LCARS Boot Progress Bar + Intel 8237A ISA DMA — Boot Sequence Complete

lcars_boot_progress completes the LCARS boot sequence — a gold left-fill progress bar called per kernel init step, positioned below lcars_boot_banner. Together: banner → progress updates → Lumen hands off. sigil-drivers adds the Intel 8237A ISA DMA controller (page registers, flip-flop, mode byte arithmetic, mask/unmask, master reset, x86 QEMU PASS), completing the legacy ISA peripheral set alongside PIT + i8042 + RTC + PIC + UART. (sigil-video 104bc96; sigil-drivers fede276)

lcars_boot_progress (104bc96)

lcars_boot_progress is the kernel-init companion to lcars_boot_banner. The banner paints the splash once; the progress bar is called on each init step to advance the fill. Together they give real hardware a live visual boot status with no compositor, font system, or window manager — only the raw GOP framebuffer.

• Signature: lcars_boot_progress(fb, pitch, fbw, fbh, bh, value, max) — value/max = current fill fraction
• Bar position: derived from boot banner geometry — bar_y = fbh/2 + bh + gap + bot_h + gap2 (sits below the tan bottom band)
• Fill: gold (lcars_gold()) left-fill, value * fbw / max pixels wide; track: black remainder
• GPU path: gpu_submit (CAP_ACCEL; silicon-pending). SW path: fill_span rows
• Test (160×120, bh=16, value=50, max=100 = 50% fill): fill pixel = gold, track pixel = black, pixel above bar = black
• Result: LCARS-BOOTPROG-PASS fill=ok track=ok above=ok

Complete boot sequence

The LCARS boot surface is now a two-function API. The pattern for a real x86 kernel bring-up:

lcars_boot_banner(fb, pitch, fbw, fbh, bh)   // called once: orange+gold+tan splash
while (init_step < total_steps):
    do_init_step(step)
    lcars_boot_progress(fb, pitch, fbw, fbh, bh, init_step, total_steps)
// Lumen compositor takes over

This gives real x86 hardware (sigil-os#18) a live boot status without any rendering infrastructure beyond the raw GOP framebuffer — no compositor, no font system, no WM. The progress bar is the last thing the kernel draws before Lumen takes ownership of the framebuffer.

Intel 8237A ISA DMA (fede276 — sigil-drivers)

The 8237A is the ISA DMA controller, gating legacy sound (ISA SB16/AdLib), floppy, and LPT DMA on all x86 PC-compatible hardware. Without the 8237A, drivers that depend on DMA transfers cannot configure their channels.

• Ports: 0x00–0x0F (ch0–3 addr/count/cmd/request/mask/mode/flip-flop/temp/master-reset/all-mask), 0x81–0x83 (page registers ch2/3/1)
• Mask/unmask per channel; flip-flop reset (write 0 to 0x0C); master reset (write to 0x0D)
• State base: 0x860000

Live QEMU verification:

• Status register = 0 at reset (no TC, no request)
• Page register CH2 round-trip: write 0xAA, read back 0xAA
• Address flip-flop: write 4660 (two bytes, lo/hi), read back 4660
• Mode byte arithmetic: CH2-read = 0x4A, CH1-sound = 0x55, cascade = 0xC3

QEMU note: Port 0x0F (all-channel mask) is write-only on real 8237A — QEMU returns 0 on read. The test uses the status register for post-mask verification rather than reading back the mask register directly, matching real-hardware behavior.

The complete ISA peripheral set

With the 8237A DMA controller wired, every ISA peripheral a real x86 kernel needs for initial bring-up is covered by a live-verified sigil-drivers driver:

Every ISA peripheral a real x86 kernel needs to bring up is now covered by a live-verified sigil-drivers driver. The ISA layer is complete.