[Qemu-devel] [6102] Correctly normalize values and handle zero inputs to scalbn functions.

[Qemu-devel] [6102] Correctly normalize values and handle zero inputs to scalbn functions.

[Paul Brook]

Revision: 6102
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=6102
Author:   pbrook
Date:     2008-12-19 12:59:28 +0000 (Fri, 19 Dec 2008)

Log Message:
-----------
Correctly normalize values and handle zero inputs to scalbn functions.

Signed-off-by: Paul Brook <paul@codesourcery.com>

Modified Paths:
--------------
    trunk/fpu/softfloat.c

Modified: trunk/fpu/softfloat.c
===================================================================
--- trunk/fpu/softfloat.c	2008-12-19 12:57:18 UTC (rev 6101)
+++ trunk/fpu/softfloat.c	2008-12-19 12:59:28 UTC (rev 6102)
@@ -5479,8 +5479,14 @@
     if ( aExp == 0xFF ) {
         return a;
     }
-    aExp += n;
-    return roundAndPackFloat32( aSign, aExp, aSig STATUS_VAR );
+    if ( aExp != 0 )
+        aSig |= 0x00800000;
+    else if ( aSig == 0 )
+        return a;
+
+    aExp += n - 1;
+    aSig <<= 7;
+    return normalizeRoundAndPackFloat32( aSign, aExp, aSig STATUS_VAR );
 }
 
 float64 float64_scalbn( float64 a, int n STATUS_PARAM )
@@ -5496,8 +5502,14 @@
     if ( aExp == 0x7FF ) {
         return a;
     }
-    aExp += n;
-    return roundAndPackFloat64( aSign, aExp, aSig STATUS_VAR );
+    if ( aExp != 0 )
+        aSig |= LIT64( 0x0010000000000000 );
+    else if ( aSig == 0 )
+        return a;
+
+    aExp += n - 1;
+    aSig <<= 10;
+    return normalizeRoundAndPackFloat64( aSign, aExp, aSig STATUS_VAR );
 }
 
 #ifdef FLOATX80
@@ -5514,9 +5526,12 @@
     if ( aExp == 0x7FF ) {
         return a;
     }
+    if (aExp == 0 && aSig == 0)
+        return a;
+
     aExp += n;
-    return roundAndPackFloatx80( STATUS(floatx80_rounding_precision),
-                                 aSign, aExp, aSig, 0 STATUS_VAR );
+    return normalizeRoundAndPackFloatx80( STATUS(floatx80_rounding_precision),
+                                          aSign, aExp, aSig, 0 STATUS_VAR );
 }
 #endif
 
@@ -5534,8 +5549,14 @@
     if ( aExp == 0x7FFF ) {
         return a;
     }
-    aExp += n;
-    return roundAndPackFloat128( aSign, aExp, aSig0, aSig1, 0 STATUS_VAR );
+    if ( aExp != 0 )
+        aSig0 |= LIT64( 0x0001000000000000 );
+    else if ( aSig0 == 0 && aSig1 == 0 )
+        return a;
 
+    aExp += n - 1;
+    return normalizeRoundAndPackFloat128( aSign, aExp, aSig0, aSig1
+                                          STATUS_VAR );
+
 }
 #endif