fixed and cleaned up fp support, optimisation yet to come

[fw/sdcc] / device / lib / _fsdiv.c

diff --git a/device/lib/_fsdiv.c b/device/lib/_fsdiv.c
index f597027f167c7bbffaef119fc356ec91fd931080..93a5f86d43f79574e62ac73effc2ba449cd9d309 100644 (file)
--- a/device/lib/_fsdiv.c
+++ b/device/lib/_fsdiv.c
@@ -6,61 +6,17 @@
 ** 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?).
-
-Warning! Only single-precision is actually implemented.  This file
-won't really be much use until double-precision is supported.
-
-However, once that is done, this file might eventually become a
-replacement for libgcc1.c.  It might also make possible
-cross-compilation for an IEEE target machine from a non-IEEE
-host such as a VAX.
-
-If you'd like to work on completing this, please talk to rms@gnu.ai.mit.edu.
-
-
 **
 ** Pat Wood
 ** Pipeline Associates, Inc.
 ** pipeline!phw@motown.com or
 ** sun!pipeline!phw or
 ** uunet!motown!pipeline!phw
-**
-** 05/01/91 -- V1.0 -- first release to gcc mailing lists
-** 05/04/91 -- V1.1 -- added float and double prototypes and return values
-**                  -- fixed problems with adding and subtracting zero
-**                  -- fixed rounding in truncdfsf2
-**                  -- fixed SWAP define and tested on 386
 */
 
-/*
-** The following are routines that replace the libgcc soft floating point
-** routines that are called automatically when -msoft-float is selected.
-** The support single and double precision IEEE format, with provisions
-** for byte-swapped machines (tested on 386).  Some of the double-precision
-** routines work at full precision, but most of the hard ones simply punt
-** and call the single precision routines, producing a loss of accuracy.
-** long long support is not assumed or included.
-** Overall accuracy is close to IEEE (actually 68882) for single-precision
-** arithmetic.  I think there may still be a 1 in 1000 chance of a bit
-** being rounded the wrong way during a multiply.  I'm not fussy enough to
-** bother with it, but if anyone is, knock yourself out.
-**
-** Efficiency has only been addressed where it was obvious that something
-** would make a big difference.  Anyone who wants to do this right for
-** best speed should go in and rewrite in assembler.
-**
-** I have tested this only on a 68030 workstation and 386/ix integrated
-** in with -msoft-float.
-*/
+/* (c)2000/2001: hacked a little by johan.knol@iduna.nl for sdcc */
 
-/* the following deal with IEEE single-precision numbers */
-#define EXCESS         126
-#define SIGNBIT                ((unsigned long)0x80000000)
-#define HIDDEN         (unsigned long)(1 << 23)
-#define SIGN(fp)       ((fp >> (8*sizeof(fp)-1)) & 1)
-#define EXP(fp)                (((fp) >> 23) & (unsigned int)0x00FF)
-#define MANT(fp)       (((fp) & (unsigned long)0x007FFFFF) | HIDDEN)
-#define PACK(s,e,m)    ((s) | ((e) << 23) | (m))
+#include <float.h>
 
 union float_long
   {
@@ -69,8 +25,7 @@ union float_long
   };
 
 /* divide two floats */
-float
-__fsdiv (float a1, float a2)
+float __fsdiv (float a1, float a2)
 {
   volatile union float_long fl1, fl2;
   volatile long result;
@@ -134,6 +89,7 @@ __fsdiv (float a1, float a2)
   result &= ~HIDDEN;
 
   /* pack up and go home */
-  fl1.l = PACK (sign, (unsigned long) exp, result);
+  fl1.l = PACK (sign ? 1<<31 : 0, (unsigned long) exp, result);
   return (fl1.f);
 }
+