190 lines
6.3 KiB
C
190 lines
6.3 KiB
C
/****************************************************************************
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* libs/libc/stdio/lib_dtoa_engine.h
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*
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* Copyright © 2018, Keith Packard
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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#ifndef __LIBS_LIBC_STDIO_LIB_DTOA_ENGINE_H
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#define __LIBS_LIBC_STDIO_LIB_DTOA_ENGINE_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <stdint.h>
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#include <float.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define DTOA_MAX_DIG DBL_DIG
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#define DTOA_MINUS 1
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#define DTOA_ZERO 2
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#define DTOA_INF 4
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#define DTOA_NAN 8
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#define DTOA_CARRY 16 /* Carry was to master position. */
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#if DBL_MAX_10_EXP >= 1 && DBL_MAX_10_EXP < 2
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# define DTOA_SCALE_UP_NUM 1
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#endif
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#if DBL_MAX_10_EXP >= 2 && DBL_MAX_10_EXP < 4
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# define DTOA_SCALE_UP_NUM 2
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#endif
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#if DBL_MAX_10_EXP >= 4 && DBL_MAX_10_EXP < 8
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# define DTOA_SCALE_UP_NUM 3
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#endif
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#if DBL_MAX_10_EXP >= 8 && DBL_MAX_10_EXP < 16
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# define DTOA_SCALE_UP_NUM 4
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#endif
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#if DBL_MAX_10_EXP >= 16 && DBL_MAX_10_EXP < 32
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# define DTOA_SCALE_UP_NUM 5
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#endif
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#if DBL_MAX_10_EXP >= 32 && DBL_MAX_10_EXP < 64
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# define DTOA_SCALE_UP_NUM 6
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#endif
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#if DBL_MAX_10_EXP >= 64 && DBL_MAX_10_EXP < 128
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# define DTOA_SCALE_UP_NUM 7
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#endif
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#if DBL_MAX_10_EXP >= 128 && DBL_MAX_10_EXP < 256
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# define DTOA_SCALE_UP_NUM 8
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#endif
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#if DBL_MAX_10_EXP >= 256 && DBL_MAX_10_EXP < 512
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# define DTOA_SCALE_UP_NUM 9
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#endif
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#if DBL_MAX_10_EXP >= 512 && DBL_MAX_10_EXP < 1024
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# define DTOA_SCALE_UP_NUM 10
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#endif
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#if DBL_MAX_10_EXP >= 1024 && DBL_MAX_10_EXP < 2048
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# define DTOA_SCALE_UP_NUM 11
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#endif
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#if DBL_MAX_10_EXP >= 2048 && DBL_MAX_10_EXP < 4096
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# define DTOA_SCALE_UP_NUM 12
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#endif
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#if DBL_MAX_10_EXP >= 4096 && DBL_MAX_10_EXP < 8192
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# define DTOA_SCALE_UP_NUM 13
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#endif
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#if DBL_MAX_10_EXP >= 8192 && DBL_MAX_10_EXP < 16384
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# define DTOA_SCALE_UP_NUM 14
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#endif
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#if DBL_MAX_10_EXP >= 16384 && DBL_MAX_10_EXP < 32768
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# define DTOA_SCALE_UP_NUM 15
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#endif
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#if DBL_MAX_10_EXP >= 32768 && DBL_MAX_10_EXP < 65536
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# define DTOA_SCALE_UP_NUM 16
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#endif
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#if DBL_MAX_10_EXP >= 65536 && DBL_MAX_10_EXP < 131072
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# define DTOA_SCALE_UP_NUM 17
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#endif
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#if DBL_MIN_10_EXP <= -1 && DBL_MIN_10_EXP > -2
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# define DTOA_SCALE_DOWN_NUM 1
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#endif
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#if DBL_MIN_10_EXP <= -2 && DBL_MIN_10_EXP > -4
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# define DTOA_SCALE_DOWN_NUM 2
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#endif
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#if DBL_MIN_10_EXP <= -4 && DBL_MIN_10_EXP > -8
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# define DTOA_SCALE_DOWN_NUM 3
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#endif
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#if DBL_MIN_10_EXP <= -8 && DBL_MIN_10_EXP > -16
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# define DTOA_SCALE_DOWN_NUM 4
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#endif
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#if DBL_MIN_10_EXP <= -16 && DBL_MIN_10_EXP > -32
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# define DTOA_SCALE_DOWN_NUM 5
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#endif
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#if DBL_MIN_10_EXP <= -32 && DBL_MIN_10_EXP > -64
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# define DTOA_SCALE_DOWN_NUM 6
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#endif
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#if DBL_MIN_10_EXP <= -64 && DBL_MIN_10_EXP > -128
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# define DTOA_SCALE_DOWN_NUM 7
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#endif
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#if DBL_MIN_10_EXP <= -128 && DBL_MIN_10_EXP > -256
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# define DTOA_SCALE_DOWN_NUM 8
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#endif
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#if DBL_MIN_10_EXP <= -256 && DBL_MIN_10_EXP > -512
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# define DTOA_SCALE_DOWN_NUM 9
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#endif
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#if DBL_MIN_10_EXP <= -512 && DBL_MIN_10_EXP > -1024
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# define DTOA_SCALE_DOWN_NUM 10
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#endif
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#if DBL_MIN_10_EXP <= -1024 && DBL_MIN_10_EXP > -2048
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# define DTOA_SCALE_DOWN_NUM 11
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#endif
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#if DBL_MIN_10_EXP <= -2048 && DBL_MIN_10_EXP > -4096
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# define DTOA_SCALE_DOWN_NUM 12
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#endif
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#if DBL_MIN_10_EXP <= -4096 && DBL_MIN_10_EXP > -8192
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# define DTOA_SCALE_DOWN_NUM 13
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#endif
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#if DBL_MIN_10_EXP <= -8192 && DBL_MIN_10_EXP > -16384
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# define DTOA_SCALE_DOWN_NUM 14
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#endif
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#if DBL_MIN_10_EXP <= -16384 && DBL_MIN_10_EXP > -32768
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# define DTOA_SCALE_DOWN_NUM 15
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#endif
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#if DBL_MIN_10_EXP <= -32768 && DBL_MIN_10_EXP > -65536
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# define DTOA_SCALE_DOWN_NUM 16
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#endif
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#if DBL_MIN_10_EXP <= -65536 && DBL_MIN_10_EXP > -131072
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# define DTOA_SCALE_DOWN_NUM 17
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#endif
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#define DTOA_ROUND_NUM (DBL_DIG + 1)
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/****************************************************************************
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* Public Types
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****************************************************************************/
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struct dtoa_s
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{
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int32_t exp;
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uint8_t flags;
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char digits[DTOA_MAX_DIG + 1];
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};
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/****************************************************************************
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* Public Data
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****************************************************************************/
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extern const double g_dtoa_scale_up[];
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extern const double g_dtoa_scale_down[];
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extern const double g_dtoa_round[];
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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int __dtoa_engine(double x, FAR struct dtoa_s *dtoa, int max_digits,
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int max_decimals);
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#endif /* __LIBS_LIBC_STDIO_LIB_DTOA_ENGINE_H */
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