1 files changed, 35 insertions, 0 deletions
diff --git a/benchmark/so_nsieve.rb b/benchmark/so_nsieve.rb
new file mode 100644
index 0000000000..a65cc78233
--- /dev/null
+++ b/benchmark/so_nsieve.rb
@@ -0,0 +1,35 @@
+# The Computer Language Shootout
+# http://shootout.alioth.debian.org/
+#
+# contributed by Glenn Parker, March 2005
+# modified by Evan Phoenix, Sept 2006
+
+def sieve(m)
+  flags = Flags.dup[0,m]
+  count = 0
+  pmax = m - 1
+  p = 2
+  while p <= pmax
+    unless flags[p].zero?
+      count += 1
+      mult = p
+      while mult <= pmax
+        flags[mult] = 0
+        mult += p
+      end
+    end
+    p += 1
+  end
+  count
+end
+
+n = 9 # (ARGV[0] || 2).to_i
+Flags = ("\x1" * ( 2 ** n * 10_000)).unpack("c*")
+
+n.downto(n-2) do |exponent|
+  break if exponent < 0
+  m = (1 << exponent) * 10_000
+  # m = (2 ** exponent) * 10_000
+  count = sieve(m)
+  printf "Primes up to %8d %8d\n", m, count
+end