rv64i: changes shamt functions & tests

Author: mrLSD

DecodeI.fs

@@ -62,11 +62,6 @@ type InstructionI =
 //================================================================
 // Sub-opcodes for 'I' instructions
 
-// Sub opcode_OP_IMM.SLLI/SRLI/SRAI - 32 & 64 bit
-let msbs6_SLLI      = 0b0000000L
-let msbs6_SRLI      = 0b0000000L
-let msbs6_SRAI      = 0b0100000L
-
 // opcode_MISC_MEM sub-opcodes
 let funct3_FENCE         = 0b000L
 
@@ -76,7 +71,7 @@ let funct12_ECALL    = 0b000000000000L
 let funct12_EBREAK   = 0b000000000001L
 
 /// Decode 'I' instructions
-let Decode (instr: InstrField) : InstructionI =
+let Decode (mstate : MachineState) (instr: InstrField) : InstructionI =
     let opcode = instr.bitSlice 6   0
     // Register number can be: 0-32
     let rd     = int32(instr.bitSlice 11  7)
@@ -87,11 +82,15 @@ let Decode (instr: InstrField) : InstructionI =
     let funct7 = instr.bitSlice 31 25
 
     // Shamt funcs
-    let shamt   = instr.bitSlice 24 20
-    let shamt5  = instr.bitSlice 24 20
-    let shamt6  = instr.bitSlice 25 20
-    // TODO: x32/64 check for Shamt
-    let shamt_ok = true
+    let shamt =
+        if mstate.Arch.archBits = RV32 then
+            instr.bitSlice 24 20
+        else
+            instr.bitSlice 24 20
+    let funct6 = instr.bitSlice 31 26
+    let shamt_ok =
+        ((instr.bitSlice 25 25) = 0L) ||
+        (mstate.Arch.archBits = RV64)
 
     let imm12_I = (instr.bitSlice 31 20).signExtend 12
     let imm20_U = ((instr.bitSlice 31 12) <<< 12).signExtend 32
@@ -172,9 +171,9 @@ let Decode (instr: InstrField) : InstructionI =
         | 0b111L -> ANDI  {| rd = rd; rs1 = rs1; imm12 = imm12_I |}
 
         // Shift Immediate Opcodes
-        | 0b001L when funct7 = msbs6_SLLI  -> SLLI {| rd = rd; rs1 = rs1; shamt = shamt |}
-        | 0b101L when funct7 = msbs6_SRLI  -> SRLI {| rd = rd; rs1 = rs1; shamt = shamt |}
-        | 0b101L when funct7 = msbs6_SRAI  -> SRAI {| rd = rd; rs1 = rs1; shamt = shamt |}
+        | 0b001L when funct6 = 0b000000L && shamt_ok -> SLLI {| rd = rd; rs1 = rs1; shamt = shamt |}
+        | 0b101L when funct6 = 0b000000L && shamt_ok -> SRLI {| rd = rd; rs1 = rs1; shamt = shamt |}
+        | 0b101L when funct6 = 0b010000L && shamt_ok -> SRAI {| rd = rd; rs1 = rs1; shamt = shamt |}
         | _      -> None
 
     // ALU Opcodes

Decoder.fs

@@ -16,8 +16,8 @@ type execFunc = MachineState -> MachineState
 //    | None
 
 // Aggregate decoded data
-let Decode (instr: InstrField) : execFunc option =
-    let decI32 = I.Decode instr
+let Decode (mstate : MachineState) (instr: InstrField) : execFunc option =
+    let decI32 = I.Decode mstate instr
     let decI64 =
         if decI32 = I.InstructionI.None then
             I64.Decode instr

Run.fs

@@ -48,7 +48,7 @@ let rec runCycle (mstate : MachineState) =
         | None -> mstate.setRunState (Trap (InstructionFetch mstate.PC))
         | _ ->
             let instrValue = instr.Value
-            let executor = Decoder.Decode instrValue
+            let executor = Decoder.Decode mstate instrValue
 
             match executor with
             | None -> mstate.setRunState (Trap TrapErrors.InstructionDecode)

Tests/rv32i/alu.fs

@@ -15,7 +15,7 @@ let ALU instr x1 x2 x3 =
     let mstate = mstate.setRegister 1 x1
     let mstate = mstate.setRegister 2 x2
 
-    let executor = Decoder.Decode instr
+    let executor = Decoder.Decode mstate instr
     Assert.NotEqual(executor, None)
     let mstate = executor.Value mstate
     Assert.Equal(x1, mstate.getRegister 1)

Tests/rv32i/alui.fs

@@ -15,7 +15,7 @@ let ALUimmediate instr x2 x3 =
     let mstate = mstate.setPC addr
     let mstate = mstate.setRegister 2 x2
 
-    let executor = Decoder.Decode instr
+    let executor = Decoder.Decode mstate instr
     Assert.NotEqual(executor, None)
     let mstate = executor.Value mstate
     Assert.Equal(x2, mstate.getRegister 2)

Tests/rv32i/br.fs

@@ -15,7 +15,7 @@ let Branch instr x1 x2 resultAddr =
     let mstate = mstate.setRegister 1 x1
     let mstate = mstate.setRegister 2 x2
 
-    let executor = Decoder.Decode instr
+    let executor = Decoder.Decode mstate instr
     Assert.NotEqual(executor, None)
     let mstate = executor.Value mstate
     Assert.Equal(x1, mstate.getRegister 1)

Tests/rv32i/j.fs

@@ -16,7 +16,7 @@ let Jump instr x2 x3 resultAddr =
     let mstate = mstate.setRegister 2 x2
     let resMstate = mstate.incPC
 
-    let executor = Decoder.Decode instr
+    let executor = Decoder.Decode mstate instr
     Assert.NotEqual(executor, None)
     let mstate = executor.Value mstate
 

Tests/rv32i/mem.fs

@@ -34,7 +34,7 @@ let loadMemory instr x2 imm nBytes unsign =
             let mstate = mstate.setMemoryByte (memAddr+2L) 0xb2uy
             (mstate.setMemoryByte (memAddr+3L) 0xc3uy, int64(0xc3b2a10fl))
 
-    let executor = Decoder.Decode instr
+    let executor = Decoder.Decode mstate instr
     Assert.NotEqual(executor, None)
     let mstate = executor.Value mstate
     Assert.Equal(x2, mstate.getRegister 2)
@@ -49,7 +49,7 @@ let storeMemory instr x3 x2 imm nBytes =
     let mstate = mstate.setRegister 2 x2
     let mstate = mstate.setRegister 3 x3
 
-    let executor = Decoder.Decode instr
+    let executor = Decoder.Decode mstate instr
     Assert.NotEqual(executor, None)
 
     // Get memory value

Tests/rv32i/sys.fs

@@ -15,7 +15,7 @@ let System instr trap =
     let mstate = mstate.setPC addr
     let newmstate = mstate.incPC
 
-    let executor = Decoder.Decode instr
+    let executor = Decoder.Decode mstate instr
     Assert.NotEqual(executor, None)
     let mstate = executor.Value mstate
 

Tests/rv32i/ui.fs

@@ -13,7 +13,7 @@ let Ui instr x3 =
     let mstate = MachineState.InitMachineState Map.empty RV32i true
     let mstate = mstate.setPC addr
 
-    let executor = Decoder.Decode instr
+    let executor = Decoder.Decode mstate instr
     Assert.NotEqual(executor, None)
     let mstate = executor.Value mstate
     Assert.Equal(x3, mstate.getRegister 3)

Tests/rv64i/alu.fs

@@ -15,7 +15,7 @@ let ALU instr x1 x2 x3 =
     let mstate = mstate.setRegister 1 x1
     let mstate = mstate.setRegister 2 x2
 
-    let executor = Decoder.Decode instr
+    let executor = Decoder.Decode mstate instr
     Assert.NotEqual(executor, None)
     let mstate = executor.Value mstate
     Assert.Equal(x1, mstate.getRegister 1)