/* * linux/arch/arm/lib/delay.S * * Copyright (C) 1995, 1996 Russell King * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/linkage.h> #include <asm/assembler.h> #include <asm/delay.h> .text .LC0: .word loops_per_jiffy .LC1: .word UDELAY_MULT /* * loops = r0 * HZ * loops_per_jiffy / 1000000 * * r0 <= 2000 * HZ <= 1000 */ ENTRY(__loop_udelay) ldr r2, .LC1 mul r0, r2, r0 @ r0 = delay_us * UDELAY_MULT ENTRY(__loop_const_udelay) @ 0 <= r0 <= 0xfffffaf0 ldr r2, .LC0 ldr r2, [r2] umull r1, r0, r2, r0 @ r0-r1 = r0 * loops_per_jiffy adds r1, r1, #0xffffffff @ rounding up ... adcs r0, r0, r0 @ and right shift by 31 reteq lr .align 3 @ Delay routine ENTRY(__loop_delay) subs r0, r0, #1 #if 0 retls lr subs r0, r0, #1 retls lr subs r0, r0, #1 retls lr subs r0, r0, #1 retls lr subs r0, r0, #1 retls lr subs r0, r0, #1 retls lr subs r0, r0, #1 retls lr subs r0, r0, #1 #endif bhi __loop_delay ret lr ENDPROC(__loop_udelay) ENDPROC(__loop_const_udelay) ENDPROC(__loop_delay)