X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/e40955b56456a6191ebff48b00c667a0674b3bdb..f4535c6454395e6d56ce0091a07b6d4f7d54a47f:/mpreduce.c

diff --git a/mpreduce.c b/mpreduce.c
index 13e705e..d99ff16 100644
--- a/mpreduce.c
+++ b/mpreduce.c
@@ -47,12 +47,12 @@ DA_DECL(instr_v, mpreduce_instr);
  * Arguments:	@gfreduce *r@ = structure to fill in
  *		@mp *x@ = an integer
  *
- * Returns:	---
+ * Returns:	Zero if successful; nonzero on failure.
  *
  * Use:		Initializes a context structure for reduction.
  */
 
-void mpreduce_create(mpreduce *r, mp *p)
+int mpreduce_create(mpreduce *r, mp *p)
 {
   mpscan sc;
   enum { Z = 0, Z1 = 2, X = 4, X0 = 6 };
@@ -64,7 +64,8 @@ void mpreduce_create(mpreduce *r, mp *p)
 
   /* --- Fill in the easy stuff --- */
 
-  assert(MP_POSP(p));
+  if (!MP_POSP(p))
+    return (-1);
   d = mp_bits(p);
   r->lim = d/MPW_BITS;
   r->s = d%MPW_BITS;
@@ -118,9 +119,9 @@ void mpreduce_create(mpreduce *r, mp *p)
     }
   }
   if ((DA(&iv)[DA_LEN(&iv) - 1].op & ~1u) == MPRI_SUB) {
-    fprintf(stderr,
-	    "mpreduce can't handle moduli of the form 2^m + x\n");
-    abort();
+    mp_drop(r->p);
+    DA_DESTROY(&iv);
+    return (-1);
   }
 
 #undef INSTR
@@ -149,7 +150,8 @@ void mpreduce_create(mpreduce *r, mp *p)
       r->iv[i + r->in].argy = b;
     }
   }
-  DA_DESTROY(&iv);  
+  DA_DESTROY(&iv);
+  return (0);
 }
 
 /* --- @mpreduce_destroy@ --- *