73 lines
2.2 KiB
Nim
73 lines
2.2 KiB
Nim
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# Mpint
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# Copyright 2018 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 ./uint_type,
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macros
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template convBool(typ: typedesc): untyped =
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# needed for carry conversion
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converter boolMpUint*(b: bool): MpUintImpl[typ] {.noSideEffect, inline.}=
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result.lo = b.typ
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convBool(uint8)
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convBool(uint16)
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convBool(uint32)
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convBool(uint64)
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proc zero*(typ: typedesc[BaseUint]): typ {.compileTime.} =
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typ()
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proc one*[T: BaseUint](typ: typedesc[T]): T {.noSideEffect, inline.}=
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when T is SomeUnsignedInt:
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T(1)
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else:
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result.lo = 1
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proc toUint*(n: MpUIntImpl): auto {.noSideEffect, inline.}=
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## Casts a multiprecision integer to an uint of the same size
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# TODO: uint128 support
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when n.sizeof > 8:
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raise newException("Unreachable. You are trying to cast a MpUint with more than 64-bit of precision")
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elif n.sizeof == 8:
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cast[uint64](n)
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elif n.sizeof == 4:
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cast[uint32](n)
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elif n.sizeof == 2:
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cast[uint16](n)
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else:
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raise newException("Unreachable. MpUInt must be 16-bit minimum and a power of 2")
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proc toUint*(n: SomeUnsignedInt): SomeUnsignedInt {.noSideEffect, inline.}=
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## No-op overload of multi-precision int casting
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n
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proc asDoubleUint*(n: BaseUint): auto {.noSideEffect, inline.} =
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## Convert an integer or MpUint to an uint with double the size
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type Double = (
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when n.sizeof == 4: uint64
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elif n.sizeof == 2: uint32
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else: uint16
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)
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n.toUint.Double
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proc toMpUintImpl*(n: uint16|uint32|uint64): auto {.noSideEffect, inline.} =
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## Cast an integer to the corresponding size MpUintImpl
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# Sometimes direct casting doesn't work and we must cast through a pointer
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when n is uint64:
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return (cast[ptr [MpUintImpl[uint32]]](unsafeAddr n))[]
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elif n is uint32:
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return (cast[ptr [MpUintImpl[uint16]]](unsafeAddr n))[]
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elif n is uint16:
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return (cast[ptr [MpUintImpl[uint8]]](unsafeAddr n))[]
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