longjmp.c

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/*
 * PROJECT:     ReactOS vcruntime library
 * LICENSE:     MIT (https://spdx.org/licenses/MIT)
 * PURPOSE:     Implementation of longjmp for x64.
 * COPYRIGHT:   Copyright 2025 Timo Kreuzer <timo.kreuzer@reactos.org>
 */
 
#include <setjmp.h>
#include <windef.h>
 
__declspec(noreturn)
void __longjmp_noframe(const _JUMP_BUFFER* _Buf, int _Value);
 
__declspec(noreturn)
void __cdecl longjmp(
    _In_reads_(_JBLEN) jmp_buf _Buf,
    _In_ int _Value)
{
    const _JUMP_BUFFER* jumpBuffer = (_JUMP_BUFFER*)_Buf;
 
    /* Ensure _Value is non-zero */
    _Value = (_Value == 0) ? 1 : _Value;
 
    if (jumpBuffer->Frame != 0)
    {
        EXCEPTION_RECORD exceptionRecord = { 0 };
        exceptionRecord.ExceptionCode = STATUS_LONGJUMP;
        exceptionRecord.NumberParameters = 1;
        exceptionRecord.ExceptionInformation[0] = (ULONG_PTR)jumpBuffer;
 
        RtlUnwind((PVOID)jumpBuffer->Frame,
                  (PVOID)jumpBuffer->Rip,
                  &exceptionRecord,
                  (PVOID)(ULONG_PTR)_Value);
    }
 
    __longjmp_noframe(jumpBuffer, _Value);
}