25 lines
959 B
Zig
25 lines
959 B
Zig
const symbol = @import("../compiler_rt.zig").symbol;
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const testing = @import("std").testing;
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comptime {
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symbol(&__addvdi3, "__addvdi3");
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}
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pub fn __addvdi3(a: i64, b: i64) callconv(.c) i64 {
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const sum = a +% b;
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// Overflow occurred iff both operands have the same sign, and the sign of the sum does
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// not match it. In other words, iff the sum sign is not the sign of either operand.
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if (((sum ^ a) & (sum ^ b)) < 0) @panic("compiler-rt: integer overflow");
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return sum;
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}
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test "addvdi3" {
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// const min: i64 = -9223372036854775808
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// const max: i64 = 9223372036854775807
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// TODO write panic handler for testing panics
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// try test__addvdi3(-9223372036854775808, -1, -1); // panic
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// try test__addvdi3(9223372036854775807, 1, 1); // panic
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try testing.expectEqual(-9223372036854775808, __addvdi3(-9223372036854775807, -1));
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try testing.expectEqual(9223372036854775807, __addvdi3(9223372036854775806, 1));
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}
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