Robert Allan JamesandClaude Sonnet 5
986d042aa7
Fourth stage of the preemptive context-switching plan, and the biggest. LithosAnanke now genuinely, continuously preempts between Hera, Hermes, and Artemis -- timer-driven, running live for the entire remainder of every boot once the Tripod fleet registers, not a bounded probe. A real design fork was resolved before writing code: the naive approach (the timer ISR calling Stage 2's sk_vm_context_switch() directly) is broken -- Stage 0's trap frame lives on whatever stack was active at interrupt time, and jumping to a different stack via Stage 2's own independent swap mid-handler would abandon that trap frame unresumed, guaranteed corruption on the first tick. Chose the safer of two named options: the ISR only ever sets a flag and returns completely normally through its own full epilogue; the actual switch happens moments later, via Stage 2's already-proven mechanism, at a safe cooperative checkpoint on the mainline (execute_colon_word()'s per-word dispatch loop, checked on literally every word, not throttled to the existing 256-word heartbeat-tuning cadence) -- confirmed with the user that word-level granularity is fine-grained enough given the eventual Zynq FPGA target where a word is a mnemonic. New capsule_vm_switch_signal.c/.h: a purpose-built run-readiness signal, deliberately separate from capsule_vm_physics.c's execution-heat engine (that one's own header documents itself as never touched from interrupt context, by design). Slot table sized with headroom (8) rather than hardcoded to today's 3 participants, so extending participation later is another register() call, not a redesign -- per direct request to leave room for swapping the participant set. Simple linear accumulate-then- threshold for this first cut; a fancier law can replace it later without touching the mechanism around it. heartbeat_tick() gains its one deliberate, documented amendment to this file's own top-half/bottom-half discipline -- the first time this codebase reaches into VM-scheduling state from real ISR context. Registration happens only after all three VMs are fully born, right before the REPL starts -- no critical-section protection yet against being switched away mid-birth-setup. Known, flagged rough edge (not reconciled this pass): MSG-TICK's own idle-pump and this new mechanism can still independently move control between the same VMs; not observed to interact badly in verification, but not fully unified either. Verified interactively at the console on all 3 architectures with continuous background preemption running throughout -- amd64 computed `1 1 + .` -> 2, aarch64 computed `1 1 + dup DUP * . CR` -> 4, both correct, REPL fully responsive, zero fault indicators over sustained runtime. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_016UNhH1mhi52i6Qihh7ZV5S
include/starkernel/
Headers for LithosAnanke, the bare-metal UEFI kernel (src/starkernel/).
Built only via Makefile.starkernel; gated by __STARKERNEL__ when shared
with hosted code.
uefi.h— UEFI protocol/type definitions consumed by the loader.elf64.h,elf_loader.h— ELF64 parsing and kernel-image loading.boot_info_offsets.h— struct-offset constants shared between the assembly bootstrap and the C boot path.arch.h,apic.h,timer.h— architecture init, APIC interrupt controller, timer (TSC/HPET/APIC, 100 Hz heartbeat).console.h,framebuffer.h,vt100.h— UART 16550 console, framebuffer driver, and VT100 terminal emulation over the framebuffer.pmm.h,vmm.h,kmalloc.h— physical memory manager (bitmap allocator), 4-level x86_64 paging, kernel heap allocator.pci.h,virtio_blk.h— PCI enumeration and the VirtIO block device driver (disk backend for the kernel block subsystem).capsule.h,capsule_birth.h,capsule_loader.h,capsule_run.h,capsule_vm_physics.h,capsule_generated.h— capsule system types, birth protocol, physics-runtime capsule bindings, and the build-time- generated capsule directory (seetools/mkcapsule.c).kernel_args.h,cmdline.h— boot-time kernel argument parsing (starforth.cfg/ command line).repl.h— kernel REPL.log.h,doe_log.h— kernel logging and DoE metrics logging.q48_16.h— kernel-build copy of Q48.16 fixed-point arithmetic.xxhash64.h— content-addressing hash used for capsule IDs.hal_memory.h— hardware-abstraction-layer memory interface.
Subdirectories:
hal/— top-level hardware-abstraction-layer interface.vm/— kernel VM subsystem headers (capsule arena, parity logging, bootstrap wiring).freestanding/— minimal libc-shim headers (assert.h,ctype.h,errno.h,inttypes.h,math.h,sched.h,signal.h,stdio.h,stdlib.h,string.h,time.h,sys/time.h,sys/types.h) for building shared VM code in the freestanding kernel environment, where no real libc is available.