diff options
Diffstat (limited to 'arch/arm/lib/delay.S')
| -rw-r--r-- | arch/arm/lib/delay.S | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/arch/arm/lib/delay.S b/arch/arm/lib/delay.S new file mode 100644 index 0000000..8d6a876 --- /dev/null +++ b/arch/arm/lib/delay.S @@ -0,0 +1,65 @@ +/* + * 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 + ldr r2, .LC0 + ldr r2, [r2] @ max = 0x01ffffff + mov r0, r0, lsr #14 @ max = 0x0001ffff + mov r2, r2, lsr #10 @ max = 0x00007fff + mul r0, r2, r0 @ max = 2^32-1 + 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) |
