diff --git a/hs/Isa/Decode.hs b/hs/Isa/Decode.hs
index edd6b70..cc6729d 100644
--- a/hs/Isa/Decode.hs
+++ b/hs/Isa/Decode.hs
@@ -58,25 +58,32 @@ getRs1 instr = bitCoerce $ slice d19 d15 (pack instr)
 
 decodeRType :: Insn -> Opcode
 decodeRType insn =
-  case funct3 of
-        0x00 -> ADD   (RTypeFields opcode rd funct3 rs1 rs2 funct7)
-        0x00 -> SUB   (RTypeFields opcode rd funct3 rs1 rs2 funct7)
-        0x04 -> XOR   (RTypeFields opcode rd funct3 rs1 rs2 funct7)
-        0x06 -> OR    (RTypeFields opcode rd funct3 rs1 rs2 funct7)
-        0x07 -> AND   (RTypeFields opcode rd funct3 rs1 rs2 funct7)
-        0x01 -> SLL   (RTypeFields opcode rd funct3 rs1 rs2 funct7)
-        0x05 -> SRL   (RTypeFields opcode rd funct3 rs1 rs2 funct7)
-        0x05 -> SRA   (RTypeFields opcode rd funct3 rs1 rs2 funct7)
-        0x02 -> SLT   (RTypeFields opcode rd funct3 rs1 rs2 funct7)
-        0x03 -> SLTU  (RTypeFields opcode rd funct3 rs1 rs2 funct7)
-        _ -> Unimplemented
+  case opcode of
+    0b0110011 ->
+      case funct3 of
+        0x00 -> case funct7 of
+                  0x00 -> ADD (RTypeFields opcode rd funct3 rs1 rs2 funct7)
+                  0x20 -> SUB (RTypeFields opcode rd funct3 rs1 rs2 funct7)
+                  _    -> Unimplemented
+        0x04 -> XOR (RTypeFields opcode rd funct3 rs1 rs2 funct7)
+        0x06 -> OR  (RTypeFields opcode rd funct3 rs1 rs2 funct7)
+        0x07 -> AND (RTypeFields opcode rd funct3 rs1 rs2 funct7)
+        0x01 -> SLL (RTypeFields opcode rd funct3 rs1 rs2 funct7)
+        0x05 -> case funct7 of
+                  0x00 -> SRL (RTypeFields opcode rd funct3 rs1 rs2 funct7)
+                  0x20 -> SRA (RTypeFields opcode rd funct3 rs1 rs2 funct7)
+                  _    -> Unimplemented
+        0x02 -> SLT  (RTypeFields opcode rd funct3 rs1 rs2 funct7)
+        0x03 -> SLTU (RTypeFields opcode rd funct3 rs1 rs2 funct7)
+        _    -> Unimplemented
+    _ -> Unimplemented
   where
-    opcode  = getOpcode insn
-    rd      = getRd     insn
-    funct3  = getFunct3 insn
-    rs1     = getRs1    insn
-    rs2     = getRs2    insn
-    funct7  = getFunct7 insn
+    opcode = getOpcode insn
+    rd     = getRd     insn
+    funct3 = getFunct3 insn
+    rs1    = getRs1    insn
+    rs2    = getRs2    insn
+    funct7 = getFunct7 insn
 
 decodeIType :: Insn -> Opcode
 decodeIType insn = case opcode of
@@ -122,11 +129,14 @@ decodeIType insn = case opcode of
     imm    = getImm12  insn
 
 decodeSType :: Insn -> Opcode
-decodeSType insn = case funct3 of
-    0x0 -> SB (STypeFields opcode funct3 rs1 rs2 imm12)  -- Store Byte
-    0x1 -> SH (STypeFields opcode funct3 rs1 rs2 imm12)  -- Store Halfword
-    0x2 -> SW (STypeFields opcode funct3 rs1 rs2 imm12)  -- Store Word
-    _   -> Unimplemented
+decodeSType insn =
+  case opcode of
+    0b0100011 -> case funct3 of
+        0x0 -> SB (STypeFields opcode funct3 rs1 rs2 imm12)  -- Store Byte
+        0x1 -> SH (STypeFields opcode funct3 rs1 rs2 imm12)  -- Store Halfword
+        0x2 -> SW (STypeFields opcode funct3 rs1 rs2 imm12)  -- Store Word
+        _   -> Unimplemented
+    _ -> Unimplemented
   where
     opcode = getOpcode insn
     funct3 = getFunct3 insn
@@ -135,14 +145,17 @@ decodeSType insn = case funct3 of
     imm12  = getImm12SType insn
 
 decodeBType :: Insn -> Opcode
-decodeBType insn = case funct3 of
-    0x0 -> BEQ  (BTypeFields opcode funct3 rs1 rs2 imm13)  -- Branch if equal
-    0x1 -> BNE  (BTypeFields opcode funct3 rs1 rs2 imm13)  -- Branch if not equal
-    0x4 -> BLT  (BTypeFields opcode funct3 rs1 rs2 imm13)  -- Branch if less than
-    0x5 -> BGE  (BTypeFields opcode funct3 rs1 rs2 imm13)  -- Branch if greater or equal
-    0x6 -> BLTU (BTypeFields opcode funct3 rs1 rs2 imm13)  -- Branch if less than (unsigned)
-    0x7 -> BGEU (BTypeFields opcode funct3 rs1 rs2 imm13)  -- Branch if greater or equal (unsigned)
-    _   -> Unimplemented
+decodeBType insn =
+  case opcode of
+    0b1100011 -> case funct3 of
+        0x0 -> BEQ  (BTypeFields opcode funct3 rs1 rs2 imm13)  -- Branch if equal
+        0x1 -> BNE  (BTypeFields opcode funct3 rs1 rs2 imm13)  -- Branch if not equal
+        0x4 -> BLT  (BTypeFields opcode funct3 rs1 rs2 imm13)  -- Branch if less than
+        0x5 -> BGE  (BTypeFields opcode funct3 rs1 rs2 imm13)  -- Branch if greater or equal
+        0x6 -> BLTU (BTypeFields opcode funct3 rs1 rs2 imm13)  -- Branch if less than (unsigned)
+        0x7 -> BGEU (BTypeFields opcode funct3 rs1 rs2 imm13)  -- Branch if greater or equal (unsigned)
+        _   -> Unimplemented
+    _ -> Unimplemented
   where
     opcode = getOpcode insn
     funct3 = getFunct3 insn
@@ -170,7 +183,8 @@ getImm21JType instr = bitCoerce $ imm20 ++# imm10_1 ++# imm11 ++# imm19_12 ++# z
     zero     = 0 :: BitVector 1                -- LSB always zero for J-type
 
 decodeJType :: Insn -> Opcode
-decodeJType insn = case getOpcode insn of
+decodeJType insn =
+  case opcode of
     0b1101111 -> JAL (JTypeFields opcode rd imm21)   -- JAL
     _         -> Unimplemented
   where
diff --git a/hs/Simulation.hs b/hs/Simulation.hs
index 5229765..6ab137d 100644
--- a/hs/Simulation.hs
+++ b/hs/Simulation.hs
@@ -79,6 +79,6 @@ simulation args = do
     InitializedPeripherals ram -> do
 
       let initState = machineInit $ Machine.Peripherals ram
-      sim <- simulationLoop 5 initState
+      sim <- simulationLoop 15 initState
       teardownPeripherals
       return $ Success sim