TODO for 5.2 v3

[bodrato at mail.dm.unipi.it]

Ciao,

Il Mar, 7 Gennaio 2014 4:58 pm, Niels Möller ha scritto:
> Here's a first patch adding a couple of other functions. Benchmarking
> and testing is missing (except that the sec_minvert tests still pass).

Interesting...

> diff -r 84343784aa3d mpn/x86_64/cnd_neg.asm
> --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
> +++ b/mpn/x86_64/cnd_neg.asm	Tue Jan 07 15:13:37 2014 +0100

What about _itch functions when the .asm source is used?

> +C scratch parameter is ignored

_itch should return 0...

And some obvious patch like the following would take advantage of this.

diff -r 639a0512bdd9 mpn/generic/sec_minvert.c
--- a/mpn/generic/sec_minvert.c Sun Jan 12 20:27:20 2014 +0100
+++ b/mpn/generic/sec_minvert.c Mon Jan 13 11:21:20 2014 +0100
@@ -85,7 +85,7 @@
 mp_size_t
 mpn_sec_minvert_itch (mp_size_t n)
 {
-  return 4*n;
+  return 3*n + MIN (mpn_cnd_neg_itch (n), mpn_sec_add_1_itch (n));
 }

 /* Compute V <-- A^{-1} (mod M), in data-independent time. M must be
@@ -106,7 +106,8 @@
   ASSERT (! MPN_OVERLAP_P (ap, n, vp, n));
 #define bp (scratch + n)
 #define up (scratch + 2*n)
-#define m1hp (scratch + 3*n)
+#define m1hp (scratch)
+#define top_scratch (scratch + 3*n)

   /* Maintain

@@ -126,7 +127,7 @@
   mpn_zero (vp, n);

   ASSERT_CARRY (mpn_rshift (m1hp, mp, n, 1));
-  ASSERT_NOCARRY (mpn_sec_add_1 (m1hp, m1hp, n, 1, scratch));
+  ASSERT_NOCARRY (mpn_sec_add_1 (m1hp, m1hp, n, 1, top_scratch));

   while (bit_size-- > 0)
     {
@@ -171,7 +172,7 @@

       swap = mpn_cnd_sub_n (odd, ap, ap, bp, n);
       mpn_cnd_add_n (swap, bp, bp, ap, n);
-      mpn_cnd_neg (swap, ap, ap, n, scratch);
+      mpn_cnd_neg (swap, ap, ap, n, top_scratch);

       mpn_cnd_swap (swap, up, vp, n);
       cy = mpn_cnd_sub_n (odd, up, up, vp, n);

Best regards,
m

-- 
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