Ciao,
4 set 2023, 08:02 da [email protected]:
> As Vincent suggested, it would be good to document somewhere what the
> convention is (values 0 or ~0).
>
Would a comment "It returns 0 or ~0, depending on the sign of the result"
added to all the mpn_toom_eval_ functions suffice?
> And maybe change to 0 and 1 convention,
>
I see a line
mpn/generic/toom42_mul.c: vm1_neg = mpn_toom_eval_dgr3_pm1 (as1, asm1, ap, n,
s, a0_a2) & 1;
where we actually use 0 or 1, and many lines like
mpn/generic/toom52_mul.c: flags = (enum toom6_flags) (toom6_vm2_neg &
mpn_toom_eval_pm2 (as2, asm2, 4, ap, n, s, a1a3));
where we use the value as a mask: 0 or ~ 0.
>From the value in {0,1} we can get mask = -value, and from the mask in {0, ~0}
>we can get value = mask & 1.
Of course we can switch to a different convention, if someone feels it's
important. I don't.
> since that fits better with assigning it from the return value from
> mpn_sub_n, and it seems generally more consistent with how we handle
>
We never use mpn_sub_n to assign that value.
> boolean values elsewhere. But may need further changes, like to
> abs_sub_add_n, also noted by Vincent.
>
Yes, Vincent is right. New patch.
Should the value ~0 be written as ~0U to be correctly assigned to an unsigned?
Ĝis,
m
diff -r e3cc6f9e9753 gmp-impl.h
--- a/gmp-impl.h Sun Aug 27 20:47:01 2023 +0200
+++ b/gmp-impl.h Mon Sep 04 09:40:02 2023 +0200
@@ -1481,25 +1481,25 @@
__GMP_DECLSPEC void mpn_toom_interpolate_16pts (mp_ptr, mp_ptr, mp_ptr, mp_ptr, mp_ptr, mp_size_t, mp_size_t, int, mp_ptr);
#define mpn_toom_couple_handling __MPN(toom_couple_handling)
-__GMP_DECLSPEC void mpn_toom_couple_handling (mp_ptr, mp_size_t, mp_ptr, int, mp_size_t, int, int);
+__GMP_DECLSPEC void mpn_toom_couple_handling (mp_ptr, mp_size_t, mp_ptr, unsigned, mp_size_t, int, int);
#define mpn_toom_eval_dgr3_pm1 __MPN(toom_eval_dgr3_pm1)
-__GMP_DECLSPEC int mpn_toom_eval_dgr3_pm1 (mp_ptr, mp_ptr, mp_srcptr, mp_size_t, mp_size_t, mp_ptr);
+__GMP_DECLSPEC unsigned mpn_toom_eval_dgr3_pm1 (mp_ptr, mp_ptr, mp_srcptr, mp_size_t, mp_size_t, mp_ptr);
#define mpn_toom_eval_dgr3_pm2 __MPN(toom_eval_dgr3_pm2)
-__GMP_DECLSPEC int mpn_toom_eval_dgr3_pm2 (mp_ptr, mp_ptr, mp_srcptr, mp_size_t, mp_size_t, mp_ptr);
+__GMP_DECLSPEC unsigned mpn_toom_eval_dgr3_pm2 (mp_ptr, mp_ptr, mp_srcptr, mp_size_t, mp_size_t, mp_ptr);
#define mpn_toom_eval_pm1 __MPN(toom_eval_pm1)
-__GMP_DECLSPEC int mpn_toom_eval_pm1 (mp_ptr, mp_ptr, unsigned, mp_srcptr, mp_size_t, mp_size_t, mp_ptr);
+__GMP_DECLSPEC unsigned mpn_toom_eval_pm1 (mp_ptr, mp_ptr, unsigned, mp_srcptr, mp_size_t, mp_size_t, mp_ptr);
#define mpn_toom_eval_pm2 __MPN(toom_eval_pm2)
-__GMP_DECLSPEC int mpn_toom_eval_pm2 (mp_ptr, mp_ptr, unsigned, mp_srcptr, mp_size_t, mp_size_t, mp_ptr);
+__GMP_DECLSPEC unsigned mpn_toom_eval_pm2 (mp_ptr, mp_ptr, unsigned, mp_srcptr, mp_size_t, mp_size_t, mp_ptr);
#define mpn_toom_eval_pm2exp __MPN(toom_eval_pm2exp)
-__GMP_DECLSPEC int mpn_toom_eval_pm2exp (mp_ptr, mp_ptr, unsigned, mp_srcptr, mp_size_t, mp_size_t, unsigned, mp_ptr);
+__GMP_DECLSPEC unsigned mpn_toom_eval_pm2exp (mp_ptr, mp_ptr, unsigned, mp_srcptr, mp_size_t, mp_size_t, unsigned, mp_ptr);
#define mpn_toom_eval_pm2rexp __MPN(toom_eval_pm2rexp)
-__GMP_DECLSPEC int mpn_toom_eval_pm2rexp (mp_ptr, mp_ptr, unsigned, mp_srcptr, mp_size_t, mp_size_t, unsigned, mp_ptr);
+__GMP_DECLSPEC unsigned mpn_toom_eval_pm2rexp (mp_ptr, mp_ptr, unsigned, mp_srcptr, mp_size_t, mp_size_t, unsigned, mp_ptr);
#define mpn_toom22_mul __MPN(toom22_mul)
__GMP_DECLSPEC void mpn_toom22_mul (mp_ptr, mp_srcptr, mp_size_t, mp_srcptr, mp_size_t, mp_ptr);
diff -r e3cc6f9e9753 mpn/generic/toom54_mul.c
--- a/mpn/generic/toom54_mul.c Sun Aug 27 20:47:01 2023 +0200
+++ b/mpn/generic/toom54_mul.c Mon Sep 04 09:40:02 2023 +0200
@@ -61,7 +61,7 @@
mp_srcptr bp, mp_size_t bn, mp_ptr scratch)
{
mp_size_t n, s, t;
- int sign;
+ unsigned sign;
/***************************** decomposition *******************************/
#define a4 (ap + 4 * n)
diff -r e3cc6f9e9753 mpn/generic/toom63_mul.c
--- a/mpn/generic/toom63_mul.c Sun Aug 27 20:47:01 2023 +0200
+++ b/mpn/generic/toom63_mul.c Mon Sep 04 09:40:02 2023 +0200
@@ -37,8 +37,9 @@
#include "gmp-impl.h"
-/* Stores |{ap,n}-{bp,n}| in {rp,n}, returns the sign. */
-static int
+/* Stores |{ap,n}-{bp,n}| in {rp,n}. */
+/* It returns 0 or ~0, depending on the sign of the result. */
+static unsigned
abs_sub_n (mp_ptr rp, mp_srcptr ap, mp_srcptr bp, mp_size_t n)
{
mp_limb_t x, y;
@@ -65,9 +66,10 @@
return 0;
}
-static int
+/* It returns 0 or ~0, depending on the sign of the result rm. */
+static unsigned
abs_sub_add_n (mp_ptr rm, mp_ptr rp, mp_srcptr rs, mp_size_t n) {
- int result;
+ unsigned result;
result = abs_sub_n (rm, rp, rs, n);
ASSERT_NOCARRY(mpn_add_n (rp, rp, rs, n));
return result;
@@ -99,7 +101,7 @@
{
mp_size_t n, s, t;
mp_limb_t cy;
- int sign;
+ unsigned sign;
/***************************** decomposition *******************************/
#define a5 (ap + 5 * n)
diff -r e3cc6f9e9753 mpn/generic/toom6h_mul.c
--- a/mpn/generic/toom6h_mul.c Sun Aug 27 20:47:01 2023 +0200
+++ b/mpn/generic/toom6h_mul.c Mon Sep 04 09:40:02 2023 +0200
@@ -109,7 +109,7 @@
{
mp_size_t n, s, t;
int p, q, half;
- int sign;
+ unsigned sign;
/***************************** decomposition *******************************/
diff -r e3cc6f9e9753 mpn/generic/toom8h_mul.c
--- a/mpn/generic/toom8h_mul.c Sun Aug 27 20:47:01 2023 +0200
+++ b/mpn/generic/toom8h_mul.c Mon Sep 04 09:40:02 2023 +0200
@@ -119,7 +119,7 @@
{
mp_size_t n, s, t;
int p, q, half;
- int sign;
+ unsigned sign;
/***************************** decomposition *******************************/
diff -r e3cc6f9e9753 mpn/generic/toom_couple_handling.c
--- a/mpn/generic/toom_couple_handling.c Sun Aug 27 20:47:01 2023 +0200
+++ b/mpn/generic/toom_couple_handling.c Mon Sep 04 09:40:02 2023 +0200
@@ -45,7 +45,7 @@
*/
void
mpn_toom_couple_handling (mp_ptr pp, mp_size_t n, mp_ptr np,
- int nsign, mp_size_t off, int ps, int ns)
+ unsigned nsign, mp_size_t off, int ps, int ns)
{
if (nsign) {
#ifdef HAVE_NATIVE_mpn_rsh1sub_n
diff -r e3cc6f9e9753 mpn/generic/toom_eval_dgr3_pm1.c
--- a/mpn/generic/toom_eval_dgr3_pm1.c Sun Aug 27 20:47:01 2023 +0200
+++ b/mpn/generic/toom_eval_dgr3_pm1.c Mon Sep 04 09:40:02 2023 +0200
@@ -37,11 +37,13 @@
#include "gmp-impl.h"
-int
+/* Evaluates a polynomial of degree 3, in the points +1 and -1. */
+/* It returns 0 or ~0, depending on the sign of the result xm1. */
+unsigned
mpn_toom_eval_dgr3_pm1 (mp_ptr xp1, mp_ptr xm1,
mp_srcptr xp, mp_size_t n, mp_size_t x3n, mp_ptr tp)
{
- int neg;
+ unsigned neg;
ASSERT (x3n > 0);
ASSERT (x3n <= n);
diff -r e3cc6f9e9753 mpn/generic/toom_eval_dgr3_pm2.c
--- a/mpn/generic/toom_eval_dgr3_pm2.c Sun Aug 27 20:47:01 2023 +0200
+++ b/mpn/generic/toom_eval_dgr3_pm2.c Mon Sep 04 09:40:02 2023 +0200
@@ -37,13 +37,15 @@
#include "gmp-impl.h"
+/* Evaluates a polynomial of degree 3, in the points +2 and -2. */
/* Needs n+1 limbs of temporary storage. */
-int
+/* It returns 0 or ~0, depending on the sign of the result xm2. */
+unsigned
mpn_toom_eval_dgr3_pm2 (mp_ptr xp2, mp_ptr xm2,
mp_srcptr xp, mp_size_t n, mp_size_t x3n, mp_ptr tp)
{
mp_limb_t cy;
- int neg;
+ unsigned neg;
ASSERT (x3n > 0);
ASSERT (x3n <= n);
diff -r e3cc6f9e9753 mpn/generic/toom_eval_pm1.c
--- a/mpn/generic/toom_eval_pm1.c Sun Aug 27 20:47:01 2023 +0200
+++ b/mpn/generic/toom_eval_pm1.c Mon Sep 04 09:40:02 2023 +0200
@@ -38,12 +38,13 @@
#include "gmp-impl.h"
/* Evaluates a polynomial of degree k > 3, in the points +1 and -1. */
-int
+/* It returns 0 or ~0, depending on the sign of the result xm1. */
+unsigned
mpn_toom_eval_pm1 (mp_ptr xp1, mp_ptr xm1, unsigned k,
mp_srcptr xp, mp_size_t n, mp_size_t hn, mp_ptr tp)
{
unsigned i;
- int neg;
+ unsigned neg;
ASSERT (k >= 4);
diff -r e3cc6f9e9753 mpn/generic/toom_eval_pm2.c
--- a/mpn/generic/toom_eval_pm2.c Sun Aug 27 20:47:01 2023 +0200
+++ b/mpn/generic/toom_eval_pm2.c Mon Sep 04 09:40:02 2023 +0200
@@ -65,12 +65,13 @@
/* Evaluates a polynomial of degree 2 < k < GMP_NUMB_BITS, in the
points +2 and -2. */
-int
+/* It returns 0 or ~0, depending on the sign of the result xm2. */
+unsigned
mpn_toom_eval_pm2 (mp_ptr xp2, mp_ptr xm2, unsigned k,
mp_srcptr xp, mp_size_t n, mp_size_t hn, mp_ptr tp)
{
int i;
- int neg;
+ unsigned neg;
mp_limb_t cy;
ASSERT (k >= 3);
diff -r e3cc6f9e9753 mpn/generic/toom_eval_pm2exp.c
--- a/mpn/generic/toom_eval_pm2exp.c Sun Aug 27 20:47:01 2023 +0200
+++ b/mpn/generic/toom_eval_pm2exp.c Mon Sep 04 09:40:02 2023 +0200
@@ -38,13 +38,14 @@
#include "gmp-impl.h"
/* Evaluates a polynomial of degree k > 2, in the points +2^shift and -2^shift. */
-int
+/* It returns 0 or ~0, depending on the sign of the result xm2. */
+unsigned
mpn_toom_eval_pm2exp (mp_ptr xp2, mp_ptr xm2, unsigned k,
mp_srcptr xp, mp_size_t n, mp_size_t hn, unsigned shift,
mp_ptr tp)
{
unsigned i;
- int neg;
+ unsigned neg;
#if HAVE_NATIVE_mpn_addlsh_n
mp_limb_t cy;
#endif
diff -r e3cc6f9e9753 mpn/generic/toom_eval_pm2rexp.c
--- a/mpn/generic/toom_eval_pm2rexp.c Sun Aug 27 20:47:01 2023 +0200
+++ b/mpn/generic/toom_eval_pm2rexp.c Mon Sep 04 09:40:02 2023 +0200
@@ -54,13 +54,14 @@
#endif
/* Evaluates a polynomial of degree k >= 3. */
-int
+/* It returns 0 or ~0, depending on the sign of the result rm. */
+unsigned
mpn_toom_eval_pm2rexp (mp_ptr rp, mp_ptr rm,
unsigned int q, mp_srcptr ap, mp_size_t n, mp_size_t t,
unsigned int s, mp_ptr ws)
{
unsigned int i;
- int neg;
+ unsigned neg;
/* {ap,q*n+t} -> {rp,n+1} {rm,n+1} , with {ws, n+1}*/
ASSERT (n >= t);
ASSERT (s != 0); /* or _eval_pm1 should be used */
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