43 lines
1.4 KiB
Nim
43 lines
1.4 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 ./bithacks, ./conversion, ./initialization,
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./datatypes,
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./uint_comparison,
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./uint_bitwise_ops
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# ############ Addition & Substraction ############ #
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func `+`*(x, y: UintImpl): UintImpl {.inline.}
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# Forward declaration
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func `+=`*(x: var UintImpl, y: UintImpl) {.inline.}=
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## In-place addition for multi-precision unsigned int
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type SubTy = type x.lo
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x.lo += y.lo
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x.hi += (x.lo < y.lo).toSubtype(SubTy) + y.hi # This helps the compiler produce ADC (add with carry)
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func `+`*(x, y: UintImpl): UintImpl {.inline.}=
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# Addition for multi-precision unsigned int
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result = x
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result += y
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func `-`*(x, y: UintImpl): UintImpl {.inline.}=
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# Substraction for multi-precision unsigned int
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type SubTy = type x.lo
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result.lo = x.lo - y.lo
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result.hi = x.hi - y.hi - (x.lo < y.lo).toSubtype(SubTy) # This might (?) help the compiler produce SBB (sub with borrow)
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func `-=`*(x: var UintImpl, y: UintImpl) {.inline.}=
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## In-place substraction for multi-precision unsigned int
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x = x - y
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func inc*(x: var UintImpl){.inline.}=
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x += one(type x)
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