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// TITLE("Capture and Restore Context")
//++
//
// Copyright (c) 1990 Microsoft Corporation
//
// Module Name:
//
// capture.s
//
// Abstract:
//
// This module implements the code necessary to capture and restore
// the context of the caller.
//
// Author:
//
// David N. Cutler (davec) 14-Sep-1990
//
// Environment:
//
// Any mode.
//
// Revision History:
//
//--
#include "ksmips.h"
//
// Define local symbols.
//
#define UserPsr (1 << PSR_CU1) | (0xff << PSR_INTMASK) | (1 << PSR_UX) | \
(2 << PSR_KSU) | (1 << PSR_IE) // constant user PSR value
SBTTL("Capture Context")
//++
//
// VOID
// RtlCaptureContext (
// OUT PCONTEXT ContextRecord
// )
//
// Routine Description:
//
// This function captures the context of the caller in the specified
// context record.
//
// Arguments:
//
// ContextRecord (a0) - Supplies the address of a context record.
//
// Return Value:
//
// None.
//
//--
LEAF_ENTRY(RtlCaptureContext)
//
// Save integer registers zero, at - t9, s8, gp, sp, ra, lo, and hi.
//
.set noreorder
.set noat
sd zero,CxXIntZero(a0) //
sd AT,CxXIntAt(a0) //
sd v0,CxXIntV0(a0) //
mflo v0 //
sd v1,CxXIntV1(a0) //
mfhi v1 //
sd v0,CxXIntLo(a0) //
sd v1,CxXIntHi(a0) //
sd a0,CxXIntA0(a0) //
sd a1,CxXIntA1(a0) //
sd a2,CxXIntA2(a0) //
sd a3,CxXIntA3(a0) //
sd t0,CxXIntT0(a0) //
sd t1,CxXIntT1(a0) //
sd t2,CxXIntT2(a0) //
sd t3,CxXIntT3(a0) //
sd t4,CxXIntT4(a0) //
sd t5,CxXIntT5(a0) //
sd t6,CxXIntT6(a0) //
sd t7,CxXIntT7(a0) //
sd s0,CxXIntS0(a0) //
sd s1,CxXIntS1(a0) //
sd s2,CxXIntS2(a0) //
sd s3,CxXIntS3(a0) //
sd s4,CxXIntS4(a0) //
sd s5,CxXIntS5(a0) //
sd s6,CxXIntS6(a0) //
sd s7,CxXIntS7(a0) //
sd t8,CxXIntT8(a0) //
sd t9,CxXIntT9(a0) //
sd zero,CxXIntK0(a0) //
sd zero,CxXIntK1(a0) //
sd s8,CxXIntS8(a0) //
sd gp,CxXIntGp(a0) //
sd sp,CxXIntSp(a0) //
sd ra,CxXIntRa(a0) //
//
// Save floating status and floating registers f0 - f31.
//
cfc1 v0,fsr //
sdc1 f0,CxFltF0(a0) //
sdc1 f2,CxFltF2(a0) //
sdc1 f4,CxFltF4(a0) //
sdc1 f6,CxFltF6(a0) //
sdc1 f8,CxFltF8(a0) //
sdc1 f10,CxFltF10(a0) //
sdc1 f12,CxFltF12(a0) //
sdc1 f14,CxFltF14(a0) //
sdc1 f16,CxFltF16(a0) //
sdc1 f18,CxFltF18(a0) //
sdc1 f20,CxFltF20(a0) //
sdc1 f22,CxFltF22(a0) //
sdc1 f24,CxFltF24(a0) //
sdc1 f26,CxFltF26(a0) //
sdc1 f28,CxFltF28(a0) //
sdc1 f30,CxFltF30(a0) //
.set at
.set reorder
//
// Save control information and set context flags.
//
sw v0,CxFsr(a0) // save floating status
sw ra,CxFir(a0) // set continuation address
li v0,UserPsr // set constant user processor status
bgez sp,10f // if gez, called from user mode
.set noreorder
.set noat
mfc0 v0,psr // get current processor status
nop //
.set at
.set reorder
10: sw v0,CxPsr(a0) // set processor status
li t0,CONTEXT_FULL // set context control flags
sw t0,CxContextFlags(a0) //
j ra // return
.end RtlCaptureContext
SBTTL("Restore Context")
//++
//
// VOID
// RtlpRestoreContext (
// IN PCONTEXT ContextRecord,
// IN PEXCEPTION_RECORD ExceptionRecord OPTIONAL
// )
//
// Routine Description:
//
// This function restores the context of the caller to the specified
// context.
//
// N.B. This is a special routine that is used by RtlUnwind to restore
// context in the current mode. PSR, t0, and t1 are not restored.
//
// Arguments:
//
// ContextRecord (a0) - Supplies the address of a context record.
//
// ExceptionRecord (a1) - Supplies an optional pointer to an exception
// record.
//
// Return Value:
//
// None.
//
// N.B. There is no return from this routine.
//
//--
LEAF_ENTRY(RtlpRestoreContext)
//
// If an exception record is specified and the exception status is
// STATUS_LONGJUMP, then restore the nonvolatile registers to their
// state at the call to setjmp before restoring the context record.
//
li t0,STATUS_LONGJUMP // get long jump status code
beq zero,a1,5f // if eq, no exception record
lw t1,ErExceptionCode(a1) // get exception code
lw a2,ErExceptionInformation(a1) // get address of jump buffer
bne t0,t1,5f // if ne, not a long jump
ldc1 f20,JbFltF20(a2) // move floating registers f20 - f31
ldc1 f22,JbFltF22(a2) //
ldc1 f24,JbFltF24(a2) //
ldc1 f26,JbFltF26(a2) //
ldc1 f28,JbFltF28(a2) //
ldc1 f30,JbFltF30(a2) //
sdc1 f20,CxFltF20(a0) //
sdc1 f22,CxFltF22(a0) //
sdc1 f24,CxFltF24(a0) //
sdc1 f26,CxFltF26(a0) //
sdc1 f28,CxFltF28(a0) //
sdc1 f30,CxFltF30(a0) //
lw s0,JbIntS0(a2) // move integer registers s0 - s8
lw s1,JbIntS1(a2) //
lw s2,JbIntS2(a2) //
lw s3,JbIntS3(a2) //
lw s4,JbIntS4(a2) //
lw s5,JbIntS5(a2) //
lw s6,JbIntS6(a2) //
lw s7,JbIntS7(a2) //
lw s8,JbIntS8(a2) //
sd s0,CxXIntS0(a0) //
sd s1,CxXIntS1(a0) //
sd s2,CxXIntS2(a0) //
sd s3,CxXIntS3(a0) //
sd s4,CxXIntS4(a0) //
sd s5,CxXIntS5(a0) //
sd s6,CxXIntS6(a0) //
sd s7,CxXIntS7(a0) //
sd s8,CxXIntS8(a0) //
lw v0,JbFir(a2) // move fir and sp
lw v1,JbIntSp(a2) //
sw v0,CxFir(a0) //
sd v0,CxXIntRa(a0) //
sd v1,CxXIntSp(a0) //
//
// If the call is from user mode, then use the continue system service to
// continue execution. Otherwise, restore the context directly since the
// current mode is kernel and threads can't be arbitrarily interrupted.
//
5: bltz ra,10f // if lt, kernel mode restore
move a1,zero // set test alert argument
jal ZwContinue // continue execution
//
// Save the address of the context record and contuation address in
// registers t0 and t1. These registers are not restored.
//
10: move t0,a0 // save context record address
lw t1,CxFir(t0) // get continuation address
//
// Restore floating status and floating registers f0 - f31.
//
.set noreorder
.set noat
lw v0,CxFsr(t0) // restore floating status
ctc1 v0,fsr //
ldc1 f0,CxFltF0(t0) // restore floating registers f0 - f31
ldc1 f2,CxFltF2(t0) //
ldc1 f4,CxFltF4(t0) //
ldc1 f6,CxFltF6(t0) //
ldc1 f8,CxFltF8(t0) //
ldc1 f10,CxFltF10(t0) //
ldc1 f12,CxFltF12(t0) //
ldc1 f14,CxFltF14(t0) //
ldc1 f16,CxFltF16(t0) //
ldc1 f18,CxFltF18(t0) //
ldc1 f20,CxFltF20(t0) //
ldc1 f22,CxFltF22(t0) //
ldc1 f24,CxFltF24(t0) //
ldc1 f26,CxFltF26(t0) //
ldc1 f28,CxFltF28(t0) //
ldc1 f30,CxFltF30(t0) //
//
// Restore integer registers and continue execution.
//
ld v0,CxXIntLo(t0) // restore multiply/divide registers
ld v1,CxXIntHi(t0) //
mtlo v0 //
mthi v1 //
ld AT,CxXIntAt(t0) // restore integer registers at - a3
ld v0,CxXIntV0(t0) //
ld v1,CxXIntV1(t0) //
ld a0,CxXIntA0(t0) //
ld a1,CxXIntA1(t0) //
ld a2,CxXIntA2(t0) //
ld a3,CxXIntA3(t0) //
ld t2,CxXIntT2(t0) // restore integer registers t2 - t7
ld t3,CxXIntT3(t0) //
ld t4,CxXIntT4(t0) //
ld t5,CxXIntT5(t0) //
ld t6,CxXIntT6(t0) //
ld t7,CxXIntT7(t0) //
ld s0,CxXIntS0(t0) // restore integer registers s0 - s7
ld s1,CxXIntS1(t0) //
ld s2,CxXIntS2(t0) //
ld s3,CxXIntS3(t0) //
ld s4,CxXIntS4(t0) //
ld s5,CxXIntS5(t0) //
ld s6,CxXIntS6(t0) //
ld s7,CxXIntS7(t0) //
ld t8,CxXIntT8(t0) // restore integer registers t8 and t9
ld t9,CxXIntT9(t0) //
ld s8,CxXIntS8(t0) // restore integer register s8
ld gp,CxXIntGp(t0) // restore integer register gp
ld sp,CxXIntSp(t0) //
j t1 // continue execution
ld ra,CxXIntRa(t0) //
.set at
.set reorder
.end RtlRestoreContext
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