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

Wills Wang
2015-12-26T16:54:24Z

On 12/26/2015 09:09 PM, Daniel Schwierzeck wrote:
>
> 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.
I missed this file, please ignore this patch.
>> 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 */
>>