implement proper IRQL, DPCs, kernel and user APCs, alertable waits, async file I/O with cancellation, trap frames, selftests, a real driver/device model, native async FAT32, VFAT dotfile fixes, syscall ABI cleanup, async_apc and async_cancel tests, POSIX multi-volume paths, and pimp the readme.

code/kernel/ke_irq.h

@@ -5,3 +5,10 @@
 void KeIrqInitialize(const HAL_API *hal);
 __declspec(dllexport) void KeIrqRegister(uint8_t irq, void (*handler)(void));
 void KeIrqDispatch(uint8_t irq);   // called from ke_syscall.asm
+
+// Low-level interrupt entry/exit hooks.  These are called by the common IRQ
+// assembly stub around KeIrqDispatch.  The exit hook is where deferred
+// interrupt-time scheduling now happens, so IRQ handlers never switch away
+// before KeIrqDispatch has returned and sent EOI.
+void KiEnterInterrupt(void);
+void KiExitInterrupt(void);