ARM: Decode the clz instruction.

2 files changed, 14 insertions, 4 deletions

diff --git a/src/arch/arm/isa/formats/branch.isa b/src/arch/arm/isa/formats/branch.isa
index 999126081..07f39b129 100644
--- a/src/arch/arm/isa/formats/branch.isa
+++ b/src/arch/arm/isa/formats/branch.isa
@@ -71,10 +71,20 @@ def format ArmBlBlxImm() {{
     '''
 }};
 
-def format ArmBx() {{
+def format ArmBxClz() {{
     decode_block = '''
-        return new BxReg(machInst, (IntRegIndex)(uint32_t)bits(machInst, 3, 0),
-                         (ConditionCode)(uint32_t)machInst.condCode);
+    {
+        const IntRegIndex rm = (IntRegIndex)(uint32_t)bits(machInst, 3, 0);
+        const IntRegIndex rd = (IntRegIndex)(uint32_t)bits(machInst, 15, 12);
+        if (OPCODE == 0x9) {
+            return new BxReg(machInst, rm,
+                    (ConditionCode)(uint32_t)machInst.condCode);
+        } else if (OPCODE == 0xb) {
+            return new Clz(machInst, rd, rm);
+        } else {
+            return new Unknown(machInst);
+        }
+    }
     '''
 }};
 
diff --git a/src/arch/arm/isa/formats/data.isa b/src/arch/arm/isa/formats/data.isa
index 9dca0e8a3..03f94075c 100644
--- a/src/arch/arm/isa/formats/data.isa
+++ b/src/arch/arm/isa/formats/data.isa
@@ -803,7 +803,7 @@ def format Thumb32DataProcReg() {{
                     break;
                   case 0x3:
                     if (op2 == 0) {
-                        return new WarnUnimplemented("clz", machInst);
+                        return new Clz(machInst, rd, rm);
                     }
                 }
             }