Changeset 76e501 in git for kernel/rmodulo2m.h

Timestamp:

Jul 21, 2010, 10:37:19 AM (13 years ago)

Author:

Frank Seelisch <seelisch@…>

Branches:

(u'jengelh-datetime', 'ceac47cbc86fe4a15902392bdbb9bd2ae0ea02c6')(u'spielwiese', 'a657104b677b4c461d018cbf3204d72d34ad66a9')

Children:

f0a801bdd99a5337cb60770f49d314447999474b

Parents:

cf21dd42f35f06862c90e2223eea0f33e4ff0fbc

Message:

extends Z/2^m to m =32 resp. 64 (depending on platform)

git-svn-id: file:///usr/local/Singular/svn/trunk@13036 2c84dea3-7e68-4137-9b89-c4e89433aadc

File:

• kernel/rmodulo2m.h (modified) (2 diffs)

kernel/rmodulo2m.h

@@ -12 +12 @@
 
 extern int nr2mExp;
-extern NATNUMBER nr2mModul;
+extern NATNUMBER nr2mModul; /* for storing 2^m - 1, i.e., the
+                               bit pattern '11..1' of length m */
 
 BOOLEAN nr2mGreaterZero (number k);
@@ -51 +52 @@
 static inline number nr2mMultM(number a, number b)
 {
-  return (number) 
-    ((((NATNUMBER) a)*((NATNUMBER) b)) % ((NATNUMBER) currRing->nr2mModul));
+  return (number)
+    ((((NATNUMBER) a) * ((NATNUMBER) b)) & ((NATNUMBER) currRing->nr2mModul));
 }
 
 static inline number nr2mAddM(number a, number b)
 {
-  NATNUMBER r = (NATNUMBER)a + (NATNUMBER)b;
-  return (number) (r >= currRing->nr2mModul ? r - currRing->nr2mModul : r);
+  return (number)
+    ((((NATNUMBER) a) + ((NATNUMBER) b)) & ((NATNUMBER) currRing->nr2mModul));
 }
 
 static inline number nr2mSubM(number a, number b)
 {
-  return (number)((NATNUMBER)a<(NATNUMBER)b ?
-                       currRing->nr2mModul-(NATNUMBER)b+(NATNUMBER)a : (NATNUMBER)a-(NATNUMBER)b);
+  return (number)((NATNUMBER)a < (NATNUMBER)b ?
+                     currRing->nr2mModul - (NATNUMBER)b + (NATNUMBER)a + 1 :
+                     (NATNUMBER)a - (NATNUMBER)b);
 }
 
-#define nr2mNegM(A) (number)(currRing->nr2mModul-(NATNUMBER)(A))
+#define nr2mNegM(A) (number)(currRing->nr2mModul - (NATNUMBER)(A) + 1)
 #define nr2mEqualM(A,B)  ((A)==(B))