[libmath-prime-util-perl] 01/16: Tweak to mulmod use

[Partha P. Mukherjee]

This is an automated email from the git hooks/post-receive script.

ppm-guest pushed a commit to annotated tag v0.06
in repository libmath-prime-util-perl.

commit e0ab486cf9bbb4e2f7a153c97d8bb7eabe5ea44e
Author: Dana Jacobsen <dana at acm.org>
Date:   Fri Jun 8 14:13:11 2012 -0600

    Tweak to mulmod use
---
 Changes  |  3 +++
 factor.c | 13 +++++++------
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/Changes b/Changes
index 9277d67..980499a 100644
--- a/Changes
+++ b/Changes
@@ -1,5 +1,8 @@
 Revision history for Perl extension Math::Prime::Util.
 
+0.05  8 June 2012
+    - Use assembler for mulmod if 64-bit and gcc and x86
+
 0.04  7 June 2012
     - Didn't do tests on 32-bit machine before release.  Test suite caught
       problem with next_prime overflow.
diff --git a/factor.c b/factor.c
index b02ff1a..1b06519 100644
--- a/factor.c
+++ b/factor.c
@@ -100,9 +100,11 @@ int trial_factor(UV n, UV *factors, UV maxtrial)
 
   /* UV is the largest integral type available (that we know of). */
 
+  /* if n is smaller than this, you can multiply without overflow */
+  #define HALF_WORD (UVCONST(1) << (BITS_PER_WORD/2))
+
   #if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
     /* Inline assembly -- basically as fast as a regular (a*b)%m */
-    /* Arguably we don't need all the ifs to avoid it */
     static UV _mulmod(UV a, UV b, UV c) {
       UV d; /* to hold the result of a*b mod c */
       /* calculates a*b mod c, stores result in d */
@@ -116,6 +118,8 @@ int trial_factor(UV n, UV *factors, UV maxtrial)
           );
       return d;
     }
+    #define mulmod(a,b,m) _mulmod(a,b,m)
+    #define sqrmod(n,m)   _mulmod(n,n,m)
   #else
     /* Do it by hand */
     static UV _mulmod(UV a, UV b, UV m) {
@@ -134,14 +138,11 @@ int trial_factor(UV n, UV *factors, UV maxtrial)
       }
       return r;
     }
+    #define mulmod(a,b,m) (((a)|(b)) < HALF_WORD) ? ((a)*(b))%(m):_mulmod(a,b,m)
+    #define sqrmod(n,m)   ((n) < HALF_WORD)       ? ((n)*(n))%(m):_mulmod(n,n,m)
   #endif
 
-  /* if n is smaller than this, you can multiply without overflow */
-  #define HALF_WORD (UVCONST(1) << (BITS_PER_WORD/2))
-
   #define addmod(n,a,m) ((((m)-(n)) > (a))  ?  ((n)+(a))  :  ((n)+(a)-(m)))
-  #define mulmod(a,b,m) (((a)|(b)) < HALF_WORD) ? ((a)*(b))%(m) : _mulmod(a,b,m)
-  #define sqrmod(n,m)   ((n) < HALF_WORD)       ? ((n)*(n))%(m) : _mulmod(n,n,m)
 
   /* n^power mod m */
   static UV powmod(UV n, UV power, UV m) {

-- 
Alioth's /usr/local/bin/git-commit-notice on /srv/git.debian.org/git/pkg-perl/packages/libmath-prime-util-perl.git