Merge rust-lang#108

108: coshf tanhf and atan2f r=japaric a=burrbull

closes rust-lang#44
closes rust-lang#52
closes rust-lang#41

Co-authored-by: Andrey Zgarbul <[email protected]>
Co-authored-by: Zgarbul Andrey <[email protected]>

Author: bors[bot]

src/lib.rs

@@ -96,7 +96,6 @@ pub trait F32Ext: private::Sealed {
 
     fn atan(self) -> Self;
 
-    #[cfg(todo)]
     fn atan2(self, other: Self) -> Self;
 
     #[cfg(todo)]
@@ -109,13 +108,10 @@ pub trait F32Ext: private::Sealed {
 
     fn ln_1p(self) -> Self;
 
-    #[cfg(todo)]
     fn sinh(self) -> Self;
 
-    #[cfg(todo)]
     fn cosh(self) -> Self;
 
-    #[cfg(todo)]
     fn tanh(self) -> Self;
 
     #[cfg(todo)]
@@ -272,7 +268,6 @@ impl F32Ext for f32 {
         atanf(self)
     }
 
-    #[cfg(todo)]
     #[inline]
     fn atan2(self, other: Self) -> Self {
         atan2f(self, other)
@@ -288,19 +283,16 @@ impl F32Ext for f32 {
         log1pf(self)
     }
 
-    #[cfg(todo)]
     #[inline]
     fn sinh(self) -> Self {
         sinhf(self)
     }
 
-    #[cfg(todo)]
     #[inline]
     fn cosh(self) -> Self {
         coshf(self)
     }
 
-    #[cfg(todo)]
     #[inline]
     fn tanh(self) -> Self {
         tanhf(self)

src/math/atan2f.rs

@@ -0,0 +1,71 @@
+use super::atanf;
+use super::fabsf;
+
+const PI: f32 = 3.1415927410e+00; /* 0x40490fdb */
+const PI_LO: f32 = -8.7422776573e-08; /* 0xb3bbbd2e */
+
+#[inline]
+pub fn atan2f(y: f32, x: f32) -> f32 {
+    if x.is_nan() || y.is_nan() {
+        return x + y;
+    }
+    let mut ix = x.to_bits();
+    let mut iy = y.to_bits();
+
+    if ix == 0x3f800000 {
+        /* x=1.0 */
+        return atanf(y);
+    }
+    let m = ((iy >> 31) & 1) | ((ix >> 30) & 2); /* 2*sign(x)+sign(y) */
+    ix &= 0x7fffffff;
+    iy &= 0x7fffffff;
+
+    /* when y = 0 */
+    if iy == 0 {
+        return match m {
+            0 | 1 => y,   /* atan(+-0,+anything)=+-0 */
+            2 => PI,      /* atan(+0,-anything) = pi */
+            3 | _ => -PI, /* atan(-0,-anything) =-pi */
+        };
+    }
+    /* when x = 0 */
+    if ix == 0 {
+        return if m & 1 != 0 { -PI / 2. } else { PI / 2. };
+    }
+    /* when x is INF */
+    if ix == 0x7f800000 {
+        return if iy == 0x7f800000 {
+            match m {
+                0 => PI / 4.,           /* atan(+INF,+INF) */
+                1 => -PI / 4.,          /* atan(-INF,+INF) */
+                2 => 3. * PI / 4.,      /* atan(+INF,-INF)*/
+                3 | _ => -3. * PI / 4., /* atan(-INF,-INF)*/
+            }
+        } else {
+            match m {
+                0 => 0.,      /* atan(+...,+INF) */
+                1 => -0.,     /* atan(-...,+INF) */
+                2 => PI,      /* atan(+...,-INF) */
+                3 | _ => -PI, /* atan(-...,-INF) */
+            }
+        };
+    }
+    /* |y/x| > 0x1p26 */
+    if (ix + (26 << 23) < iy) || (iy == 0x7f800000) {
+        return if m & 1 != 0 { -PI / 2. } else { PI / 2. };
+    }
+
+    /* z = atan(|y/x|) with correct underflow */
+    let z = if (m & 2 != 0) && (iy + (26 << 23) < ix) {
+        /*|y/x| < 0x1p-26, x < 0 */
+        0.
+    } else {
+        atanf(fabsf(y / x))
+    };
+    match m {
+        0 => z,                /* atan(+,+) */
+        1 => -z,               /* atan(-,+) */
+        2 => PI - (z - PI_LO), /* atan(+,-) */
+        _ => (z - PI_LO) - PI, /* case 3 */ /* atan(-,-) */
+    }
+}

src/math/coshf.rs

@@ -0,0 +1,33 @@
+use super::expf;
+use super::expm1f;
+use super::k_expo2f;
+
+#[inline]
+pub fn coshf(mut x: f32) -> f32 {
+    let x1p120 = f32::from_bits(0x7b800000); // 0x1p120f === 2 ^ 120
+
+    /* |x| */
+    let mut ix = x.to_bits();
+    ix &= 0x7fffffff;
+    x = f32::from_bits(ix);
+    let w = ix;
+
+    /* |x| < log(2) */
+    if w < 0x3f317217 {
+        if w < (0x3f800000 - (12 << 23)) {
+            force_eval!(x + x1p120);
+            return 1.;
+        }
+        let t = expm1f(x);
+        return 1. + t * t / (2. * (1. + t));
+    }
+
+    /* |x| < log(FLT_MAX) */
+    if w < 0x42b17217 {
+        let t = expf(x);
+        return 0.5 * (t + 1. / t);
+    }
+
+    /* |x| > log(FLT_MAX) or nan */
+    k_expo2f(x)
+}

src/math/k_expo2f.rs

@@ -0,0 +1,14 @@
+use super::expf;
+
+/* k is such that k*ln2 has minimal relative error and x - kln2 > log(FLT_MIN) */
+const K: i32 = 235;
+
+/* expf(x)/2 for x >= log(FLT_MAX), slightly better than 0.5f*expf(x/2)*expf(x/2) */
+#[inline]
+pub(crate) fn k_expo2f(x: f32) -> f32 {
+    let k_ln2 = f32::from_bits(0x4322e3bc);
+    /* note that k is odd and scale*scale overflows */
+    let scale = f32::from_bits(((0x7f + K / 2) as u32) << 23);
+    /* exp(x - k ln2) * 2**(k-1) */
+    expf(x - k_ln2) * scale * scale
+}

src/math/mod.rs

@@ -11,13 +11,15 @@ mod acos;
 mod acosf;
 mod asin;
 mod asinf;
+mod atan2f;
 mod atanf;
 mod cbrt;
 mod cbrtf;
 mod ceil;
 mod ceilf;
 mod cos;
 mod cosf;
+mod coshf;
 mod exp;
 mod exp2;
 mod exp2f;
@@ -51,10 +53,12 @@ mod scalbnf;
 mod sin;
 mod sinf;
 mod sinh;
+mod sinhf;
 mod sqrt;
 mod sqrtf;
 mod tan;
 mod tanf;
+mod tanhf;
 mod trunc;
 mod truncf;
 
@@ -63,13 +67,15 @@ pub use self::acos::acos;
 pub use self::acosf::acosf;
 pub use self::asin::asin;
 pub use self::asinf::asinf;
+pub use self::atan2f::atan2f;
 pub use self::atanf::atanf;
 pub use self::cbrt::cbrt;
 pub use self::cbrtf::cbrtf;
 pub use self::ceil::ceil;
 pub use self::ceilf::ceilf;
 pub use self::cos::cos;
 pub use self::cosf::cosf;
+pub use self::coshf::coshf;
 pub use self::exp::exp;
 pub use self::exp2::exp2;
 pub use self::exp2f::exp2f;
@@ -103,17 +109,20 @@ pub use self::scalbnf::scalbnf;
 pub use self::sin::sin;
 pub use self::sinf::sinf;
 pub use self::sinh::sinh;
+pub use self::sinhf::sinhf;
 pub use self::sqrt::sqrt;
 pub use self::sqrtf::sqrtf;
 pub use self::tan::tan;
 pub use self::tanf::tanf;
+pub use self::tanhf::tanhf;
 pub use self::trunc::trunc;
 pub use self::truncf::truncf;
 
 // Private modules
 mod expo2;
 mod k_cos;
 mod k_cosf;
+mod k_expo2f;
 mod k_sin;
 mod k_sinf;
 mod k_tan;
@@ -126,6 +135,7 @@ mod rem_pio2f;
 use self::expo2::expo2;
 use self::k_cos::k_cos;
 use self::k_cosf::k_cosf;
+use self::k_expo2f::k_expo2f;
 use self::k_sin::k_sin;
 use self::k_sinf::k_sinf;
 use self::k_tan::k_tan;

src/math/sinhf.rs

@@ -0,0 +1,30 @@
+use super::expm1f;
+use super::k_expo2f;
+
+#[inline]
+pub fn sinhf(x: f32) -> f32 {
+    let mut h = 0.5f32;
+    let mut ix = x.to_bits();
+    if (ix >> 31) != 0 {
+        h = -h;
+    }
+    /* |x| */
+    ix &= 0x7fffffff;
+    let absx = f32::from_bits(ix);
+    let w = ix;
+
+    /* |x| < log(FLT_MAX) */
+    if w < 0x42b17217 {
+        let t = expm1f(absx);
+        if w < 0x3f800000 {
+            if w < (0x3f800000 - (12 << 23)) {
+                return x;
+            }
+            return h * (2. * t - t * t / (t + 1.));
+        }
+        return h * (t + t / (t + 1.));
+    }
+
+    /* |x| > logf(FLT_MAX) or nan */
+    2. * h * k_expo2f(absx)
+}

src/math/tanhf.rs

@@ -0,0 +1,39 @@
+use super::expm1f;
+
+#[inline]
+pub fn tanhf(mut x: f32) -> f32 {
+    /* x = |x| */
+    let mut ix = x.to_bits();
+    let sign = (ix >> 31) != 0;
+    ix &= 0x7fffffff;
+    x = f32::from_bits(ix);
+    let w = ix;
+
+    let tt = if w > 0x3f0c9f54 {
+        /* |x| > log(3)/2 ~= 0.5493 or nan */
+        if w > 0x41200000 {
+            /* |x| > 10 */
+            1. + 0. / x
+        } else {
+            let t = expm1f(2. * x);
+            1. - 2. / (t + 2.)
+        }
+    } else if w > 0x3e82c578 {
+        /* |x| > log(5/3)/2 ~= 0.2554 */
+        let t = expm1f(2. * x);
+        t / (t + 2.)
+    } else if w >= 0x00800000 {
+        /* |x| >= 0x1p-126 */
+        let t = expm1f(-2. * x);
+        -t / (t + 2.)
+    } else {
+        /* |x| is subnormal */
+        force_eval!(x * x);
+        x
+    };
+    if sign {
+        -tt
+    } else {
+        tt
+    }
+}

test-generator/src/main.rs

@@ -659,7 +659,7 @@ f32_f32! {
     cbrtf,
     cosf,
     ceilf,
-    // coshf,
+    coshf,
     exp2f,
     expf,
     expm1f,
@@ -669,16 +669,16 @@ f32_f32! {
     logf,
     roundf,
     sinf,
-    // sinhf,
+    sinhf,
     tanf,
-    // tanhf,
+    tanhf,
     fabsf,
     sqrtf,
 }
 
 // With signature `fn(f32, f32) -> f32`
 f32f32_f32! {
-    // atan2f,
+    atan2f,
     fdimf,
     hypotf,
     fmodf,