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An Intel 8080 emulator written in Swift
.package(url: "https://github.com/timsearle/emul8080r.git", from: "0.2.0")


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Emul8080r is an Intel 8080 emulator written in Swift! Created initially to support a full emulation of the classic Space Invaders 👾 game on Apple platforms, found here.

Getting started

The core type to get started with is CPU, this is where the all the instruction handling is interpreted, with all the helper functions for each instruction found in CPU+InstructionHelpers. Get started by initialising an instance of CPU with the available RAM and an implementation of a SystemClock to allow the emulate to approximate the speed at which it should be operating on the native system.

The Intel 8080 supported 256 instructions and emul8080r handles this via a switch from 0x00 through to 0xff.

In action

Work in progress

There are still many unimplemented instructions as the initial goal was to get Space Invaders running, over time will finalise populating these missing instructions and contributions are of course welcome!

There is a chance there are currently issues with certain instructions that yet to be discovered - I did not prioritise unit tests during the initial implementation but this is something planned to be improved over time! If you spot an issue, feel free to raise a PR.

Outstanding Instructions

Instruction Value Instruction Name
0x08 ?
0x10 ?
0x17 RAL
0x18 ?
0x1c INR E
0x1d DCR E
0x20 ?
0x25 DCR H
0x28 ?
0x2d DCR L
0x30 ?
0x33 INX SP
0x38 ?
0x39 DAD SP
0x3b DCX SP
0x3f CMC
0x76 HLT
0x98 SBB B
0x99 SBB C
0x9a SBB D
0x9b SBB E
0x9c SBB H
0x9d SBB L
0x9e SBB M
0x9f SBB A
0xc7 RST 0
0xcb ?
0xce ACI D8
0xcf RST 1
0xd7 RST 2
0xd9 ?
0xdc CC adr
0xdd ?
0xdf RST 3
0xe2 JPO adr
0xe4 CPO adr
0xe7 RST 4
0xea JPE adr
0xec CPE adr
0xed ?
0xee XRI D8
0xef RST 5
0xf2 JP adr
0xf4 CP adr
0xf7 RST 6
0xf9 SPHL
0xfc CM adr
0xfd ?
0xff RST 7


  • emulator101.com - if it wasn't for this site, this almost certainly would've taken me far longer to produce.
  • classiccmp.org - a brilliant, high-level mapping of instruction values to descriptions
  • computerarcheology.com - this site proved invaluable for debugging my implementation, understanding ROM and RAM ranges and just how Space Invaders originally operated on the 8080 and its associated hardware, helping me to build my own version here.
  • Official Intel 8080 Assembly manual


Happy to receive any and all contributions relating directly to making this package a more accurate reflection of an Intel 8080 processor! Please do raise PRs including instruction implementations/bug fixes/enhancements alongside a unit test.


Stars: 17
Last commit: 4 weeks ago

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iOS Software Engineer @ Perry Street Software
Perry Street Software is Jack’d and SCRUFF. We are two of the world’s largest gay, bi, trans and queer social dating apps on iOS and Android. Our brands reach more than 20 million members worldwide so members can connect, meet and express themselves on a platform that prioritizes privacy and security. We invest heavily into SwiftUI and using Swift Packages to modularize the codebase.

Release Notes

12 weeks ago

This release adds some missing instructions and improves the approach for unit testing so it's easier to cover any new instructions with tests.

Swiftpack is being maintained by Petr Pavlik | @ptrpavlik | @swiftpackco | API