taitep/trve
1
1
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Implement LB and LBU

Browse Source
This commit is contained in:
taitep
2025-12-21 15:56:50 +01:00
parent 25ecfca912
commit 390a2b3228
2 changed files with 40 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
src/instructions/rvi.rs
View File

@@ -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);