71 lines
2.8 KiB
C
71 lines
2.8 KiB
C
/*
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* Copyright (C) 2015 Southern Storm Software, Pty Ltd.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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#ifndef CRYPTO_LIMBUTIL_H
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#define CRYPTO_LIMBUTIL_H
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#include "ProgMemUtil.h"
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// Number of limbs in a big number value of various sizes.
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#define NUM_LIMBS_BITS(n) \
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(((n) + sizeof(limb_t) * 8 - 1) / (8 * sizeof(limb_t)))
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#define NUM_LIMBS_128BIT NUM_LIMBS_BITS(128)
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#define NUM_LIMBS_256BIT NUM_LIMBS_BITS(256)
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#define NUM_LIMBS_512BIT NUM_LIMBS_BITS(512)
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// The number of bits in a limb.
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#define LIMB_BITS (8 * sizeof(limb_t))
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// Read a limb-sized quantity from program memory.
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#if BIGNUMBER_LIMB_8BIT
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#define pgm_read_limb(x) (pgm_read_byte((x)))
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#elif BIGNUMBER_LIMB_16BIT
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#define pgm_read_limb(x) (pgm_read_word((x)))
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#elif BIGNUMBER_LIMB_32BIT
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#define pgm_read_limb(x) (pgm_read_dword((x)))
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#elif BIGNUMBER_LIMB_64BIT
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#define pgm_read_limb(x) (pgm_read_qword((x)))
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#endif
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// Expand a 32-bit value into a set of limbs depending upon the limb size.
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// This is used when initializing constant big number values in the code.
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// For 64-bit system compatibility it is necessary to use LIMB_PAIR(x, y).
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#if BIGNUMBER_LIMB_8BIT
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#define LIMB(value) ((uint8_t)(value)), \
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((uint8_t)((value) >> 8)), \
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((uint8_t)((value) >> 16)), \
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((uint8_t)((value) >> 24))
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#define LIMB_PAIR(x,y) LIMB((x)), LIMB((y))
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#elif BIGNUMBER_LIMB_16BIT
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#define LIMB(value) ((uint16_t)(value)), \
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((uint16_t)(((uint32_t)(value)) >> 16))
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#define LIMB_PAIR(x,y) LIMB((x)), LIMB((y))
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#elif BIGNUMBER_LIMB_32BIT
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#define LIMB(value) (value)
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#define LIMB_PAIR(x,y) LIMB((x)), LIMB((y))
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#elif BIGNUMBER_LIMB_64BIT
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#define LIMB(value) (value)
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#define LIMB_PAIR(x,y) ((((uint64_t)(y)) << 32) | ((uint64_t)(x)))
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#endif
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#endif
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