From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001 From: root Date: Fri, 25 Dec 2015 04:40:36 +0000 Subject: initial_commit --- arch/arm/lib/delay.S | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) create mode 100644 arch/arm/lib/delay.S (limited to 'arch/arm/lib/delay.S') diff --git a/arch/arm/lib/delay.S b/arch/arm/lib/delay.S new file mode 100644 index 00000000..3c9a05c8 --- /dev/null +++ b/arch/arm/lib/delay.S @@ -0,0 +1,69 @@ +/* + * 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 +#include +#include + .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) -- cgit v1.2.3