added int_to_float.h as might be needed in future for new sort alg idea

int_to_float.h

@@ -0,0 +1,118 @@
+#ifndef INT_TO_FLOAT_H
+#define INT_TO_FLOAT_H
+
+/* Taken from here: */
+/* https://android.googlesource.com/toolchain/gcc/+/master/gcc-4.9/libgcc/config/m68k/fpgnulib.c */
+
+/* the following deal with IEEE single-precision numbers */
+#define EXCESS		126L
+#define SIGNBIT		0x80000000L
+#define HIDDEN		(1L << 23L)
+#define SIGN(fp)	((fp) & SIGNBIT)
+#define EXP(fp)		(((fp) >> 23L) & 0xFF)
+#define MANT(fp)	(((fp) & 0x7FFFFFL) | HIDDEN)
+#define PACK(s,e,m)	((s) | ((e) << 23L) | (m))
+/* the following deal with IEEE double-precision numbers */
+#define EXCESSD		1022L
+#define HIDDEND		(1L << 20L)
+#define EXPDBITS	11
+#define EXPDMASK	0x7FFL
+#define EXPD(fp)	(((fp.l.upper) >> 20L) & 0x7FFL)
+#define SIGND(fp)	((fp.l.upper) & SIGNBIT)
+#define MANTD(fp)	(((((fp.l.upper) & 0xFFFFF) | HIDDEND) << 10) | \
+				(fp.l.lower >> 22))
+#define MANTDMASK	0xFFFFFL /* mask of upper part */
+
+union double_long 
+{
+  double d;
+  struct {
+      long upper;
+      unsigned long lower;
+    } l;
+};
+
+/* convert unsigned int to double */
+double
+__floatunsidf (unsigned long a1)
+{
+  long exp = 32 + EXCESSD;
+  union double_long dl;
+  if (!a1)
+    {
+      dl.l.upper = dl.l.lower = 0;
+      return dl.d;
+    }
+  while (a1 < 0x2000000L)
+    {
+      a1 <<= 4;
+      exp -= 4;
+    }
+  while (a1 < 0x80000000L)
+    {
+      a1 <<= 1;
+      exp--;
+    }
+  /* pack up and go home */
+  dl.l.upper = exp << 20L;
+  dl.l.upper |= (a1 >> 11L) & ~HIDDEND;
+  dl.l.lower = a1 << 21L;
+  return dl.d;
+}
+/* convert int to double */
+double
+__floatsidf (long a1)
+{
+  long sign = 0, exp = 31 + EXCESSD;
+  union double_long dl;
+  if (!a1)
+    {
+      dl.l.upper = dl.l.lower = 0;
+      return dl.d;
+    }
+  if (a1 < 0)
+    {
+      sign = SIGNBIT;
+      a1 = (long)-(unsigned long)a1;
+      if (a1 < 0)
+	{
+	  dl.l.upper = SIGNBIT | ((32 + EXCESSD) << 20L);
+	  dl.l.lower = 0;
+	  return dl.d;
+        }
+    }
+  while (a1 < 0x1000000L)
+    {
+      a1 <<= 4;
+      exp -= 4;
+    }
+  while (a1 < 0x40000000L)
+    {
+      a1 <<= 1;
+      exp--;
+    }
+  /* pack up and go home */
+  dl.l.upper = sign;
+  dl.l.upper |= exp << 20L;
+  dl.l.upper |= (a1 >> 10L) & ~HIDDEND;
+  dl.l.lower = a1 << 22L;
+  return dl.d;
+}
+
+/* convert unsigned int to float */
+float
+__floatunsisf (unsigned long l)
+{
+  double foo = __floatunsidf (l);
+  return foo;
+}
+
+/* convert int to float */
+float
+__floatsisf (long l)
+{
+  double foo = __floatsidf (l);
+  return foo;
+}
+
+#endif /* INT_TO_FLOAT_H */