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| author | root <root@artemis.panaceas.org> | 2015-12-25 04:40:36 +0000 |
|---|---|---|
| committer | root <root@artemis.panaceas.org> | 2015-12-25 04:40:36 +0000 |
| commit | 849369d6c66d3054688672f97d31fceb8e8230fb (patch) | |
| tree | 6135abc790ca67dedbe07c39806591e70eda81ce /arch/arm/lib/delay.S | |
| download | linux-3.0.35-kobo-849369d6c66d3054688672f97d31fceb8e8230fb.tar.gz linux-3.0.35-kobo-849369d6c66d3054688672f97d31fceb8e8230fb.tar.bz2 linux-3.0.35-kobo-849369d6c66d3054688672f97d31fceb8e8230fb.zip | |
initial_commit
Diffstat (limited to 'arch/arm/lib/delay.S')
| -rw-r--r-- | arch/arm/lib/delay.S | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/arch/arm/lib/delay.S b/arch/arm/lib/delay.S new file mode 100644 index 00000000..3c9a05c8 --- /dev/null +++ b/arch/arm/lib/delay.S @@ -0,0 +1,69 @@ +/* + * 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) |