diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/isa/funct3.rs | 12 | ||||
| -rw-r--r-- | src/simulator.rs | 116 |
2 files changed, 76 insertions, 52 deletions
diff --git a/src/isa/funct3.rs b/src/isa/funct3.rs index 94f2f41..7cb3c5d 100644 --- a/src/isa/funct3.rs +++ b/src/isa/funct3.rs @@ -39,6 +39,12 @@ pub const BGE: u32 = 0b101; pub const BLTU: u32 = 0b110; pub const BGEU: u32 = 0b111; -pub const LW: u32 = 0x2; - -pub const SW: u32 = 0x2; +pub const LB: u32 = 0b000; +pub const LH: u32 = 0b001; +pub const LW: u32 = 0b010; +pub const LBU: u32 = 0b100; +pub const LHU: u32 = 0b101; + +pub const SB: u32 = 0b000; +pub const SH: u32 = 0b001; +pub const SW: u32 = 0b010; diff --git a/src/simulator.rs b/src/simulator.rs index 4feb1c0..006244a 100644 --- a/src/simulator.rs +++ b/src/simulator.rs @@ -280,61 +280,79 @@ impl<'a> Core<'a> { self.registers.write_word(inst.rd(), value); } }, - isa::opcodes::LOAD => match inst.funct3() { - isa::funct3::LW => { - let imm = inst.i_imm(); - let base = self.registers.read_word(inst.rs1()); - let address = ((base as isa::SignedWord) + imm) as isa::Address; - let address = self.mmu.translate(address); + isa::opcodes::LOAD => { + let imm = inst.i_imm(); + let base = self.registers.read_word(inst.rs1()); + let address = ((base as isa::SignedWord) + imm) as isa::Address; + let address = self.mmu.translate(address); - let result = self.cache.borrow_mut().read_word(address); - match result { - Ok(value) => self.registers.write_word(inst.rd(), value), - Err(MemoryError::CacheMiss { stall_cycles }) => { - self.stall = stall_cycles; - return; - }, - Err(MemoryError::InvalidAddress) => { - self.trap(Trap::IllegalRead { - address: pc, - instruction: inst, - memory_address: address, - }); - } - } - }, - _ => { - panic!("Invalid load funct3code: 0x{:x}", inst.funct3()); + let result = match inst.funct3() { + isa::funct3::LB => + self.cache.borrow_mut() + .read_byte(address) + .map(|b| (b as isa::SignedByte) as isa::Word), + isa::funct3::LH => + panic!("{:x}: Unimplemented LH"), + isa::funct3::LW => + self.cache.borrow_mut().read_word(address), + isa::funct3::LBU => + self.cache.borrow_mut() + .read_byte(address) + .map(|b| b as isa::Word), + isa::funct3::LHU => + panic!("{:x}: Unimplemented LHU"), + _ => panic!("{:x}: Invalid load funct3code: 0x{:x}", + pc, inst.funct3()), + }; + + match result { + Ok(value) => self.registers.write_word(inst.rd(), value), + Err(MemoryError::CacheMiss { stall_cycles }) => { + self.stall = stall_cycles; + return; // don't increment PC + }, + Err(MemoryError::InvalidAddress) => { + self.trap(Trap::IllegalRead { + address: pc, + instruction: inst, + memory_address: address, + }); + }, } }, - isa::opcodes::STORE => match inst.funct3() { - isa::funct3::SW => { - let imm = inst.s_imm(); - let base = self.registers.read_word(inst.rs1()); - let val = self.registers.read_word(inst.rs2()); - let address = ((base as isa::SignedWord) + imm) as isa::Address; - let address = self.mmu.translate(address); + isa::opcodes::STORE => { + let imm = inst.s_imm(); + let base = self.registers.read_word(inst.rs1()); + let val = self.registers.read_word(inst.rs2()); + let address = ((base as isa::SignedWord) + imm) as isa::Address; + let address = self.mmu.translate(address); - let result = self.cache.borrow_mut().write_word(address, val); - match result { - Ok(()) => (), - Err(MemoryError::CacheMiss { stall_cycles }) => { - self.stall = stall_cycles - 1; - return; - }, - Err(MemoryError::InvalidAddress) => { - self.trap(Trap::IllegalWrite { - address: pc, - instruction: inst, - memory_address: address, - memory_value: val, - }) - } + let result = match inst.funct3() { + isa::funct3::SB => + self.cache.borrow_mut().write_byte(address, val as u8), + isa::funct3::SH => + panic!("PC {:x}: Unimplemented SH"), + isa::funct3::SW => + self.cache.borrow_mut().write_word(address, val), + _ => panic!("PC {:x}: Invalid store funct3code: 0x{:x}", + pc, inst.funct3()), + }; + + match result { + Ok(()) => (), + Err(MemoryError::CacheMiss { stall_cycles }) => { + self.stall = stall_cycles; + return; // don't increment PC + }, + Err(MemoryError::InvalidAddress) => { + self.trap(Trap::IllegalWrite { + address: pc, + instruction: inst, + memory_address: address, + memory_value: val, + }) } } - _ => { - panic!("Invalid store funct3code: 0x{:x}", inst.funct3()); - } }, isa::opcodes::SYSTEM => match inst.i_imm() { 0x0 => { |