Impl thumb Format4

Former-commit-id: 7b8705ee7b76bbeb5b2a21e830d16db06ce8d63c

src/arm7tdmi/cpu.rs

@@ -200,6 +200,18 @@ impl Core {
         }
     }
 
+    pub fn get_required_multipiler_array_cycles(&self, rs: i32) -> usize {
+        if rs & 0xff == rs {
+            1
+        } else if rs & 0xffff == rs {
+            2
+        } else if rs & 0xffffff == rs {
+            3
+        } else {
+            4
+        }
+    }
+
     pub fn load_32(&mut self, addr: Addr, bus: &mut Bus) -> u32 {
         self.add_cycles(addr, bus, self.cycle_type(addr) + MemoryAccess32);
         self.memreq = addr;

src/arm7tdmi/thumb/display.rs

@@ -27,6 +27,25 @@ impl ThumbInstruction {
         )
     }
 
+    fn fmt_thumb_mul(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "mul\t{Rd}, {Rs}",
+            Rd = reg_string(self.rd()),
+            Rs = reg_string(self.rs())
+        )
+    }
+
+    fn fmt_thumb_alu_ops(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "{op}\t{Rd}, {Rs}",
+            op = self.alu_opcode(),
+            Rd = reg_string(self.rd()),
+            Rs = reg_string(self.rs())
+        )
+    }
+
     fn fmt_thumb_high_reg_op_or_bx(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let op = self.format5_op();
         let dst_reg = if self.flag(ThumbInstruction::FLAG_H1) {
@@ -147,6 +166,8 @@ impl fmt::Display for ThumbInstruction {
             ThumbFormat::MoveShiftedReg => self.fmt_thumb_move_shifted_reg(f),
             ThumbFormat::AddSub => self.fmt_thumb_add_sub(f),
             ThumbFormat::DataProcessImm => self.fmt_thumb_data_process_imm(f),
+            ThumbFormat::Mul => self.fmt_thumb_mul(f),
+            ThumbFormat::AluOps => self.fmt_thumb_alu_ops(f),
             ThumbFormat::HiRegOpOrBranchExchange => self.fmt_thumb_high_reg_op_or_bx(f),
             ThumbFormat::LdrPc => self.fmt_thumb_ldr_pc(f),
             ThumbFormat::LdrStrRegOffset => self.fmt_thumb_ldr_str_reg_offset(f),

src/arm7tdmi/thumb/exec.rs

@@ -45,7 +45,30 @@ impl Core {
     ) -> CpuExecResult {
         let arm_alu_op: ArmOpCode = insn.format3_op().into();
         let op1 = self.get_reg(insn.rd()) as i32;
-        let op2 = insn.offset8() as i32;
+        let op2 = insn.offset8() as u8 as i32;
+        let result = self.alu(arm_alu_op, op1, op2, true);
+        if let Some(result) = result {
+            self.set_reg(insn.rd(), result as u32);
+        }
+
+        Ok(CpuPipelineAction::IncPC)
+    }
+
+    fn exec_thumb_mul(&mut self, bus: &mut Bus, insn: ThumbInstruction) -> CpuExecResult {
+        let op1 = self.get_reg(insn.rd()) as i32;
+        let op2 = self.get_reg(insn.rs()) as i32;
+        let m = self.get_required_multipiler_array_cycles(op2);
+        for i in 0..m {
+            self.add_cycle();
+        }
+        self.gpr[insn.rd()] = (op1 * op2) as u32;
+        Ok(CpuPipelineAction::IncPC)
+    }
+
+    fn exec_thumb_alu_ops(&mut self, bus: &mut Bus, insn: ThumbInstruction) -> CpuExecResult {
+        let arm_alu_op: ArmOpCode = insn.alu_opcode();
+        let op1 = self.get_reg(insn.rd()) as i32;
+        let op2 = self.get_reg(insn.rs()) as i32;
         let result = self.alu(arm_alu_op, op1, op2, true);
         if let Some(result) = result {
             self.set_reg(insn.rd(), result as u32);
@@ -141,7 +164,6 @@ impl Core {
         Ok(CpuPipelineAction::IncPC)
     }
 
-
     fn exec_thumb_add_sp(&mut self, bus: &mut Bus, insn: ThumbInstruction) -> CpuExecResult {
         let op1 = self.gpr[REG_SP] as i32;
         let op2 = insn.sword7();
@@ -192,7 +214,7 @@ impl Core {
         if !self.check_arm_cond(insn.cond()) {
             Ok(CpuPipelineAction::IncPC)
         } else {
-            let offset = insn.offset8() as i8 as i32;
+            let offset = insn.offset8() as u8 as i32;
             self.pc = (insn.pc as i32).wrapping_add(offset) as u32;
             Ok(CpuPipelineAction::Flush)
         }
@@ -202,6 +224,8 @@ impl Core {
         match insn.fmt {
             ThumbFormat::AddSub => self.exec_thumb_add_sub(bus, insn),
             ThumbFormat::DataProcessImm => self.exec_thumb_data_process_imm(bus, insn),
+            ThumbFormat::Mul => self.exec_thumb_mul(bus, insn),
+            ThumbFormat::AluOps => self.exec_thumb_alu_ops(bus, insn),
             ThumbFormat::HiRegOpOrBranchExchange => self.exec_thumb_hi_reg_op_or_bx(bus, insn),
             ThumbFormat::LdrPc => self.exec_thumb_ldr_pc(bus, insn),
             ThumbFormat::LdrStrRegOffset => self.exec_thumb_ldr_str_reg_offset(bus, insn),

src/arm7tdmi/thumb/mod.rs

@@ -42,6 +42,8 @@ pub enum ThumbFormat {
     AddSub,
     /// Format 3
     DataProcessImm,
+    /// Belongs to Format 4, but decoded seperatly because ArmOpcode doesn't have MUL
+    Mul,
     /// Format 4
     AluOps,
     /// Format 5
@@ -95,6 +97,8 @@ impl InstructionDecoder for ThumbInstruction {
             Ok(MoveShiftedReg)
         } else if raw & 0xe000 == 0x2000 {
             Ok(DataProcessImm)
+        } else if raw & 0xffc0 == 0x4340 {
+            Ok(Mul)
         } else if raw & 0xfc00 == 0x4000 {
             Ok(AluOps)
         } else if raw & 0xfc00 == 0x4400 {
@@ -233,6 +237,13 @@ impl ThumbInstruction {
         OpFormat5::from_u8(self.raw.bit_range(8..10) as u8).unwrap()
     }
 
+    pub fn alu_opcode(&self) -> ArmOpCode {
+        match self.raw.bit_range(6..10) {
+            0b1101 => panic!("tried to decode MUL"),
+            op => ArmOpCode::from_u16(op).unwrap(),
+        }
+    }
+
     pub fn offset5(&self) -> i8 {
         self.raw.bit_range(6..11) as i8
     }