factor expressions into single file

1 files changed, 12 insertions, 0 deletions

diff --git a/mppa_k1c/bitmasks.py b/mppa_k1c/bitmasks.py
new file mode 100755
index 00000000..9f6987d6
--- /dev/null
+++ b/mppa_k1c/bitmasks.py
@@ -0,0 +1,12 @@
+#!/usr/bin/env python3
+def bitmask(to, fr):
+    bit_to = 1<<to
+    return (bit_to | (bit_to - 1)) & ~((1<<fr)-1)
+
+def bitmask2(to, fr):
+    bit_to = 1<<to
+    return bit_to + (bit_to - (1 << fr))
+
+for stop in range(32):
+    for start in range(stop+1):
+        assert(bitmask(stop, start) == bitmask2(stop, start))