Some rough floating point macros!

math/__fpclassify.c

@@ -0,0 +1,91 @@
+#include <math.h>
+
+int __fpclassifyd(double x) {
+  union fp {
+    double d;
+    long i;
+  } f;
+
+  f.d = x;
+
+  if((f.i & 0x7fffffffffffffff) == 0) {
+    return FP_ZERO;
+  }
+
+  if((f.i & 0x7ff0000000000000) == 0 && (f.i & 0xfffffffffffff != 0)) {
+    return FP_SUBNORMAL;
+  }
+
+  if((f.i & 0x7ff0000000000000) == 0x7ff0000000000000) {
+    if((f.i & 0xfffffffffffff) == 0) {
+      return FP_INFINITE;
+    }
+    else {
+      return FP_NAN;
+    }
+  }
+
+  return FP_NORMAL;
+}
+
+int __fpclassifyf(float x) {
+  union fp {
+    float f;
+    int i;
+  } f;
+
+  f.f = x;
+
+  if((f.i & 0x7fffffff) == 0) {
+    return FP_ZERO;
+  }
+
+  if((f.i & 0x7f800000) == 0 && (f.i & 0x7fffff != 0)) {
+    return FP_SUBNORMAL;
+  }
+
+  if((f.i & 0x7f800000) == 0x7f800000) {
+    if((f.i & 0x7fffff) == 0) {
+      return FP_INFINITE;
+    }
+    else {
+      return FP_NAN;
+    }
+  }
+
+  return FP_NORMAL;
+}
+
+/*
+  This is based off IEEE 754 binary128 (A.K.A quad-precision) FP numbers. 
+  Apparently, C tends to actually use 80-bit extended precision, which would
+  mean this doesn't actually work. We'll worry about that later, though.
+  -Kat
+*/
+int __fpclassifyl(long double x) {
+  union fp {
+    long double d;
+    long long i;
+  } f;
+
+  f.d = x;
+
+  if((f.i & 0x7fffffffffffffffffffffffffffffff) == 0) {
+    return FP_ZERO;
+  }
+
+  if((f.i & 0x7fff0000000000000000000000000000) == 0 && (f.i & 0xffffffffffffffffffffffffffff != 0)) {
+    return FP_SUBNORMAL;
+  }
+
+  if((f.i & 0x7fff0000000000000000000000000000) == 0x7fff0000000000000000000000000000) {
+    if((f.i & 0xffffffffffffffffffffffffffff) == 0) {
+      return FP_INFINITE;
+    }
+    else {
+      return FP_NAN;
+    }
+  }
+
+  return FP_NORMAL;
+}

math/__signbit.c

@@ -0,0 +1,34 @@
+#include <math.h>
+
+int __signbitd(double x) {
+  union fp {
+    double d;
+    long i;
+  } f;
+
+  f.d = x;
+
+  return f.i & 0x8000000000000000;
+}
+
+int __signbitf(float x) {
+  union fp {
+    float f;
+    int i;
+  } f;
+
+  f.f = x;
+
+  return f.i & 0x80000000;
+}
+
+int __signbitl(long double x) {
+  union fp {
+    long double d;
+    long long i;
+  } f;
+
+  f.d = x;
+
+  return f.i & 0x80000000000000000000000000000000;
+}