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Amiga Format 106
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af106sub.adf
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datatypes.LZX
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anim_datatype
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stackswap.c
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C/C++ Source or Header
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2001-01-02
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/*
**
** $VER: stackswap.c 1.1 (12.11.97)
** anim.datatype 1.1
**
** Dispatch routine for a DataTypes class
**
** Written 1997 by Roland 'Gizzy' Mainz
** Original example source from David N. Junod
**
*/
/* main includes */
#include "classbase.h"
/*****************************************************************************/
typedef ULONG ASM (*DMHOOKFUNC)( REGA0 struct Hook *, REGA2 APTR, REGA1 APTR );
struct MyStackSwapStruct
{
struct StackSwapStruct stk;
struct IClass *cl;
Object *o;
Msg msg;
};
/*****************************************************************************/
DISPATCHERFLAGS
ULONG StackSwapDispatch( REGA0 struct IClass *cl, REGA2 Object *o, REGA1 Msg msg )
{
struct ClassBase *cb = (struct ClassBase *)(cl -> cl_UserData);
ULONG retval;
struct MyStackSwapStruct mystk;
UBYTE *lower,
*upper,
*sp;
struct Task *ThisTask;
ULONG stacksize,
required_stacksize = (ULONG)(cl -> cl_Dispatcher . h_Data);
/* Fill in data */
mystk . cl = cl;
mystk . o = o;
mystk . msg = msg;
ThisTask = FindTask( NULL );
stacksize = (ULONG)(((UBYTE *)(ThisTask -> tc_SPReg)) - ((UBYTE *)(ThisTask -> tc_SPLower)));
/* Enougth stack ? */
if( stacksize > ((required_stacksize * 2UL) / 3UL) )
{
retval = MyDispatch( (&mystk) );
}
else
{
/* Alloc a new stack frame... */
while( !(lower = (UBYTE *)AllocMem( required_stacksize, MEMF_PUBLIC )) );
sp = upper = lower + required_stacksize;
mystk . stk . stk_Lower = lower;
mystk . stk . stk_Upper = (ULONG)upper;
mystk . stk . stk_Pointer = sp;
retval = SwapMe( (&mystk) );
FreeMem( lower, required_stacksize );
}
return( retval );
}
/* swap stack */
DISPATCHERFLAGS
ULONG SwapMe( REGA0 struct MyStackSwapStruct *mystk )
{
register ULONG retval;
#define cb ((struct ClassBase *)(mystk -> cl -> cl_UserData))
StackSwap( (&(mystk -> stk)) );
retval = MyDispatch( mystk );
StackSwap( (&(mystk -> stk)) );
#undef cb
return( retval );
}
/* call class dispatcher */
DISPATCHERFLAGS
ULONG MyDispatch( REGA0 struct MyStackSwapStruct *mystk )
{
struct IClass *cl = mystk -> cl;
return( (*((DMHOOKFUNC)(cl -> cl_Dispatcher . h_SubEntry)))( (&(cl -> cl_Dispatcher)), (APTR)(mystk -> o), (APTR)(mystk -> msg) ) );
}