| /* | |
| * 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/delay.h> | |
| .text | |
| .LC0: .word loops_per_jiffy | |
| .LC1: .word UDELAY_MULT | |
| /* | |
| * loops = r0 * HZ * loops_per_jiffy / 1000000 | |
| * | |
| * r0 <= 2000 | |
| * HZ <= 1000 | |
| */ | |
| ENTRY(__loop_udelay) | |
| ldr r2, .LC1 | |
| mul r0, r2, r0 @ r0 = delay_us * UDELAY_MULT | |
| ENTRY(__loop_const_udelay) @ 0 <= r0 <= 0xfffffaf0 | |
| ldr r2, .LC0 | |
| ldr r2, [r2] | |
| umull r1, r0, r2, r0 @ r0-r1 = r0 * loops_per_jiffy | |
| adds r1, r1, #0xffffffff @ rounding up ... | |
| adcs r0, r0, r0 @ and right shift by 31 | |
| reteq lr | |
| .align 3 | |
| @ Delay routine | |
| ENTRY(__loop_delay) | |
| subs r0, r0, #1 | |
| #if 0 | |
| retls lr | |
| subs r0, r0, #1 | |
| retls lr | |
| subs r0, r0, #1 | |
| retls lr | |
| subs r0, r0, #1 | |
| retls lr | |
| subs r0, r0, #1 | |
| retls lr | |
| subs r0, r0, #1 | |
| retls lr | |
| subs r0, r0, #1 | |
| retls lr | |
| subs r0, r0, #1 | |
| #endif | |
| bhi __loop_delay | |
| ret lr | |
| ENDPROC(__loop_udelay) | |
| ENDPROC(__loop_const_udelay) | |
| ENDPROC(__loop_delay) |