[U-Boot-Users] [Patch 2/9] U-boot-V2:ARM: Introduce additional bitops
Sascha Hauer
s.hauer at pengutronix.de
Wed Jun 18 17:30:49 CEST 2008
On Wed, Jun 18, 2008 at 07:34:05AM -0500, Menon, Nishanth wrote:
> Add linux-like bitops definitions - this is based on 2.6.25 rc5 kernel
I haven't looked at it, but I guess you need these for the following
patches. It would be better to first introduce generic bitops. Otherwise
we end up with i2c only working on arm.
Sascha
>
> Signed-off-by: Nishanth Menon <x0nishan at ti.com>
>
> ---
> arch/arm/lib/Makefile | 1
> arch/arm/lib/findbit.S | 181 +++++++++++++++++++++++++++++++++++++++++++++++
> include/asm-arm/bitops.h | 86 +++++++++++++++++++++-
> 3 files changed, 265 insertions(+), 3 deletions(-)
>
> Index: u-boot-v2.git/arch/arm/lib/findbit.S
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ u-boot-v2.git/arch/arm/lib/findbit.S 2008-06-17 17:01:06.000000000 -0500
> @@ -0,0 +1,181 @@
> +/**
> + * @file
> + * @brief common bitops
> + */
> +/*
> + * Originally from Linux kernel
> + * arch/arm/lib/findbit.S
> + *
> + * Copyright (C) 1995-2000 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.
> + *
> + * 16th March 2001 - John Ripley <jripley at sonicblue.com>
> + * Fixed so that "size" is an exclusive not an inclusive quantity.
> + * All users of these functions expect exclusive sizes, and may
> + * also call with zero size.
> + * Reworked by rmk.
> + */
> + .text
> +
> +/*
> + * Purpose : Find a 'zero' bit
> + * Prototype: int find_first_zero_bit(void *addr, unsigned int maxbit);
> + */
> + .globl _find_first_zero_bit_le;
> +_find_first_zero_bit_le:
> + teq r1, #0
> + beq 3f
> + mov r2, #0
> +1: ldrb r3, [r0, r2, lsr #3]
> + eors r3, r3, #0xff @ invert bits
> + bne .L_found @ any now set - found zero bit
> + add r2, r2, #8 @ next bit pointer
> +2: cmp r2, r1 @ any more?
> + blo 1b
> +3: mov r0, r1 @ no free bits
> + mov pc, lr
> +
> +/*
> + * Purpose : Find next 'zero' bit
> + * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit,
> + * int offset)
> + */
> + .globl _find_next_zero_bit_le;
> +_find_next_zero_bit_le:
> + teq r1, #0
> + beq 3b
> + ands ip, r2, #7
> + beq 1b @ If new byte, goto old routine
> + ldrb r3, [r0, r2, lsr #3]
> + eor r3, r3, #0xff @ now looking for a 1 bit
> + movs r3, r3, lsr ip @ shift off unused bits
> + bne .L_found
> + orr r2, r2, #7 @ if zero, then no bits here
> + add r2, r2, #1 @ align bit pointer
> + b 2b @ loop for next bit
> +
> +/*
> + * Purpose : Find a 'one' bit
> + * Prototype: int find_first_bit(const unsigned long *addr, unsigned int maxbit)
> + */
> + .globl _find_first_bit_le;
> +_find_first_bit_le:
> + teq r1, #0
> + beq 3f
> + mov r2, #0
> +1: ldrb r3, [r0, r2, lsr #3]
> + movs r3, r3
> + bne .L_found @ any now set - found zero bit
> + add r2, r2, #8 @ next bit pointer
> +2: cmp r2, r1 @ any more?
> + blo 1b
> +3: mov r0, r1 @ no free bits
> + mov pc, lr
> +
> +/*
> + * Purpose : Find next 'one' bit
> + * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit,
> + * int offset)
> + */
> + .globl _find_next_bit_le;
> +_find_next_bit_le:
> + teq r1, #0
> + beq 3b
> + ands ip, r2, #7
> + beq 1b @ If new byte, goto old routine
> + ldrb r3, [r0, r2, lsr #3]
> + movs r3, r3, lsr ip @ shift off unused bits
> + bne .L_found
> + orr r2, r2, #7 @ if zero, then no bits here
> + add r2, r2, #1 @ align bit pointer
> + b 2b @ loop for next bit
> +
> +#ifdef __ARMEB__
> +
> + .globl _find_first_zero_bit_be;
> +_find_first_zero_bit_be:
> + teq r1, #0
> + beq 3f
> + mov r2, #0
> +1: eor r3, r2, #0x18 @ big endian byte ordering
> + ldrb r3, [r0, r3, lsr #3]
> + eors r3, r3, #0xff @ invert bits
> + bne .L_found @ any now set - found zero bit
> + add r2, r2, #8 @ next bit pointer
> +2: cmp r2, r1 @ any more?
> + blo 1b
> +3: mov r0, r1 @ no free bits
> + mov pc, lr
> +
> + .globl _find_next_zero_bit_be;
> +_find_next_zero_bit_be:
> + teq r1, #0
> + beq 3b
> + ands ip, r2, #7
> + beq 1b @ If new byte, goto old routine
> + eor r3, r2, #0x18 @ big endian byte ordering
> + ldrb r3, [r0, r3, lsr #3]
> + eor r3, r3, #0xff @ now looking for a 1 bit
> + movs r3, r3, lsr ip @ shift off unused bits
> + bne .L_found
> + orr r2, r2, #7 @ if zero, then no bits here
> + add r2, r2, #1 @ align bit pointer
> + b 2b @ loop for next bit
> +
> + .globl _find_first_bit_be;
> +_find_first_bit_be:
> + teq r1, #0
> + beq 3f
> + mov r2, #0
> +1: eor r3, r2, #0x18 @ big endian byte ordering
> + ldrb r3, [r0, r3, lsr #3]
> + movs r3, r3
> + bne .L_found @ any now set - found zero bit
> + add r2, r2, #8 @ next bit pointer
> +2: cmp r2, r1 @ any more?
> + blo 1b
> +3: mov r0, r1 @ no free bits
> + mov pc, lr
> +
> + .globl _find_next_bit_be;
> +_find_next_bit_be:
> + teq r1, #0
> + beq 3b
> + ands ip, r2, #7
> + beq 1b @ If new byte, goto old routine
> + eor r3, r2, #0x18 @ big endian byte ordering
> + ldrb r3, [r0, r3, lsr #3]
> + movs r3, r3, lsr ip @ shift off unused bits
> + bne .L_found
> + orr r2, r2, #7 @ if zero, then no bits here
> + add r2, r2, #1 @ align bit pointer
> + b 2b @ loop for next bit
> +
> +#endif
> +
> +/*
> + * One or more bits in the LSB of r3 are assumed to be set.
> + */
> +.L_found:
> +#if __LINUX_ARM_ARCH__ >= 5
> + rsb r1, r3, #0
> + and r3, r3, r1
> + clz r3, r3
> + rsb r3, r3, #31
> + add r0, r2, r3
> +#else
> + tst r3, #0x0f
> + addeq r2, r2, #4
> + movne r3, r3, lsl #4
> + tst r3, #0x30
> + addeq r2, r2, #2
> + movne r3, r3, lsl #2
> + tst r3, #0x40
> + addeq r2, r2, #1
> + mov r0, r2
> +#endif
> + mov pc, lr
> +
> Index: u-boot-v2.git/arch/arm/lib/Makefile
> ===================================================================
> --- u-boot-v2.git.orig/arch/arm/lib/Makefile 2008-06-17 16:52:31.000000000 -0500
> +++ u-boot-v2.git/arch/arm/lib/Makefile 2008-06-17 17:01:06.000000000 -0500
> @@ -8,6 +8,7 @@
> obj-y += _udivsi3.o
> obj-y += _umodsi3.o
> obj-y += _lshrdi3.o
> +obj-y += findbit.o
> obj-y += arm.o
> obj-$(CONFIG_MODULES) += module.o
> extra-$(CONFIG_GENERIC_LINKER_SCRIPT) += u-boot.lds
> Index: u-boot-v2.git/include/asm-arm/bitops.h
> ===================================================================
> --- u-boot-v2.git.orig/include/asm-arm/bitops.h 2008-06-17 16:52:31.000000000 -0500
> +++ u-boot-v2.git/include/asm-arm/bitops.h 2008-06-17 17:01:06.000000000 -0500
> @@ -75,9 +75,6 @@
> return oldval & mask;
> }
>
> -extern int find_first_zero_bit(void * addr, unsigned size);
> -extern int find_next_zero_bit(void * addr, int size, int offset);
> -
> /*
> * This routine doesn't need to be atomic.
> */
> @@ -86,6 +83,44 @@
> return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7));
> }
>
> +
> +
> +
> +#ifndef __ARMEB__
> +/*
> + * These are the little endian definitions.
> + */
> +extern int _find_first_zero_bit_le(const void *p, unsigned size);
> +extern int _find_next_zero_bit_le(const void *p, int size, int offset);
> +extern int _find_first_bit_le(const unsigned long *p, unsigned size);
> +extern int _find_next_bit_le(const unsigned long *p, int size, int offset);
> +#define find_first_zero_bit(p, sz) _find_first_zero_bit_le(p, sz)
> +#define find_next_zero_bit(p, sz, off) _find_next_zero_bit_le(p, sz, off)
> +#define find_first_bit(p, sz) _find_first_bit_le(p, sz)
> +#define find_next_bit(p, sz, off) _find_next_bit_le(p, sz, off)
> +
> +#define WORD_BITOFF_TO_LE(x) ((x))
> +
> +#else
> +
> +/*
> + * These are the big endian definitions.
> + */
> +extern int _find_first_zero_bit_be(const void *p, unsigned size);
> +extern int _find_next_zero_bit_be(const void *p, int size, int offset);
> +extern int _find_first_bit_be(const unsigned long *p, unsigned size);
> +extern int _find_next_bit_be(const unsigned long *p, int size, int offset);
> +#define find_first_zero_bit(p, sz) _find_first_zero_bit_be(p, sz)
> +#define find_next_zero_bit(p, sz, off) _find_next_zero_bit_be(p, sz, off)
> +#define find_first_bit(p, sz) _find_first_bit_be(p, sz)
> +#define find_next_bit(p, sz, off) _find_next_bit_be(p, sz, off)
> +
> +#define WORD_BITOFF_TO_LE(x) ((x) ^ 0x18)
> +
> +#endif
> +
> +#if (defined(__LINUX_ARM_ARCH__) && (__LINUX_ARM_ARCH__ < 5))
> +
> /*
> * ffz = Find First Zero in word. Undefined if no zero exists,
> * so code should check against ~0UL first..
> @@ -112,6 +147,51 @@
>
> #define ffs(x) generic_ffs(x)
>
> +#else
> +
> +static inline int constant_fls(int x)
> +{
> + int r = 32;
> +
> + if (!x)
> + return 0;
> + if (!(x & 0xffff0000u)) {
> + x <<= 16;
> + r -= 16;
> + }
> + if (!(x & 0xff000000u)) {
> + x <<= 8;
> + r -= 8;
> + }
> + if (!(x & 0xf0000000u)) {
> + x <<= 4;
> + r -= 4;
> + }
> + if (!(x & 0xc0000000u)) {
> + x <<= 2;
> + r -= 2;
> + }
> + if (!(x & 0x80000000u)) {
> + x <<= 1;
> + r -= 1;
> + }
> + return r;
> +}
> +
> +/*
> + * On ARMv5 and above those functions can be implemented around
> + * the clz instruction for much better code efficiency.
> + */
> +
> +#define fls(x) \
> + (__builtin_constant_p(x) ? constant_fls(x) : \
> + ({ int __r; asm("clz\t%0, %1" : "=r"(__r) : "r"(x) : "cc"); 32-__r; }))
> +#define ffs(x) ({ unsigned long __t = (x); fls(__t &-__t); })
> +#define __ffs(x) (ffs(x) - 1)
> +#define ffz(x) __ffs(~(x))
> +
> +#endif
> +
> /*
> * hweightN: returns the hamming weight (i.e. the number
> * of bits set) of a N-bit word
>
--
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