andre@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
andre@0: /* This Source Code Form is subject to the terms of the Mozilla Public
andre@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
andre@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
andre@0: 
andre@0: /*
andre@0:  * GC related routines
andre@0:  *
andre@0:  */
andre@0: #include <windows.h>
andre@0: #include "primpl.h"
andre@0: 
andre@0: PRWord *_MD_HomeGCRegisters(PRThread *t, int isCurrent, int *np) 
andre@0: {
andre@0: #if defined(_X86_)
andre@0:     CONTEXT context;
andre@0:     context.ContextFlags = CONTEXT_INTEGER;
andre@0: 
andre@0:     if (_PR_IS_NATIVE_THREAD(t)) {
andre@0:         context.ContextFlags |= CONTEXT_CONTROL;
andre@0:         if (GetThreadContext(t->md.handle, &context)) {
andre@0:             t->md.gcContext[0] = context.Eax;
andre@0:             t->md.gcContext[1] = context.Ebx;
andre@0:             t->md.gcContext[2] = context.Ecx;
andre@0:             t->md.gcContext[3] = context.Edx;
andre@0:             t->md.gcContext[4] = context.Esi;
andre@0:             t->md.gcContext[5] = context.Edi;
andre@0:             t->md.gcContext[6] = context.Esp;
andre@0:             t->md.gcContext[7] = context.Ebp;
andre@0:             *np = PR_NUM_GCREGS;
andre@0:         } else {
andre@0:             PR_ASSERT(0);/* XXX */
andre@0:         }
andre@0:     } else {
andre@0:         /* WARNING WARNING WARNING WARNING WARNING WARNING WARNING
andre@0:          *
andre@0:          * This code is extremely machine dependant and completely 
andre@0:          * undocumented by MS.  Its only known to work experimentally.  
andre@0:          * Ready for a walk on the wild * side?
andre@0:          *
andre@0:          * WARNING WARNING WARNING WARNING WARNING WARNING WARNING */
andre@0: 
andre@0: #if !defined WIN95 // Win95 does not have fibers
andre@0:         int *fiberData = t->md.fiber_id;
andre@0: 
andre@0:         /* I found these offsets by disassembling SwitchToFiber().
andre@0:          * Are your palms sweating yet?
andre@0:          */
andre@0: 
andre@0:         /* 
andre@0:         ** EAX is on the stack (ESP+0)
andre@0:         ** EDX is on the stack (ESP+4)
andre@0:         ** ECX is on the stack (ESP+8)
andre@0:         */
andre@0:         t->md.gcContext[0] = 0;                /* context.Eax */
andre@0:         t->md.gcContext[1] = fiberData[0x2e];  /* context.Ebx */
andre@0:         t->md.gcContext[2] = 0;                /* context.Ecx */
andre@0:         t->md.gcContext[3] = 0;                /* context.Edx */
andre@0:         t->md.gcContext[4] = fiberData[0x2d];  /* context.Esi */
andre@0:         t->md.gcContext[5] = fiberData[0x2c];  /* context.Edi */
andre@0:         t->md.gcContext[6] = fiberData[0x36];  /* context.Esp */
andre@0:         t->md.gcContext[7] = fiberData[0x32];  /* context.Ebp */
andre@0:         *np = PR_NUM_GCREGS;
andre@0: #endif
andre@0:     }
andre@0:     return (PRWord *)&t->md.gcContext;
andre@0: #else
andre@0:     PR_NOT_REACHED("not implemented");
andre@0:     return NULL;
andre@0: #endif /* defined(_X86_) */
andre@0: }
andre@0: 
andre@0: /* This function is not used right now, but is left as a reference.
andre@0:  * If you ever need to get the fiberID from the currently running fiber, 
andre@0:  * this is it.
andre@0:  */
andre@0: void *
andre@0: GetMyFiberID()
andre@0: {
andre@0: #if defined(_X86_) && !defined(__MINGW32__)
andre@0:     void *fiberData;
andre@0: 
andre@0:     /* A pointer to our tib entry is found at FS:[18]
andre@0:      * At offset 10h is the fiberData pointer.  The context of the 
andre@0:      * fiber is stored in there.  
andre@0:      */
andre@0:     __asm {
andre@0:         mov    EDX, FS:[18h]
andre@0:         mov    EAX, DWORD PTR [EDX+10h]
andre@0:         mov    [fiberData], EAX
andre@0:     }
andre@0:   
andre@0:     return fiberData;
andre@0: #else
andre@0:     PR_NOT_REACHED("not implemented");
andre@0:     return NULL;
andre@0: #endif /* defined(_X86_) */
andre@0: }