boot.splash¶

Boot splash screen displaying the Asuro logo, a progress bar, and a status label during kernel initialization.

Overview¶

boot.splash renders a full-screen LVGL splash screen that is visible while kmain works through the boot sequence. Because the graphics render daemon (svc.gfxd) has not yet started at this stage, boot.splash drives the LVGL timer pipeline and flushes the framebuffer manually on every update.

The screen uses a dark background (#1A1A2E) with a vertically-centred flex column containing three children: an LVGL image widget displaying the Asuro logo, a progress bar, and a status text label.

The logo is decoded at runtime from a TGA file that is embedded in the kernel binary via a NASM incbin stub. The decoded ARGB8888 pixel buffer is wrapped in a heap-allocated TLVImageDsc that conforms to the LVGL lv_image_dsc_t layout so it can be passed directly to lv_image_set_src.

teardown restores the previously-active LVGL screen, deletes all splash widgets, and frees the decoded texture and image descriptor.

Dependencies¶

driver.video.lvgl
driver.video
core.fmt.targa
core.gfx.texture
memory.heap

Constants¶

LV_IMAGE_HEADER_MAGIC¶

$19 — Magic byte placed in the first byte of the LVGL lv_image_header_t.

LV_CF_ARGB8888¶

$10 — LVGL color format constant for 32-bit ARGB8888 pixel data.

BAR_WIDTH / BAR_HEIGHT¶

300 / 16 — Progress bar dimensions in pixels.

Types¶

TLVImageHeader¶

TLVImageHeader = packed record
    magic_cf_flags : uint32;  { magic:8 | cf:8 | flags:16 }
    w_h            : uint32;  { w:16 | h:16 }
    stride_res     : uint32;  { stride:16 | reserved:16 }
end;

Mirrors lv_image_header_t with manual bitfield packing. magic_cf_flags encodes LV_IMAGE_HEADER_MAGIC in bits 0–7 and LV_CF_ARGB8888 in bits 8–15. stride is set to width * 4 bytes per pixel.

TLVImageDsc / PLVImageDsc¶

TLVImageDsc = packed record
    header    : TLVImageHeader;
    data_size : uint32;
    data      : pointer;
    reserved  : pointer;
end;

Mirrors the 24-byte lv_image_dsc_t on 32-bit. data points to the decoded ARGB pixel buffer; data_size is width * height * 4.

Functions and Procedures¶

init¶

procedure init;

Saves the currently active LVGL screen, decodes the embedded TGA logo, creates the splash screen with a flex-column layout, and renders the first frame. The image is scaled to 50% (lv_image_set_scale(logoImage, 128)).

update¶

procedure update(percent: uint32; status: pchar);

Sets the progress bar value (clamped to 0..100), updates the status label text, redraws the frame, and calls busywait_500ms to hold the display visible for approximately 500 ms. Called by kmain at each boot milestone.

teardown¶

procedure teardown;

Restores the previous LVGL screen, deletes the splash screen object and all its children, and frees the heap-allocated image descriptor and decoded texture.

Notes¶

busywait_500ms reads the PIT channel-0 counter in a tight loop without using interrupts, making it safe to call before STI. It counts approximately 4000 PIT rollovers (~500 ms at a ~8 kHz tick rate). This is a debug-only mechanism intended to make each boot step visible on screen.

The redraw helper passes a 100 ms tick increment to lv_tick_inc so LVGL always considers the display stale and renders pending invalidations immediately, without relying on the scheduler-driven tick source.

The embedded TGA data is referenced via linker-provided symbols _splash_tga_start and _splash_tga_size inserted by the NASM incbin stub.