From ecdd6e0ed47575995dd9c26235f693ac881a8688 Mon Sep 17 00:00:00 2001
From: Michel Heily <michelheily@gmail.com>
Date: Mon, 8 Jul 2019 01:47:41 +0300
Subject: [PATCH] thumb: Fix ALU ops for barrel shifter opcodes

I kinda missed these when I read the manual ><


Former-commit-id: 7d6c21b6c3b46bf065a177c1c7f7a7a1baa6b8fa
---
 src/arm7tdmi/thumb/display.rs |  9 +++++++--
 src/arm7tdmi/thumb/exec.rs    | 18 +++++++++++++-----
 src/arm7tdmi/thumb/mod.rs     | 34 +++++++++++++++++++++++++++++++---
 3 files changed, 51 insertions(+), 10 deletions(-)

diff --git a/src/arm7tdmi/thumb/display.rs b/src/arm7tdmi/thumb/display.rs
index 7deff87..7a1d529 100644
--- a/src/arm7tdmi/thumb/display.rs
+++ b/src/arm7tdmi/thumb/display.rs
@@ -37,10 +37,15 @@ impl ThumbInstruction {
     }
 
     fn fmt_thumb_alu_ops(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let (op, shft) = self.alu_opcode();
+        if let Some(ArmRegisterShift::ShiftRegister(_, shftOp)) = shft {
+            write!(f, "{}", shftOp)?;
+        } else {
+            write!(f, "{}", op)?;
+        }
         write!(
             f,
-            "{op}\t{Rd}, {Rs}",
-            op = self.alu_opcode(),
+            "\t{Rd}, {Rs}",
             Rd = reg_string(self.rd()),
             Rs = reg_string(self.rs())
         )
diff --git a/src/arm7tdmi/thumb/exec.rs b/src/arm7tdmi/thumb/exec.rs
index bec4dbb..65bfb16 100644
--- a/src/arm7tdmi/thumb/exec.rs
+++ b/src/arm7tdmi/thumb/exec.rs
@@ -1,4 +1,4 @@
-use crate::arm7tdmi::arm::*;
+use crate::arm7tdmi::arm::exec::*;
 use crate::arm7tdmi::bus::Bus;
 use crate::arm7tdmi::cpu::{Core, CpuExecResult, CpuPipelineAction};
 use crate::arm7tdmi::*;
@@ -82,12 +82,20 @@ impl Core {
     }
 
     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 rd = insn.rd();
+
+        let (arm_alu_op, shft) = insn.alu_opcode();
+        let op1 = self.get_reg(rd) as i32;
+        let op2 = if let Some(shft) = shft {
+            let bs_result = self.register_shift(rd, shft)?;
+            bs_result
+        } else {
+            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);
+            self.set_reg(rd, result as u32);
         }
 
         Ok(CpuPipelineAction::IncPC)
diff --git a/src/arm7tdmi/thumb/mod.rs b/src/arm7tdmi/thumb/mod.rs
index ea40faa..c4e84e5 100644
--- a/src/arm7tdmi/thumb/mod.rs
+++ b/src/arm7tdmi/thumb/mod.rs
@@ -4,7 +4,7 @@ use crate::bit::BitIndex;
 use crate::byteorder::{LittleEndian, ReadBytesExt};
 use crate::num::FromPrimitive;
 
-use super::arm::{ArmCond, ArmOpCode, ArmShiftType};
+use super::arm::*;
 use super::{Addr, InstructionDecoder, InstructionDecoderError};
 
 pub mod display;
@@ -241,10 +241,38 @@ impl ThumbInstruction {
         OpFormat5::from_u8(self.raw.bit_range(8..10) as u8).unwrap()
     }
 
-    pub fn alu_opcode(&self) -> ArmOpCode {
+    pub fn alu_opcode(&self) -> (ArmOpCode, Option<ArmRegisterShift>) {
         match self.raw.bit_range(6..10) {
+            0b0010 => (
+                ArmOpCode::MOV,
+                Some(ArmRegisterShift::ShiftRegister(
+                    self.rs(),
+                    ArmShiftType::LSL,
+                )),
+            ),
+            0b0011 => (
+                ArmOpCode::MOV,
+                Some(ArmRegisterShift::ShiftRegister(
+                    self.rs(),
+                    ArmShiftType::LSR,
+                )),
+            ),
+            0b0100 => (
+                ArmOpCode::MOV,
+                Some(ArmRegisterShift::ShiftRegister(
+                    self.rs(),
+                    ArmShiftType::ASR,
+                )),
+            ),
+            0b0111 => (
+                ArmOpCode::MOV,
+                Some(ArmRegisterShift::ShiftRegister(
+                    self.rs(),
+                    ArmShiftType::ROR,
+                )),
+            ),
             0b1101 => panic!("tried to decode MUL"),
-            op => ArmOpCode::from_u16(op).unwrap(),
+            op => (ArmOpCode::from_u16(op).unwrap(), None),
         }
     }