46 lines
1.2 KiB
Nim
46 lines
1.2 KiB
Nim
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# Copyright (c) 2018 Status Research & Development GmbH
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# Distributed under the MIT License (license terms are at http://opensource.org/licenses/MIT).
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import ../src/mpint, unittest
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suite "Testing addition implementation":
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test "In-place addition gives expected result":
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var a = initMpUint(20182018, uint32)
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let b = initMpUint(20172017, uint32)
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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 = initMpUint(20182018, uint32)
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let b = initMpUint(20172017, uint32)
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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 = initMpUint(100, uint8)
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let b = initMpUint(100, uint8)
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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 = initMpUint(100, uint8)
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var z = initMpUint(0, uint8)
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let o = initMpUint(36, uint8)
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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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