Module panic_screen 

Panic-safe framebuffer drawing.

Provides a set of globals and direct-draw functions that allow the panic handler to render a visual panic screen even when VGA_WRITER is locked by the faulting context. The framebuffer parameters are snapshotted once during vga::init() via init_panic_fb_globals() and are read-only afterwards, making them safe to access from the panic path without any locking.

Constants

PANIC_SCREEN_MAX_LINES 🔒

Maximum number of lines for the panic screen.

Statics

PANIC_FB_ADDR 🔒

Raw framebuffer virtual address (HHDM-mapped), 0 if framebuffer is not available.

PANIC_FB_FORMAT 🔒

Packed pixel-format info: (bpp << 32) | (red_shift << 24) | (green_shift << 16) | (blue_shift << 8) | format_flags

PANIC_FB_HEIGHT 🔒

Framebuffer height in pixels.

PANIC_FB_PITCH 🔒

Framebuffer pitch in bytes.

PANIC_FB_WIDTH 🔒

Framebuffer width in pixels.

PANIC_FONT_8X16 🔒

Minimal 8×16 bitmap font for panic-screen rendering (ASCII 0x20–0x7E). Each glyph is 16 bytes (one byte per row, MSB = leftmost pixel). Derived from the standard VGA 8×16 ROM font.

Functions

init_panic_fb_globals

Initialise the panic-screen framebuffer globals. Must be called once from vga::init() after configure() succeeds.

panic_draw_char 🔒

Draw a single character at (x, y) using the panic font. fg and bg are packed pixel-colour values for the current pixel format.

panic_draw_direct

Draw the full panic screen directly to the framebuffer (no locking).

panic_draw_str 🔒

Draw a NUL-terminated ASCII string at (x, y) using the panic framebuffer. Returns the X position after the last character.

panic_font_8x16 🔒

panic_pack_rgb 🔒

Pack RGB into a u32 using the pixel-format globals.