1 files changed, 79 insertions, 0 deletions
diff --git a/vendor/compiler_builtins/libm/src/math/acosf.rs b/vendor/compiler_builtins/libm/src/math/acosf.rs
new file mode 100644
index 000000000..1a60479e3
--- /dev/null
+++ b/vendor/compiler_builtins/libm/src/math/acosf.rs
@@ -0,0 +1,79 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/e_acosf.c */
+/*
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+use super::sqrtf::sqrtf;
+
+const PIO2_HI: f32 = 1.5707962513e+00; /* 0x3fc90fda */
+const PIO2_LO: f32 = 7.5497894159e-08; /* 0x33a22168 */
+const P_S0: f32 = 1.6666586697e-01;
+const P_S1: f32 = -4.2743422091e-02;
+const P_S2: f32 = -8.6563630030e-03;
+const Q_S1: f32 = -7.0662963390e-01;
+
+fn r(z: f32) -> f32 {
+    let p = z * (P_S0 + z * (P_S1 + z * P_S2));
+    let q = 1. + z * Q_S1;
+    p / q
+}
+
+/// Arccosine (f32)
+///
+/// Computes the inverse cosine (arc cosine) of the input value.
+/// Arguments must be in the range -1 to 1.
+/// Returns values in radians, in the range of 0 to pi.
+#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
+pub fn acosf(x: f32) -> f32 {
+    let x1p_120 = f32::from_bits(0x03800000); // 0x1p-120 === 2 ^ (-120)
+
+    let z: f32;
+    let w: f32;
+    let s: f32;
+
+    let mut hx = x.to_bits();
+    let ix = hx & 0x7fffffff;
+    /* |x| >= 1 or nan */
+    if ix >= 0x3f800000 {
+        if ix == 0x3f800000 {
+            if (hx >> 31) != 0 {
+                return 2. * PIO2_HI + x1p_120;
+            }
+            return 0.;
+        }
+        return 0. / (x - x);
+    }
+    /* |x| < 0.5 */
+    if ix < 0x3f000000 {
+        if ix <= 0x32800000 {
+            /* |x| < 2**-26 */
+            return PIO2_HI + x1p_120;
+        }
+        return PIO2_HI - (x - (PIO2_LO - x * r(x * x)));
+    }
+    /* x < -0.5 */
+    if (hx >> 31) != 0 {
+        z = (1. + x) * 0.5;
+        s = sqrtf(z);
+        w = r(z) * s - PIO2_LO;
+        return 2. * (PIO2_HI - (s + w));
+    }
+    /* x > 0.5 */
+    z = (1. - x) * 0.5;
+    s = sqrtf(z);
+    hx = s.to_bits();
+    let df = f32::from_bits(hx & 0xfffff000);
+    let c = (z - df * df) / (s + df);
+    w = r(z) * s + c;
+    2. * (df + w)
+}