| /* |
| * 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) |
