X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/f94b972d1c0389e4e9203cc9919ceaadbe655b61..025c5f4aa5ffbf8948482a4233318db81c2df5d2:/f-prime.c

diff --git a/f-prime.c b/f-prime.c
index 9b1ceb6..422c386 100644
--- a/f-prime.c
+++ b/f-prime.c
@@ -111,20 +111,20 @@ static mp *fsqrt(field *ff, mp *d, mp *x) {
 
 static mp *fdbl(field *ff, mp *d, mp *x) {
   fctx_prime *f = (fctx_prime *)ff; d = mp_lsl(d, x, 1);
-  if (MP_CMP(d, >, f->mm.m)) d = mp_sub(d, d, f->mm.m);
+  if (MP_CMP(d, >=, f->mm.m)) d = mp_sub(d, d, f->mm.m);
   return (d);
 }
 
 static mp *ftpl(field *ff, mp *d, mp *x) {
   fctx_prime *f = (fctx_prime *)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->mm.m)) d = mp_sub(d, d, f->mm.m);
+  MPX_UMULN(d->v, d->vl, x->v, x->vl, 3); d->f &= ~MP_UNDEF;
+  while (MP_CMP(d, >=, f->mm.m)) d = mp_sub(d, d, f->mm.m);
   return (d);
 }
 
 static mp *fqdl(field *ff, mp *d, mp *x) {
   fctx_prime *f = (fctx_prime *)ff; d = mp_lsl(d, x, 2);
-  while (MP_CMP(d, >, f->mm.m)) d = mp_sub(d, d, f->mm.m);
+  while (MP_CMP(d, >=, f->mm.m)) d = mp_sub(d, d, f->mm.m);
   return (d);
 }
 
@@ -160,16 +160,18 @@ field *field_prime(mp *p)
 {
   fctx_prime *f;
 
-  if (!MP_POSP(p) || !MP_ODDP(p))
-    return (0);
   f = CREATE(fctx_prime);
   f->f.ops = &fops;
-  mpmont_create(&f->mm, p);
+  if (mpmont_create(&f->mm, p)) {
+    DESTROY(f);
+    return (0);
+  }
   f->f.zero = MP_ZERO;
   f->f.one = f->mm.r;
   f->f.m = f->mm.m;
   f->f.nbits = mp_bits(p);
   f->f.noctets = (f->f.nbits + 7) >> 3;
+  f->f.q = f->mm.m;
   return (&f->f);
 }