Trait Z80Bus 

pub trait Z80Bus {
    // Required methods
    fn read_internal(&mut self, addr: u16) -> u8;
    fn write_internal(&mut self, addr: u16, data: u8);
    fn wait_mreq(&mut self, addr: u16, clk: usize);
    fn wait_no_mreq(&mut self, addr: u16, clk: usize);
    fn wait_internal(&mut self, clk: usize);
    fn read_io(&mut self, port: u16) -> u8;
    fn write_io(&mut self, port: u16, data: u8);
    fn read_interrupt(&mut self) -> u8;
    fn reti(&mut self);
    fn halt(&mut self, halted: bool);
    fn int_active(&self) -> bool;
    fn nmi_active(&self) -> bool;
    fn pc_callback(&mut self, addr: u16);

    // Provided methods
    fn wait_loop(&mut self, addr: u16, clk: usize) { ... }
    fn read(&mut self, addr: u16, clk: usize) -> u8 { ... }
    fn write(&mut self, addr: u16, value: u8, clk: usize) { ... }
    fn write_word(&mut self, addr: u16, data: u16, clk: usize) { ... }
    fn read_word(&mut self, addr: u16, clk: usize) -> u16 { ... }
    fn process_unknown_opcode(&mut self, _prefix: Prefix, _opcode: Opcode) { ... }
}

Z80 processor System bus Implement it for communication with CPU.

Required Methods

fn read_internal(&mut self, addr: u16) -> u8

Required method for reading byte without waiting pass self as mut, because method can change state of bus or something

fn write_internal(&mut self, addr: u16, data: u8)

Required method for write byte to bus without waiting

fn wait_mreq(&mut self, addr: u16, clk: usize)

Wait some clocks

fn wait_no_mreq(&mut self, addr: u16, clk: usize)

Wait while mreq is not active (can be different from active mreq contention as it works in ZX Spectrum 2+/3)

fn wait_internal(&mut self, clk: usize)

Internal wait, avoiding contentions

fn read_io(&mut self, port: u16) -> u8

fn write_io(&mut self, port: u16, data: u8)

fn read_interrupt(&mut self) -> u8

Reads value from bus during interrupt. mutable because on interrupt read some internal system attributes may be changed

fn reti(&mut self)

Method, invoked by Z80 in case of RETI instruction. Default implementation is empty

fn halt(&mut self, halted: bool)

Method, invoked by Z80 in case of HALT line change

fn int_active(&self) -> bool

Checks int signal

fn nmi_active(&self) -> bool

Checks nmi signal

fn pc_callback(&mut self, addr: u16)

invokes breakpoints check on bus device

Provided Methods

fn wait_loop(&mut self, addr: u16, clk: usize)

Any single clock (t-state) can cause contention on ULA or any other chipm which not detects MREQ signal

fn read(&mut self, addr: u16, clk: usize) -> u8

fn write(&mut self, addr: u16, value: u8, clk: usize)

fn write_word(&mut self, addr: u16, data: u16, clk: usize)

Provided method to write word, LSB first (clk - clocks per byte)

fn read_word(&mut self, addr: u16, clk: usize) -> u16

Provided method to read word (clk - clocks per byte)

fn process_unknown_opcode(&mut self, _prefix: Prefix, _opcode: Opcode)

Implementors