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

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

diff --git a/device/lib/pic/libsdcc/fsmul.c b/device/lib/pic/libsdcc/fsmul.c
new file mode 100644 (file)
index 0000000..93cc9cc
--- /dev/null
+++ b/device/lib/pic/libsdcc/fsmul.c
@@ -0,0 +1,81 @@
+/*
+** 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: fsmul.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;
+    unsigned long l;
+  };
+
+/* multiply two floats */
+float __fsmul (float a1, float a2) _FS_REENTRANT
+{
+  FS_STATIC volatile union float_long fl1, fl2;
+  unsigned long result;
+  int exp;
+  char sign;
+  
+  fl1.f = a1;
+  fl2.f = a2;
+
+  if (!fl1.l || !fl2.l)
+    return (0);
+
+  /* compute sign and exponent */
+  sign = SIGN (fl1.l) ^ SIGN (fl2.l);
+  exp = EXP (fl1.l) - EXCESS;
+  exp += EXP (fl2.l);
+
+  fl1.l = MANT (fl1.l);
+  fl2.l = MANT (fl2.l);
+
+  /* the multiply is done as one 16x16 multiply and two 16x8 multiples */
+  result = (fl1.l >> 8) * (fl2.l >> 8);
+  result += ((fl1.l & (unsigned long) 0xFF) * (fl2.l >> 8)) >> 8;
+  result += ((fl2.l & (unsigned long) 0xFF) * (fl1.l >> 8)) >> 8;
+
+  if (0 != (result & SIGNBIT))
+    {
+      /* round */
+      result += 0x80;
+      result >>= 8;
+    }
+  else
+    {
+      /* round */
+      result += 0x40;
+      result >>= 7;
+      exp--;
+    }
+
+  result &= ~HIDDEN;
+
+  /* pack up and go home */
+  fl1.l = PACK (sign ? SIGNBIT : 0 , (unsigned long)exp, result);  
+  return (fl1.f);
+}
+
+
+
+