rajamesandClaude Opus 5.5
029a8ed9cf
FABRIC-3.5 SXXXII, closing FABRIC-3 SXXIX bug 2 (SXXXVI). A send marks the receiver for the switch signal; the VM's own loop on its native stack takes its messages and yields; Hera's idle beat makes the pending switch instead of running other VMs' messages on her stack; every VM gets switcher turns from birth; the drain refuses any call outside the VM's own context (the test: it held every relayed line before, none now). Found on the way: amd64's first-entry frame left rsp 8 bytes off the SysV entry alignment (#GP on the first interpreter run on a VM's own stack), and a VM yielding from its loop was marked SWITCHED_OUT, which stopped console relay after one message and would have made KILL refuse it. Relay of four lines to a WIREBIND identity on all three ISAs, five hot-plugged identities, and standard acceptance (POST 1052, hash 0x08873e0f44b7cb2a) all pass. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
72 lines
2.7 KiB
C
72 lines
2.7 KiB
C
/*
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StarForth — Steady-State Virtual Machine Runtime
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Copyright (c) 2023–2025 Robert A. James
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All rights reserved.
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This file is part of the StarForth project.
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Licensed under the StarForth License, Version 1.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at:
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https://github.com/star.4th@proton.me/StarForth/LICENSE.txt
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This software is provided "AS IS", WITHOUT WARRANTY OF ANY KIND,
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express or implied, including but not limited to the warranties of
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merchantability, fitness for a particular purpose, and noninfringement.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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/**
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* switch.h - Cooperative VM context switch (FABRIC-3.md §XXVIII, Stage 2,
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* 2026-09-13).
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*
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* sk_vm_context_switch() suspends `from`'s execution exactly where it is
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* (mid-C-call-stack, on from's own native stack -- Stage 1) and resumes
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* `to` -- either for the first time ever (a synthesized initial frame,
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* entering sk_vm_switch_entry()) or exactly where `to` was itself last
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* switched out. Returns to the caller only once something later switches
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* back to `from` -- from from's own point of view, this call simply
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* takes a while to return, like any blocking call.
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*
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* Cooperative only: nothing here is interrupt-driven yet (that's Stage
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* 3), so this is safe to call only from ordinary FORTH word dispatch,
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* never from ISR context.
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*/
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#ifndef STARKERNEL_VM_SWITCH_H
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#define STARKERNEL_VM_SWITCH_H
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#ifdef __STARKERNEL__
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struct VM;
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int sk_vm_context_switch(struct VM *from, struct VM *to);
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/* Performs the switch the switch signal has pending, if any, from `from`
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* -- the VM that owns the native stack now running. Returns 1 once it has
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* switched and been switched back to, 0 when there was nothing to do.
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* Called at the colon-word checkpoint (vm_core.c) and at Hera's idle beat
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* (repl.c). */
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int sk_vm_switch_service_pending(struct VM *from);
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/* FABRIC-3.md §XXVIII Stage 3 follow-on (2026-09-14): which VM is
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* currently physically running, tracked by the switch mechanism itself --
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* see switch.c's own doc comment on g_switch_current_vm for why this
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* exists instead of reusing vm_log_attributed_vm(). sk_vm_switch_set_
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* current() seeds the initial value (whoever is running before any
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* switch has ever happened) -- call once, at Stage 3 registration time. */
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struct VM *sk_vm_switch_current_vm(void);
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void sk_vm_switch_set_current(struct VM *vm);
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/* True when at most one vm_interpret() is in progress, i.e. the word now
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* running belongs to the outermost text on this stack (vm_core.c). */
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int sk_vm_at_outermost_interpret(void);
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#endif /* __STARKERNEL__ */
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#endif /* STARKERNEL_VM_SWITCH_H */
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