compiler_rt: add __absvsi2, __absvdi2, __absvti2
- abs can only overflow, if a == MIN
- comparing the sign change from wrapping addition is branchless
- tests: MIN, MIN+1,..MIN+4, -42, -7, -1, 0, 1, 7..
See #1290
2021-12-12 21:25:29 +00:00
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const testing = @import("std").testing;
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2022-06-16 23:14:12 +01:00
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const __absvsi2 = @import("absvsi2.zig").__absvsi2;
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compiler_rt: add __absvsi2, __absvdi2, __absvti2
- abs can only overflow, if a == MIN
- comparing the sign change from wrapping addition is branchless
- tests: MIN, MIN+1,..MIN+4, -42, -7, -1, 0, 1, 7..
See #1290
2021-12-12 21:25:29 +00:00
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fn test__absvsi2(a: i32, expected: i32) !void {
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2022-06-16 23:14:12 +01:00
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var result = __absvsi2(a);
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compiler_rt: add __absvsi2, __absvdi2, __absvti2
- abs can only overflow, if a == MIN
- comparing the sign change from wrapping addition is branchless
- tests: MIN, MIN+1,..MIN+4, -42, -7, -1, 0, 1, 7..
See #1290
2021-12-12 21:25:29 +00:00
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try testing.expectEqual(expected, result);
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}
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test "absvsi2" {
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// -2^31 <= i32 <= 2^31-1
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// 2^31 = 2147483648
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// 2^31-1 = 2147483647
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// TODO write panic handler for testing panics
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//try test__absvsi2(-2147483648, -5); // tested with return -5; and panic
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try test__absvsi2(-2147483647, 2147483647);
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try test__absvsi2(-2147483646, 2147483646);
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try test__absvsi2(-2147483645, 2147483645);
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try test__absvsi2(-2147483644, 2147483644);
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try test__absvsi2(-42, 42);
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try test__absvsi2(-7, 7);
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try test__absvsi2(-1, 1);
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try test__absvsi2(0, 0);
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try test__absvsi2(1, 1);
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try test__absvsi2(7, 7);
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try test__absvsi2(42, 42);
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try test__absvsi2(2147483644, 2147483644);
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try test__absvsi2(2147483645, 2147483645);
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try test__absvsi2(2147483646, 2147483646);
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try test__absvsi2(2147483647, 2147483647);
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}
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