nga-python: add stubs for benchmark device (#28); add support for running under Python2 (for use w/pypy)

FossilOrigin-Name: 2b8e1c48bdb444f0b08f9813fa09493455f801e058146e75a27acb35a2907393

vm/nga-python/BenchmarkDevice.py

@@ -0,0 +1,23 @@
+# Benchmark Support
+#
+# This is intended to help support benchmarking by
+# providing high resolution timing and instruction
+# usage data.
+#
+
+import time
+
+
+class BenchmarkDevice:
+    def __init__(self):
+        pass
+
+    def execute(self, retro_instance, pointer):
+        return 0
+
+    def timer_resolution(self):
+        try:
+            time.time_ns()
+            return 1
+        except:
+            return 0

vm/nga-python/retro.py

@@ -1,8 +1,10 @@
 #!/usr/bin/env python3
 
 # Nga: a Virtual Machine
-# Copyright (c) 2010 - 2020, Charles Childers
+#
+# Copyright (c) 2010 - 2021, Charles Childers
 # Floating Point I/O by Arland Childers, (c) 2020
+# Pythonista UI support by Arland Childers, (c) 2021
 # Optimizations and process() rewrite by Greg Copeland
 # -------------------------------------------------------------
 # This implementation of the VM differs from the reference
@@ -36,6 +38,20 @@ from IntegerStack import IntegerStack
 from Memory import Memory
 from InitialImage import InitialImage
 
+from BenchmarkDevice import BenchmarkDevice
+
+# -------------------------------------------------------------
+# To Support Python 2.x
+# -------------------------------------------------------------
+
+from sys import version_info
+if version_info.major == 3:
+    pass
+elif version_info.major == 2:
+    try:
+        input = raw_input
+    except NameError:
+        pass
 
 class Retro:
     def map_in(self, name):