ARM: Rearrange the load/store double/exclusive, table branch thumb decoding.

4 files changed, 64 insertions, 42 deletions

diff --git a/src/arch/arm/isa/bitfields.isa b/src/arch/arm/isa/bitfields.isa
index abaedd024..5a8b5db6d 100644
--- a/src/arch/arm/isa/bitfields.isa
+++ b/src/arch/arm/isa/bitfields.isa
@@ -148,6 +148,7 @@ def bitfield HTOPCODE_8_6   htopcode8_6;
 def bitfield HTOPCODE_8_5   htopcode8_5;
 def bitfield HTOPCODE_7     htopcode7;
 def bitfield HTOPCODE_7_5   htopcode7_5;
+def bitfield HTOPCODE_6     htopcode6;
 def bitfield HTOPCODE_6_5   htopcode6_5;
 def bitfield HTOPCODE_5_4   htopcode5_4;
 def bitfield HTOPCODE_4     htopcode4;
diff --git a/src/arch/arm/isa/decoder/thumb.isa b/src/arch/arm/isa/decoder/thumb.isa
index b76599232..da8248683 100644
--- a/src/arch/arm/isa/decoder/thumb.isa
+++ b/src/arch/arm/isa/decoder/thumb.isa
@@ -68,50 +68,16 @@
     // 32 bit thumb instructions.
     1: decode HTOPCODE_12_11 {
         0x1: decode HTOPCODE_10_9 {
-            0x0: decode HTOPCODE_8_6 {
-                0x0, 0x6: decode HTOPCODE_4 {
-                    0x0: WarnUnimpl::srs();
-                    0x1: WarnUnimpl::rfe();
-                }
-                0x1: decode HTOPCODE_5_4 {
-                    0x0: WarnUnimpl::strex();
-                    0x1: WarnUnimpl::ldrex();
-                    0x2: WarnUnimpl::strd(); // immediate
-                    0x3: decode HTRN {
-                        0xf: WarnUnimpl::ldrd(); // literal
-                        default: WarnUnimpl::ldrd(); // immediate
-                    }
-                }
-                // This uses the same encoding as regular ARM.
-                0x2: ArmMacroMem::armMacroMem();
-                0x3: decode HTOPCODE_5_4 {
-                    0x0: decode LTOPCODE_7_4 {
-                        0x4: WarnUnimpl::strexb();
-                        0x5: WarnUnimpl::strexh();
-                        0x7: WarnUnimpl::strexd();
-                    }
-                    0x1: decode LTOPCODE_7_4 {
-                        0x0: WarnUnimpl::tbb();
-                        0x1: WarnUnimpl::tbh();
-                        0x4: WarnUnimpl::ldrexb();
-                        0x5: WarnUnimpl::ldrexh();
-                        0x7: WarnUnimpl::ldrexd();
-                    }
-                    0x2: WarnUnimpl::strd(); // immediate
-                    0x3: decode HTRN {
-                        0xf: WarnUnimpl::ldrd(); // literal
-                        default: WarnUnimpl::ldrd(); // immediate
-                    }
-                }
-                // This uses the same encoding as regular ARM.
-                0x4: ArmMacroMem::armMacroMem();
-                0x5, 0x7: decode HTOPCODE_4 {
-                    0x0: WarnUnimpl::strd(); // immediate
-                    0x1: decode HTRN {
-                        0xf: WarnUnimpl::ldrd(); // literal
-                        default: WarnUnimpl::ldrd(); // immediate
+            0x0: decode HTOPCODE_6 {
+                0x0: decode HTOPCODE_8_7 {
+                    0x0, 0x3: decode HTOPCODE_4 {
+                        0x0: WarnUnimpl::srs();
+                        0x1: WarnUnimpl::rfe();
                     }
+                    // This uses the same encoding as regular ARM.
+                    default: ArmMacroMem::armMacroMem();
                 }
+                0x1: Thumb32LdrStrDExTbh::thumb32LdrStrDExTbh();
             }
             0x1: Thumb32DataProcShiftReg::thumb32DataProcShiftReg();
             default: decode HTOPCODE_9_8 {
diff --git a/src/arch/arm/isa/formats/mem.isa b/src/arch/arm/isa/formats/mem.isa
index 2ea45733b..209f62af4 100644
--- a/src/arch/arm/isa/formats/mem.isa
+++ b/src/arch/arm/isa/formats/mem.isa
@@ -235,6 +235,60 @@ def format ArmSyncMem() {{
     '''
 }};
 
+def format Thumb32LdrStrDExTbh() {{
+    decode_block = '''
+    {
+        const uint32_t op1 = bits(machInst, 24, 23);
+        const uint32_t op2 = bits(machInst, 21, 20);
+        const uint32_t op3 = bits(machInst, 7, 4);
+        const IntRegIndex rn = (IntRegIndex)(uint32_t)bits(machInst, 19, 16);
+        if (bits(op1, 1) == 0 && bits(op2, 1) == 0) {
+            if (op1 == 0) {
+                if (op2 == 0) {
+                    return new WarnUnimplemented("strex", machInst);
+                } else {
+                    return new WarnUnimplemented("ldrex", machInst);
+                }
+            } else {
+                if (op2 == 0) {
+                    switch (op3) {
+                      case 0x4:
+                        return new WarnUnimplemented("strexb", machInst);
+                      case 0x5:
+                        return new WarnUnimplemented("strexh", machInst);
+                      case 0x7:
+                        return new WarnUnimplemented("strexd", machInst);
+                      default:
+                        return new Unknown(machInst);
+                    }
+                } else {
+                    switch (op3) {
+                      case 0x0:
+                        return new WarnUnimplemented("tbb", machInst);
+                      case 0x1:
+                        return new WarnUnimplemented("tbh", machInst);
+                      case 0x4:
+                        return new WarnUnimplemented("ldrexb", machInst);
+                      case 0x5:
+                        return new WarnUnimplemented("ldrexh", machInst);
+                      case 0x7:
+                        return new WarnUnimplemented("ldrexd", machInst);
+                      default:
+                        return new Unknown(machInst);
+                    }
+                }
+            }
+        } else {
+            if (bits(op2, 0) == 0) {
+                return new WarnUnimplemented("strd", machInst);
+            } else {
+                return new WarnUnimplemented("ldrd", machInst);
+            }
+        }
+    }
+    '''
+}};
+
 def format Thumb32LoadWord() {{
     decode = '''
     {
diff --git a/src/arch/arm/types.hh b/src/arch/arm/types.hh
index 7c961daa4..e99a00435 100644
--- a/src/arch/arm/types.hh
+++ b/src/arch/arm/types.hh
@@ -159,6 +159,7 @@ namespace ArmISA
         Bitfield<24, 21> htopcode8_5;
         Bitfield<23>     htopcode7;
         Bitfield<23, 21> htopcode7_5;
+        Bitfield<22>     htopcode6;
         Bitfield<22, 21> htopcode6_5;
         Bitfield<21, 20> htopcode5_4;
         Bitfield<20>     htopcode4;