63 lines
1.9 KiB
Nim
63 lines
1.9 KiB
Nim
# Stint
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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 ./datatypes, ./bitops2_priv
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func `not`*(x: UintImpl): UintImpl {.inline.}=
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## Bitwise complement of unsigned integer x
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applyHiLo(x, `not`)
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func `or`*(x, y: UintImpl): UintImpl {.inline.}=
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## `Bitwise or` of numbers x and y
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applyHiLo(x, y, `or`)
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func `and`*(x, y: UintImpl): UintImpl {.inline.}=
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## `Bitwise and` of numbers x and y
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applyHiLo(x, y, `and`)
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func `xor`*(x, y: UintImpl): UintImpl {.inline.}=
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## `Bitwise xor` of numbers x and y
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applyHiLo(x, y, `xor`)
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func `shr`*(x: UintImpl, y: SomeInteger): UintImpl {.inline.}
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# Forward declaration
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func `shl`*(x: UintImpl, y: SomeInteger): UintImpl {.inline.}=
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## Compute the `shift left` operation of x and y
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# Note: inlining this poses codegen/aliasing issue when doing `x = x shl 1`
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# TODO: would it be better to reimplement this with words iteration?
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const halfSize: type(y) = bitsof(x) div 2
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if y == 0:
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return x
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elif y == halfSize:
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result.hi = x.lo
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elif y < halfSize:
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result.hi = (x.hi shl y) or (x.lo shr (halfSize - y))
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result.lo = x.lo shl y
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else:
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result.hi = x.lo shl (y - halfSize)
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func `shr`*(x: UintImpl, y: SomeInteger): UintImpl {.inline.}=
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## Compute the `shift right` operation of x and y
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## Similar to C standard, result is undefined if y is bigger
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## than the number of bits in x.
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const halfSize: type(y) = bitsof(x) div 2
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if y == 0:
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return x
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elif y == halfSize:
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result.lo = x.hi
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elif y < halfSize:
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result.lo = (x.lo shr y) or (x.hi shl (halfSize - y))
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result.hi = x.hi shr y
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else:
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result.lo = x.hi shr (y - halfSize)
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