The compositor recomposited and re-uploaded the entire screen on every pass of
its loop. At the 1280x720 the desktop actually boots into, gui_gfx_present()
memcpy'd 3.6 MB into the framebuffer per frame, and the background underneath
it was recomputed pixel by pixel every time.
Present only the damage
- Keep a RAM shadow of what the framebuffer currently holds and diff the back
buffer against it, pushing just the changed span of each row. Reading the
shadow costs a RAM access; the framebuffer write it avoids costs far more,
and the framebuffer is never read back.
- Each row is narrowed to its first and last differing pixel rather than
tracked as a set of runs: one memcpy per row keeps the loop tight, and a row
that changed in two distant places is rare enough that bridging the gap is
cheaper than the bookkeeping.
- gui_gfx_invalidate() forces a full push for when something outside the
compositor owns the screen, which the desktop calls on entry and on exit
around the framebuffer console.
Cache the wallpaper
- The vertical gradient, the blended grid and the branding text never change
between frames, so they are painted once into a cached buffer and blitted
back per frame. The cache is keyed on resolution and the grid setting, so
toggling the grid from the context menu still repaints it.
No drawing code changed: the damage is derived from the frame itself, so every
widget, window and app keeps rendering exactly as before.
Measured in QEMU at 1280x720: an idle desktop with two windows open went from
921600 pixels per frame to 3609, about 0.4% of a full blit. A screendump of
the running desktop is unchanged -- wallpaper, grid, icons, both windows,
taskbar and cursor all render identically.
Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_0161Jh7uCEMLYEMNPsjC1LKf
Pressing Esc left the desktop and started the shell, but nothing appeared in the
emulator window -- the session was only visible on the host terminal. Once the
VBE adapter is switched into graphics mode the VGA text buffer at 0xB8000 stops
being scanned out, so every printk after that point reached serial and the
dmesg ring but never the display.
Disabling the DISPI interface does not bring the text console back; QEMU keeps
presenting the last framebuffer surface. So rather than clawing the adapter back
to text mode, the console is now rendered into the framebuffer:
drivers/video/fbcon.c draws the console with the shared 8x8 font and carries a
VT100 subset -- SGR colours, cursor addressing, relative moves, erase-display,
erase-line and save/restore. It presents a fixed 80x25 grid, because that is
the geometry the userland assumes (nano pads its bars with %-80s, the shell
wraps at TTY_WIDTH), with the glyph cell scaled to fill the active resolution.
The TTY driver became the console dispatcher: tty_write, tty_clear and
tty_set_cursor route to fbcon while it owns the display. That last one is what
makes nano work -- it positions with tty_set_cursor() rather than escapes, so
its full-screen repaint was landing as an append-only stream.
Also in this change:
- `video=WIDTHxHEIGHT` on the kernel command line selects the display mode,
defaulting to 1280x720 so a 16:9 host panel is filled rather than pillarboxed
when QEMU goes fullscreen. Rejects modes the heap cannot back.
- `make run-fullscreen`, plus zoom-to-fit on the windowed target, so scaling
preserves the guest aspect ratio instead of stretching it.
- QEMU targets raise vgamem_mb, since a 1280x720 32-bit surface exceeds the
default VGA memory.
- bochs_vbe_disable()/fb_set_active() let the framebuffer be marked dormant so
drawing routines no-op after a mode teardown.
Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01L5yKJT4Wo2cV3rfPrwY5MP
The GUI terminal recognised four hardcoded strings and answered everything else
with "Executed: '<cmd>'". It now dispatches to the same LazyBox applet table and
shell builtins the kernel TTY uses, so ls, free, uname, lspci, ktest, neofetch,
sort, cd and the rest all work, with cwd tracked across commands.
LazyBox reports through printk, so before running a command the terminal
installs a printk sink and streams the output into its own scrollback:
- ANSI SGR codes become per-line colours instead of being stripped.
- CP437 box-drawing and block characters fall back to ASCII, so the colour
swatch in neofetch renders as '#' rather than a row of '?'.
- 256 lines of scrollback, command history on Up/Down, PgUp/PgDn/Home/End.
- Applets that read the keyboard directly (nano, snake, sh, top) are refused
with a pointer to the TTY, since they would block the compositor.
The window's paint and event handlers moved out of gui_apps.c into
gui/gui_terminal.c, and gui_gfx.c now draws from the shared lib/font8x8.c table
rather than its own copy.
Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01L5yKJT4Wo2cV3rfPrwY5MP
Boot logo (init/bootlogo.c, init/logo_data.c, scripts/mklogo.py):
The logo appears in two forms because the framebuffer does not exist for the
first third of boot. An ASCII rendition goes to the text console and serial
line from the first moments; once the video driver is up at step [5/14] the
real bitmap takes over as a graphical splash with a progress bar tied to the
actual boot stages.
The asset is 4-bit palette indexed, so 160x160 pixels cost 12.5 KB instead of
100 KB, and carries a transparency mask so the mark composites onto the
gradient rather than stamping a flat rectangle over it. scripts/mklogo.py
regenerates init/logo_data.c from the source PNG.
Boot reaches the desktop in well under a second, so the splash is held for a
minimum duration and the bar sweeps to 100% during the hold; without that the
logo would flash past unseen. `splashtime=<ms>` tunes it and `nosplash`,
`nogui` or `text` skip it.
Bootloader (boot/stage2.asm):
stage2 staged the whole kernel in conventional RAM before copying it to 1 MB,
which capped the kernel at roughly 576 KB before the load ran into video
memory at 0xA0000. The logo pushed it over that line and the kernel stopped
booting. Each 32 KB chunk now goes into one fixed low buffer and is copied
straight to its final address, using unreal mode for the 32-bit reach. The
ceiling is now the image itself, 1.375 MB.
Console font (lib/font8x8.c):
fb_draw_char was a stub that ignored its character argument and drew a filled
rectangle, which is why the splash rendered its text as solid blocks. It now
renders real glyphs, and the table it uses is shared: the framebuffer console,
the canvas rasterizer and the desktop compositor had three divergent private
copies, two of which still carried the `// \` line-continuation defect.
printk console sink (kernel/printk.c):
printk output can be redirected to a callback, so a caller can run a subsystem
that reports via printk and capture what it printed. Serial and the dmesg ring
still see everything, which keeps a captured run debuggable.
Shell builtins (userland/lazybox/shell.c):
The builtin chain is extracted into shell_execute_builtin(), so the kernel TTY
and the desktop terminal accept the same vocabulary instead of the GUI seeing
only the applet table. Callers that cannot be suspended pass allow_blocking =
false to refuse the animating ones.
Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01L5yKJT4Wo2cV3rfPrwY5MP
Turns the desktop from a fixed set of hand-drawn panels into a real
environment applications can be written against.
SUB-WT immediate-mode toolkit (gui/gui_widgets.c):
Buttons, labels, checkboxes, radios, sliders, list boxes, text fields, tab
bars, scrollbars, progress bars, sparklines and badges. An app feeds the WM
event into the toolkit and then calls widgets from its paint routine, so
each call both draws the control and reports what the user did with it --
no retained widget tree to keep in sync with window state.
Icons and dialogs:
gui_icons.c holds 14 16x16 palette-indexed glyphs stored as hex text, so the
art stays hand-editable and picks up theme changes for free; they scale by
integer factors and can be drawn as tint stencils. gui_dialog.c adds modal
info/warning/error/confirm dialogs that dim the desktop, take exclusive
input, word-wrap on spaces and report results through a callback.
Applications (gui/gui_apps_ext.c):
Settings (tabbed appearance/input/power), Task Manager (live process table
over task_find_by_pid with memory and heap gauges), Kernel Log viewer (reads
the dmesg ring, strips ANSI, colours by severity, scrolls), KTest Runner
(drives the in-kernel suites and reports 21/21 with timing), Clock & Calendar
(Zeller's congruence month grid) and a Text Editor.
Window manager (gui/gui_wm.c):
Minimize/maximize/restore buttons, a corner resize grip, edge snapping, tile
and cascade layouts, F5-F9 shortcuts, title truncation, and index-based
enumeration so the taskbar no longer assumes window ids stay dense.
Desktop shell (gui/gui_desktop.c):
Launcher icon grid, richer start menu, right-click context menu, taskbar
buttons that minimize and restore, and a live CPU trace in the tray.
Two interaction bugs fixed along the way:
- keyboard_get_key() blocks until a key arrives, so calling it every frame
froze the compositor; it is now gated on keyboard_has_key(), and stale
console input is drained before the first frame.
- When the desktop consumed a click, the WM's press-edge detector kept the
pre-press state and read the still-held button as a fresh press on the
next frame, stealing focus from whatever the click had just opened.
gui_wm_sync_button_state() keeps the two layers in step.
Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01L5yKJT4Wo2cV3rfPrwY5MP
Expands the kernel-and-TTY core with the primitives the higher layers have
been missing, plus an in-kernel harness that proves they work.
Data structures (lib/):
- rbtree.c: Linux-compatible red-black tree with parent pointers, full
insert/erase rebalancing, in-order iteration and an invariant validator.
- kfifo.c: power-of-two byte ring with free-running indices, so the wrap
path costs one mask instead of a branch per byte.
- hashtable.c: separately-chained table with FNV-1a hashing, string or
u64 keys, and rehash-on-growth at a 3/4 load factor.
Kernel subsystems:
- kernel/wait.c: wait queues and one-shot completion barriers, backed by a
static sleeper pool so a blocking path never re-enters the allocator.
- kernel/futex.c: 32-bucket futex hash with value re-check, requeue, and an
fmutex_t sleeping mutex built on the uncontended-fastpath protocol.
- kernel/rcu.c: tiny RCU with reader nesting, deferred callbacks, kfree_rcu
and rcu_assign_pointer/rcu_dereference publish barriers.
- mm/page_cache.c: write-back block page cache, 4 KB pages indexed by
(device, page), CLOCK second-chance eviction and dirty write-back.
- kernel/ktest.c: KUnit-style harness with 6 built-in suites, 21 cases and
735 assertions covering every subsystem above (all passing under QEMU).
LazyBox userland:
- coreutils.c: sort, uniq, cut, tr, rev, tac, nl, seq, diff, xxd, du,
factor, sum and truncate, reading through the VFS and handling the
zero-length synthetic nodes that procfs and sysfs expose.
- ktest, rcuinfo, futexinfo, waitinfo and pagecache diagnostics applets.
Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01L5yKJT4Wo2cV3rfPrwY5MP
- Upgrade resolution to 800x600 @ 32bpp TrueColor with Bochs/QEMU VBE LFB
- Implement full 8042 Aux PS/2 mouse controller driver on IRQ 12 (vector 44) with packet decode and bounds clamping
- Add high-definition 8x16 font rasterizer with text drop shadows for sharp typography
- Upgrade to smooth 16x24 anti-aliased cursor with dark slate outline and drop shadow
- Increase titlebars to 24px and taskbar to 32px with modern desktop styling
- Re-architect applications (SysMon, Terminal, Explorer, Calc, Paint, About) for spacious high-res display
- Integrate Bochs/QEMU VBE physical LFB mapping directly to hardware video memory (0xFD000000)
- Update kernel boot sequence to directly boot into GUI Desktop by default
- Fall back to Emergency Kernel TTY Mode upon GUI exit (Esc key / Exit menu item)
- Support 'nogui', 'text', 'emergency', and 'single' boot arguments to boot directly into text mode
- Remove frame limits so GUI runs persistently
- Create separate feature branch 'feat/gui-desktop'
- Implement double-buffered 2D graphics engine with alpha blending, gradients, rounded rects, and font rasterization in gui/gui_gfx.c and include/gui/gui_gfx.h
- Implement alpha-blended mouse pointer overlay in gui/gui_cursor.c and include/gui/gui_cursor.h
- Implement SUB-WM Window Manager with draggable titlebars, close/minimize buttons, drop shadows, and event routing in gui/gui_wm.c and include/gui/gui_wm.h
- Implement Cyberpunk/Nord desktop environment with wallpaper, taskbar, start menu popup, and system tray in gui/gui_desktop.c and include/gui/gui_desktop.h
- Implement built-in GUI apps: System Performance Monitor, GUI Terminal Emulator, File Explorer, Calculator, Paint Studio, and About dialog in gui/gui_apps.c and include/gui/gui_apps.h
- Add 'startx', 'gui', and 'desktop' applets in LazyBox suite
- Verified multi-architecture compilation across x86_64, AArch64, and ARMv8i
- Implement Intel 82574L / 82567LM / I217 / I219 PCIe Gigabit NIC driver with DMA ring buffers and auto-negotiation in drivers/net/e1000e.c and include/drivers/e1000e.h
- Implement VirtIO-GPU 2D hardware graphics display adapter driver with dirty rect flushing in drivers/virtio/virtio_gpu.c and include/drivers/virtio_gpu.h
- Implement Dynamic CPU Frequency Scaling and ACPI CPPC Power Governor with performance, powersave, ondemand, conservative, and schedutil policies in drivers/power/cpufreq.c and include/drivers/cpufreq.h
- Implement VirtIO-Input para-virtualized tablet/mouse event driver in drivers/virtio/virtio_input.c and include/drivers/virtio_input.h
- Expand stage2 kernel bootloader loading boundary to 768 KB (1536 sectors)
- Add LazyBox applets: 'cpufreq', 'gpuinfo', 'e1000e'
- Verified across x86_64, AArch64, and ARMv8i targets
- Add dedicated Linux-compatible Tree visualizer with UTF-8/ASCII branch tracking, -L depth filtering, human sizes, and permissions in userland/lazybox/tree.c
- Implement Hardware Invariant Timestamp Counter (TSC) calibration and microsecond delay timer in kernel/tsc.c and include/kernel/tsc.h
- Add Virtual Terminal color palette, live resource utilization bars, and logo banner in kernel/vt_art.c and include/kernel/vt_art.h
- Add LazyBox applets: 'tree', 'tscinfo', and 'vtart'
- Update README.md documentation and command matrix
- Implement modern freestanding C++17 containers (Vector<T>, UniquePtr<T>, String) in kernel/cpp/cpp_containers.hpp
- Implement object-oriented Device driver model (Device, BlockDevice, CharDevice, VirtualRamDiskDevice, VirtualNullDevice, VirtualZeroDevice, DeviceManager) in kernel/cpp/cpp_device.hpp and kernel/cpp/cpp_device.cpp
- Add C++ kernel performance microbenchmark suite in kernel/cpp/cpp_bench.cpp
- Export C-FFI bridges and add cross-architecture fallbacks in kernel/cpp/cpp_fallback.c and include/kernel/cpp_kernel.h
- Add LazyBox applets: 'cppdevs' and 'cppbench'
- Update README.md documentation and command matrix
- Add memory-safe ELF-64/32 binary header and program header inspector in rust/src/kernel/elf.rs
- Implement Buddy allocator and external memory fragmentation analyzer in rust/src/mm/buddy_analyzer.rs
- Add RFC-8439 Poly1305 128-bit message authenticator and ChaCha20-Poly1305 AEAD in rust/src/crypto/poly1305.rs and rust/src/crypto/chacha20poly1305.rs
- Export C-FFI bridges and add cross-architecture fallbacks in rust/rust_fallback.c and include/kernel/rust.h
- Add LazyBox applets: 'readelf', 'buddyinfo', and 'aead'
- Update README.md documentation and command matrix
- Implement flicker-free atomic double-buffered frame rendering and sub-tick input polling in userland/lazybox/snake.c
- Add multi-input support (PS/2 keyboard scancodes and serial ANSI arrow escape sequences)
- Add sound effects (food beep, game over chime) and live speed scaling (+/- keys, P to pause)
- Add POSIX /dev/shm shared memory subsystem in ipc/shm_posix.c and include/ipc/shm_posix.h
- Add DNS resolver cache with TTL tracking in net/ipv4/dns_cache.c and include/net/dns_cache.h
- Add audio tone and jingle synthesizer in sound/beep.c and include/sound/beep.h
- Add %o octal formatting support in lib/vsprintf.c
- Add LazyBox applets: 'shm', 'dnscache', and 'beep'
- Add freestanding C++17 runtime with operator new/delete, pure virtual handlers, and global constructor execution in kernel/cpp/cxx_runtime.cpp
- Implement C++ Object-Oriented telemetry and hardware services with polymorphism in kernel/cpp/cpp_module.cpp and include/kernel/cpp_kernel.h
- Add interactive ANSI Snake Game in userland/lazybox/snake.c with real-time keyboard control and automated simulation mode
- Initialize C++ subsystem during kernel boot step [8/14] in kernel/main.c
- Add LazyBox applets: 'snake', 'cppinfo', and 'cpptest'
- Add #include <lib/printf.h> in fs/vfs.c, include/lib/string.h, and include/kernel/printk.h
- Ensure snprintf is always declared during freestanding compilation
- Add native .sb kernel modules in sub/ (signature.sb, power_governor.sb, benchmark.sb, easter_egg.sb)
- Implement in-kernel SUB Language VM and AST interpreter in kernel/sub/sub_vm.c
- Implement C-interop runtime in kernel/sub/sub_runtime.c and include/kernel/sub_lang.h
- Initialize SUB Language Engine in boot sequence step [8/14] in kernel/main.c
- Implement strtol in lib/string.c
- Add LazyBox applets: 'subinfo', 'subi', 'subpower', 'subbench', and 'subquote'
- Add 'clear' and 'cls' builtin handlers in LazyBox shell
- Output ANSI \033[2J\033[H sequence on tty_clear() to clear serial/UART terminals
- Support both ASCII 0x7F (DEL) and 0x08 (BS) for Backspace in shell and nano editor
- Connect 16550 serial input to keyboard_get_key() on x86_64 for headless terminals
- Add ANSI escape sequence decoding for arrow keys (Up/Down/Left/Right/Home/End/Del)
- Update Makefile 'make run' and 'make qemu' with -display none for smooth terminal execution
- Add 'make run-gui' target for optional graphical SDL/GTK window
