From f7b2b48e5df7e82eeda162d7170bfaaf5c1330e1 Mon Sep 17 00:00:00 2001 From: Michel Heily Date: Mon, 8 Jul 2019 19:56:12 +0300 Subject: [PATCH] Refactor ALU code into its own module, and fix things. * Fix overflow flag being ignored * Fix barrel shifter misimplementations * Rustfmt fixes Former-commit-id: a14d50372f7850a04b204accf4e5d8b924e4b48e --- src/arm7tdmi/alu.rs | 262 ++++++++++++++++++++++++++++++++++ src/arm7tdmi/arm/display.rs | 43 +++--- src/arm7tdmi/arm/exec.rs | 128 ++--------------- src/arm7tdmi/arm/mod.rs | 157 +++++--------------- src/arm7tdmi/mod.rs | 2 + src/arm7tdmi/thumb/display.rs | 5 +- src/arm7tdmi/thumb/exec.rs | 21 ++- src/arm7tdmi/thumb/mod.rs | 82 ++++++----- 8 files changed, 388 insertions(+), 312 deletions(-) create mode 100644 src/arm7tdmi/alu.rs diff --git a/src/arm7tdmi/alu.rs b/src/arm7tdmi/alu.rs new file mode 100644 index 0000000..a3f013b --- /dev/null +++ b/src/arm7tdmi/alu.rs @@ -0,0 +1,262 @@ +use bit::BitIndex; +use num::FromPrimitive; + +use super::{Core, CpuError, CpuResult, REG_PC}; + +#[derive(Debug, Primitive)] +pub enum AluOpCode { + AND = 0b0000, + EOR = 0b0001, + SUB = 0b0010, + RSB = 0b0011, + ADD = 0b0100, + ADC = 0b0101, + SBC = 0b0110, + RSC = 0b0111, + TST = 0b1000, + TEQ = 0b1001, + CMP = 0b1010, + CMN = 0b1011, + ORR = 0b1100, + MOV = 0b1101, + BIC = 0b1110, + MVN = 0b1111, +} + +impl AluOpCode { + pub fn is_setting_flags(&self) -> bool { + use AluOpCode::*; + match self { + TST | TEQ | CMP | CMN => true, + _ => false, + } + } + + pub fn is_logical(&self) -> bool { + use AluOpCode::*; + match self { + MOV | MVN | ORR | EOR | AND | BIC | TST | TEQ => true, + _ => false, + } + } + pub fn is_arithmetic(&self) -> bool { + use AluOpCode::*; + match self { + ADD | ADC | SUB | SBC | RSB | RSC | CMP | CMN => true, + _ => false, + } + } +} + +#[derive(Debug, PartialEq, Primitive)] +pub enum BarrelShiftOpCode { + LSL = 0, + LSR = 1, + ASR = 2, + ROR = 3, +} + +#[derive(Debug, PartialEq)] +pub enum ShiftedRegister { + ByAmount(u32, BarrelShiftOpCode), + ByRegister(usize, BarrelShiftOpCode), +} + +impl From for ShiftedRegister { + fn from(v: u32) -> ShiftedRegister { + let typ = BarrelShiftOpCode::from_u8(v.bit_range(5..7) as u8).unwrap(); + if v.bit(4) { + let rs = v.bit_range(8..12) as usize; + ShiftedRegister::ByRegister(rs, typ) + } else { + let amount = v.bit_range(7..12) as u32; + ShiftedRegister::ByAmount(amount, typ) + } + } +} + +#[derive(Debug, PartialEq)] +pub enum BarrelShifterValue { + ImmediateValue(i32), + RotatedImmediate(u32, u32), + ShiftedRegister { + reg: usize, + shift: ShiftedRegister, + added: Option, + }, +} + +impl BarrelShifterValue { + /// Decode operand2 as an immediate value + pub fn decode_rotated_immediate(&self) -> Option { + if let BarrelShifterValue::RotatedImmediate(immediate, rotate) = self { + return Some(immediate.rotate_right(*rotate) as i32); + } + None + } +} + +impl Core { + /// Performs a generic barrel shifter operation + fn barrel_shift(&mut self, val: i32, amount: u32, shift: BarrelShiftOpCode) -> i32 { + // + // From GBATEK: + // Zero Shift Amount (Shift Register by Immediate, with Immediate=0) + // LSL#0: No shift performed, ie. directly Op2=Rm, the C flag is NOT affected. + // LSR#0: Interpreted as LSR#32, ie. Op2 becomes zero, C becomes Bit 31 of Rm. + // ASR#0: Interpreted as ASR#32, ie. Op2 and C are filled by Bit 31 of Rm. + // ROR#0: Interpreted as RRX#1 (RCR), like ROR#1, but Op2 Bit 31 set to old C. + // + // From ARM7TDMI Datasheet: + // 1 LSL by 32 has result zero, carry out equal to bit 0 of Rm. + // 2 LSL by more than 32 has result zero, carry out zero. + // 3 LSR by 32 has result zero, carry out equal to bit 31 of Rm. + // 4 LSR by more than 32 has result zero, carry out zero. + // 5 ASR by 32 or more has result filled with and carry out equal to bit 31 of Rm. + // 6 ROR by 32 has result equal to Rm, carry out equal to bit 31 of Rm. + // 7 ROR by n where n is greater than 32 will give the same result and carry out + // as ROR by n-32; therefore repeatedly subtract 32 from n until the amount is + // in the range 1 to 32 and see above. + // + match shift { + BarrelShiftOpCode::LSL => match amount { + 0 => val, + x if x < 32 => { + self.cpsr.set_C(val.wrapping_shr(32 - x) & 1 == 1); + val << x + } + 32 => { + self.cpsr.set_C(val & 1 == 1); + 0 + } + _ => { + self.cpsr.set_C(false); + 0 + } + }, + BarrelShiftOpCode::LSR => match amount { + x if x > 0 && x < 32 => { + self.cpsr.set_C(val >> (amount - 1) & 1 == 1); + ((val as u32) >> amount) as i32 + } + 0 | 32 => { + self.cpsr.set_C((val as u32).bit(31)); + 0 + } + _ => { + self.cpsr.set_C(false); + 0 + } + }, + BarrelShiftOpCode::ASR => { + if 0 < amount && amount < 32 { + self.cpsr.set_C(val.wrapping_shr(amount - 1) & 1 == 1); + val.wrapping_shr(amount) + } else { + let bit31 = (val as u32).bit(31); + self.cpsr.set_C(bit31); + if bit31 { + -1 + } else { + 0 + } + } + } + BarrelShiftOpCode::ROR => { + match amount { + 0 => + /* RRX */ + { + let val = val as u32; + let old_c = self.cpsr.C() as u32; + (val.rotate_right(1) | (old_c << 31)) as i32 + } + 32 => { + self.cpsr.set_C((val as u32).bit(31)); + val + } + _ => { + let result = val.rotate_right(amount); + self.cpsr.set_C((result >> 1) & 1 == 1); + result + } + } + } + } + } + + pub fn register_shift(&mut self, reg: usize, shift: ShiftedRegister) -> CpuResult { + let val = self.get_reg(reg) as i32; + match shift { + ShiftedRegister::ByAmount(amount, shift) => Ok(self.barrel_shift(val, amount, shift)), + ShiftedRegister::ByRegister(reg, shift) => { + if reg != REG_PC { + Ok(self.barrel_shift(val, self.get_reg(reg) & 0xff, shift)) + } else { + Err(CpuError::IllegalInstruction) + } + } + } + } + + fn alu_sub_flags(a: i32, b: i32, carry: &mut bool, overflow: &mut bool) -> i32 { + let res = a.wrapping_sub(b); + *carry = res > a; + let (_, would_overflow) = a.overflowing_sub(b); + *overflow = would_overflow; + res + } + + fn alu_add_flags(a: i32, b: i32, carry: &mut bool, overflow: &mut bool) -> i32 { + let res = a.wrapping_add(b); + *carry = res < a; + let (_, would_overflow) = a.overflowing_add(b); + *overflow = would_overflow; + res + } + + #[allow(non_snake_case)] + pub fn alu( + &mut self, + opcode: AluOpCode, + op1: i32, + op2: i32, + set_cond_flags: bool, + ) -> Option { + use AluOpCode::*; + + let C = self.cpsr.C() as i32; + + let mut carry = self.cpsr.C(); + let mut overflow = self.cpsr.V(); + + let result = match opcode { + AND | TST => op1 & op2, + EOR | TEQ => op1 ^ op2, + SUB | CMP => Self::alu_sub_flags(op1, op2, &mut carry, &mut overflow), + RSB => Self::alu_sub_flags(op2, op1, &mut carry, &mut overflow), + ADD | CMN => Self::alu_add_flags(op1, op2, &mut carry, &mut overflow), + ADC => Self::alu_add_flags(op1, op2.wrapping_add(C), &mut carry, &mut overflow), + SBC => Self::alu_sub_flags(op1, op2.wrapping_sub(1 - C), &mut carry, &mut overflow), + RSC => Self::alu_sub_flags(op2, op1.wrapping_sub(1 - C), &mut carry, &mut overflow), + ORR => op1 | op2, + MOV => op2, + BIC => op1 & (!op2), + MVN => !op2, + }; + + if set_cond_flags { + self.cpsr.set_N(result < 0); + self.cpsr.set_Z(result == 0); + self.cpsr.set_C(carry); + if opcode.is_arithmetic() { + self.cpsr.set_V(overflow); + } + } + + match opcode { + TST | TEQ | CMP | CMN => None, + _ => Some(result), + } + } +} diff --git a/src/arm7tdmi/arm/display.rs b/src/arm7tdmi/arm/display.rs index 0a7fc16..ba56276 100644 --- a/src/arm7tdmi/arm/display.rs +++ b/src/arm7tdmi/arm/display.rs @@ -1,10 +1,9 @@ use std::fmt; -use super::{ - ArmCond, ArmFormat, ArmHalfwordTransferType, ArmInstruction, ArmOpCode, ArmRegisterShift, - ArmShiftType, ArmShiftedValue, +use super::{AluOpCode, ArmCond, ArmFormat, ArmHalfwordTransferType, ArmInstruction}; +use crate::arm7tdmi::{ + reg_string, Addr, BarrelShiftOpCode, BarrelShifterValue, ShiftedRegister, REG_PC, }; -use crate::arm7tdmi::{reg_string, Addr, REG_PC}; impl fmt::Display for ArmCond { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { @@ -29,9 +28,9 @@ impl fmt::Display for ArmCond { } } -impl fmt::Display for ArmOpCode { +impl fmt::Display for AluOpCode { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - use ArmOpCode::*; + use AluOpCode::*; match self { AND => write!(f, "and"), EOR => write!(f, "eor"), @@ -53,9 +52,9 @@ impl fmt::Display for ArmOpCode { } } -impl fmt::Display for ArmShiftType { +impl fmt::Display for BarrelShiftOpCode { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - use ArmShiftType::*; + use BarrelShiftOpCode::*; match self { LSL => write!(f, "lsl"), LSR => write!(f, "lsr"), @@ -76,25 +75,23 @@ impl fmt::Display for ArmHalfwordTransferType { } } -fn is_shift(shift: &ArmRegisterShift) -> bool { - if let ArmRegisterShift::ShiftAmount(val, typ) = shift { - return !(*val == 0 && *typ == ArmShiftType::LSL); +fn is_shift(shift: &ShiftedRegister) -> bool { + if let ShiftedRegister::ByAmount(val, typ) = shift { + return !(*val == 0 && *typ == BarrelShiftOpCode::LSL); } true } impl ArmInstruction { - fn make_shifted_reg_string(&self, reg: usize, shift: ArmRegisterShift) -> String { + fn make_shifted_reg_string(&self, reg: usize, shift: ShiftedRegister) -> String { let reg = reg_string(reg).to_string(); if !is_shift(&shift) { return reg; } match shift { - ArmRegisterShift::ShiftAmount(imm, typ) => format!("{}, {} #{}", reg, typ, imm), - ArmRegisterShift::ShiftRegister(rs, typ) => { - format!("{}, {} {}", reg, typ, reg_string(rs)) - } + ShiftedRegister::ByAmount(imm, typ) => format!("{}, {} #{}", reg, typ, imm), + ShiftedRegister::ByRegister(rs, typ) => format!("{}, {} {}", reg, typ, reg_string(rs)), } } @@ -121,7 +118,7 @@ impl ArmInstruction { } fn fmt_data_processing(&self, f: &mut fmt::Formatter) -> fmt::Result { - use ArmOpCode::*; + use AluOpCode::*; let opcode = self.opcode().unwrap(); @@ -154,11 +151,11 @@ impl ArmInstruction { let operand2 = self.operand2().unwrap(); match operand2 { - ArmShiftedValue::RotatedImmediate(_, _) => { + BarrelShifterValue::RotatedImmediate(_, _) => { let value = operand2.decode_rotated_immediate().unwrap(); write!(f, "#{}\t; {:#x}", value, value) } - ArmShiftedValue::ShiftedRegister { + BarrelShifterValue::ShiftedRegister { reg, shift, added: _, @@ -175,10 +172,10 @@ impl ArmInstruction { } } - fn fmt_rn_offset(&self, f: &mut fmt::Formatter, offset: ArmShiftedValue) -> fmt::Result { + fn fmt_rn_offset(&self, f: &mut fmt::Formatter, offset: BarrelShifterValue) -> fmt::Result { write!(f, "[{Rn}", Rn = reg_string(self.rn()))?; let (ofs_string, comment) = match offset { - ArmShiftedValue::ImmediateValue(value) => { + BarrelShifterValue::ImmediateValue(value) => { let value_for_commnet = if self.rn() == REG_PC { value + (self.pc as i32) + 8 // account for pipelining } else { @@ -189,7 +186,7 @@ impl ArmInstruction { Some(format!("\t; {:#x}", value_for_commnet)), ) } - ArmShiftedValue::ShiftedRegister { + BarrelShifterValue::ShiftedRegister { reg, shift, added: Some(added), @@ -232,7 +229,7 @@ impl ArmInstruction { Rd = reg_string(self.rd()), )?; - self.fmt_rn_offset(f, self.ldr_str_offset().unwrap()) + self.fmt_rn_offset(f, self.ldr_str_offset()) } fn fmt_ldm_stm(&self, f: &mut fmt::Formatter) -> fmt::Result { diff --git a/src/arm7tdmi/arm/exec.rs b/src/arm7tdmi/arm/exec.rs index a8b2463..01c47d7 100644 --- a/src/arm7tdmi/arm/exec.rs +++ b/src/arm7tdmi/arm/exec.rs @@ -1,5 +1,6 @@ use crate::bit::BitIndex; +use crate::arm7tdmi::alu::*; use crate::arm7tdmi::bus::Bus; use crate::arm7tdmi::cpu::{Core, CpuExecResult, CpuPipelineAction}; use crate::arm7tdmi::exception::Exception; @@ -83,114 +84,6 @@ impl Core { Ok(CpuPipelineAction::IncPC) } - fn barrel_shift(&mut self, val: i32, amount: u32, shift: ArmShiftType) -> i32 { - match shift { - ArmShiftType::LSL => { - if amount < 32 { - self.cpsr.set_C(val.wrapping_shr(32 - amount) & 1 == 1); - } else { - if amount == 32 { - self.cpsr.set_C(val & 1 == 1); - } else { - self.cpsr.set_C(false) - } - } - val.wrapping_shl(amount) - } - ArmShiftType::LSR => { - if 0 < amount && amount < 32 { - self.cpsr.set_C(val.wrapping_shr(amount - 1) & 1 == 1); - } else { - self.cpsr.set_C(false); - } - (val as u32).wrapping_shr(amount) as i32 - } - ArmShiftType::ASR => { - if 0 < amount && amount < 32 { - self.cpsr.set_C(val.wrapping_shr(amount - 1) & 1 == 1); - } else { - self.cpsr.set_C(val >> 31 == 1); - } - val.wrapping_shr(amount) - } - ArmShiftType::ROR => { - let amount = amount % 32; - let result = val.rotate_right(amount); - self.cpsr.set_C((result >> 1) & 1 == 1); - result - } - } - } - - pub fn register_shift(&mut self, reg: usize, shift: ArmRegisterShift) -> CpuResult { - let val = self.get_reg(reg) as i32; - match shift { - ArmRegisterShift::ShiftAmount(amount, shift) => { - Ok(self.barrel_shift(val, amount, shift)) - } - ArmRegisterShift::ShiftRegister(reg, shift) => { - if reg != REG_PC { - Ok(self.barrel_shift(val, self.get_reg(reg) & 0xff, shift)) - } else { - Err(CpuError::IllegalInstruction) - } - } - } - } - - fn alu_sub_update_carry(a: i32, b: i32, carry: &mut bool) -> i32 { - let res = a.wrapping_sub(b); - *carry = res > a; - res - } - - fn alu_add_update_carry(a: i32, b: i32, carry: &mut bool) -> i32 { - let res = a.wrapping_add(b); - *carry = res < a; - res - } - - #[allow(non_snake_case)] - pub fn alu( - &mut self, - opcode: ArmOpCode, - op1: i32, - op2: i32, - set_cond_flags: bool, - ) -> Option { - let C = self.cpsr.C() as i32; - - let mut carry = self.cpsr.C(); - let overflow = self.cpsr.V(); - - let result = match opcode { - ArmOpCode::AND | ArmOpCode::TST => op1 & op2, - ArmOpCode::EOR | ArmOpCode::TEQ => op1 ^ op2, - ArmOpCode::SUB | ArmOpCode::CMP => Self::alu_sub_update_carry(op1, op2, &mut carry), - ArmOpCode::RSB => Self::alu_sub_update_carry(op2, op1, &mut carry), - ArmOpCode::ADD | ArmOpCode::CMN => Self::alu_add_update_carry(op1, op2, &mut carry), - ArmOpCode::ADC => Self::alu_add_update_carry(op1, op2.wrapping_add(C), &mut carry), - ArmOpCode::SBC => Self::alu_sub_update_carry(op1, op2.wrapping_sub(1 - C), &mut carry), - ArmOpCode::RSC => Self::alu_sub_update_carry(op2, op1.wrapping_sub(1 - C), &mut carry), - ArmOpCode::ORR => op1 | op2, - ArmOpCode::MOV => op2, - ArmOpCode::BIC => op1 & (!op2), - ArmOpCode::MVN => !op2, - }; - - if set_cond_flags { - self.cpsr.set_N(result < 0); - self.cpsr.set_Z(result == 0); - self.cpsr.set_C(carry); - self.cpsr.set_V(overflow); - } - - match opcode { - ArmOpCode::TST | ArmOpCode::TEQ | ArmOpCode::CMP | ArmOpCode::CMN => None, - _ => Some(result), - } - } - /// Logical/Arithmetic ALU operations /// /// Cycles: 1S+x+y (from GBATEK) @@ -214,20 +107,21 @@ impl Core { let rd = insn.rd(); let op2: i32 = match op2 { - ArmShiftedValue::RotatedImmediate(immediate, rotate) => { - Ok(immediate.rotate_right(rotate) as i32) + BarrelShifterValue::RotatedImmediate(immediate, rotate) => { + immediate.rotate_right(rotate) as i32 } - ArmShiftedValue::ShiftedRegister { + BarrelShifterValue::ShiftedRegister { reg, shift, added: _, } => { // +1I self.add_cycle(); - self.register_shift(reg, shift) + let result = self.register_shift(reg, shift)?; + result } _ => unreachable!(), - }?; + }; let opcode = insn.opcode().unwrap(); let set_flags = opcode.is_setting_flags() || insn.set_cond_flag(); @@ -241,11 +135,11 @@ impl Core { Ok(pipeline_action) } - fn get_rn_offset(&mut self, sval: ArmShiftedValue) -> i32 { + fn get_rn_offset(&mut self, sval: BarrelShifterValue) -> i32 { // TODO decide if error handling or panic here match sval { - ArmShiftedValue::ImmediateValue(offset) => offset, - ArmShiftedValue::ShiftedRegister { + BarrelShifterValue::ImmediateValue(offset) => offset, + BarrelShifterValue::ShiftedRegister { reg, shift, added: Some(added), @@ -284,7 +178,7 @@ impl Core { addr = insn.pc + 8; // prefetching } - let offset = self.get_rn_offset(insn.ldr_str_offset().unwrap()); + let offset = self.get_rn_offset(insn.ldr_str_offset()); let effective_addr = (addr as i32).wrapping_add(offset) as Addr; addr = if insn.pre_index_flag() { diff --git a/src/arm7tdmi/arm/mod.rs b/src/arm7tdmi/arm/mod.rs index d689a37..e5c0434 100644 --- a/src/arm7tdmi/arm/mod.rs +++ b/src/arm7tdmi/arm/mod.rs @@ -1,13 +1,13 @@ pub mod display; pub mod exec; +use super::alu::*; use crate::arm7tdmi::{Addr, InstructionDecoder, InstructionDecoderError}; use crate::bit::BitIndex; use crate::byteorder::{LittleEndian, ReadBytesExt}; use crate::num::FromPrimitive; -use std::convert::TryFrom; use std::io; #[derive(Debug, PartialEq)] @@ -90,35 +90,6 @@ pub enum ArmFormat { MSR_FLAGS, } -#[derive(Debug, Primitive)] -pub enum ArmOpCode { - AND = 0b0000, - EOR = 0b0001, - SUB = 0b0010, - RSB = 0b0011, - ADD = 0b0100, - ADC = 0b0101, - SBC = 0b0110, - RSC = 0b0111, - TST = 0b1000, - TEQ = 0b1001, - CMP = 0b1010, - CMN = 0b1011, - ORR = 0b1100, - MOV = 0b1101, - BIC = 0b1110, - MVN = 0b1111, -} - -impl ArmOpCode { - pub fn is_setting_flags(&self) -> bool { - match self { - ArmOpCode::TST | ArmOpCode::TEQ | ArmOpCode::CMP | ArmOpCode::CMN => true, - _ => false, - } - } -} - #[derive(Debug, PartialEq, Primitive)] pub enum ArmHalfwordTransferType { UnsignedHalfwords = 0b01, @@ -204,59 +175,6 @@ impl InstructionDecoder for ArmInstruction { } } -#[derive(Debug, PartialEq, Primitive)] -pub enum ArmShiftType { - LSL = 0, - LSR = 1, - ASR = 2, - ROR = 3, -} - -#[derive(Debug, PartialEq)] -pub enum ArmRegisterShift { - ShiftAmount(u32, ArmShiftType), - ShiftRegister(usize, ArmShiftType), -} - -impl TryFrom for ArmRegisterShift { - type Error = ArmDecodeErrorKind; - - fn try_from(v: u32) -> Result { - let typ = match ArmShiftType::from_u8(v.bit_range(5..7) as u8) { - Some(s) => Ok(s), - _ => Err(InvalidShiftType(v.bit_range(5..7))), - }?; - if v.bit(4) { - let rs = v.bit_range(8..12) as usize; - Ok(ArmRegisterShift::ShiftRegister(rs, typ)) - } else { - let amount = v.bit_range(7..12) as u32; - Ok(ArmRegisterShift::ShiftAmount(amount, typ)) - } - } -} - -#[derive(Debug, PartialEq)] -pub enum ArmShiftedValue { - ImmediateValue(i32), - RotatedImmediate(u32, u32), - ShiftedRegister { - reg: usize, - shift: ArmRegisterShift, - added: Option, - }, -} - -impl ArmShiftedValue { - /// Decode operand2 as an immediate value - pub fn decode_rotated_immediate(&self) -> Option { - if let ArmShiftedValue::RotatedImmediate(immediate, rotate) = self { - return Some(immediate.rotate_right(*rotate) as i32); - } - None - } -} - impl ArmInstruction { fn make_decode_error(&self, kind: ArmDecodeErrorKind) -> ArmDecodeError { ArmDecodeError { @@ -298,8 +216,8 @@ impl ArmInstruction { self.raw.bit_range(16..20) as usize } - pub fn opcode(&self) -> Option { - ArmOpCode::from_u32(self.raw.bit_range(21..25)) + pub fn opcode(&self) -> Option { + AluOpCode::from_u32(self.raw.bit_range(21..25)) } pub fn branch_offset(&self) -> i32 { @@ -363,28 +281,27 @@ impl ArmInstruction { } /// gets offset used by ldr/str instructions - pub fn ldr_str_offset(&self) -> Result { + pub fn ldr_str_offset(&self) -> BarrelShifterValue { let ofs = self.raw.bit_range(0..12); if self.raw.bit(25) { let rm = ofs & 0xf; - let shift = - ArmRegisterShift::try_from(ofs).map_err(|kind| self.make_decode_error(kind))?; - Ok(ArmShiftedValue::ShiftedRegister { + let shift = ShiftedRegister::from(ofs); + BarrelShifterValue::ShiftedRegister { reg: rm as usize, shift: shift, added: Some(self.add_offset_flag()), - }) + } } else { let ofs = if self.add_offset_flag() { ofs as i32 } else { -(ofs as i32) }; - Ok(ArmShiftedValue::ImmediateValue(ofs)) + BarrelShifterValue::ImmediateValue(ofs) } } - pub fn ldr_str_hs_offset(&self) -> Result { + pub fn ldr_str_hs_offset(&self) -> Result { match self.fmt { ArmFormat::LDR_STR_HS_IMM => { let offset8 = (self.raw.bit_range(8..12) << 4) + self.raw.bit_range(0..4); @@ -393,28 +310,27 @@ impl ArmInstruction { } else { -(offset8 as i32) }; - Ok(ArmShiftedValue::ImmediateValue(offset8)) + Ok(BarrelShifterValue::ImmediateValue(offset8)) } - ArmFormat::LDR_STR_HS_REG => Ok(ArmShiftedValue::ShiftedRegister { + ArmFormat::LDR_STR_HS_REG => Ok(BarrelShifterValue::ShiftedRegister { reg: (self.raw & 0xf) as usize, - shift: ArmRegisterShift::ShiftAmount(0, ArmShiftType::LSL), + shift: ShiftedRegister::ByAmount(0, BarrelShiftOpCode::LSL), added: Some(self.add_offset_flag()), }), _ => Err(self.make_decode_error(DecodedPartDoesNotBelongToInstruction)), } } - pub fn operand2(&self) -> Result { + pub fn operand2(&self) -> Result { let op2 = self.raw.bit_range(0..12); if self.raw.bit(25) { let immediate = op2 & 0xff; let rotate = 2 * op2.bit_range(8..12); - Ok(ArmShiftedValue::RotatedImmediate(immediate, rotate)) + Ok(BarrelShifterValue::RotatedImmediate(immediate, rotate)) } else { let reg = op2 & 0xf; - let shift = - ArmRegisterShift::try_from(op2).map_err(|kind| self.make_decode_error(kind))?; // TODO error handling - Ok(ArmShiftedValue::ShiftedRegister { + let shift = ShiftedRegister::from(op2); // TODO error handling + Ok(BarrelShifterValue::ShiftedRegister { reg: reg as usize, shift: shift, added: None, @@ -530,11 +446,11 @@ mod tests { assert_eq!(decoded.rn(), 5); assert_eq!( decoded.ldr_str_offset(), - Ok(ArmShiftedValue::ShiftedRegister { + BarrelShifterValue::ShiftedRegister { reg: 6, - shift: ArmRegisterShift::ShiftAmount(5, ArmShiftType::LSL), + shift: ShiftedRegister::ByAmount(5, BarrelShiftOpCode::LSL), added: Some(false) - }) + } ); assert_eq!(format!("{}", decoded), "ldreq\tr2, [r5, -r6, lsl #5]"); @@ -545,13 +461,12 @@ mod tests { core.gpr[6] = 1; core.gpr[2] = 0; + #[rustfmt::skip] let bytes = vec![ - /* 00h: */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, - 0x00, 0x00, 0x00, 0x00, /* 10h: */ 0x00, 0x00, 0x00, 0x00, 0x37, 0x13, 0x00, 0x00, - 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 20h: */ 0x00, 0x00, 0x00, 0x00, - 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, - /* 30h: */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, - 0x00, 0x00, 0x00, 0x00, + /* 00h: */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + /* 10h: */ 0x00, 0x00, 0x00, 0x00, 0x37, 0x13, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + /* 20h: */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + /* 30h: */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, ]; let mut mem = BoxedMemory::new(bytes.into_boxed_slice()); @@ -575,11 +490,11 @@ mod tests { assert_eq!(decoded.rn(), 4); assert_eq!( decoded.ldr_str_offset(), - Ok(ArmShiftedValue::ShiftedRegister { + BarrelShifterValue::ShiftedRegister { reg: 7, - shift: ArmRegisterShift::ShiftAmount(8, ArmShiftType::ASR), + shift: ShiftedRegister::ByAmount(8, BarrelShiftOpCode::ASR), added: Some(false) - }) + } ); assert_eq!(format!("{}", decoded), "strteq\tr2, [r4], -r7, asr #8"); @@ -590,13 +505,12 @@ mod tests { core.gpr[7] = 1; core.gpr[2] = 0xabababab; + #[rustfmt::skip] let bytes = vec![ - /* 00h: */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, - 0x00, 0x00, 0x00, 0x00, /* 10h: */ 0x00, 0x00, 0x00, 0x00, 0x37, 0x13, 0x00, 0x00, - 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 20h: */ 0x00, 0x00, 0x00, 0x00, - 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, - /* 30h: */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, - 0x00, 0x00, 0x00, 0x00, + /* 00h: */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + /* 10h: */ 0x00, 0x00, 0x00, 0x00, 0x37, 0x13, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + /* 20h: */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + /* 30h: */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, ]; let mut mem = BoxedMemory::new(bytes.into_boxed_slice()); @@ -618,9 +532,12 @@ mod tests { core.set_reg(4, 0x12345678); core.set_reg(REG_SP, 0); + #[rustfmt::skip] let bytes = vec![ - /* 0: */ 0xaa, 0xbb, 0xcc, 0xdd, /* 4: */ 0xaa, 0xbb, 0xcc, 0xdd, - /* 8: */ 0xaa, 0xbb, 0xcc, 0xdd, /* c: */ 0xaa, 0xbb, 0xcc, 0xdd, + /* 0: */ 0xaa, 0xbb, 0xcc, 0xdd, + /* 4: */ 0xaa, 0xbb, 0xcc, 0xdd, + /* 8: */ 0xaa, 0xbb, 0xcc, 0xdd, + /* c: */ 0xaa, 0xbb, 0xcc, 0xdd, /* 10: */ 0xaa, 0xbb, 0xcc, 0xdd, ]; let mut mem = BoxedMemory::new(bytes.into_boxed_slice()); diff --git a/src/arm7tdmi/mod.rs b/src/arm7tdmi/mod.rs index 7ed374a..cfafbeb 100644 --- a/src/arm7tdmi/mod.rs +++ b/src/arm7tdmi/mod.rs @@ -10,6 +10,8 @@ use thumb::{ThumbDecodeError, ThumbInstruction}; pub mod cpu; pub use cpu::*; +pub mod alu; +pub use alu::*; pub mod bus; pub use bus::*; pub mod exception; diff --git a/src/arm7tdmi/thumb/display.rs b/src/arm7tdmi/thumb/display.rs index 7a1d529..45c2473 100644 --- a/src/arm7tdmi/thumb/display.rs +++ b/src/arm7tdmi/thumb/display.rs @@ -38,8 +38,8 @@ 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)?; + if let Some(ShiftedRegister::ByRegister(_, op)) = shft { + write!(f, "{}", op)?; } else { write!(f, "{}", op)?; } @@ -115,7 +115,6 @@ impl ThumbInstruction { (false, true) => "ldrh", (true, false) => "ldsb", (true, true) => "ldsh", - _ => panic!("invalid flags"), } }, Rd = reg_string(self.rd()), diff --git a/src/arm7tdmi/thumb/exec.rs b/src/arm7tdmi/thumb/exec.rs index 65bfb16..2043512 100644 --- a/src/arm7tdmi/thumb/exec.rs +++ b/src/arm7tdmi/thumb/exec.rs @@ -1,4 +1,3 @@ -use crate::arm7tdmi::arm::exec::*; use crate::arm7tdmi::bus::Bus; use crate::arm7tdmi::cpu::{Core, CpuExecResult, CpuPipelineAction}; use crate::arm7tdmi::*; @@ -25,7 +24,7 @@ impl Core { let result = self .register_shift( insn.rs(), - ArmRegisterShift::ShiftAmount(insn.offset5() as u8 as u32, insn.format1_op()), + ShiftedRegister::ByAmount(insn.offset5() as u8 as u32, insn.format1_op()), ) .unwrap(); self.gpr[insn.rd()] = result as u32; @@ -41,9 +40,9 @@ impl Core { self.get_reg(insn.rn()) as i32 }; let arm_alu_op = if insn.is_subtract() { - ArmOpCode::SUB + AluOpCode::SUB } else { - ArmOpCode::ADD + AluOpCode::ADD }; let result = self.alu(arm_alu_op, op1, op2, true); @@ -59,7 +58,7 @@ impl Core { _bus: &mut Bus, insn: ThumbInstruction, ) -> CpuExecResult { - let arm_alu_op: ArmOpCode = insn.format3_op().into(); + let arm_alu_op: AluOpCode = insn.format3_op().into(); let op1 = self.get_reg(insn.rd()) as i32; let op2 = insn.offset8() as u8 as i32; let result = self.alu(arm_alu_op, op1, op2, true); @@ -139,10 +138,10 @@ impl Core { } else { insn.rs() }; - let arm_alu_op: ArmOpCode = insn.format5_op().into(); + let arm_alu_op: AluOpCode = insn.format5_op().into(); let op1 = self.get_reg(dst_reg) as i32; let op2 = self.get_reg(src_reg) as i32; - let result = self.alu(arm_alu_op, op1, op2, true); + let result = self.alu(arm_alu_op, op1, op2, false); if let Some(result) = result { self.set_reg(dst_reg, result as u32); if dst_reg == REG_PC { @@ -235,7 +234,6 @@ impl Core { let val = self.load_16(addr, bus) as i16 as i32 as u32; self.gpr[rd] = val; } - _ => panic!("invalid flags"), } Ok(CpuPipelineAction::IncPC) @@ -277,7 +275,7 @@ impl Core { self.do_exec_thumb_ldr_str_with_addr(bus, insn, addr) } - fn exec_thumb_load_address(&mut self, bus: &mut Bus, insn: ThumbInstruction) -> CpuExecResult { + fn exec_thumb_load_address(&mut self, _bus: &mut Bus, insn: ThumbInstruction) -> CpuExecResult { let result = if insn.flag(ThumbInstruction::FLAG_SP) { self.gpr[REG_SP] + (insn.word8() as Addr) } else { @@ -307,7 +305,7 @@ impl Core { 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(); - let arm_alu_op = ArmOpCode::ADD; + let arm_alu_op = AluOpCode::ADD; let result = self.alu(arm_alu_op, op1, op2, false); if let Some(result) = result { @@ -352,7 +350,6 @@ impl Core { let is_load = insn.is_load(); let rb = insn.rb(); - let mut pipeline_action = CpuPipelineAction::IncPC; let mut addr = self.gpr[rb]; let rlist = insn.register_list(); @@ -370,7 +367,7 @@ impl Core { } } - Ok(pipeline_action) + Ok(CpuPipelineAction::IncPC) } fn exec_thumb_branch_with_cond( diff --git a/src/arm7tdmi/thumb/mod.rs b/src/arm7tdmi/thumb/mod.rs index c4e84e5..277417e 100644 --- a/src/arm7tdmi/thumb/mod.rs +++ b/src/arm7tdmi/thumb/mod.rs @@ -4,6 +4,7 @@ use crate::bit::BitIndex; use crate::byteorder::{LittleEndian, ReadBytesExt}; use crate::num::FromPrimitive; +use super::alu::*; use super::arm::*; use super::{Addr, InstructionDecoder, InstructionDecoderError}; @@ -42,7 +43,7 @@ pub enum ThumbFormat { AddSub, /// Format 3 DataProcessImm, - /// Belongs to Format 4, but decoded seperatly because ArmOpcode doesn't have MUL + /// Belongs to Format 4, but decoded seperatly because AluOpCode doesn't have MUL Mul, /// Format 4 AluOps, @@ -163,13 +164,13 @@ pub enum OpFormat3 { SUB = 3, } -impl From for ArmOpCode { - fn from(op: OpFormat3) -> ArmOpCode { +impl From for AluOpCode { + fn from(op: OpFormat3) -> AluOpCode { match op { - OpFormat3::MOV => ArmOpCode::MOV, - OpFormat3::CMP => ArmOpCode::CMP, - OpFormat3::ADD => ArmOpCode::ADD, - OpFormat3::SUB => ArmOpCode::SUB, + OpFormat3::MOV => AluOpCode::MOV, + OpFormat3::CMP => AluOpCode::CMP, + OpFormat3::ADD => AluOpCode::ADD, + OpFormat3::SUB => AluOpCode::SUB, } } } @@ -182,12 +183,12 @@ pub enum OpFormat5 { BX = 3, } -impl From for ArmOpCode { - fn from(op: OpFormat5) -> ArmOpCode { +impl From for AluOpCode { + fn from(op: OpFormat5) -> AluOpCode { match op { - OpFormat5::ADD => ArmOpCode::ADD, - OpFormat5::CMP => ArmOpCode::CMP, - OpFormat5::MOV => ArmOpCode::MOV, + OpFormat5::ADD => AluOpCode::ADD, + OpFormat5::CMP => AluOpCode::CMP, + OpFormat5::MOV => AluOpCode::MOV, OpFormat5::BX => panic!("this should not be called if op = BX"), } } @@ -229,8 +230,8 @@ impl ThumbInstruction { self.raw.bit_range(6..9) as usize } - pub fn format1_op(&self) -> ArmShiftType { - ArmShiftType::from_u8(self.raw.bit_range(11..13) as u8).unwrap() + pub fn format1_op(&self) -> BarrelShiftOpCode { + BarrelShiftOpCode::from_u8(self.raw.bit_range(11..13) as u8).unwrap() } pub fn format3_op(&self) -> OpFormat3 { @@ -241,38 +242,38 @@ impl ThumbInstruction { OpFormat5::from_u8(self.raw.bit_range(8..10) as u8).unwrap() } - pub fn alu_opcode(&self) -> (ArmOpCode, Option) { + pub fn alu_opcode(&self) -> (AluOpCode, Option) { match self.raw.bit_range(6..10) { 0b0010 => ( - ArmOpCode::MOV, - Some(ArmRegisterShift::ShiftRegister( + AluOpCode::MOV, + Some(ShiftedRegister::ByRegister( self.rs(), - ArmShiftType::LSL, + BarrelShiftOpCode::LSL, )), ), 0b0011 => ( - ArmOpCode::MOV, - Some(ArmRegisterShift::ShiftRegister( + AluOpCode::MOV, + Some(ShiftedRegister::ByRegister( self.rs(), - ArmShiftType::LSR, + BarrelShiftOpCode::LSR, )), ), 0b0100 => ( - ArmOpCode::MOV, - Some(ArmRegisterShift::ShiftRegister( + AluOpCode::MOV, + Some(ShiftedRegister::ByRegister( self.rs(), - ArmShiftType::ASR, + BarrelShiftOpCode::ASR, )), ), 0b0111 => ( - ArmOpCode::MOV, - Some(ArmRegisterShift::ShiftRegister( + AluOpCode::MOV, + Some(ShiftedRegister::ByRegister( self.rs(), - ArmShiftType::ROR, + BarrelShiftOpCode::ROR, )), ), 0b1101 => panic!("tried to decode MUL"), - op => (ArmOpCode::from_u16(op).unwrap(), None), + op => (AluOpCode::from_u16(op).unwrap(), None), } } @@ -383,9 +384,13 @@ mod tests { // ldr r0, [pc, #4] let insn = ThumbInstruction::decode(0x4801, 0x6).unwrap(); + #[rustfmt::skip] let bytes = vec![ - /* 0: */ 0x00, 0x00, /* 2: */ 0x00, 0x00, /* 4: */ 0x00, 0x00, - /* 6: */ 0x00, 0x00, /* 8: */ 0x00, 0x00, 0x00, 0x00, + /* 0: */ 0x00, 0x00, + /* 2: */ 0x00, 0x00, + /* 4: */ 0x00, 0x00, + /* 6: */ 0x00, 0x00, + /* 8: */ 0x00, 0x00, 0x00, 0x00, /* c: */ 0x78, 0x56, 0x34, 0x12, ]; let mut mem = BoxedMemory::new(bytes.into_boxed_slice()); @@ -413,10 +418,13 @@ mod tests { core.set_reg(1, 0x4); core.set_reg(4, 0xc); + #[rustfmt::skip] let bytes = vec![ - /* 0: */ 0xaa, 0xbb, 0xcc, 0xdd, /* 4: */ 0xaa, 0xbb, 0xcc, 0xdd, - /* 8: */ 0xaa, 0xbb, 0xcc, 0xdd, /* c: */ 0xaa, 0xbb, 0xcc, 0xdd, - /* 10: */ 0xaa, 0xbb, 0xcc, 0xdd, + /* 00h: */ 0xaa, 0xbb, 0xcc, 0xdd, + /* 04h: */ 0xaa, 0xbb, 0xcc, 0xdd, + /* 08h: */ 0xaa, 0xbb, 0xcc, 0xdd, + /* 0ch: */ 0xaa, 0xbb, 0xcc, 0xdd, + /* 10h: */ 0xaa, 0xbb, 0xcc, 0xdd, ]; let mut mem = BoxedMemory::new(bytes.into_boxed_slice()); @@ -438,14 +446,14 @@ mod tests { #[test] fn format8() { let mut core = Core::new(); + #[rustfmt::skip] let bytes = vec![ - /* 0: */ 0xaa, 0xbb, 0xcc, 0xdd, 0xaa, 0xbb, 0xcc, 0xdd, - /* 8: */ 0xaa, 0xbb, 0xcc, 0xdd, 0xaa, 0xbb, 0xcc, 0xdd, - /* 10: */ 0xaa, 0xbb, 0xcc, 0xdd, 0xaa, 0xbb, 0xcc, 0xdd, + /* 00h: */ 0xaa, 0xbb, 0xcc, 0xdd, 0xaa, 0xbb, 0xcc, 0xdd, + /* 08h: */ 0xaa, 0xbb, 0xcc, 0xdd, 0xaa, 0xbb, 0xcc, 0xdd, + /* 10h: */ 0xaa, 0xbb, 0xcc, 0xdd, 0xaa, 0xbb, 0xcc, 0xdd, ]; let mut mem = BoxedMemory::new(bytes.into_boxed_slice()); - core.gpr[4] = 0x12345678; core.gpr[3] = 0x2; core.gpr[0] = 0x4;