1 files changed, 99 insertions, 0 deletions
diff --git a/vendor/libm-0.1.4/src/math/log1pf.rs b/vendor/libm-0.1.4/src/math/log1pf.rs
new file mode 100644
index 000000000..8e9651357
--- /dev/null
+++ b/vendor/libm-0.1.4/src/math/log1pf.rs
@@ -0,0 +1,99 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/s_log1pf.c */
+/*
+ * ====================================================
+ * 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 core::f32;
+
+const LN2_HI: f32 = 6.9313812256e-01; /* 0x3f317180 */
+const LN2_LO: f32 = 9.0580006145e-06; /* 0x3717f7d1 */
+/* |(log(1+s)-log(1-s))/s - Lg(s)| < 2**-34.24 (~[-4.95e-11, 4.97e-11]). */
+const LG1: f32 = 0.66666662693; /* 0xaaaaaa.0p-24 */
+const LG2: f32 = 0.40000972152; /* 0xccce13.0p-25 */
+const LG3: f32 = 0.28498786688; /* 0x91e9ee.0p-25 */
+const LG4: f32 = 0.24279078841; /* 0xf89e26.0p-26 */
+
+#[inline]
+#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
+pub fn log1pf(x: f32) -> f32 {
+    let mut ui: u32 = x.to_bits();
+    let hfsq: f32;
+    let mut f: f32 = 0.;
+    let mut c: f32 = 0.;
+    let s: f32;
+    let z: f32;
+    let r: f32;
+    let w: f32;
+    let t1: f32;
+    let t2: f32;
+    let dk: f32;
+    let ix: u32;
+    let mut iu: u32;
+    let mut k: i32;
+
+    ix = ui;
+    k = 1;
+    if ix < 0x3ed413d0 || (ix >> 31) > 0 {
+        /* 1+x < sqrt(2)+  */
+        if ix >= 0xbf800000 {
+            /* x <= -1.0 */
+            if x == -1. {
+                return x / 0.0; /* log1p(-1)=+inf */
+            }
+            return (x - x) / 0.0; /* log1p(x<-1)=NaN */
+        }
+        if ix << 1 < 0x33800000 << 1 {
+            /* |x| < 2**-24 */
+            /* underflow if subnormal */
+            if (ix & 0x7f800000) == 0 {
+                force_eval!(x * x);
+            }
+            return x;
+        }
+        if ix <= 0xbe95f619 {
+            /* sqrt(2)/2- <= 1+x < sqrt(2)+ */
+            k = 0;
+            c = 0.;
+            f = x;
+        }
+    } else if ix >= 0x7f800000 {
+        return x;
+    }
+    if k > 0 {
+        ui = (1. + x).to_bits();
+        iu = ui;
+        iu += 0x3f800000 - 0x3f3504f3;
+        k = (iu >> 23) as i32 - 0x7f;
+        /* correction term ~ log(1+x)-log(u), avoid underflow in c/u */
+        if k < 25 {
+            c = if k >= 2 {
+                1. - (f32::from_bits(ui) - x)
+            } else {
+                x - (f32::from_bits(ui) - 1.)
+            };
+            c /= f32::from_bits(ui);
+        } else {
+            c = 0.;
+        }
+        /* reduce u into [sqrt(2)/2, sqrt(2)] */
+        iu = (iu & 0x007fffff) + 0x3f3504f3;
+        ui = iu;
+        f = f32::from_bits(ui) - 1.;
+    }
+    s = f / (2.0 + f);
+    z = s * s;
+    w = z * z;
+    t1 = w * (LG2 + w * LG4);
+    t2 = z * (LG1 + w * LG3);
+    r = t2 + t1;
+    hfsq = 0.5 * f * f;
+    dk = k as f32;
+    s * (hfsq + r) + (dk * LN2_LO + c) - hfsq + f + dk * LN2_HI
+}