26 lines
920 B
Zig
26 lines
920 B
Zig
const compiler_rt = @import("../compiler_rt.zig");
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const symbol = compiler_rt.symbol;
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const testing = @import("std").testing;
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comptime {
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symbol(&__addvsi3, "__addvsi3");
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}
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pub fn __addvsi3(a: i32, b: i32) callconv(.c) i32 {
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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 "addvsi3" {
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// const min: i32 = -2147483648
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// const max: i32 = 2147483647
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// TODO write panic handler for testing panics
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// try test__addvsi3(-2147483648, -1, -1); // panic
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// try test__addvsi3(2147483647, 1, 1); // panic
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try testing.expectEqual(-2147483648, __addvsi3(-2147483647, -1));
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try testing.expectEqual(2147483647, __addvsi3(2147483646, 1));
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}
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