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33 lines
1.0 KiB
Zig
33 lines
1.0 KiB
Zig
// SPDX-License-Identifier: MIT
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// Copyright (c) 2015-2021 Zig Contributors
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// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
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// The MIT license requires this copyright notice to be included in all copies
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// and substantial portions of the software.
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const __popcountdi2 = @import("popcountdi2.zig").__popcountdi2;
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const testing = @import("std").testing;
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fn naive_popcount(a_param: i64) i32 {
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var a = a_param;
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var r: i32 = 0;
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while (a != 0) : (a = @bitCast(i64, @bitCast(u64, a) >> 1)) {
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r += @intCast(i32, a & 1);
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}
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return r;
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}
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fn test__popcountdi2(a: i64) void {
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const x = __popcountdi2(a);
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const expected = naive_popcount(a);
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testing.expect(expected == x);
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}
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test "popcountdi2" {
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test__popcountdi2(0);
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test__popcountdi2(1);
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test__popcountdi2(2);
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test__popcountdi2(@bitCast(i64, @as(u64, 0xFFFFFFFFFFFFFFFD)));
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test__popcountdi2(@bitCast(i64, @as(u64, 0xFFFFFFFFFFFFFFFE)));
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test__popcountdi2(@bitCast(i64, @as(u64, 0xFFFFFFFFFFFFFFFF)));
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// TODO some fuzz testing
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}
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