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use crate::{
consts::{Addr, Byte, DWord, Word},
core::Core,
instructions::{Instruction, InstructionResult},
mem::PageNum,
};
// TODO: Support misaligned memory access
pub fn sd(core: &mut Core, instr: Instruction) -> InstructionResult {
let addr = core.reg_read(instr.rs1()).wrapping_add(instr.imm_s());
if !addr.is_multiple_of(std::mem::size_of::<DWord>() as Addr) {
return InstructionResult::Exception(());
}
let page = (addr / 4096) as PageNum;
let offset = (addr / 8 & ((4096 / 8 as Addr) - 1)) as u16;
let value = core.reg_read(instr.rs2());
match core.mem.write_dword(page, offset, value) {
Ok(_) => {
core.advance_pc();
InstructionResult::Normal
}
Err(_) => InstructionResult::Exception(()),
}
}
pub fn ld(core: &mut Core, instr: Instruction) -> InstructionResult {
let addr = core.reg_read(instr.rs1()).wrapping_add(instr.imm_i());
if !addr.is_multiple_of(std::mem::size_of::<DWord>() as Addr) {
return InstructionResult::Exception(());
}
let page = (addr / 4096) as PageNum;
let offset = (addr / 8 & ((4096 / 8 as Addr) - 1)) as u16;
match core.mem.read_dword(page, offset) {
Ok(x) => {
core.reg_write(instr.rd(), x);
core.advance_pc();
InstructionResult::Normal
}
Err(_) => InstructionResult::Exception(()),
}
}
pub fn sw(core: &mut Core, instr: Instruction) -> InstructionResult {
let addr = core.reg_read(instr.rs1()).wrapping_add(instr.imm_s());
if !addr.is_multiple_of(std::mem::size_of::<Word>() as Addr) {
return InstructionResult::Exception(());
}
let page = (addr / 4096) as PageNum;
let offset = (addr / 4 & ((4096 / 4 as Addr) - 1)) as u16;
let value = core.reg_read(instr.rs2()) as Word;
match core.mem.write_word(page, offset, value) {
Ok(_) => {
core.advance_pc();
InstructionResult::Normal
}
Err(_) => InstructionResult::Exception(()),
}
}
pub fn sb(core: &mut Core, instr: Instruction) -> InstructionResult {
let addr = core.reg_read(instr.rs1()).wrapping_add(instr.imm_s());
let page = (addr / 4096) as PageNum;
let offset = (addr & (4096 as Addr - 1)) as u16;
let value = core.reg_read(instr.rs2()) as Byte;
match core.mem.write_byte(page, offset, value) {
Ok(_) => {
core.advance_pc();
InstructionResult::Normal
}
Err(_) => InstructionResult::Exception(()),
}
}
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.advance_pc();
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.advance_pc();
InstructionResult::Normal
}
Err(_) => InstructionResult::Exception(()),
}
}
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