Merge remote-tracking branch 'origin/master' into zig-ast-to-zir

1 files changed, 37 insertions, 0 deletions

diff --git a/lib/std/math/trunc.zig b/lib/std/math/trunc.zig
index b70f0c6be3..cdd2fa3c6b 100644
--- a/lib/std/math/trunc.zig
+++ b/lib/std/math/trunc.zig
@@ -20,6 +20,7 @@ pub fn trunc(x: var) @TypeOf(x) {
     return switch (T) {
         f32 => trunc32(x),
         f64 => trunc64(x),
+        f128 => trunc128(x),
         else => @compileError("trunc not implemented for " ++ @typeName(T)),
     };
 }
@@ -66,9 +67,31 @@ fn trunc64(x: f64) f64 {
     }
 }
 
+fn trunc128(x: f128) f128 {
+    const u = @bitCast(u128, x);
+    var e = @intCast(i32, ((u >> 112) & 0x7FFF)) - 0x3FFF + 16;
+    var m: u128 = undefined;
+
+    if (e >= 112 + 16) {
+        return x;
+    }
+    if (e < 16) {
+        e = 1;
+    }
+
+    m = @as(u128, maxInt(u128)) >> @intCast(u7, e);
+    if (u & m == 0) {
+        return x;
+    } else {
+        math.forceEval(x + 0x1p120);
+        return @bitCast(f128, u & ~m);
+    }
+}
+
 test "math.trunc" {
     expect(trunc(@as(f32, 1.3)) == trunc32(1.3));
     expect(trunc(@as(f64, 1.3)) == trunc64(1.3));
+    expect(trunc(@as(f128, 1.3)) == trunc128(1.3));
 }
 
 test "math.trunc32" {
@@ -83,6 +106,12 @@ test "math.trunc64" {
     expect(trunc64(0.2) == 0.0);
 }
 
+test "math.trunc128" {
+    expect(trunc128(1.3) == 1.0);
+    expect(trunc128(-1.3) == -1.0);
+    expect(trunc128(0.2) == 0.0);
+}
+
 test "math.trunc32.special" {
     expect(trunc32(0.0) == 0.0); // 0x3F800000
     expect(trunc32(-0.0) == -0.0);
@@ -98,3 +127,11 @@ test "math.trunc64.special" {
     expect(math.isNegativeInf(trunc64(-math.inf(f64))));
     expect(math.isNan(trunc64(math.nan(f64))));
 }
+
+test "math.trunc128.special" {
+    expect(trunc128(0.0) == 0.0);
+    expect(trunc128(-0.0) == -0.0);
+    expect(math.isPositiveInf(trunc128(math.inf(f128))));
+    expect(math.isNegativeInf(trunc128(-math.inf(f128))));
+    expect(math.isNan(trunc128(math.nan(f128))));
+}