/* * linux/arch/arm/lib/delay.S * * Copyright (C) 1995-2003 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 #include #include .text /* * See linux/include/asm-arm/delay.h for a description of the maths. */ #if NDELAY_FACTOR > 255 #error NDELAY_FACTOR out of range #endif #if UDELAY_FACTOR > 65535 #error UDELAY_FACTOR out of range #endif LC0: .word SYMBOL_NAME(loops_per_jiffy) ENTRY(__const_delay) ldr r3, LC0 mov r1, r0, lsr #11 ldr r2, [r3, #0] b 2f ENTRY(__ndelay) mov r2, #NDELAY_FACTOR b 1f ENTRY(__udelay) mov r2, #UDELAY_FACTOR & 0xff00 orr r2, r2, #UDELAY_FACTOR & 0x00ff 1: ldr r3, LC0 mul r1, r0, r2 ldr r2, [r3, #0] mov r1, r1, lsr #11 2: mov r2, r2, lsr #12 mul r0, r1, r2 movs r0, r0, lsr #5 RETINSTR(moveq,pc,lr) /* * loops = (r0 * 0x10c6 * HZ * loops_per_jiffy) / 2^32 * * Oh, if only we had a cycle counter... */ ENTRY(__delay) subs r0, r0, #1 bcs SYMBOL_NAME(__delay) RETINSTR(mov,pc,lr)
