Split out predicates and settings.

- cdsl.predicates defines classes for describing predicates.
- cdsl.settings defines classes for describing settings.
- base.settings defines shared settings.

lib/cretonne/meta/base/settings.py

@@ -0,0 +1,35 @@
+"""
+Cretonne shared settings.
+
+This module defines settings are are relevant for all code generators.
+"""
+from __future__ import absolute_import
+from cdsl.settings import SettingGroup, BoolSetting, EnumSetting
+
+group = SettingGroup('shared')
+
+opt_level = EnumSetting(
+        """
+        Optimization level:
+
+        - default: Very profitable optimizations enabled, none slow.
+        - best: Enable all optimizations
+        - fastest: Optimize for compile time by disabling most optimizations.
+        """,
+        'default', 'best', 'fastest')
+
+is_64bit = BoolSetting("Enable 64-bit code generation")
+
+enable_float = BoolSetting(
+        """Enable the use of floating-point instructions""",
+        default=True)
+
+enable_simd = BoolSetting(
+        """Enable the use of SIMD instructions.""",
+        default=True)
+
+enable_atomics = BoolSetting(
+        """Enable the use of atomic instructions""",
+        default=True)
+
+group.close(globals())