[U-Boot] [PATCH v4 1/8] include: Add support for "do_div" macro

[Daniel Schwierzeck]

Am 25.12.2015 um 19:56 schrieb Wills Wang:
> Use the div64 header files from the kernel.
> 
> Signed-off-by: Wills Wang <wills.wang at live.com>
> ---
> 
> Changes in v4: None
> Changes in v3: None
> Changes in v2: None
> 
>  arch/mips/include/asm/div64.h | 68 +++++++++++++++++++++++++++++++++++++++++++
>  include/asm-generic/div64.h   | 59 +++++++++++++++++++++++++++++++++++++
>  2 files changed, 127 insertions(+)
>  create mode 100644 arch/mips/include/asm/div64.h
>  create mode 100644 include/asm-generic/div64.h

please drop this patch, we already have a generic do_div()
implementation. Also we do not really need an assembly optimized
implementation for MIPS.

> 
> diff --git a/arch/mips/include/asm/div64.h b/arch/mips/include/asm/div64.h
> new file mode 100644
> index 0000000..e5e6782
> --- /dev/null
> +++ b/arch/mips/include/asm/div64.h
> @@ -0,0 +1,68 @@
> +/*
> + * Copyright (C) 2000, 2004  Maciej W. Rozycki
> + * Copyright (C) 2003, 07 Ralf Baechle (ralf at linux-mips.org)
> + *
> + * This file is subject to the terms and conditions of the GNU General Public
> + * License.  See the file "COPYING" in the main directory of this archive
> + * for more details.
> + */
> +#ifndef __ASM_DIV64_H
> +#define __ASM_DIV64_H
> +
> +#include <asm-generic/div64.h>
> +
> +#if BITS_PER_LONG == 64
> +
> +#include <linux/types.h>
> +
> +/*
> + * No traps on overflows for any of these...
> + */
> +
> +#define __div64_32(n, base)						\
> +({									\
> +	unsigned long __cf, __tmp, __tmp2, __i;				\
> +	unsigned long __quot32, __mod32;				\
> +	unsigned long __high, __low;					\
> +	unsigned long long __n;						\
> +									\
> +	__high = *__n >> 32;						\
> +	__low = __n;							\
> +	__asm__(							\
> +	"	.set	push\n"						\
> +	"	.set	noat\n"						\
> +	"	.set	noreorder\n"					\
> +	"	move	%2, $0\n"					\
> +	"	move	%3, $0\n"					\
> +	"	b	1f\n"						\
> +	"	 li	%4, 0x21\n"					\
> +	"0:\n"								\
> +	"	sll	$1, %0, 0x1\n"					\
> +	"	srl	%3, %0, 0x1f\n"					\
> +	"	or	%0, $1, %5\n"					\
> +	"	sll	%1, %1, 0x1\n"					\
> +	"	sll	%2, %2, 0x1\n"					\
> +	"1:\n"								\
> +	"	bnez	%3, 2f\n"					\
> +	"	 sltu	%5, %0, %z6\n"					\
> +	"	bnez	%5, 3f\n"					\
> +	"2:\n"								\
> +	"	 addiu	%4, %4, -1\n"					\
> +	"	subu	%0, %0, %z6\n"					\
> +	"	addiu	%2, %2, 1\n"					\
> +	"3:\n"								\
> +	"	bnez	%4, 0b\n\t"					\
> +	"	 srl	%5, %1, 0x1f\n\t"				\
> +	"	.set	pop"						\
> +	: "=&r" (__mod32), "=&r" (__tmp),				\
> +	  "=&r" (__quot32), "=&r" (__cf),				\
> +	  "=&r" (__i), "=&r" (__tmp2)					\
> +	: "Jr" (base), "0" (__high), "1" (__low));			\
> +									\
> +	(__n) = __quot32;						\
> +	__mod32;							\
> +})
> +
> +#endif /* BITS_PER_LONG == 64 */
> +
> +#endif /* __ASM_DIV64_H */
> diff --git a/include/asm-generic/div64.h b/include/asm-generic/div64.h
> new file mode 100644
> index 0000000..d689fc4
> --- /dev/null
> +++ b/include/asm-generic/div64.h
> @@ -0,0 +1,59 @@
> +/*
> + * Copyright (C) 2003 Bernardo Innocenti <bernie at develer.com>
> + * Based on former asm-ppc/div64.h and asm-m68knommu/div64.h
> + *
> + * The semantics of do_div() are:
> + *
> + * uint32_t do_div(uint64_t *n, uint32_t base)
> + * {
> + *  uint32_t remainder = *n % base;
> + *  *n = *n / base;
> + *  return remainder;
> + * }
> + *
> + * NOTE: macro parameter n is evaluated multiple times,
> + *       beware of side effects!
> + */
> +
> +#ifndef _ASM_GENERIC_DIV64_H
> +#define _ASM_GENERIC_DIV64_H
> +
> +#include <linux/types.h>
> +#include <linux/compiler.h>
> +
> +#if BITS_PER_LONG == 64
> +
> +# define do_div(n, base) ({					\
> +	uint32_t __base = (base);				\
> +	uint32_t __rem;						\
> +	__rem = ((uint64_t)(n)) % __base;			\
> +	(n) = ((uint64_t)(n)) / __base;				\
> +	__rem;							\
> +})
> +
> +#elif BITS_PER_LONG == 32
> +
> +extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor);
> +
> +/* The unnecessary pointer compare is there
> + * to check for type safety (n must be 64bit)
> + */
> +# define do_div(n, base) ({				\
> +	uint32_t __base = (base);			\
> +	uint32_t __rem;					\
> +	(void)(((typeof((n)) *)0) == ((uint64_t *)0));	\
> +	if (likely(((n) >> 32) == 0)) {			\
> +		__rem = (uint32_t)(n) % __base;		\
> +		(n) = (uint32_t)(n) / __base;		\
> +	} else						\
> +		__rem = __div64_32(&(n), __base);	\
> +	__rem;						\
> +})
> +
> +#else /* BITS_PER_LONG == ?? */
> +
> +# error do_div() does not yet support the C64
> +
> +#endif /* BITS_PER_LONG */
> +
> +#endif /* _ASM_GENERIC_DIV64_H */
> 

-- 
- Daniel