Import Upstream version 2c3upstream/2c3

1 files changed, 17 insertions, 11 deletions

diff --git a/primes.scm b/primes.scm
index 769e2bc..672e899 100644
--- a/primes.scm
+++ b/primes.scm
@@ -85,23 +85,26 @@
 
 ;; Is `n' Divisible By a Small Prime?
 ;;
-(define (primes:dbsp? n)
-  (let ((limit (min (sqrt n) primes:max-small-prime))
-	(divisible #f)
-	)
-    (do ((i 0 (1+ i)))
-	((let* ((divisor (vector-ref primes:small-primes i)))
-	   (set! divisible (= (modulo n divisor) 0))
-	   (or divisible (>= divisor limit)))
-	 divisible)
-      )))
+(define primes:dbsp?
+  (let ((sqrt (cond ((provided? 'inexact) sqrt)
+		    (else (require 'root) integer-sqrt))))
+    (lambda (n)
+      (let ((limit (min (sqrt n) primes:max-small-prime))
+	    (divisible #f)
+	    )
+	(do ((i 0 (1+ i)))
+	    ((let* ((divisor (vector-ref primes:small-primes i)))
+	       (set! divisible (= (modulo n divisor) 0))
+	       (or divisible (> divisor limit)))
+	     divisible)
+	  )))))
 
 
 ;; Does `n' pass the R.-M. primality test for `m' random numbers?
 ;;
 (define (primes:rm-prime? n m)
   (do ((i 0 (1+ i))
-       (x (+ 2 (random (- n 2)))))
+       (x (+ 2 (random (- n 2) primes:prngs))))
       ((or (= i m) (primes:rm-composite? n x))
        (= i m))))
 
@@ -150,6 +153,9 @@
 	(set! y (modulo (* y z) modulus)))
     ))
 
+(define primes:prngs
+  (make-random-state "repeatable seed for primes"))
+
 ;; This table seems big enough so that making it larger really
 ;; doesn't have much effect.
 ;;