diff options
Diffstat (limited to 'arch/arm/lib/delay.S')
| -rw-r--r-- | arch/arm/lib/delay.S | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/arch/arm/lib/delay.S b/arch/arm/lib/delay.S new file mode 100644 index 00000000000..3c7f7e675dd --- /dev/null +++ b/arch/arm/lib/delay.S @@ -0,0 +1,58 @@ +/* + * 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> + .text + +LC0: .word loops_per_jiffy + +/* + * 0 <= r0 <= 2000 + */ +ENTRY(__udelay) + mov r2, #0x6800 + orr r2, r2, #0x00db + mul r0, r2, r0 +ENTRY(__const_udelay) @ 0 <= r0 <= 0x01ffffff + ldr r2, LC0 + ldr r2, [r2] @ max = 0x0fffffff + mov r0, r0, lsr #11 @ max = 0x00003fff + mov r2, r2, lsr #11 @ max = 0x0003ffff + mul r0, r2, r0 @ max = 2^32-1 + movs r0, r0, lsr #6 + RETINSTR(moveq,pc,lr) + +/* + * loops = (r0 * 0x10c6 * 100 * loops_per_jiffy) / 2^32 + * + * Oh, if only we had a cycle counter... + */ + +@ Delay routine +ENTRY(__delay) + subs r0, r0, #1 +#if 0 + RETINSTR(movls,pc,lr) + subs r0, r0, #1 + RETINSTR(movls,pc,lr) + subs r0, r0, #1 + RETINSTR(movls,pc,lr) + subs r0, r0, #1 + RETINSTR(movls,pc,lr) + subs r0, r0, #1 + RETINSTR(movls,pc,lr) + subs r0, r0, #1 + RETINSTR(movls,pc,lr) + subs r0, r0, #1 + RETINSTR(movls,pc,lr) + subs r0, r0, #1 +#endif + bhi __delay + RETINSTR(mov,pc,lr) |