emulator improvements

h8536/emulator/cpu.py

@@ -0,0 +1,34 @@
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+
+
+@dataclass
+class CPUState:
+    pc: int = 0
+    sr: int = 0
+    br: int = 0
+    regs: list[int] = field(default_factory=lambda: [0] * 8)
+    cycles: int = 0
+    steps: int = 0
+    z: bool = False
+    c: bool = False
+    n: bool = False
+    v: bool = False
+    interrupt_depth: int = 0
+
+
+def s8(value: int) -> int:
+    return value - 0x100 if value & 0x80 else value
+
+
+def s16(value: int) -> int:
+    return value - 0x10000 if value & 0x8000 else value
+
+
+def mask(size: int) -> int:
+    return 0xFFFF if size == 2 else 0xFF
+
+
+def sign_bit(size: int) -> int:
+    return 0x8000 if size == 2 else 0x80