Trait z80emu::z80::Flavour

pub trait Flavour: Clone + Copy + Default + PartialEq + Eq {
    const CONSTANT_OUT_DATA: u8;
    const ACCEPTING_INT_RESETS_IFF2_EARLY: bool;

    // Required methods
    fn tag() -> &'static str;
    fn memptr_mix(msb: u8, lsb: u8) -> (u8, u8);
    fn begin_instruction(&mut self);
    fn flags_modified(&mut self);
    fn get_q(&self, acc: u8, flags: CpuFlags) -> u8;
    fn cpu_into_any(cpu: Z80<Self>) -> Z80Any;
    fn unwrap_cpu_any(cpu_any: Z80Any) -> Z80<Self>;

    // Provided method
    fn reset(&mut self) { ... }
}

A trait for implementing exceptions to the undocumented Z80 behaviour.

It’s been reported that depending on the CPU technology (NMOS, CMOS) and the manufacturer (Zilog, NEC, other clones) there are certain differences of undocumented behaviour and mainly affects the way the Flags’ undocumented bits 3 and 5 are being modified.

Required Associated Constants

const CONSTANT_OUT_DATA: u8

The value being actually put on the data bus while executing the undocumented instruction OUT (C),(HL).

const ACCEPTING_INT_RESETS_IFF2_EARLY: bool

Should be true if the IFF2 is being reset early when accepting an interrupt, while an instruction is being executed, so LD A,I or LD A,R may report modified IFF2 value.

Required Methods

fn tag() -> &'static str

Returns the string identifier of this flavour.

fn memptr_mix(msb: u8, lsb: u8) -> (u8, u8)

The way MEMPTR is being updated for: LD (nnnn),A, LD (BC),A, LD (DE),A and OUT (nn),A is being controlled by this function. The current Accumulator value is being passed as msb and the lower 8-bits of the current destination address is being provided as lsb. The function should return the (MSB, LSB) value to set the MEMPTR with.

fn begin_instruction(&mut self)

This method is being called each time before an instructions is being executed or an interrupt is being accepted, including NMI. It might modify some state and is being used together with Flavour::flags_modified and Flavour::get_q to prepare a value applied to bits 3 and 5 of the Flags for the SCF/CCF instructions.

fn flags_modified(&mut self)

This method is being called each time an instructions modifies the Flags register.

fn get_q(&self, acc: u8, flags: CpuFlags) -> u8

Bits 3 and 5 of the returned value will be copied to the Flags register.

fn cpu_into_any(cpu: Z80<Self>) -> Z80Any

Converts a Z80 struct of this flavour into an Z80Any enum.

fn unwrap_cpu_any(cpu_any: Z80Any) -> Z80<Self>

Returns the contained Z80<Self> value, consuming the cpu value.

Panics

Panics if the cpu_any value is not a variant corresponding to this Flavour.

Provided Methods

fn reset(&mut self)

Should reset the state. Called by crate::Cpu::reset. The default implementation resets the state to default.

Object Safety

This trait is not object safe.

Implementors

impl Flavour for BM1

const CONSTANT_OUT_DATA: u8 = 0u8

const ACCEPTING_INT_RESETS_IFF2_EARLY: bool = false

impl Flavour for CMOS

const CONSTANT_OUT_DATA: u8 = 255u8

const ACCEPTING_INT_RESETS_IFF2_EARLY: bool = false

impl Flavour for NMOS

const CONSTANT_OUT_DATA: u8 = 0u8

const ACCEPTING_INT_RESETS_IFF2_EARLY: bool = true