arch/arm/lib/delay.S

   1 /*
   2  *  linux/arch/arm/lib/delay.S
   3  *
   4  *  Copyright (C) 1995, 1996 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/linkage.h>
  11 #include <asm/assembler.h>
  12                 .text
  13
  14 LC0:            .word   SYMBOL_NAME(loops_per_sec)
  15
  16 ENTRY(udelay)
  17                 mov     r2, #0x1000
  18                 orr     r2, r2, #0x00c6
  19                 mul     r1, r0, r2
  20                 ldr     r2, LC0
  21                 ldr     r2, [r2]
  22                 mov     r1, r1, lsr #11
  23                 mov     r2, r2, lsr #11
  24                 mul     r0, r1, r2
  25                 movs    r0, r0, lsr #10
  26                 RETINSTR(moveq,pc,lr)
  27
  28 @ Delay routine
  29 ENTRY(__delay)
  30                 subs    r0, r0, #1
  31                 RETINSTR(movcc,pc,lr)
  32                 subs    r0, r0, #1
  33                 RETINSTR(movcc,pc,lr)
  34                 subs    r0, r0, #1
  35                 RETINSTR(movcc,pc,lr)
  36                 subs    r0, r0, #1
  37                 RETINSTR(movcc,pc,lr)
  38                 subs    r0, r0, #1
  39                 RETINSTR(movcc,pc,lr)
  40                 subs    r0, r0, #1
  41                 RETINSTR(movcc,pc,lr)
  42                 subs    r0, r0, #1
  43                 RETINSTR(movcc,pc,lr)
  44                 subs    r0, r0, #1
  45                 bcs     SYMBOL_NAME(__delay)
  46                 RETINSTR(mov,pc,lr)