Robert Allan JamesandClaude Opus 5
f81e9c92bc
fb_scroll_rows() hardcoded the pixel distance it physically shifts the framebuffer by as char_rows * 16 * scale -- the bitmap-font (font_8x16.c) cell height -- regardless of which glyph mode vt100.c actually had active. In TTF mode (the REPL's default, cell height 24px via VT100_TTF_CELL_H_PX) this meant every scroll_up(1) call physically shifted the framebuffer by only 16px while the text model (g_vt.rows, py_of()) placed each row 24px apart. That 8px-per-scroll shortfall compounds with every subsequent scroll: a few scrolls barely show it, but enough scrolls -- or scrolling quickly, which is just many scrolls in a short span -- accumulates into visible pixel overlap between rows, with newer lines drawn on top of the tail end of older ones. fb_scroll_rect() (the box-confined scroll added later for 4.4t) already carried a doc comment calling this out explicitly, describing its own explicit pixel_rows parameter as the fix for fb_scroll_rows()'s "fixed 16px-row assumption" -- fb_scroll_rows() itself was just never updated to match. Fixed by changing fb_scroll_rows()'s parameter from an implicit char_rows count to an explicit pixel_rows count (matching fb_scroll_rect()'s existing convention), and having its one caller (vt100.c's scroll_up()) pass lines * cell_h() -- the real active cell height -- instead of a raw line count for the callee to guess at. Verified: booted amd64 to the REPL (TTF mode active per sk_repl()'s own console_fb_enable_ttf() call), let boot chatter + WORDS output scroll the screen through thousands of accumulated scroll_up() calls, then measured every visible line's y-position via a QMP screendump. Spacing held at a perfectly consistent 24px (TTF cell height) top to bottom with zero drift -- the old hardcoded-16px bug could not have produced that after this many scrolls. Re-verified boot to ok> on all three architectures (amd64/aarch64/riscv64) per repo acceptance policy. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
src/starkernel/
LithosAnanke — the bare-metal UEFI kernel that boots StarForth directly on
hardware (amd64/aarch64/riscv64). Built only via Makefile.starkernel; the
only valid acceptance test is the three-arch QEMU boot (see
.claude/CLAUDE.md), never make test.
kernel_main.c— kernel entry point, driving the boot milestones (console init, PMM, VMM, interrupts, timers, kmalloc heap, VM bootstrap).repl.c— kernel REPL.doe_log.c— kernel-side DoE (Design of Experiments) metrics logging.
Subdirectories:
arch/{amd64,aarch64,riscv64}/— per-architecture support (APIC/GIC/ PLIC interrupt controller, timers, boot/ISR assembly).boot/— UEFI loader, ELF loading, kernel command-line parsing.capsule/— capsule birth/run/load/validate pipeline.hal/— hardware-abstraction-layer implementation (console, framebuffer, VT100, memory, host services).hash/— XXHash64 content-addressing implementation.math/— kernel-build Q48.16 fixed-point arithmetic.memory/— physical/virtual memory managers and the kernel heap.pci/— PCI bus enumeration.virtio/— VirtIO block device driver.vm/— kernel VM subsystem (bootstrap, core interpreter, parity logging, capsule arena).
See include/starkernel/README.md for the corresponding headers.