Add arch directory into src package

src/arch/__init__.py

@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# vim:ts=4:et:sw=4:
+
+import importlib
+
+
+__all__ = [
+    'zx48k',
+    'zxnext'
+]
+
+AVAILABLE_ARCHITECTURES = __all__
+target = None
+
+
+def set_target_arch(target_arch: str):
+    global target
+    assert target_arch in AVAILABLE_ARCHITECTURES
+    target = importlib.import_module(f'.{target_arch}', 'src.arch')
+
+
+set_target_arch(AVAILABLE_ARCHITECTURES[0])

src/arch/zx48k/__init__.py

@@ -0,0 +1,26 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# vim:ts=4:et:sw=4:
+
+from . import beep
+from .translator import *  # noqa
+
+import src.api.global_
+from src.api.constants import TYPE
+
+
+__all__ = [
+    'beep',
+]
+
+
+# -----------------------------------------
+# Arch initialization setup
+# -----------------------------------------
+src.api.global_.PARAM_ALIGN = 2  # Z80 param align
+src.api.global_.BOUND_TYPE = TYPE.uinteger
+src.api.global_.SIZE_TYPE = TYPE.ubyte
+src.api.global_.PTR_TYPE = TYPE.uinteger
+src.api.global_.STR_INDEX_TYPE = TYPE.uinteger
+src.api.global_.MIN_STRSLICE_IDX = 0      # Min. string slicing position
+src.api.global_.MAX_STRSLICE_IDX = 65534  # Max. string slicing position