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

Daniel Schwierzeck
2015-12-26T13:09:16Z

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@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@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