89 lines
2.3 KiB
Rust
89 lines
2.3 KiB
Rust
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use crate::{Inner, Memory, Register, State};
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pub struct CPU {
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pub memory: Memory,
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pub state: State,
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}
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impl CPU {
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pub fn exec_next(&mut self) -> u8 {
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let opcode = self.next_opcode();
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match opcode {
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0x0 => {
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// noop
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}
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0x01 => {
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self.state.bc = self.ld_immediate_word();
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}
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0x11 => {
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self.state.de = self.ld_immediate_word();
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}
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0x21 => {
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self.state.hl = self.ld_immediate_word();
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}
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0x2C => {
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unsafe {
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self.state.hl.as_u8s.right += 1;
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};
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}
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0x3E => {
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self.state.af.as_u8s.left = self.ld_immediate_byte();
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}
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0x4A => {
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unsafe {
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self.state.bc.as_u8s.right = self.state.de.as_u8s.left;
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};
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}
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0x4B => {
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unsafe {
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self.state.bc.as_u8s.right = self.state.de.as_u8s.right;
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};
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}
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0x53 => {
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unsafe {
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self.state.de.as_u8s.left = self.state.de.as_u8s.right;
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};
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}
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0x66 => {
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unsafe {
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self.state.hl.as_u8s.left = self.memory.get(self.state.hl.as_u16);
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};
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}
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0xC3 => {
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self.state.pc = self.ld_immediate_word();
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}
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0xEA => {
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unsafe {
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let address = self.ld_immediate_word().as_u16;
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self.memory.set(address, self.state.af.as_u8s.left);
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};
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}
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_ => {
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panic!("unimplemented opcode: {:#X}", opcode);
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}
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};
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return opcode;
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}
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fn next_opcode(&mut self) -> u8 {
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unsafe {
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let opcode = self.memory.get(self.state.pc.as_u16);
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self.state.pc.as_u16 += 0x1;
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return opcode;
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};
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}
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fn ld_immediate_word(&mut self) -> Register {
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Register {
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as_u8s: Inner {
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left: self.next_opcode(),
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right: self.next_opcode(),
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},
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}
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}
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fn ld_immediate_byte(&mut self) -> u8 {
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self.next_opcode()
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}
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}
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