r3, r0, r3
	b       2f
1:	ldr     r2, [sp]
	ldr     r2, [sp]
	add     r2, r2, #1
	str     r2, [sp]
2:	ldr     r2, [sp]
	cmp     r2, r3
	bcc     1b
	add     sp, sp, #4
	bx      lr