Crate rz80 [−] [src]
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 Definitions
| RegT |
generic integer type for 8- and 16-bit values |