mirror of
https://github.com/status-im/nim-stint.git
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c8190df152
* cosmetic changes * fix zero conversion * Div using divided and conquer algorithm. (Compiles but doesn't work) * Passes test with production flag
59 lines
1.7 KiB
Nim
59 lines
1.7 KiB
Nim
# 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 ../src/mpint, unittest
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suite "Testing multiplication implementation":
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test "Multiplication with result fitting in low half":
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let a = 10000.initMpUint(64)
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let b = 10000.initMpUint(64)
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check: cast[uint64](a*b) == 100_000_000'u64 # need 27-bits
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test "Multiplication with result overflowing low half":
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let a = 1_000_000.initMpUint(64)
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let b = 1_000_000.initMpUint(64)
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check: cast[uint64](a*b) == 1_000_000_000_000'u64 # need 40 bits
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test "Full overflow is handled like native unsigned types":
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let a = 1_000_000_000.initMpUint(64)
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let b = 1_000_000_000.initMpUint(64)
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let c = 1_000.initMpUint(64)
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check: cast[uint64](a*b*c) == 1_000_000_000_000_000_000_000'u64 # need 70-bits
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suite "Testing division and modulo implementation":
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test "Divmod(100, 13) returns the correct result":
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let a = 100.initMpUint(64)
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let b = 13.initMpUint(64)
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let qr = divmod(a, b)
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check: cast[uint64](qr.quot) == 7'u64
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check: cast[uint64](qr.rem) == 9'u64
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test "Divmod(2^64, 3) returns the correct result":
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let a = 1.initMpUint(128) shl 64
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let b = 3.initMpUint(128)
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let qr = divmod(a, b)
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let q = cast[MpUintImpl[uint64]](qr.quot)
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let r = cast[MpUintImpl[uint64]](qr.rem)
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check: q.lo == 6148914691236517205'u64
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check: q.hi == 0'u64
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check: r.lo == 1'u64
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check: r.hi == 0'u64
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