[mirror_edk2.git] / EdkCompatibilityPkg / Foundation / Library / Thunk16 / Thunk16Lib.h

/*++\r
\r
Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>\r
This program and the accompanying materials                          \r
are licensed and made available under the terms and conditions of the BSD License         \r
which accompanies this distribution.  The full text of the license may be found at        \r
http://opensource.org/licenses/bsd-license.php                                            \r
                                                                                          \r
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     \r
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             \r
\r
Module Name:\r
\r
  Thunk16Lib.h\r
\r
Abstract:\r
\r
  Real Mode Thunk Header file\r
\r
--*/\r
\r
#ifndef __THUNK_16_LIB_H__\r
#define __THUNK_16_LIB_H__\r
#include "Tiano.h"\r
\r
//\r
// Thunk Flags\r
//\r
#define THUNK_SAVE_FP_STATE         0x1\r
#define THUNK_USER_STACK            0x2\r
#define THUNK_INTERRUPT             0x10000\r
\r
//\r
// Byte packed structure for 16-bit Real Mode FLAGS\r
//\r
typedef union {\r
  struct {\r
    UINT32  CF:1;           // Carry Flag\r
    UINT32  Reserved_0:1;   // Reserved\r
    UINT32  PF:1;           // Parity Flag\r
    UINT32  Reserved_1:1;   // Reserved\r
    UINT32  AF:1;           // Auxiliary Carry Flag\r
    UINT32  Reserved_2:1;   // Reserved\r
    UINT32  ZF:1;           // Zero Flag\r
    UINT32  SF:1;           // Sign Flag\r
    UINT32  TF:1;           // Trap Flag\r
    UINT32  IF:1;           // Interrupt Enable Flag\r
    UINT32  DF:1;           // Direction Flag\r
    UINT32  OF:1;           // Overflow Flag\r
    UINT32  IOPL:2;         // I/O Privilege Level\r
    UINT32  NT:1;           // Nested Task\r
    UINT32  Reserved_3:1;   // Reserved\r
  } Bits;\r
  UINTN     UintN;\r
} IA32_FLAGS16;\r
\r
//\r
// Byte packed structure for EFLAGS\r
// 32-bits on IA32\r
// 64-bits on X64\r
//\r
\r
typedef union {\r
  struct {\r
    UINT32  CF:1;           // Carry Flag\r
    UINT32  Reserved_0:1;   // Reserved\r
    UINT32  PF:1;           // Parity Flag\r
    UINT32  Reserved_1:1;   // Reserved\r
    UINT32  AF:1;           // Auxiliary Carry Flag\r
    UINT32  Reserved_2:1;   // Reserved\r
    UINT32  ZF:1;           // Zero Flag\r
    UINT32  SF:1;           // Sign Flag\r
    UINT32  TF:1;           // Trap Flag\r
    UINT32  IF:1;           // Interrupt Enable Flag\r
    UINT32  DF:1;           // Direction Flag\r
    UINT32  OF:1;           // Overflow Flag\r
    UINT32  IOPL:2;         // I/O Privilege Level\r
    UINT32  NT:1;           // Nested Task\r
    UINT32  Reserved_3:1;   // Reserved\r
    UINT32  RF:1;           // Resume Flag\r
    UINT32  VM:1;           // Virtual 8086 Mode\r
    UINT32  AC:1;           // Alignment Check\r
    UINT32  VIF:1;          // Virtual Interrupt Flag\r
    UINT32  VIP:1;          // Virtual Interrupt Pending\r
    UINT32  ID:1;           // ID Flag\r
    UINT32  Reserved_4:10;  // Reserved\r
  } Bits;\r
  UINTN     UintN;\r
} IA32_EFLAGS32;\r
\r
//\r
// Byte packed structure for an FP/SSE/SSE2 context\r
//\r
typedef struct {\r
  UINT8  Buffer[512];\r
} IA32_FX_BUFFER;\r
\r
//\r
// Structures for the 16-bit real mode thunks\r
//\r
typedef struct {\r
  UINT32                            Reserved1;\r
  UINT32                            Reserved2;\r
  UINT32                            Reserved3;\r
  UINT32                            Reserved4;\r
  UINT8                             BL;\r
  UINT8                             BH;\r
  UINT16                            Reserved5;\r
  UINT8                             DL;\r
  UINT8                             DH;\r
  UINT16                            Reserved6;\r
  UINT8                             CL;\r
  UINT8                             CH;\r
  UINT16                            Reserved7;\r
  UINT8                             AL;\r
  UINT8                             AH;\r
  UINT16                            Reserved8;\r
} IA32_BYTE_REGS;\r
\r
typedef struct {\r
  UINT16                            DI;\r
  UINT16                            Reserved1;\r
  UINT16                            SI;\r
  UINT16                            Reserved2;\r
  UINT16                            BP;\r
  UINT16                            Reserved3;\r
  UINT16                            SP;\r
  UINT16                            Reserved4;\r
  UINT16                            BX;\r
  UINT16                            Reserved5;\r
  UINT16                            DX;\r
  UINT16                            Reserved6;\r
  UINT16                            CX;\r
  UINT16                            Reserved7;\r
  UINT16                            AX;\r
  UINT16                            Reserved8;\r
  UINT16                            DS;\r
  UINT16                            ES;\r
  UINT16                            FS;\r
  UINT16                            GS;\r
  IA32_FLAGS16                      Flags;\r
  UINT16                            IP;\r
  UINT16                            Reserved10;\r
  UINT16                            CS;\r
  UINT16                            SS;\r
} IA32_WORD_REGS;\r
\r
typedef struct {\r
  UINT32                            EDI;\r
  UINT32                            ESI;\r
  UINT32                            EBP;\r
  UINT32                            ESP;\r
  UINT32                            EBX;\r
  UINT32                            EDX;\r
  UINT32                            ECX;\r
  UINT32                            EAX;\r
  UINT16                            DS;\r
  UINT16                            ES;\r
  UINT16                            FS;\r
  UINT16                            GS;\r
  IA32_EFLAGS32                     EFLAGS;\r
  UINT32                            EIP;\r
  UINT16                            CS;\r
  UINT16                            SS;\r
} IA32_DWORD_REGS;\r
\r
typedef union {\r
  IA32_DWORD_REGS                   E;\r
  IA32_WORD_REGS                    X;\r
  IA32_BYTE_REGS                    H;\r
} IA32_REGISTER_SET;\r
\r
//\r
// Byte packed structure for an 16-bit real mode thunks\r
//\r
typedef struct {\r
  UINT32                            RealModeBuffer;\r
  UINT32                            DefaultStack;\r
} THUNK_CONTEXT;\r
\r
//\r
// 16-bit thunking services\r
//\r
\r
UINTN\r
EFIAPI\r
AsmThunk16GetProperties (\r
  OUT     UINTN                     *MinimumStackSize OPTIONAL\r
  )\r
/*++\r
\r
Routine Description:\r
\r
  Returns the properties of this real mode thunk implementation. Currently\r
  there are 2 properties has been defined, the minimum real mode buffer size\r
  and the minimum stack size.\r
\r
Arguments:\r
\r
  MinimumStackSize  - The minimum size required for a 16-bit stack.\r
\r
Returns:\r
\r
  The minimum size of the real mode buffer needed by this thunk implementation\r
  is returned.\r
\r
--*/\r
;\r
\r
THUNK_CONTEXT *\r
EFIAPI\r
AsmThunk16SetProperties (\r
  OUT     THUNK_CONTEXT             *ThunkContext,\r
  IN      VOID                      *RealModeBuffer,\r
  IN      UINTN                     BufferSize\r
  )\r
/*++\r
\r
Routine Description:\r
\r
  Tell this real mode thunk implementation the address and size of the real\r
  mode buffer needed.\r
\r
Arguments:\r
\r
  ThunkContext    - The thunk context whose properties to set.\r
  RealModeBuffer  - The address of the buffer allocated by caller. It should be\r
                    aligned on a 16-byte boundary.\r
                    This buffer must be in identity mapped pages.\r
  BufferSize      - The size of RealModeBuffer. Must be larger than the minimum\r
                    size required as returned by AsmThunk16GetProperties().\r
\r
Returns:\r
\r
  None\r
\r
--*/\r
;\r
\r
VOID\r
EFIAPI\r
AsmThunk16Destroy (\r
  IN OUT  THUNK_CONTEXT             *ThunkContext\r
  )\r
/*++\r
\r
Routine Description:\r
\r
  Reset all internal states to their initial values. The caller should not\r
  release the real mode buffer until after a call to this function.\r
\r
Arguments:\r
\r
  ThunkContext  - The thunk context to destroy.\r
\r
Returns:\r
\r
  None\r
\r
--*/\r
;\r
\r
IA32_REGISTER_SET *\r
EFIAPI\r
AsmThunk16FarCall86 (\r
  IN      THUNK_CONTEXT             *ThunkContext,\r
  IN OUT  IA32_REGISTER_SET         *RegisterSet,\r
  IN      UINT32                    ThunkFlags\r
  )\r
/*++\r
\r
Routine Description:\r
\r
  Make a far call to 16-bit code.\r
\r
  NOTE: This function must be called on TPL_HIGH_LEVEL or with interrupts\r
        disabled because of GDTR and IDTR manipulations.\r
        This function must be placed in identity mapped pages.\r
\r
Arguments:\r
\r
  ThunkContext  - Thunk context to use.\r
  RegisterSet   - CPU registers would be set to the values contained in this\r
                  structure before making the far call. Then CPU registers are\r
                  copied back to this structure.\r
                  CS:EIP points to the real mode code being called on input.\r
                  SS:ESP points to the real mode stack if THUNK_USER_STACK is\r
                  set on input, otherwise ignored.\r
                  EFlages is ignored on input.\r
                  On output, values of CS, EIP, SS and ESP should be ignored.\r
  ThunkFlags    - 2 flags have currently been defined, THUNK_SAVE_FP_STATE and\r
                  THUNK_USER_STACK.\r
                  THUNK_SAVE_FP_STATE - FPU state would be saved/restored\r
                                        before/after calling real mode code.\r
                  THUNK_USER_STACK    - The stack specified by SS:ESP would be\r
                                        used instead of the default stack.\r
\r
Returns:\r
\r
  RegisterSet is returned.\r
\r
--*/\r
;\r
\r
IA32_REGISTER_SET *\r
EFIAPI\r
AsmThunk16Int86 (\r
  IN      THUNK_CONTEXT             *ThunkContext,\r
  IN      UINT8                     IntNumber,\r
  IN OUT  IA32_REGISTER_SET         *RegisterSet,\r
  IN      UINT32                    ThunkFlags\r
  )\r
/*++\r
\r
Routine Description:\r
\r
  Invoke a 16-bit interrupt handler.\r
\r
  NOTE: This function must be called on TPL_HIGH_LEVEL or with interrupts\r
        disabled because of GDTR and IDTR manipulations.\r
        This function must be placed in identity mapped pages.\r
\r
Arguments:\r
\r
  ThunkContext  - Thunk context to use.\r
  IntNumber     - The ordinal of the interrupt handler ranging from 0 to 255.\r
  RegisterSet   - CPU registers would be set to the values contained in this\r
                  structure before making the far call. Then CPU registers are\r
                  copied back to this structure.\r
                  SS:ESP points to the real mode stack if THUNK_USER_STACK is\r
                  set on input, otherwise ignored.\r
                  EFlages is ignored on input.\r
                  On output, values of CS, EIP, SS and ESP should be ignored.\r
  ThunkFlags    - 2 flags have currently been defined, THUNK_SAVE_FP_STATE and\r
                  THUNK_USER_STACK.\r
                  THUNK_SAVE_FP_STATE - FPU state would be saved/restored\r
                                        before/after calling real mode code.\r
                  THUNK_USER_STACK    - The stack specified by SS:ESP would be\r
                                        used instead of the default stack.\r
\r
Returns:\r
\r
  RegisterSet is returned.\r
\r
--*/\r
;\r
\r
#endif\r
Commit	Line	Data
3eb9473e	1	/*++\r
3eb9473e	2	\r
4ea9375a HT	3	Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>\r
4ea9375a HT	4	This program and the accompanying materials \r
3eb9473e	5	are licensed and made available under the terms and conditions of the BSD License \r
	6	which accompanies this distribution. The full text of the license may be found at \r
	7	http://opensource.org/licenses/bsd-license.php \r
	8	\r
	9	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, \r
	10	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. \r
	11	\r
	12	Module Name:\r
	13	\r
	14	Thunk16Lib.h\r
	15	\r
	16	Abstract:\r
	17	\r
	18	Real Mode Thunk Header file\r
	19	\r
	20	--*/\r
	21	\r
	22	#ifndef __THUNK_16_LIB_H__\r
	23	#define __THUNK_16_LIB_H__\r
	24	#include "Tiano.h"\r
	25	\r
	26	//\r
	27	// Thunk Flags\r
	28	//\r
	29	#define THUNK_SAVE_FP_STATE 0x1\r
	30	#define THUNK_USER_STACK 0x2\r
	31	#define THUNK_INTERRUPT 0x10000\r
	32	\r
	33	//\r
	34	// Byte packed structure for 16-bit Real Mode FLAGS\r
	35	//\r
	36	typedef union {\r
	37	struct {\r
	38	UINT32 CF:1; // Carry Flag\r
	39	UINT32 Reserved_0:1; // Reserved\r
	40	UINT32 PF:1; // Parity Flag\r
	41	UINT32 Reserved_1:1; // Reserved\r
	42	UINT32 AF:1; // Auxiliary Carry Flag\r
	43	UINT32 Reserved_2:1; // Reserved\r
	44	UINT32 ZF:1; // Zero Flag\r
	45	UINT32 SF:1; // Sign Flag\r
	46	UINT32 TF:1; // Trap Flag\r
	47	UINT32 IF:1; // Interrupt Enable Flag\r
	48	UINT32 DF:1; // Direction Flag\r
	49	UINT32 OF:1; // Overflow Flag\r
	50	UINT32 IOPL:2; // I/O Privilege Level\r
	51	UINT32 NT:1; // Nested Task\r
	52	UINT32 Reserved_3:1; // Reserved\r
	53	} Bits;\r
	54	UINTN UintN;\r
	55	} IA32_FLAGS16;\r
	56	\r
	57	//\r
	58	// Byte packed structure for EFLAGS\r
	59	// 32-bits on IA32\r
	60	// 64-bits on X64\r
	61	//\r
	62	\r
	63	typedef union {\r
	64	struct {\r
	65	UINT32 CF:1; // Carry Flag\r
	66	UINT32 Reserved_0:1; // Reserved\r
	67	UINT32 PF:1; // Parity Flag\r
	68	UINT32 Reserved_1:1; // Reserved\r
69	UINT32 AF:1; // Auxiliary Carry Flag\r
70	UINT32 Reserved_2:1; // Reserved\r
71	UINT32 ZF:1; // Zero Flag\r
72	UINT32 SF:1; // Sign Flag\r
73	UINT32 TF:1; // Trap Flag\r
74	UINT32 IF:1; // Interrupt Enable Flag\r
75	UINT32 DF:1; // Direction Flag\r
76	UINT32 OF:1; // Overflow Flag\r
77	UINT32 IOPL:2; // I/O Privilege Level\r
78	UINT32 NT:1; // Nested Task\r
79	UINT32 Reserved_3:1; // Reserved\r
80	UINT32 RF:1; // Resume Flag\r
81	UINT32 VM:1; // Virtual 8086 Mode\r
82	UINT32 AC:1; // Alignment Check\r
83	UINT32 VIF:1; // Virtual Interrupt Flag\r
84	UINT32 VIP:1; // Virtual Interrupt Pending\r
85	UINT32 ID:1; // ID Flag\r
86	UINT32 Reserved_4:10; // Reserved\r
87	} Bits;\r
88	UINTN UintN;\r
89	} IA32_EFLAGS32;\r
90	\r
91	//\r
92	// Byte packed structure for an FP/SSE/SSE2 context\r
93	//\r
94	typedef struct {\r
95	UINT8 Buffer[512];\r
96	} IA32_FX_BUFFER;\r
97	\r
98	//\r
99	// Structures for the 16-bit real mode thunks\r
100	//\r
101	typedef struct {\r
102	UINT32 Reserved1;\r
103	UINT32 Reserved2;\r
104	UINT32 Reserved3;\r
105	UINT32 Reserved4;\r
106	UINT8 BL;\r
107	UINT8 BH;\r
108	UINT16 Reserved5;\r
109	UINT8 DL;\r
110	UINT8 DH;\r
111	UINT16 Reserved6;\r
112	UINT8 CL;\r
113	UINT8 CH;\r
114	UINT16 Reserved7;\r
115	UINT8 AL;\r
116	UINT8 AH;\r
117	UINT16 Reserved8;\r
118	} IA32_BYTE_REGS;\r
119	\r
120	typedef struct {\r
121	UINT16 DI;\r
122	UINT16 Reserved1;\r
123	UINT16 SI;\r
124	UINT16 Reserved2;\r
125	UINT16 BP;\r
126	UINT16 Reserved3;\r
127	UINT16 SP;\r
128	UINT16 Reserved4;\r
129	UINT16 BX;\r
130	UINT16 Reserved5;\r
131	UINT16 DX;\r
132	UINT16 Reserved6;\r
133	UINT16 CX;\r
134	UINT16 Reserved7;\r
135	UINT16 AX;\r
136	UINT16 Reserved8;\r
137	UINT16 DS;\r
138	UINT16 ES;\r
139	UINT16 FS;\r
140	UINT16 GS;\r
141	IA32_FLAGS16 Flags;\r
142	UINT16 IP;\r
143	UINT16 Reserved10;\r
144	UINT16 CS;\r
145	UINT16 SS;\r
146	} IA32_WORD_REGS;\r
147	\r
148	typedef struct {\r
149	UINT32 EDI;\r
150	UINT32 ESI;\r
151	UINT32 EBP;\r
152	UINT32 ESP;\r
153	UINT32 EBX;\r
154	UINT32 EDX;\r
155	UINT32 ECX;\r
156	UINT32 EAX;\r
157	UINT16 DS;\r
158	UINT16 ES;\r
159	UINT16 FS;\r
160	UINT16 GS;\r
161	IA32_EFLAGS32 EFLAGS;\r
162	UINT32 EIP;\r
163	UINT16 CS;\r
164	UINT16 SS;\r
165	} IA32_DWORD_REGS;\r
166	\r
167	typedef union {\r
168	IA32_DWORD_REGS E;\r
169	IA32_WORD_REGS X;\r
170	IA32_BYTE_REGS H;\r
171	} IA32_REGISTER_SET;\r
172	\r
173	//\r
174	// Byte packed structure for an 16-bit real mode thunks\r
175	//\r
176	typedef struct {\r
177	UINT32 RealModeBuffer;\r
178	UINT32 DefaultStack;\r
179	} THUNK_CONTEXT;\r
180	\r
181	//\r
182	// 16-bit thunking services\r
183	//\r
184	\r
185	UINTN\r
186	EFIAPI\r
187	AsmThunk16GetProperties (\r
188	OUT UINTN *MinimumStackSize OPTIONAL\r
189	)\r
190	/*++\r
191	\r
192	Routine Description:\r
193	\r
194	Returns the properties of this real mode thunk implementation. Currently\r
195	there are 2 properties has been defined, the minimum real mode buffer size\r
196	and the minimum stack size.\r
197	\r
198	Arguments:\r
199	\r
200	MinimumStackSize - The minimum size required for a 16-bit stack.\r
201	\r
202	Returns:\r
203	\r
204	The minimum size of the real mode buffer needed by this thunk implementation\r
205	is returned.\r
206	\r
207	--*/\r
208	;\r
209	\r
210	THUNK_CONTEXT *\r
211	EFIAPI\r
212	AsmThunk16SetProperties (\r
213	OUT THUNK_CONTEXT *ThunkContext,\r
214	IN VOID *RealModeBuffer,\r
215	IN UINTN BufferSize\r
216	)\r
217	/*++\r
218	\r
219	Routine Description:\r
220	\r
221	Tell this real mode thunk implementation the address and size of the real\r
222	mode buffer needed.\r
223	\r
224	Arguments:\r
225	\r
226	ThunkContext - The thunk context whose properties to set.\r
227	RealModeBuffer - The address of the buffer allocated by caller. It should be\r
228	aligned on a 16-byte boundary.\r
229	This buffer must be in identity mapped pages.\r
230	BufferSize - The size of RealModeBuffer. Must be larger than the minimum\r
231	size required as returned by AsmThunk16GetProperties().\r
232	\r
233	Returns:\r
234	\r
235	None\r
236	\r
237	--*/\r
238	;\r
239	\r
240	VOID\r
241	EFIAPI\r
242	AsmThunk16Destroy (\r
243	IN OUT THUNK_CONTEXT *ThunkContext\r
244	)\r
245	/*++\r
246	\r
247	Routine Description:\r
248	\r
249	Reset all internal states to their initial values. The caller should not\r
250	release the real mode buffer until after a call to this function.\r
251	\r
252	Arguments:\r
253	\r
254	ThunkContext - The thunk context to destroy.\r
255	\r
256	Returns:\r
257	\r
258	None\r
259	\r
260	--*/\r
261	;\r
262	\r
263	IA32_REGISTER_SET *\r
264	EFIAPI\r
265	AsmThunk16FarCall86 (\r
266	IN THUNK_CONTEXT *ThunkContext,\r
267	IN OUT IA32_REGISTER_SET *RegisterSet,\r
268	IN UINT32 ThunkFlags\r
269	)\r
270	/*++\r
271	\r
272	Routine Description:\r
273	\r
274	Make a far call to 16-bit code.\r
275	\r
276	NOTE: This function must be called on TPL_HIGH_LEVEL or with interrupts\r
277	disabled because of GDTR and IDTR manipulations.\r
278	This function must be placed in identity mapped pages.\r
279	\r
280	Arguments:\r
281	\r
282	ThunkContext - Thunk context to use.\r
283	RegisterSet - CPU registers would be set to the values contained in this\r
284	structure before making the far call. Then CPU registers are\r
285	copied back to this structure.\r
286	CS:EIP points to the real mode code being called on input.\r
287	SS:ESP points to the real mode stack if THUNK_USER_STACK is\r
288	set on input, otherwise ignored.\r
289	EFlages is ignored on input.\r
290	On output, values of CS, EIP, SS and ESP should be ignored.\r
291	ThunkFlags - 2 flags have currently been defined, THUNK_SAVE_FP_STATE and\r
292	THUNK_USER_STACK.\r
293	THUNK_SAVE_FP_STATE - FPU state would be saved/restored\r
294	before/after calling real mode code.\r
295	THUNK_USER_STACK - The stack specified by SS:ESP would be\r
296	used instead of the default stack.\r
297	\r
298	Returns:\r
299	\r
300	RegisterSet is returned.\r
301	\r
302	--*/\r
303	;\r
304	\r
305	IA32_REGISTER_SET *\r
306	EFIAPI\r
307	AsmThunk16Int86 (\r
308	IN THUNK_CONTEXT *ThunkContext,\r
309	IN UINT8 IntNumber,\r
310	IN OUT IA32_REGISTER_SET *RegisterSet,\r
311	IN UINT32 ThunkFlags\r
312	)\r
313	/*++\r
314	\r
315	Routine Description:\r
316	\r
317	Invoke a 16-bit interrupt handler.\r
318	\r
319	NOTE: This function must be called on TPL_HIGH_LEVEL or with interrupts\r
320	disabled because of GDTR and IDTR manipulations.\r
321	This function must be placed in identity mapped pages.\r
322	\r
323	Arguments:\r
324	\r
325	ThunkContext - Thunk context to use.\r
326	IntNumber - The ordinal of the interrupt handler ranging from 0 to 255.\r
327	RegisterSet - CPU registers would be set to the values contained in this\r
328	structure before making the far call. Then CPU registers are\r
329	copied back to this structure.\r
330	SS:ESP points to the real mode stack if THUNK_USER_STACK is\r
331	set on input, otherwise ignored.\r
332	EFlages is ignored on input.\r
333	On output, values of CS, EIP, SS and ESP should be ignored.\r
334	ThunkFlags - 2 flags have currently been defined, THUNK_SAVE_FP_STATE and\r
335	THUNK_USER_STACK.\r
336	THUNK_SAVE_FP_STATE - FPU state would be saved/restored\r
337	before/after calling real mode code.\r
338	THUNK_USER_STACK - The stack specified by SS:ESP would be\r
339	used instead of the default stack.\r
340	\r
341	Returns:\r
342	\r
343	RegisterSet is returned.\r
344	\r
345	--*/\r
346	;\r
347	\r
348	#endif\r