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Robert Allan JamesandClaude Sonnet 5 88eb73cfe8 starkernel: item 4.3.5 -- amd64 I/O APIC + i8042 keyboard, interrupt-driven
Punch list §25 item 4.3.5 complete.

New ioapic.c/i8042.c drivers (MADT-derived I/O APIC base, no hardcoded
constants) plus a KBD-SCAN/KBD-DEBUG diagnostic word pair. Three real
bugs found and fixed en route, all blocking this item's own acceptance:
a fatal LAPIC spurious-vector crash (nothing had driven a real external
interrupt through the I/O APIC before), OVMF leaving the keyboard device
itself scanning-disabled (0xF4 fix), and isr.S's stub table only having
individually-numbered stubs through vector 32 -- everything above that,
including our IRQ1 vector 33, silently reported as vector 255 regardless
of which IDT slot actually fired. Verified live via QEMU sendkey against
KBD-SCAN: correct XT Set-1 make/break codes for two different keys.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-08-08 00:18:48 -04:00

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/*
StarForth — Steady-State Virtual Machine Runtime
Copyright (c) 20232025 Robert A. James
All rights reserved.
This file is part of the StarForth project.
Licensed under the StarForth License, Version 1.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at:
https://github.com/star.4th@proton.me/StarForth/LICENSE.txt
This software is provided "AS IS", WITHOUT WARRANTY OF ANY KIND,
express or implied, including but not limited to the warranties of
merchantability, fitness for a particular purpose, and noninfringement.
See the License for the specific language governing permissions and
limitations under the License.
StarForth — Steady-State Virtual Machine Runtime
Copyright (c) 20232025 Robert A. James
All rights reserved.
This file is part of the StarForth project.
Licensed under the StarForth License, Version 1.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at:
https://github.com/star.4th@proton.me/StarForth/LICENSE.txt
This software is provided "AS IS", WITHOUT WARRANTY OF ANY KIND,
express or implied, including but not limited to the warranties of
merchantability, fitness for a particular purpose, and noninfringement.
See the License for the specific language governing permissions and
limitations under the License.
*/
/**
* apic.h - Local APIC interface
*/
#ifndef STARKERNEL_APIC_H
#define STARKERNEL_APIC_H
#include "uefi.h"
#include <stdint.h>
/* Heartbeat timer vector (user-defined IRQ space starts at 0x20) */
#define APIC_TIMER_VECTOR 0x20
/* Spurious-interrupt vector (APIC_REG_SIVR, set in apic_init()). A normal,
* occasional hardware race per Intel SDM Vol.3 §10.9 -- not a fault. Must
* be silently ignored with no EOI. Surfaced by item 4.3.5's I/O APIC work:
* no real external interrupt had ever been delivered through the I/O APIC
* before, so this path was previously dormant. */
#define APIC_SPURIOUS_VECTOR 0xFF
/* Initialize Local APIC (enables APIC, sets spurious vector) */
int apic_init(BootInfo *boot_info);
/* Return this CPU's xAPIC ID (APIC_REG_ID bits 31:24) — used as the
* destination field when programming I/O APIC redirection entries. */
uint8_t apic_id(void);
/* Send End-of-Interrupt signal */
void apic_eoi(void);
/*
* Initialize APIC timer for periodic heartbeat.
* @param tsc_hz TSC frequency in Hz (for calibration)
* @param tick_hz Desired tick frequency (e.g., 100 = 100 Hz = 10ms period)
* @return 0 on success, -1 on failure
*/
int apic_timer_init(uint64_t tsc_hz, uint32_t tick_hz);
/**
* Start the APIC timer (enables periodic interrupts).
* Call this after IDT and heartbeat handler are set up.
*/
void apic_timer_start(void);
/**
* Stop the APIC timer (disables periodic interrupts).
*/
void apic_timer_stop(void);
/**
* Re-arm the APIC timer at the current adaptive period (item 0.8, §26).
* Recomputes the initial count from heartbeat_next_period_ns() and writes
* it to the ICR; a periodic-mode ICR write restarts the countdown
* immediately at the new value. Called once per tick from the ISR, before
* heartbeat_tick().
*/
void apic_timer_rearm(void);
/**
* Get the configured timer period in TSC ticks.
*/
uint64_t apic_timer_period_tsc(void);
#endif /* STARKERNEL_APIC_H */