Overview

project1 - writing a simple bare metal kernel in Swift

A project to write a kernel in Swift with that can boot on a Mac or PC. The main aim is to get a simple kernel booting up with a CLI with full concurrency/thread support on multiple cores.

project1 on github

Current status:

• Boots up (Under QEMU, Bochs or VMWare)
• Scans ACPI/SMBIOS tables
• Installs interrupts and exception/fault handlers
• Sets up paging
• Scans PCI bus
• Initialises timer and keyboard
• Initialises PIC, PIT and PS/2 keyboard controller
• Runs two simple tasks, one printing 'A' and the other printing 'B' in a loop with a simple stack context switch

The next step is to get multi processor support working

The main aspects investigated were:

Development environment and compiler

• Red zone
• Using the compiler
• Libraries
• C & assembly required to get binary starting up
• Stdlib
• Swift modules
• Why is there so much C in the code?
• Will it build on OSX?

Initialisation

• From boot to swift startup()
• globalinit*()
• malloc() and free()
• Thread Local Storage (TLS)
• Streaming SIMD Extensions (SSE)
• Reading data tables in swift

Working with C

• Swift calling convention
• Pointers
• Swift function names
• Defines and constants
• Structs
• Arrays
• StaticString

Other Notes

• Testing environment (boches, qemu etc)
• What to do differently next time
• Future directions

Useful links