Changeset 14749

Timestamp:

01/26/15 06:39:06 (8 years ago)

Author:

Mark Evenson

Message:

Numeric tower repairs on promoting floats across representation boundaries.

Thanks to Massimiliano Ghilardi.

If a bignum exceeds the largest representable single-float,
EQUALP will raise a type-error when comparing it to a single-float.
The same problem happens with double-floats.

I am reporting this because my understanding of CLHS
​http://www.lispworks.com/documentation/lw51/CLHS/Body/f_equalp.htm#equalp
tells that EQUALP is not supposed to raise errors at all:
"Exceptional Situations: None."

How to reproduce:

;; =========== double-floats ===========
(= (ash 1 1024) most-positive-double-float)
NIL

(equalp (ash 1 1024) most-positive-double-float)
; Evaluation aborted on #<TYPE-ERROR {215F90FE}>.

;; =========== single-floats ===========
(= 340282360000000000000000000000000000000 0.0f0)
NIL

(equalp 340282360000000000000000000000000000000 0.0f0)
; Evaluation aborted on #<TYPE-ERROR {1CFFC364}>.

File:

• trunk/abcl/src/org/armedbear/lisp/Bignum.java (modified) (1 diff)

trunk/abcl/src/org/armedbear/lisp/Bignum.java

@@ -217 +217 @@
       return value.equals(((Bignum)obj).value);
     if (obj instanceof SingleFloat)
-      return floatValue() == ((SingleFloat)obj).value;
-    if (obj instanceof DoubleFloat)
-      return doubleValue() == ((DoubleFloat)obj).value;
+    {
+      // do not raise errors on bignums exceeding the largest representable float
+      float f = value.floatValue();
+      return !Float.isInfinite(f) && f == ((SingleFloat)obj).value;
+    }
+    if (obj instanceof DoubleFloat)
+    {
+      // do not raise errors on bignums exceeding the largest representable double
+      double d = value.doubleValue();
+      return !Double.isInfinite(d) && d == ((DoubleFloat)obj).value;
+    }
     return false;
   }