ollien
/
ferris-boi
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Simplify load8 parsing to use bitwise ops

old-bit-manip
Nick Krichevsky 2023-11-18 10:02:51 -05:00
parent 90ec09ff40
commit 9a6ccf6d48
1 changed files with 30 additions and 62 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

92
src/cpu/parse/load8/transfer.rs
View File

@ -13,71 +13,39 @@ pub struct Parser;
impl OpcodeParser for Parser {
/// Parses an opcode that transfers an 8bit values between single 8 bit registers.
fn parse_opcode(data: &View) -> ParseResult {
// I don't normally like doing this but this function was ridiculous with the line length wrapping
// caused by not doing it
#[allow(clippy::enum_glob_use)]
use register::SingleEightBit::*;
let opcode = parse::get_opcode_from_data(data);
match opcode {
0x7f => Ok(make_load_between_register_data(A, A)),
0x78 => Ok(make_load_between_register_data(A, B)),
0x79 => Ok(make_load_between_register_data(A, C)),
0x7A => Ok(make_load_between_register_data(A, D)),
0x7B => Ok(make_load_between_register_data(A, E)),
0x7C => Ok(make_load_between_register_data(A, H)),
0x7D => Ok(make_load_between_register_data(A, L)),
let dst = parse_destination_register(opcode)?;
let src = parse_source_register(opcode)?;
0x47 => Ok(make_load_between_register_data(B, A)),
0x40 => Ok(make_load_between_register_data(B, B)),
0x41 => Ok(make_load_between_register_data(B, C)),
0x42 => Ok(make_load_between_register_data(B, D)),
0x43 => Ok(make_load_between_register_data(B, E)),
0x44 => Ok(make_load_between_register_data(B, H)),
0x45 => Ok(make_load_between_register_data(B, L)),
Ok(make_load_between_register_data(dst, src))
}
}
fn parse_destination_register(opcode: u8) -> Result<register::SingleEightBit, parse::Error> {
let source_part = opcode & 0xF0;
let offset = opcode & 0x0F;
match source_part {
0x40 if offset <= 7 => Ok(register::SingleEightBit::B),
0x40 if offset > 7 => Ok(register::SingleEightBit::C),
0x50 if offset <= 7 => Ok(register::SingleEightBit::D),
0x50 if offset > 7 => Ok(register::SingleEightBit::E),
0x60 if offset <= 7 => Ok(register::SingleEightBit::H),
0x60 if offset > 7 => Ok(register::SingleEightBit::L),
0x70 if offset > 7 => Ok(register::SingleEightBit::A),
_ => Err(Error::UnknownOpcode(opcode))
}
}
0x4F => Ok(make_load_between_register_data(C, A)),
0x48 => Ok(make_load_between_register_data(C, B)),
0x49 => Ok(make_load_between_register_data(C, C)),
0x4A => Ok(make_load_between_register_data(C, D)),
0x4B => Ok(make_load_between_register_data(C, E)),
0x4C => Ok(make_load_between_register_data(C, H)),
0x4D => Ok(make_load_between_register_data(C, L)),
0x57 => Ok(make_load_between_register_data(D, A)),
0x50 => Ok(make_load_between_register_data(D, B)),
0x51 => Ok(make_load_between_register_data(D, C)),
0x52 => Ok(make_load_between_register_data(D, D)),
0x53 => Ok(make_load_between_register_data(D, E)),
0x54 => Ok(make_load_between_register_data(D, H)),
0x55 => Ok(make_load_between_register_data(D, L)),
0x5F => Ok(make_load_between_register_data(E, A)),
0x58 => Ok(make_load_between_register_data(E, B)),
0x59 => Ok(make_load_between_register_data(E, C)),
0x5A => Ok(make_load_between_register_data(E, D)),
0x5B => Ok(make_load_between_register_data(E, E)),
0x5C => Ok(make_load_between_register_data(E, H)),
0x5D => Ok(make_load_between_register_data(E, L)),
0x67 => Ok(make_load_between_register_data(H, A)),
0x60 => Ok(make_load_between_register_data(H, B)),
0x61 => Ok(make_load_between_register_data(H, C)),
0x62 => Ok(make_load_between_register_data(H, D)),
0x63 => Ok(make_load_between_register_data(H, E)),
0x64 => Ok(make_load_between_register_data(H, H)),
0x65 => Ok(make_load_between_register_data(H, L)),
0x6F => Ok(make_load_between_register_data(L, A)),
0x68 => Ok(make_load_between_register_data(L, B)),
0x69 => Ok(make_load_between_register_data(L, C)),
0x6A => Ok(make_load_between_register_data(L, D)),
0x6B => Ok(make_load_between_register_data(L, E)),
0x6c => Ok(make_load_between_register_data(L, H)),
0x6D => Ok(make_load_between_register_data(L, L)),
_ => Err(Error::UnknownOpcode(opcode)),
}
fn parse_source_register(opcode: u8) -> Result<register::SingleEightBit, parse::Error> {
let offset = opcode & 0x07;
match offset {
0x00 => Ok(register::SingleEightBit::B),
0x01 => Ok(register::SingleEightBit::C),
0x02 => Ok(register::SingleEightBit::D),
0x03 => Ok(register::SingleEightBit::E),
0x04 => Ok(register::SingleEightBit::H),
0x05 => Ok(register::SingleEightBit::L),
0x07 => Ok(register::SingleEightBit::A),
_ => Err(Error::UnknownOpcode(opcode))
}
}