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// TITLE("Set Jump Extended")//++//// Copyright (c) 1993 Microsoft Corporation// Copyright (c) 1993 Digital Equipment Corporation//// Module Name://// setjmpex.s//// Abstract://// This module implements the Alpha acc compiler specific routine to// provide SAFE handling of setjmp/longjmp with respect to structured// exception handling.//// Author://// David N. Cutler (davec) 2-Apr-1993//// Environment://// Any mode.//// Revision History://// Thomas Van Baak (tvb) 22-Apr-1993//// Adapted for Alpha AXP.////--
#include "ksalpha.h"
//// Define variable that will cause setjmp/longjmp to be safe with respect// to structured exception handling.//
.globl _setjmpexused .data_setjmpexused: .long _setjmpex // set address of safe setjmp routine SBTTL("Set Jump Extended")//++//// int// _setjmpex (// IN jmp_buf JumpBuffer// )//// Routine Description://// This function implements a safe setjmp.//// Arguments://// JumpBuffer (a0) - Supplies the address of a jump buffer to store the// jump information.//// Return Value://// A value of zero is returned.////--
.struct 0SjRa: .space 8 // saved return addressSjS0: .space 8 // saved integer register s0SjFl: .space 8 // InFunction flag variableSjEf: .space 8 // EstablisherFrame(s) structureSjCx: .space ContextFrameLength // context frameSetjmpFrameLength:
NESTED_ENTRY(_setjmpex, SetjmpFrameLength, zero)
lda sp, -SetjmpFrameLength(sp) // allocate stack frame stq ra, SjRa(sp) // save return address stq s0, SjS0(sp) // save integer register s0
PROLOGUE_END
//// Save the nonvolatile machine state.//
lda t0, SjCx(sp) // address of context record
stt f2, CxFltF2(t0) // save floating registers f2 - f9 stt f3, CxFltF3(t0) // stt f4, CxFltF4(t0) // stt f5, CxFltF5(t0) // stt f6, CxFltF6(t0) // stt f7, CxFltF7(t0) // stt f8, CxFltF8(t0) // stt f9, CxFltF9(t0) //
stq s0, CxIntS0(t0) // save integer registers s0 - fp/s6 stq s1, CxIntS1(t0) // stq s2, CxIntS2(t0) // stq s3, CxIntS3(t0) // stq s4, CxIntS4(t0) // stq s5, CxIntS5(t0) // stq fp, CxIntFp(t0) // stq gp, CxIntGp(t0) // save integer register gp
lda v0, SetjmpFrameLength(sp) // compute stack pointer address stq v0, CxIntSp(t0) // save stack pointer stq ra, CxIntRa(t0) // save return address stq ra, CxFir(t0) // save continuation address
ldil t1, 2 // get acc safe setjmp flag stl t1, JbType(a0) // set jump buffer context type stl ra, JbPc(a0) // save target instruction address mov a0, s0 // preserve jump buffer address
//// Perform unwind to determine the virtual frame pointer of the caller.//
subl ra, 4, a0 // compute control PC address bsr RtlLookupFunctionEntry // lookup function table address
ldq a0, SjRa(sp) // get return address subl a0, 4, a0 // compute control PC address mov v0, a1 // set address of function entry lda a2, SjCx(sp) // address of context record lda a3, SjFl(sp) // set address of in function variable lda a4, SjEf(sp) // set frame pointers address mov zero, a5 // set context pointer array address bsr RtlVirtualUnwind // compute virtual frame pointer value
//// Set return value, restore registers, deallocate stack frame, and return.//
ldl t0, SjEf(sp) // get virtual frame pointer stl t0, JbFp(s0) // save virtual frame pointer address mov zero, v0 // set return value
ldq s0, SjS0(sp) // restore integer register s0 ldq ra, SjRa(sp) // restore return address lda sp, SetjmpFrameLength(sp) // deallocate stack frame ret zero, (ra) // return
.end _setjmpex
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