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https://github.com/ziglang/zig.git
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6b14c58f63
This improves readability as well as compatibility with stage2. Most of compiler-rt is now enabled for stage2 with just a few functions disabled (until stage2 passes more behavior tests).
41 lines
939 B
Zig
41 lines
939 B
Zig
// absv - absolute oVerflow
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// * @panic, if value can not be represented
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// - absvXi4_generic for unoptimized version
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inline fn absvXi(comptime ST: type, a: ST) ST {
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const UT = switch (ST) {
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i32 => u32,
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i64 => u64,
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i128 => u128,
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else => unreachable,
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};
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// taken from Bit Twiddling Hacks
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// compute the integer absolute value (abs) without branching
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var x: ST = a;
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const N: UT = @bitSizeOf(ST);
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const sign: ST = a >> N - 1;
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x +%= sign;
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x ^= sign;
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if (x < 0)
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@panic("compiler_rt absv: overflow");
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return x;
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}
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pub fn __absvsi2(a: i32) callconv(.C) i32 {
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return absvXi(i32, a);
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}
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pub fn __absvdi2(a: i64) callconv(.C) i64 {
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return absvXi(i64, a);
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}
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pub fn __absvti2(a: i128) callconv(.C) i128 {
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return absvXi(i128, a);
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}
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test {
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_ = @import("absvsi2_test.zig");
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_ = @import("absvdi2_test.zig");
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_ = @import("absvti2_test.zig");
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}
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