Better reduction.

[u/mdw/catacomb] / f-niceprime.c

diff --git a/f-niceprime.c b/f-niceprime.c
index ce96977..4c9deea 100644 (file)
--- a/f-niceprime.c
+++ b/f-niceprime.c
@@ -99,20 +99,20 @@ static mp *fsqrt(field *ff, mp *d, mp *x) {
 
 static mp *fdbl(field *ff, mp *d, mp *x) {
   fctx_niceprime *f = (fctx_niceprime *)ff; d = mp_lsl(d, x, 1);
-  if (MP_CMP(d, >, f->r.p)) d = mp_sub(d, d, f->r.p);
+  if (MP_CMP(d, >=, f->r.p)) d = mp_sub(d, d, f->r.p);
   return (d);
 }
 
 static mp *ftpl(field *ff, mp *d, mp *x) {
   fctx_niceprime *f = (fctx_niceprime *)ff; MP_DEST(d, MP_LEN(x) + 1, x->f);
-  MPX_UMULN(d->v, d->vl, x->v, x->vl, 3);
-  while (MP_CMP(d, >, f->r.p)) d = mp_sub(d, d, f->r.p);
+  MPX_UMULN(d->v, d->vl, x->v, x->vl, 3); d->f &= ~MP_UNDEF;
+  while (MP_CMP(d, >=, f->r.p)) d = mp_sub(d, d, f->r.p);
   return (d);
 }
 
 static mp *fqdl(field *ff, mp *d, mp *x) {
   fctx_niceprime *f = (fctx_niceprime *)ff; d = mp_lsl(d, x, 2);
-  while (MP_CMP(d, >, f->r.p)) d = mp_sub(d, d, f->r.p);
+  while (MP_CMP(d, >=, f->r.p)) d = mp_sub(d, d, f->r.p);
   return (d);
 }
 
@@ -157,6 +157,7 @@ field *field_niceprime(mp *p)
     return (0);
   }
   f->f.m = f->r.p;
+  f->f.q = f->r.p;
   return (&f->f);
 }