69 lines
2.0 KiB
Nim
69 lines
2.0 KiB
Nim
# Stint
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# Copyright 2018-Present Status Research & Development GmbH
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# Licensed under either of
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#
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# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
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# * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
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#
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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import
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# Status lib
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stew/bitops2,
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# Internal
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./datatypes,
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./primitives/addcarry_subborrow
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# Addsub
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# --------------------------------------------------------
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{.push raises: [], inline, noInit, gcsafe.}
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func sum*(r: var Stuint, a, b: Stuint) =
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## Addition for multi-precision unsigned int
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var carry = Carry(0)
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for wr, wa, wb in leastToMostSig(r, a, b):
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addC(carry, wr, wa, wb, carry)
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r.clearExtraBits()
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func `+=`*(a: var Stuint, b: Stuint) =
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## In-place addition for multi-precision unsigned int
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var carry = Carry(0)
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for wa, wb in leastToMostSig(a, b):
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addC(carry, wa, wa, wb, carry)
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a.clearExtraBits()
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func diff*(r: var Stuint, a, b: Stuint) =
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## Substraction for multi-precision unsigned int
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var borrow = Borrow(0)
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for wr, wa, wb in leastToMostSig(r, a, b):
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subB(borrow, wr, wa, wb, borrow)
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r.clearExtraBits()
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func `-=`*(a: var Stuint, b: Stuint) =
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## In-place substraction for multi-precision unsigned int
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var borrow = Borrow(0)
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for wa, wb in leastToMostSig(a, b):
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subB(borrow, wa, wa, wb, borrow)
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a.clearExtraBits()
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func inc*(a: var Stuint, w: Word = 1) =
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var carry = Carry(0)
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when cpuEndian == littleEndian:
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addC(carry, a.limbs[0], a.limbs[0], w, carry)
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for i in 1 ..< a.limbs.len:
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addC(carry, a.limbs[i], a.limbs[i], 0, carry)
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else:
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{.error: "Not implemented.".}
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a.clearExtraBits()
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func sum*(r: var Stuint, a: Stuint, b: SomeUnsignedInt) =
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## Addition for multi-precision unsigned int
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## with an unsigned integer
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r = a
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r.inc(Word(b))
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func `+=`*(a: var Stuint, b: SomeUnsignedInt) =
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## In-place addition for multi-precision unsigned int
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## with an unsigned integer
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a.inc(Word(b))
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