X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/4468424ee46294bb2073ca546d54cced2b9bdf02..f654f4218ac36981a1174b1f09823997239b0358:/mpx-kmul.c

diff --git a/mpx-kmul.c b/mpx-kmul.c
index d53622b..dd492ad 100644
--- a/mpx-kmul.c
+++ b/mpx-kmul.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: mpx-kmul.c,v 1.3 1999/12/13 15:35:01 mdw Exp $
+ * $Id: mpx-kmul.c,v 1.4 2000/06/17 11:42:11 mdw Exp $
  *
  * Karatsuba's multiplication algorithm
  *
@@ -30,6 +30,10 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: mpx-kmul.c,v $
+ * Revision 1.4  2000/06/17 11:42:11  mdw
+ * Moved the Karatsuba macros into a separate file for better sharing.
+ * Fixed some comments.
+ *
  * Revision 1.3  1999/12/13 15:35:01  mdw
  * Simplify and improve.
  *
@@ -47,6 +51,7 @@
 #include <stdio.h>
 
 #include "mpx.h"
+#include "mpx-kmac.h"
 
 /*----- Tweakables --------------------------------------------------------*/
 
@@ -55,76 +60,6 @@
 #  define KARATSUBA_CUTOFF 2
 #endif
 
-/*----- Addition macros ---------------------------------------------------*/
-
-#define UADD(dv, av, avl) do {						\
-  mpw *_dv = (dv);							\
-  const mpw *_av = (av), *_avl = (avl);					\
-  mpw _c = 0;								\
-									\
-  while (_av < _avl) {							\
-    mpw _a, _b;								\
-    mpd _x;								\
-    _a = *_av++;							\
-    _b = *_dv;								\
-    _x = (mpd)_a + (mpd)_b + _c;					\
-    *_dv++ = MPW(_x);							\
-    _c = _x >> MPW_BITS;						\
-  }									\
-  while (_c) {								\
-    mpd _x = (mpd)*_dv + (mpd)_c;					\
-    *_dv++ = MPW(_x);							\
-    _c = _x >> MPW_BITS;						\
-  }									\
-} while (0)
-
-#define UADD2(dv, dvl, av, avl, bv, bvl) do {				\
-  mpw *_dv = (dv), *_dvl = (dvl);					\
-  const mpw *_av = (av), *_avl = (avl);					\
-  const mpw *_bv = (bv), *_bvl = (bvl);					\
-  mpw _c = 0;								\
-									\
-  while (_av < _avl || _bv < _bvl) {					\
-    mpw _a, _b;								\
-    mpd _x;								\
-    _a = (_av < _avl) ? *_av++ : 0;					\
-    _b = (_bv < _bvl) ? *_bv++ : 0;					\
-    _x = (mpd)_a + (mpd)_b + _c;					\
-    *_dv++ = MPW(_x);							\
-    _c = _x >> MPW_BITS;						\
-  }									\
-  *_dv++ = _c;								\
-  while (_dv < _dvl)							\
-    *_dv++ = 0;								\
-} while (0)
-
-#define USUB(dv, av, avl) do {						\
-  mpw *_dv = (dv);							\
-  const mpw *_av = (av), *_avl = (avl);					\
-  mpw _c = 0;								\
-									\
-  while (_av < _avl) {							\
-    mpw _a, _b;								\
-    mpd _x;								\
-    _a = *_av++;							\
-    _b = *_dv;								\
-    _x = (mpd)_b - (mpd)_a - _c;					\
-    *_dv++ = MPW(_x);							\
-    if (_x >> MPW_BITS)							\
-      _c = 1;								\
-    else								\
-      _c = 0;								\
-  }									\
-  while (_c) {								\
-    mpd _x = (mpd)*_dv - (mpd)_c;					\
-    *_dv++ = MPW(_x);							\
-    if (_x >> MPW_BITS)							\
-      _c = 1;								\
-    else								\
-      _c = 0;								\
-  }									\
-} while (0)
-
 /*----- Main code ---------------------------------------------------------*/
 
 /* --- @mpx_kmul@ --- *
@@ -172,11 +107,11 @@ void mpx_kmul(mpw *dv, mpw *dvl,
 
   /* --- How the algorithm works --- *
    *
-   * Let %$A = xb + y$% and %$B = ub + v$%.  Then, simply by expanding, %$AB
-   * = x u b^2 + b(x v + y u) + y v$%.  That's not helped any, because I've
-   * got four multiplications, each four times easier than the one I started
-   * with.  However, note that I can rewrite the coefficient of %$b$% as
-   * %$xv + yu = (x + y)(u + v) - xu - yv$%.  The terms %$xu$% and %$yv$%
+   * Let %$A = xb + y$% and %$B = ub + v$%.  Then, simply by expanding,
+   * %$AB = x u b^2 + b(x v + y u) + y v$%.  That's not helped any, because
+   * I've got four multiplications, each four times easier than the one I
+   * started with.  However, note that I can rewrite the coefficient of %$b$%
+   * as %$xv + yu = (x + y)(u + v) - xu - yv$%.  The terms %$xu$% and %$yv$%
    * I've already calculated, and that leaves only one more multiplication to
    * do.  So now I have three multiplications, each four times easier, and
    * that's a win.