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/* * 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/param.h> .text .LC0: .word loops_per_jiffy .LC1: .word (2199023*HZ)>>11 /* * r0 <= 2000 * lpj <= 0x01ffffff (max. 3355 bogomips) * HZ <= 1000 */ ENTRY(__udelay) ldr r2, .LC1 mul r0, r2, r0 ENTRY(__const_udelay) @ 0 <= r0 <= 0x7fffff06 mov r1, #-1 ldr r2, .LC0 ldr r2, [r2] @ max = 0x01ffffff add r0, r0, r1, lsr #32-14 mov r0, r0, lsr #14 @ max = 0x0001ffff add r2, r2, r1, lsr #32-10 mov r2, r2, lsr #10 @ max = 0x00007fff mul r0, r2, r0 @ max = 2^32-1 add r0, r0, r1, lsr #32-6 movs r0, r0, lsr #6 moveq pc, lr /* * loops = r0 * HZ * loops_per_jiffy / 1000000 * * Oh, if only we had a cycle counter... */ @ Delay routine ENTRY(__delay) subs r0, r0, #1 #if 0 movls pc, lr subs r0, r0, #1 movls pc, lr subs r0, r0, #1 movls pc, lr subs r0, r0, #1 movls pc, lr subs r0, r0, #1 movls pc, lr subs r0, r0, #1 movls pc, lr subs r0, r0, #1 movls pc, lr subs r0, r0, #1 #endif bhi __delay mov pc, lr ENDPROC(__udelay) ENDPROC(__const_udelay) ENDPROC(__delay) |