Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 259 insertions, 0 deletions

diff --git a/third_party/rust/libm/src/math/jnf.rs b/third_party/rust/libm/src/math/jnf.rs
new file mode 100644
index 0000000000..360f62e201
--- /dev/null
+++ b/third_party/rust/libm/src/math/jnf.rs
@@ -0,0 +1,259 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/e_jnf.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::{fabsf, j0f, j1f, logf, y0f, y1f};
+
+pub fn jnf(n: i32, mut x: f32) -> f32 {
+    let mut ix: u32;
+    let mut nm1: i32;
+    let mut sign: bool;
+    let mut i: i32;
+    let mut a: f32;
+    let mut b: f32;
+    let mut temp: f32;
+
+    ix = x.to_bits();
+    sign = (ix >> 31) != 0;
+    ix &= 0x7fffffff;
+    if ix > 0x7f800000 {
+        /* nan */
+        return x;
+    }
+
+    /* J(-n,x) = J(n,-x), use |n|-1 to avoid overflow in -n */
+    if n == 0 {
+        return j0f(x);
+    }
+    if n < 0 {
+        nm1 = -(n + 1);
+        x = -x;
+        sign = !sign;
+    } else {
+        nm1 = n - 1;
+    }
+    if nm1 == 0 {
+        return j1f(x);
+    }
+
+    sign &= (n & 1) != 0; /* even n: 0, odd n: signbit(x) */
+    x = fabsf(x);
+    if ix == 0 || ix == 0x7f800000 {
+        /* if x is 0 or inf */
+        b = 0.0;
+    } else if (nm1 as f32) < x {
+        /* Safe to use J(n+1,x)=2n/x *J(n,x)-J(n-1,x) */
+        a = j0f(x);
+        b = j1f(x);
+        i = 0;
+        while i < nm1 {
+            i += 1;
+            temp = b;
+            b = b * (2.0 * (i as f32) / x) - a;
+            a = temp;
+        }
+    } else {
+        if ix < 0x35800000 {
+            /* x < 2**-20 */
+            /* x is tiny, return the first Taylor expansion of J(n,x)
+             * J(n,x) = 1/n!*(x/2)^n  - ...
+             */
+            if nm1 > 8 {
+                /* underflow */
+                nm1 = 8;
+            }
+            temp = 0.5 * x;
+            b = temp;
+            a = 1.0;
+            i = 2;
+            while i <= nm1 + 1 {
+                a *= i as f32; /* a = n! */
+                b *= temp; /* b = (x/2)^n */
+                i += 1;
+            }
+            b = b / a;
+        } else {
+            /* use backward recurrence */
+            /*                      x      x^2      x^2
+             *  J(n,x)/J(n-1,x) =  ----   ------   ------   .....
+             *                      2n  - 2(n+1) - 2(n+2)
+             *
+             *                      1      1        1
+             *  (for large x)   =  ----  ------   ------   .....
+             *                      2n   2(n+1)   2(n+2)
+             *                      -- - ------ - ------ -
+             *                       x     x         x
+             *
+             * Let w = 2n/x and h=2/x, then the above quotient
+             * is equal to the continued fraction:
+             *                  1
+             *      = -----------------------
+             *                     1
+             *         w - -----------------
+             *                        1
+             *              w+h - ---------
+             *                     w+2h - ...
+             *
+             * To determine how many terms needed, let
+             * Q(0) = w, Q(1) = w(w+h) - 1,
+             * Q(k) = (w+k*h)*Q(k-1) - Q(k-2),
+             * When Q(k) > 1e4      good for single
+             * When Q(k) > 1e9      good for double
+             * When Q(k) > 1e17     good for quadruple
+             */
+            /* determine k */
+            let mut t: f32;
+            let mut q0: f32;
+            let mut q1: f32;
+            let mut w: f32;
+            let h: f32;
+            let mut z: f32;
+            let mut tmp: f32;
+            let nf: f32;
+            let mut k: i32;
+
+            nf = (nm1 as f32) + 1.0;
+            w = 2.0 * (nf as f32) / x;
+            h = 2.0 / x;
+            z = w + h;
+            q0 = w;
+            q1 = w * z - 1.0;
+            k = 1;
+            while q1 < 1.0e4 {
+                k += 1;
+                z += h;
+                tmp = z * q1 - q0;
+                q0 = q1;
+                q1 = tmp;
+            }
+            t = 0.0;
+            i = k;
+            while i >= 0 {
+                t = 1.0 / (2.0 * ((i as f32) + nf) / x - t);
+                i -= 1;
+            }
+            a = t;
+            b = 1.0;
+            /*  estimate log((2/x)^n*n!) = n*log(2/x)+n*ln(n)
+             *  Hence, if n*(log(2n/x)) > ...
+             *  single 8.8722839355e+01
+             *  double 7.09782712893383973096e+02
+             *  long double 1.1356523406294143949491931077970765006170e+04
+             *  then recurrent value may overflow and the result is
+             *  likely underflow to zero
+             */
+            tmp = nf * logf(fabsf(w));
+            if tmp < 88.721679688 {
+                i = nm1;
+                while i > 0 {
+                    temp = b;
+                    b = 2.0 * (i as f32) * b / x - a;
+                    a = temp;
+                    i -= 1;
+                }
+            } else {
+                i = nm1;
+                while i > 0 {
+                    temp = b;
+                    b = 2.0 * (i as f32) * b / x - a;
+                    a = temp;
+                    /* scale b to avoid spurious overflow */
+                    let x1p60 = f32::from_bits(0x5d800000); // 0x1p60 == 2^60
+                    if b > x1p60 {
+                        a /= b;
+                        t /= b;
+                        b = 1.0;
+                    }
+                    i -= 1;
+                }
+            }
+            z = j0f(x);
+            w = j1f(x);
+            if fabsf(z) >= fabsf(w) {
+                b = t * z / b;
+            } else {
+                b = t * w / a;
+            }
+        }
+    }
+
+    if sign {
+        -b
+    } else {
+        b
+    }
+}
+
+pub fn ynf(n: i32, x: f32) -> f32 {
+    let mut ix: u32;
+    let mut ib: u32;
+    let nm1: i32;
+    let mut sign: bool;
+    let mut i: i32;
+    let mut a: f32;
+    let mut b: f32;
+    let mut temp: f32;
+
+    ix = x.to_bits();
+    sign = (ix >> 31) != 0;
+    ix &= 0x7fffffff;
+    if ix > 0x7f800000 {
+        /* nan */
+        return x;
+    }
+    if sign && ix != 0 {
+        /* x < 0 */
+        return 0.0 / 0.0;
+    }
+    if ix == 0x7f800000 {
+        return 0.0;
+    }
+
+    if n == 0 {
+        return y0f(x);
+    }
+    if n < 0 {
+        nm1 = -(n + 1);
+        sign = (n & 1) != 0;
+    } else {
+        nm1 = n - 1;
+        sign = false;
+    }
+    if nm1 == 0 {
+        if sign {
+            return -y1f(x);
+        } else {
+            return y1f(x);
+        }
+    }
+
+    a = y0f(x);
+    b = y1f(x);
+    /* quit if b is -inf */
+    ib = b.to_bits();
+    i = 0;
+    while i < nm1 && ib != 0xff800000 {
+        i += 1;
+        temp = b;
+        b = (2.0 * (i as f32) / x) * b - a;
+        ib = b.to_bits();
+        a = temp;
+    }
+
+    if sign {
+        -b
+    } else {
+        b
+    }
+}