Crate rz80

Expand description

rz80 is a Z80 chip family emulation library written in Rust which can be used as basis for writing a full Z80-based computer emulator.

§Overview

The rz80 library provides chip emulators for the Z80 CPU, PIO (parallel in/out), CTC (counter/timer channels) and a Bus trait which defines how the chips are wired together in a specific emulated system.

Writing a home computer emulator usually involves the following steps

import the required chips
import ROM dumps using the include_bytes! macro
define a State struct which holds emulator state required in addition to the chip state
define a System struct which embeds all chips and the State struct wrapped in RefCells
write a System::poweron() function which initializes the embedded chips and state objects, initializes the memory map and sets the CPU PC register to the ROM dump start address
write a video-decoder function which generates a linear RGBA8 framebuffer each frame
implement the Bus trait on the System struct, this usually involves:
- the keyboard emulation
- memory bank switching
- forward interrupt requests between the various hardware components
- sound generation
implement the main loop which creates a window, forwards keyboard input, and steps the chips emulators forward

Very simple 8-bit home computer systems (similar to the ZX81) don’t require any additional code, more complex home computers will require additional custom chips emulations that are not part of the rz80 library.

Check out the two included example emulators:

> cargo run --release --example z1013
> cargo run --release --example kc87

Structs§

CPU: Z80 CPU emulation
CTC: Z80 CTC emulation
Daisychain: interrupt controller daisychain
Memory: memory access
PIO: Z80 PIO emulation
Registers: CPU register access

Constants§

CF: CPU carry flag
CTC_0: CTC channel 0
CTC_1: CTC channel 1
CTC_2: CTC channel 2
CTC_3: CTC channel 3
HF: CPU half carry flag
NF: CPU add/subtract flag
PF: CPU parity flag (same as overflow)
PIO_A: PIO channel A
PIO_B: PIO channel B
SF: CPU sign flag
VF: CPU overflow flag (same as parity)
XF: CPU undocumented ‘X’ flag
YF: CPU undocumented ‘Y’ flag
ZF: CPU zero flag

Traits§

Bus: system bus trait

Type Aliases§