diff --git a/src/instructions.rs b/src/instructions.rs index 5261dde..935a51f 100644 --- a/src/instructions.rs +++ b/src/instructions.rs @@ -34,6 +34,12 @@ pub(crate) fn find_and_exec(instr: Instruction, core: &mut Core) -> Option Some(rvi::sd(core, instr)), _ => None, }, + 0b00000 => match instr.funct3() { + // LOAD + 0b000 => Some(rvi::lb(core, instr)), + 0b100 => Some(rvi::lbu(core, instr)), + _ => None, + }, 0b01101 => Some(rvi::lui(core, instr)), 0b11011 => Some(rvi::jal(core, instr)), _ => None, diff --git a/src/instructions/rvi.rs b/src/instructions/rvi.rs index 89d142b..98fcb07 100644 --- a/src/instructions/rvi.rs +++ b/src/instructions/rvi.rs @@ -69,6 +69,40 @@ pub fn sb(core: &mut Core, instr: Instruction) -> InstructionResult { } } +pub fn lb(core: &mut Core, instr: Instruction) -> InstructionResult { + let addr = core.reg_read(instr.rs1()).wrapping_add(instr.imm_i()); + + let page = (addr / 4096) as PageNum; + let offset = (addr & (4096 as Addr - 1)) as u16; + + match core.mem.read_byte(page, offset) { + Ok(x) => { + let x = x as i8 as i64 as DWord; + core.reg_write(instr.rd(), x); + core.pc = core.pc.wrapping_add(4); + InstructionResult::Normal + } + Err(_) => InstructionResult::Exception(()), + } +} + +pub fn lbu(core: &mut Core, instr: Instruction) -> InstructionResult { + let addr = core.reg_read(instr.rs1()).wrapping_add(instr.imm_i()); + + let page = (addr / 4096) as PageNum; + let offset = (addr & (4096 as Addr - 1)) as u16; + + match core.mem.read_byte(page, offset) { + Ok(x) => { + let x = x as DWord; + core.reg_write(instr.rd(), x); + core.pc = core.pc.wrapping_add(4); + InstructionResult::Normal + } + Err(_) => InstructionResult::Exception(()), + } +} + pub fn lui(core: &mut Core, instr: Instruction) -> InstructionResult { core.reg_write(instr.rd(), instr.imm_u()); core.pc = core.pc.wrapping_add(4);