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SchOS/boot/uefi
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Filename Latest commit message Latest commit date
Nexoniarz bf9ac843f7 schcom: repaint what changed, and stop rendering frames nobody sees 
Moving the mouse repainted the whole screen. At 1280x800 that is a
million pixels of desktop fill, every surface re-blitted, and a 4 MB copy
to the framebuffer -- per event. Under emulation the pointer lagged the
mouse by whole seconds, and that was not the emulation's fault: moving a
10x10 cursor does not require touching four megabytes.

Two changes, and the second matters as much as the first.

Damage tracking: one rectangle, unioned from whatever actually changed,
and only those rows are redrawn and copied out. A pointer move damages
where it was and where it is; a commit damages that surface; a client
going away damages what it had. One rectangle rather than a list, because
in practice the changes are a cursor and the window under it, and a list
costs more bookkeeping than it saves.

Draining input: a single mouse movement produces a burst of EV_REL ending
in EV_SYN, and the loop handled one event per poll and repainted. So the
compositor rendered every intermediate position of a cursor that was
never seen at those positions. Both queues are now drained before
anything is painted. handle_input grew a distinct "queue empty" return
for it -- EV_SYN changes nothing but is not the end of the burst, and a
drain that stopped there would leave the rest queued.

Also cuts the loader's resolution prompt from four seconds to one and a
half, on both the BIOS and UEFI paths. Four was mine and it was too long:
it is paid on every unattended boot, and adding four seconds to every
start to offer a menu nobody usually wants makes the common case worse to
serve the rare one.

schcom-test passes, including two overlapping clients and stacking order.
bootcheck 108 [ok].

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-10 05:54:06 +02:00
..
efi.h boot/uefi: choose a resolution with R, the same as the BIOS path 2026-08-10 05:30:03 +02:00
main.c schcom: repaint what changed, and stop rendering frames nobody sees 2026-08-10 05:54:06 +02:00
README.md boot: separate BIOS from UEFI 2026-08-09 16:00:03 +02:00
startup.nsh boot/uefi: a working UEFI loader, with one known limitation 2026-08-09 17:13:09 +02:00

README.md

UEFI loader

Not written yet. This directory exists so the BIOS path could be moved into boot/bios/ without pretending the split was hypothetical.

See ../README.md for the hand-off contract a loader has to satisfy. The short version: the kernel wants long mode with paging on, its ELF segments placed, a 24-byte-entry E820-shaped memory map, and framebuffer geometry — and it does not care which firmware produced them.

What this will need, in rough order:

  1. A PE/COFF target. clang can emit one directly (--target=x86_64-unknown-windows -fuse-ld=lld-link), so no new toolchain: the same LLVM install already builds every other target here.
  2. The handful of UEFI structures actually used — the system table, boot services, LOADED_IMAGE, SIMPLE_FILE_SYSTEM, GRAPHICS_OUTPUT. Written from the specification rather than by importing gnu-efi or EDK II, which is both a licence question and a large dependency for something this small.
  3. GetMemoryMap translated into the same 24-byte entries e820.c already parses. Not a second format for the kernel to learn.
  4. ExitBootServices before touching the memory it described.
  5. Graphics Output Protocol for the framebuffer, filling the same VBE_INFO_ADDR structure the BIOS path fills.

The image goes at EFI/BOOT/BOOTX64.EFI on a FAT ESP, which also means the ISO gains an El Torito EFI entry alongside the BIOS one it already has.