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d38f9f8bee
Estimated hours taken: 1 Change the bit shift functions to perform checking to avoid implementation defined behaviour. library/int.m: Add checking to `int:<<' and `int:>>'. Add `int:unchecked_left_shift' and `int:unchecked_right_shift' which do not perform any checking. compiler/code_util.m: Replace `int:<<' and `int:>>' with `int:unchecked_left_shift' and `int:unchecked_right_shift' in the builtin table. NEWS: Mention the changes to int.m. tests/hard_coded/Mmakefile: tests/hard_coded/shift_test.m: tests/hard_coded/shift_test.exp: Test the shift functions.
59 lines
1.8 KiB
Mathematica
59 lines
1.8 KiB
Mathematica
% test the handling of `>>', `<<', unchecked_left_shift
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% and unchecked_right_shift.
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:- module shift_test.
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:- interface.
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:- import_module io.
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:- pred main(io__state::di, io__state::uo) is det.
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:- implementation.
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:- import_module int, list, string.
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main -->
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shift_test((<<), "<<", 64, 0, 64),
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shift_test((<<), "<<", 64, 2, 256),
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shift_test((<<), "<<", -64, 2, -256),
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shift_test((<<), "<<", 64, -2, 16),
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shift_test((<<), "<<", -64, -2, -16),
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shift_test((<<), "<<", 64, -256, 0),
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shift_test((<<), "<<", -64, -256, -1),
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shift_test((<<), "<<", 25, 3, 200),
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shift_test((<<), "<<", -25, 3, -200),
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shift_test((<<), "<<", 25, -3, 3),
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shift_test((<<), "<<", -25, -3, -4),
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shift_test((>>), ">>", 64, 0, 64),
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shift_test((>>), ">>", 64, 2, 16),
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shift_test((>>), ">>", -64, 2, -16),
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shift_test((>>), ">>", 64, -2, 256),
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shift_test((>>), ">>", -64, -2, -256),
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shift_test((>>), ">>", 64, 256, 0),
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shift_test((>>), ">>", -64, 256, -1),
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shift_test((>>), ">>", 25, 3, 3),
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shift_test((>>), ">>", -25, 3, -4),
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shift_test((>>), ">>", 25, -3, 200),
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shift_test((>>), ">>", -25, -3, -200),
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shift_test(unchecked_left_shift, "unchecked_left_shift",
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64, 2, 256),
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shift_test(unchecked_right_shift, "unchecked_right_shift",
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-64, 2, -16),
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io__write_string("The following cases test undefined behaviour\n"),
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io__write_string("(they cause overflow):\n"),
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shift_test((<<), "<<", 64, 256, 0),
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shift_test((<<), "<<", -64, 256, 0),
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shift_test((>>), ">>", 64, -256, 0),
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shift_test((>>), ">>", -64, -256, 0).
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:- pred shift_test((func(int, int) = int)::(func(in, in) = out is det),
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string::in, int::in, int::in, int::in,
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io__state::di, io__state::uo) is det.
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shift_test(Func, FuncName, Left, Right, Result) -->
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io__format("%d %s %d = %d (%d)\n",
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[i(Left), s(FuncName), i(Right),
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i(Func(Left, Right)), i(Result)]).
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