From a9025c58a47d985dd0cec10344b5f33ded1ac51c Mon Sep 17 00:00:00 2001
From: h01G3r <63418746+h01G3r@users.noreply.github.com>
Date: Thu, 20 Aug 2020 17:24:04 +0200
Subject: [PATCH] fixes an issue with ARM APSR register handling: (#1317)

- Q flag / GE flag were not included in APSR register (read/write)
  - UC_ARM_REG_APSR_NZCV register constant was ignored completely.
  - regression test added
---
 qemu/target-arm/unicorn_arm.c    |  6 ++++++
 tests/regress/arm_apsr_access.py | 30 ++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)
 create mode 100644 tests/regress/arm_apsr_access.py

diff --git a/qemu/target-arm/unicorn_arm.c b/qemu/target-arm/unicorn_arm.c
index 0e1b1828..d5b9a7d9 100644
--- a/qemu/target-arm/unicorn_arm.c
+++ b/qemu/target-arm/unicorn_arm.c
@@ -69,6 +69,9 @@ int arm_reg_read(struct uc_struct *uc, unsigned int *regs, void **vals, int coun
         else {
             switch(regid) {
                 case UC_ARM_REG_APSR:
+                    *(int32_t *)value = cpsr_read(&ARM_CPU(uc, mycpu)->env) & (CPSR_NZCV | CPSR_Q | CPSR_GE);
+                    break;
+                case UC_ARM_REG_APSR_NZCV:
                     *(int32_t *)value = cpsr_read(&ARM_CPU(uc, mycpu)->env) & CPSR_NZCV;
                     break;
                 case UC_ARM_REG_CPSR:
@@ -132,6 +135,9 @@ int arm_reg_write(struct uc_struct *uc, unsigned int *regs, void* const* vals, i
         else {
             switch(regid) {
                 case UC_ARM_REG_APSR:
+                    cpsr_write(&ARM_CPU(uc, mycpu)->env, *(uint32_t *)value, (CPSR_NZCV | CPSR_Q | CPSR_GE));
+                    break;
+                case UC_ARM_REG_APSR_NZCV:
                     cpsr_write(&ARM_CPU(uc, mycpu)->env, *(uint32_t *)value, CPSR_NZCV);
                     break;
                 case UC_ARM_REG_CPSR:
diff --git a/tests/regress/arm_apsr_access.py b/tests/regress/arm_apsr_access.py
new file mode 100644
index 00000000..33c10fd9
--- /dev/null
+++ b/tests/regress/arm_apsr_access.py
@@ -0,0 +1,30 @@
+#!/usr/bin/python
+
+from unicorn import *
+from unicorn.arm_const import *
+
+import regress
+
+class APSRAccess(regress.RegressTest):
+
+    def runTest(self):
+        code = (
+            b'\x00\x00\xa0\xe1' + #  0: mov r0, r0
+            b'\x08\x10\x9f\xe5' + #  4: ldr r1, [pc, #8]
+            b'\x01\xf0\x28\xe1' + #  8: 01 f0 28 e1  msr apsr_nzcvq, r1
+            b'\x00\x00\xa0\xe1' + #  c: mov r0, r0
+            b'\x00\x00\xa0\xe1' + # 10: mov r0, r0
+            b'\x00\x00\x00\xff')  # 14: data for inst @4
+
+        uc = Uc(UC_ARCH_ARM, UC_MODE_ARM)
+        uc.mem_map(0x1000, 0x1000)
+        uc.mem_write(0x1000, code)  # bxeq lr; mov r0, r0
+
+        uc.reg_write(UC_ARM_REG_APSR, 0)
+        uc.emu_start(0x1000, 0x100c)
+
+        self.assertEqual(uc.reg_read(UC_ARM_REG_APSR), 0xf8000000)
+        self.assertEqual(uc.reg_read(UC_ARM_REG_APSR_NZCV), 0xf0000000)
+
+if __name__ == '__main__':
+    regress.main()