Changeset 25eec4e in mainline for uspace/lib/softfloat/common.c

Timestamp:

2013-04-19T18:38:18Z (12 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

6d717a4

Parents:

a1e2df13 (diff), 289cb7dd (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge mainline chages.

File:

• uspace/lib/softfloat/common.c (modified) (2 diffs)

uspace/lib/softfloat/common.c

@@ -39 +39 @@
 /* Table for fast leading zeroes counting. */
 char zeroTable[256] = {
-        8, 7, 7, 6, 6, 6, 6, 4, 4, 4, 4, 4, 4, 4, 4, \
+        8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, \
         3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, \
         2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, \
@@ -307 +307 @@
 /**
  * Round and normalize number expressed by exponent and fraction with
- * first bit (equal to hidden bit) at 62nd bit.
+ * first bit (equal to hidden bit) at bit 62.
  *
  * @param exp Exponent part.
- * @param fraction Fraction with hidden bit shifted to 62nd bit.
+ * @param fraction Fraction with hidden bit shifted to bit 62.
  */
 void round_float64(int32_t *exp, uint64_t *fraction)
 {
-        /* rounding - if first bit after fraction is set then round up */
+        /*
+         * Rounding - if first bit after fraction is set then round up.
+         */
+
+        /*
+         * Add 1 to the least significant bit of the fraction respecting the
+         * current shift to bit 62 and see if there will be a carry to bit 63.
+         */
         (*fraction) += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3));
         
+        /* See if there was a carry to bit 63. */
         if ((*fraction) & 
-            (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 3))) {
+            (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1))) {
                 /* rounding overflow */
                 ++(*exp);