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// TITLE("Asynchronous Procedure Call (APC) Interrupt")//++//// Copyright (c) 1990 Microsoft Corporation//// Module Name://// apcint.s//// Abstract://// This module implements the code necessary to field and process the// Asynchronous Procedure Call (APC) interrupt.//// Author://// David N. Cutler (davec) 3-Apr-1990// Joe Notarangelo 15-Jul-1992 alpha version//// Environment://// Kernel mode only, IRQL APC_LEVEL.//// Revision History:////--
#include "ksalpha.h"
SBTTL("Asynchronous Procedure Call Interrupt")//++//// Routine Description://// This routine is entered as the result of a software interrupt generated// at APC_LEVEL. Its function is to allocate an exception frame and call// the kernel APC delivery routine to deliver kernel mode APCs and to check// if a user mode APC should be delivered. If a user mode APC should be// delivered, then the kernel APC delivery routine constructs a context// frame on the user stack and alters the exception and trap frames so that// control will be transfered to the user APC dispatcher on return from the// interrupt.//// N.B. On entry to this routine only the volatile integer registers have// been saved. The remainder of the machine state is saved if and only// if the previous mode was user mode. It is assumed that none of the// APC delivery code, nor any of the kernel mode APC routines themselves// use any floating point instructions.//// Arguments://// s6/fp - Supplies a pointer to a trap frame.//// Return Value://// None.////--
NESTED_ENTRY(KiApcInterrupt, ExceptionFrameLength, zero)
lda sp, -ExceptionFrameLength(sp) // allocate exception frame stq ra, ExIntRa(sp) // save return address
PROLOGUE_END
//// Save the volatile floating state and determine the previous mode.//
bsr ra, KiSaveVolatileFloatState // save volatile floats ldl t0, TrPsr(fp) // get saved processor status and t0, PSR_MODE_MASK, a0 // isolate previous mode beq a0, 10f // if eq, kernel mode
//// The previous mode was user.//// Save the nonvolatile machine state so a context record can be// properly constructed to deliver an APC to user mode if required.// It is also necessary to save the volatile floating state for// suspend/resume operations.//
stq s0, ExIntS0(sp) // save nonvolatile integer state stq s1, ExIntS1(sp) // stq s2, ExIntS2(sp) // stq s3, ExIntS3(sp) // stq s4, ExIntS4(sp) // stq s5, ExIntS5(sp) // bsr ra, KiSaveNonVolatileFloatState // save floating state
//// Attempt to deliver an APC.//
10: bis sp, zero, a1 // set address of exception frame bis fp, zero, a2 // set address of trap frame bsr ra, KiDeliverApc // call APC delivery routine
//// Restore the volatile floating state and return from the interrupt.//
bsr ra, KiRestoreVolatileFloatState // restore floating state ldq ra, ExIntRa(sp) // restore return address lda sp, ExceptionFrameLength(sp) // deallocate exception frame ret zero, (ra) // return
.end KiApcInterrupt
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