Have qdb use xPSR for Cortex M instead of CPSR

Author: elicn

qiling/debugger/qdb/arch/arch_arm.py

@@ -3,12 +3,14 @@
 # Cross Platform and Multi Architecture Advanced Binary Emulation Framework
 #
 
-from typing import Dict, Optional
+from typing import ClassVar, Dict, Optional
 
 from .arch import Arch
 
 
 class ArchARM(Arch):
+    _flags_reg: ClassVar[str] = 'cpsr'
+
     def __init__(self) -> None:
         regs = (
             'r0', 'r1', 'r2', 'r3',
@@ -134,6 +136,8 @@ def read_insn(self, address: int) -> Optional[bytearray]:
 
 
 class ArchCORTEX_M(ArchARM):
+    _flags_reg: ClassVar[str] = 'xpsr'
+
     def __init__(self):
         super().__init__()
 

qiling/debugger/qdb/branch_predictor/branch_predictor_arm.py

@@ -31,7 +31,7 @@ def get_cpsr(self) -> Tuple[bool, bool, bool, bool]:
         """Get flags map of CPSR.
         """
 
-        cpsr = self.read_reg('cpsr')
+        cpsr = self.read_reg(self._flags_reg)
 
         return (
             (cpsr & (0b1 << 28)) != 0,  # V, overflow flag

qiling/debugger/qdb/render/render_arm.py

@@ -15,7 +15,7 @@ class ContextRenderARM(ContextRender, ArchARM):
     """
 
     def print_mode_info(self) -> None:
-        cpsr = self.read_reg('cpsr')
+        cpsr = self.read_reg(self._flags_reg)
 
         flags = ArchARM.get_flags(cpsr)
         mode = ArchARM.get_mode(cpsr)