Changeset 1024Tweet

Timestamp:

Oct 14, 2011, 12:16:25 AM (11 years ago)

Author:

sam

Message:

core: implement frexp(), ldexp() and modf() for reals.

Location:

trunk/src

Files:

• real.cpp (modified) (2 diffs)
• real.h (modified) (2 diffs)

trunk/src/real.cpp

@@ -769 +769 @@
      * off, but that's about it. */
     return (exp(x) + exp(-x)) >> 1;
+}
+
+real frexp(real const &x, int *exp)
+{
+    if (!x)
+    {
+        *exp = 0;
+        return x;
+    }
+
+    real ret = x;
+    int exponent = (ret.m_signexp & 0x7fffffffu) - (1 << 30) + 1;
+    *exp = exponent + 1;
+    ret.m_signexp -= exponent + 1;
+    return ret;
+}
+
+real ldexp(real const &x, int exp)
+{
+    real ret = x;
+    if (ret)
+        ret.m_signexp += exp;
+    return ret;
+}
+
+real modf(real const &x, real *iptr)
+{
+    real absx = fabs(x);
+    real tmp = floor(absx);
+
+    *iptr = copysign(tmp, x);
+    return copysign(absx - tmp, x);
 }
 
@@ -1064 +1096 @@
 }
 
+real atan2(real const &y, real const &x)
+{
+    if (!y)
+    {
+        if ((x.m_signexp >> 31) == 0)
+            return y;
+        if (y.m_signexp >> 31)
+            return -real::R_PI;
+        return real::R_PI;
+    }
+
+    if (!x)
+    {
+        if (y.m_signexp >> 31)
+            return -real::R_PI;
+        return real::R_PI;
+    }
+
+    /* FIXME: handle the Inf and NaN cases */
+    real z = y / x;
+    real ret = atan(z);
+    if (x < real::R_0)
+        ret += (y > real::R_0) ? real::R_PI : -real::R_PI;
+    return ret;
+}
+
 void real::hexprint() const
 {

trunk/src/real.h

@@ -70 +70 @@
     friend real acos(real const &x);
     friend real atan(real const &x);
-    /* FIXME: atan2 */
+    friend real atan2(real const &y, real const &x);
 
     /* Hyperbolic functions */
@@ -83 +83 @@
     friend real log2(real const &x);
     friend real log10(real const &x);
-    /* FIXME: frexp ldexp modf */
+    friend real frexp(real const &x, int *exp);
+    friend real ldexp(real const &x, int exp);
+    friend real modf(real const &x, real *iptr);
 
     /* Power functions */