77 lines
2.0 KiB
Nim
77 lines
2.0 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 ../stint, unittest
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suite "Testing unsigned int addition implementation":
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test "In-place addition gives expected result":
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var a = 20182018.stuint(64)
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let b = 20172017.stuint(64)
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a += b
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check: cast[uint64](a) == 20182018'u64 + 20172017'u64
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test "Addition gives expected result":
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let a = 20182018.stuint(64)
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let b = 20172017.stuint(64)
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check: cast[uint64](a+b) == 20182018'u64 + 20172017'u64
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test "When the low half overflows, it is properly carried":
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# uint8 (low half) overflow at 255
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let a = 100'u16.stuint(16)
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let b = 100'u16.stuint(16)
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check: cast[uint16](a+b) == 200
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test "Full overflow is handled like native unsigned types":
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# uint16 overflows after 65535
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let a = 100'u16.stuint(16)
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var z = 0'u16.stuint(16)
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let o = 36'u16.stuint(16)
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for _ in 0 ..< 655:
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z += a
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check: cast[uint16](z) == 65500
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check: cast[uint16](z + o) == 0
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z += a
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check: cast[uint16](z) == 64
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z += a
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check: cast[uint16](z) == 164
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suite "Testing unsigned int substraction implementation":
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test "In-place substraction gives expected result":
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var a = 20182018.stuint(64)
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let b = 20172017.stuint(64)
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a -= b
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check: cast[uint64](a) == 20182018'u64 - 20172017'u64
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test "Substraction gives expected result":
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let a = 20182018.stuint(64)
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let b = 20172017.stuint(64)
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check: cast[uint64](a-b) == 20182018'u64 - 20172017'u64
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test "Full overflow is handled like native unsigned types":
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# uint16 overflows after 65535
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let a = 100'u16.stuint(16)
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let b = 101'u16.stuint(16)
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check: cast[uint16](a-b) == high(uint16)
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