* device/lib/pic/libm: NEW, added math library functions

[fw/sdcc] / device / lib / pic / libsdcc / fsdiv.c

diff --git a/device/lib/pic/libsdcc/fsdiv.c b/device/lib/pic/libsdcc/fsdiv.c
new file mode 100644 (file)
index 0000000..7b5b4f5
--- /dev/null
+++ b/device/lib/pic/libsdcc/fsdiv.c
@@ -0,0 +1,99 @@
+/*
+** libgcc support for software floating point.
+** Copyright (C) 1991 by Pipeline Associates, Inc.  All rights reserved.
+** Permission is granted to do *anything* you want with this file,
+** commercial or otherwise, provided this message remains intact.  So there!
+** I would appreciate receiving any updates/patches/changes that anyone
+** makes, and am willing to be the repository for said changes (am I
+** making a big mistake?).
+**
+** Pat Wood
+** Pipeline Associates, Inc.
+** pipeline!phw@motown.com or
+** sun!pipeline!phw or
+** uunet!motown!pipeline!phw
+*/
+
+/*
+** $Id: fsdiv.c 3513 2004-10-01 14:49:51Z vrokas $
+*/
+
+/* (c)2000/2001: hacked a little by johan.knol@iduna.nl for sdcc */
+
+#include <float.h>
+
+union float_long
+  {
+    float f;
+    long l;
+  };
+
+/* divide two floats */
+float __fsdiv (float a1, float a2) _FS_REENTRANT
+{
+  FS_STATIC volatile union float_long fl1, fl2;
+  long result;
+  unsigned long mask;
+  long mant1, mant2;
+  int exp ;
+  char sign;
+
+  fl1.f = a1;
+  fl2.f = a2;
+
+  /* subtract exponents */
+  exp = EXP (fl1.l) ;
+  exp -= EXP (fl2.l);
+  exp += EXCESS;
+
+  /* compute sign */
+  sign = SIGN (fl1.l) ^ SIGN (fl2.l);
+
+  /* divide by zero??? */
+  if (!fl2.l)
+    /* return NaN or -NaN */
+    return (-1.0);
+
+  /* numerator zero??? */
+  if (!fl1.l)
+    return (0);
+
+  /* now get mantissas */
+  mant1 = MANT (fl1.l);
+  mant2 = MANT (fl2.l);
+
+  /* this assures we have 25 bits of precision in the end */
+  if (mant1 < mant2)
+    {
+      mant1 <<= 1;
+      exp--;
+    }
+
+  /* now we perform repeated subtraction of fl2.l from fl1.l */
+  mask = 0x1000000;
+  result = 0;
+  while (mask)
+    {
+      if (mant1 >= mant2)
+       {
+         result |= mask;
+         mant1 -= mant2;
+       }
+      mant1 <<= 1;
+      mask >>= 1;
+    }
+
+  /* round */
+  result += 1;
+
+  /* normalize down */
+  exp++;
+  result >>= 1;
+
+  result &= ~HIDDEN;
+
+  /* pack up and go home */
+  fl1.l = PACK (sign ? 1ul<<31 : 0, (unsigned long) exp, result);
+  return (fl1.f);
+}
+