| /* |
| * 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 |
| 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) |