[mirror_edk2.git] / EdkCompatibilityPkg / Foundation / Library / EdkIIGlueLib / Library / BaseLib / Ia32 / Thunk16.asm

; Copyright (c) 2004 - 2010, 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
;   Thunk.asm\r
;\r
; Abstract:\r
;\r
;   Real mode thunk\r
;\r
;------------------------------------------------------------------------------\r
\r
    .686p\r
    .model  flat,C\r
\r
EXTERNDEF   C   m16Start:BYTE\r
EXTERNDEF   C   m16Size:WORD\r
EXTERNDEF   C   mThunk16Attr:WORD\r
EXTERNDEF   C   m16Gdt:WORD\r
EXTERNDEF   C   m16GdtrBase:WORD\r
EXTERNDEF   C   mTransition:WORD\r
\r
THUNK_ATTRIBUTE_BIG_REAL_MODE               EQU 1\r
THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15     EQU 2\r
THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL   EQU 4\r
\r
;\r
; Here is the layout of the real mode stack. _ToUserCode() is responsible for\r
; loading all these registers from real mode stack.\r
;\r
IA32_REGS   STRUC   4t\r
_EDI        DD      ?\r
_ESI        DD      ?\r
_EBP        DD      ?\r
_ESP        DD      ?\r
_EBX        DD      ?\r
_EDX        DD      ?\r
_ECX        DD      ?\r
_EAX        DD      ?\r
_DS         DW      ?\r
_ES         DW      ?\r
_FS         DW      ?\r
_GS         DW      ?\r
_EFLAGS     DD      ?\r
_EIP        DD      ?\r
_CS         DW      ?\r
_SS         DW      ?\r
IA32_REGS   ENDS\r
\r
    .const\r
\r
;\r
; These are global constant to convey information to C code.\r
;\r
m16Size         DW      InternalAsmThunk16 - m16Start\r
mThunk16Attr    DW      _ThunkAttr - m16Start\r
m16Gdt          DW      _NullSegDesc - m16Start\r
m16GdtrBase     DW      _16GdtrBase - m16Start\r
mTransition     DW      _EntryPoint - m16Start\r
\r
    .code\r
\r
m16Start    LABEL   BYTE\r
\r
SavedGdt    LABEL   FWORD\r
            DW      ?\r
            DD      ?\r
;------------------------------------------------------------------------------\r
; _BackFromUserCode() takes control in real mode after 'retf' has been executed\r
; by user code. It will be shadowed to somewhere in memory below 1MB.\r
;------------------------------------------------------------------------------\r
_BackFromUserCode   PROC\r
    ;\r
    ; The order of saved registers on the stack matches the order they appears\r
    ; in IA32_REGS structure. This facilitates wrapper function to extract them\r
    ; into that structure.\r
    ;\r
    push    ss\r
    push    cs\r
    DB      66h\r
    call    @Base                       ; push eip\r
@Base:\r
    pushf                               ; pushfd actually\r
    cli                                 ; disable interrupts\r
    push    gs\r
    push    fs\r
    push    es\r
    push    ds\r
    pushaw                              ; pushad actually\r
    DB      66h, 0bah                   ; mov edx, imm32\r
_ThunkAttr  DD      ?\r
    test    dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15\r
    jz      @1\r
    mov     eax, 15cd2401h              ; mov ax, 2401h & int 15h\r
    cli                                 ; disable interrupts\r
    jnc     @2\r
@1:\r
    test    dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL\r
    jz      @2\r
    in      al, 92h\r
    or      al, 2\r
    out     92h, al                     ; deactivate A20M#\r
@2:\r
    mov     ax, ss\r
    DB      67h\r
    lea     bp, [esp + sizeof (IA32_REGS)]\r
    ;\r
    ; esi's in the following 2 instructions are indeed bp in 16-bit code. Fact\r
    ; is "esi" in 32-bit addressing mode has the same encoding of "bp" in 16-\r
    ; bit addressing mode.\r
    ;\r
    mov     word ptr (IA32_REGS ptr [esi - sizeof (IA32_REGS)])._ESP, bp\r
    mov     ebx, (IA32_REGS ptr [esi - sizeof (IA32_REGS)])._EIP\r
    shl     ax, 4                       ; shl eax, 4\r
    add     bp, ax                      ; add ebp, eax\r
    DB      66h, 0b8h                   ; mov eax, imm32\r
SavedCr4    DD      ?\r
    mov     cr4, eax\r
    DB      66h\r
    lgdt    fword ptr cs:[edi + (SavedGdt - @Base)]\r
    DB      66h, 0b8h                   ; mov eax, imm32\r
SavedCr0    DD      ?\r
    mov     cr0, eax\r
    DB      0b8h                        ; mov ax, imm16\r
SavedSs     DW      ?\r
    mov     ss, eax\r
    DB      66h, 0bch                   ; mov esp, imm32\r
SavedEsp    DD      ?\r
    DB      66h\r
    retf                                ; return to protected mode\r
_BackFromUserCode   ENDP\r
\r
_EntryPoint DD      _ToUserCode - m16Start\r
            DW      8h\r
_16Idtr     FWORD   (1 SHL 10) - 1\r
_16Gdtr     LABEL   FWORD\r
            DW      GdtEnd - _NullSegDesc - 1\r
_16GdtrBase DD      _NullSegDesc\r
\r
;------------------------------------------------------------------------------\r
; _ToUserCode() takes control in real mode before passing control to user code.\r
; It will be shadowed to somewhere in memory below 1MB.\r
;------------------------------------------------------------------------------\r
_ToUserCode PROC\r
    mov     edx, ss\r
    mov     ss, ecx                     ; set new segment selectors\r
    mov     ds, ecx\r
    mov     es, ecx\r
    mov     fs, ecx\r
    mov     gs, ecx\r
    mov     cr0, eax\r
    mov     cr4, ebp                    ; real mode starts at next instruction\r
    mov     ss, esi                     ; set up 16-bit stack segment\r
    xchg    sp, bx                      ; set up 16-bit stack pointer\r
    DB      66h\r
    call    @Base                       ; push eip\r
@Base:\r
    pop     bp                          ; ebp <- address of @Base\r
    DB      67h                         ; address size override\r
    push    [esp + sizeof (IA32_REGS) + 2]\r
    lea     eax, [esi + (@RealMode - @Base)]\r
    push    eax\r
    retf\r
@RealMode:\r
    mov     cs:[esi + (SavedSs - @Base)], edx\r
    mov     cs:[esi + (SavedEsp - @Base)], bx\r
    DB      66h\r
    lidt    fword ptr cs:[esi + (_16Idtr - @Base)]\r
    popaw                               ; popad actually\r
    pop     ds\r
    pop     es\r
    pop     fs\r
    pop     gs\r
    popf                                ; popfd\r
    DB      66h                         ; Use 32-bit addressing for "retf" below\r
    retf                                ; transfer control to user code\r
_ToUserCode ENDP\r
\r
_NullSegDesc    DQ      0\r
_16CsDesc       LABEL   QWORD\r
                DW      -1\r
                DW      0\r
                DB      0\r
                DB      9bh\r
                DB      8fh             ; 16-bit segment, 4GB limit\r
                DB      0\r
_16DsDesc       LABEL   QWORD\r
                DW      -1\r
                DW      0\r
                DB      0\r
                DB      93h\r
                DB      8fh             ; 16-bit segment, 4GB limit\r
                DB      0\r
GdtEnd          LABEL   QWORD\r
\r
;------------------------------------------------------------------------------\r
; IA32_REGISTER_SET *\r
; EFIAPI\r
; InternalAsmThunk16 (\r
;   IN      IA32_REGISTER_SET         *RegisterSet,\r
;   IN OUT  VOID                      *Transition\r
;   );\r
;------------------------------------------------------------------------------\r
InternalAsmThunk16  PROC    USES    ebp ebx esi edi ds  es  fs  gs\r
    mov     esi, [esp + 36]             ; esi <- RegSet, the 1st parameter\r
    movzx   edx, (IA32_REGS ptr [esi])._SS\r
    mov     edi, (IA32_REGS ptr [esi])._ESP\r
    add     edi, - (sizeof (IA32_REGS) + 4) ; reserve stack space\r
    mov     ebx, edi                    ; ebx <- stack offset\r
    imul    eax, edx, 16                ; eax <- edx * 16\r
    push    sizeof (IA32_REGS) / 4\r
    add     edi, eax                    ; edi <- linear address of 16-bit stack\r
    pop     ecx\r
    rep     movsd                       ; copy RegSet\r
    mov     eax, [esp + 40]             ; eax <- address of transition code\r
    mov     esi, edx                    ; esi <- 16-bit stack segment\r
    lea     edx, [eax + (SavedCr0 - m16Start)]\r
    mov     ecx, eax\r
    and     ecx, 0fh\r
    shl     eax, 12\r
    lea     ecx, [ecx + (_BackFromUserCode - m16Start)]\r
    mov     ax, cx\r
    stosd                               ; [edi] <- return address of user code\r
    sgdt    fword ptr [edx + (SavedGdt - SavedCr0)]\r
    sidt    fword ptr [esp + 36]        ; save IDT stack in argument space\r
    mov     eax, cr0\r
    mov     [edx], eax                  ; save CR0 in SavedCr0\r
    and     eax, 7ffffffeh              ; clear PE, PG bits\r
    mov     ebp, cr4\r
    mov     [edx + (SavedCr4 - SavedCr0)], ebp\r
    and     ebp, 300h                   ; clear all but PCE and OSFXSR bits\r
    push    10h\r
    pop     ecx                         ; ecx <- selector for data segments\r
    lgdt    fword ptr [edx + (_16Gdtr - SavedCr0)]\r
    pushfd                              ; Save df/if indeed\r
    call    fword ptr [edx + (_EntryPoint - SavedCr0)]\r
    popfd\r
    lidt    fword ptr [esp + 36]        ; restore protected mode IDTR\r
    lea     eax, [ebp - sizeof (IA32_REGS)] ; eax <- the address of IA32_REGS\r
    ret\r
InternalAsmThunk16  ENDP\r
\r
    END\r
Commit	Line	Data
be3b67bc	1	; Copyright (c) 2004 - 2010, Intel Corporation. All rights reserved.<BR>\r
2c7e5c2f	2	; This program and the accompanying materials \r
3eb9473e	3	; are licensed and made available under the terms and conditions of the BSD License \r
	4	; which accompanies this distribution. The full text of the license may be found at \r
	5	; http://opensource.org/licenses/bsd-license.php \r
	6	; \r
	7	; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, \r
	8	; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. \r
	9	;\r
	10	; Module Name:\r
	11	;\r
	12	; Thunk.asm\r
	13	;\r
	14	; Abstract:\r
	15	;\r
	16	; Real mode thunk\r
	17	;\r
	18	;------------------------------------------------------------------------------\r
	19	\r
	20	.686p\r
	21	.model flat,C\r
	22	\r
	23	EXTERNDEF C m16Start:BYTE\r
	24	EXTERNDEF C m16Size:WORD\r
	25	EXTERNDEF C mThunk16Attr:WORD\r
	26	EXTERNDEF C m16Gdt:WORD\r
	27	EXTERNDEF C m16GdtrBase:WORD\r
	28	EXTERNDEF C mTransition:WORD\r
	29	\r
	30	THUNK_ATTRIBUTE_BIG_REAL_MODE EQU 1\r
	31	THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15 EQU 2\r
	32	THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL EQU 4\r
	33	\r
	34	;\r
	35	; Here is the layout of the real mode stack. _ToUserCode() is responsible for\r
	36	; loading all these registers from real mode stack.\r
	37	;\r
	38	IA32_REGS STRUC 4t\r
	39	_EDI DD ?\r
	40	_ESI DD ?\r
	41	_EBP DD ?\r
	42	_ESP DD ?\r
	43	_EBX DD ?\r
	44	_EDX DD ?\r
	45	_ECX DD ?\r
	46	_EAX DD ?\r
	47	_DS DW ?\r
	48	_ES DW ?\r
	49	_FS DW ?\r
	50	_GS DW ?\r
	51	_EFLAGS DD ?\r
	52	_EIP DD ?\r
	53	_CS DW ?\r
	54	_SS DW ?\r
	55	IA32_REGS ENDS\r
	56	\r
	57	.const\r
	58	\r
	59	;\r
	60	; These are global constant to convey information to C code.\r
	61	;\r
	62	m16Size DW InternalAsmThunk16 - m16Start\r
	63	mThunk16Attr DW _ThunkAttr - m16Start\r
	64	m16Gdt DW _NullSegDesc - m16Start\r
	65	m16GdtrBase DW _16GdtrBase - m16Start\r
	66	mTransition DW _EntryPoint - m16Start\r
67	\r
68	.code\r
69	\r
70	m16Start LABEL BYTE\r
71	\r
72	SavedGdt LABEL FWORD\r
73	DW ?\r
74	DD ?\r
75	;------------------------------------------------------------------------------\r
76	; _BackFromUserCode() takes control in real mode after 'retf' has been executed\r
77	; by user code. It will be shadowed to somewhere in memory below 1MB.\r
78	;------------------------------------------------------------------------------\r
79	_BackFromUserCode PROC\r
80	;\r
81	; The order of saved registers on the stack matches the order they appears\r
82	; in IA32_REGS structure. This facilitates wrapper function to extract them\r
83	; into that structure.\r
84	;\r
85	push ss\r
86	push cs\r
87	DB 66h\r
88	call @Base ; push eip\r
89	@Base:\r
90	pushf ; pushfd actually\r
91	cli ; disable interrupts\r
92	push gs\r
93	push fs\r
94	push es\r
95	push ds\r
96	pushaw ; pushad actually\r
97	DB 66h, 0bah ; mov edx, imm32\r
98	_ThunkAttr DD ?\r
99	test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15\r
100	jz @1\r
101	mov eax, 15cd2401h ; mov ax, 2401h & int 15h\r
102	cli ; disable interrupts\r
103	jnc @2\r
104	@1:\r
105	test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL\r
106	jz @2\r
107	in al, 92h\r
108	or al, 2\r
109	out 92h, al ; deactivate A20M#\r
110	@2:\r
be3b67bc	111	mov ax, ss\r
3eb9473e	112	DB 67h\r
	113	lea bp, [esp + sizeof (IA32_REGS)]\r
	114	;\r
	115	; esi's in the following 2 instructions are indeed bp in 16-bit code. Fact\r
	116	; is "esi" in 32-bit addressing mode has the same encoding of "bp" in 16-\r
	117	; bit addressing mode.\r
	118	;\r
	119	mov word ptr (IA32_REGS ptr [esi - sizeof (IA32_REGS)])._ESP, bp\r
	120	mov ebx, (IA32_REGS ptr [esi - sizeof (IA32_REGS)])._EIP\r
	121	shl ax, 4 ; shl eax, 4\r
	122	add bp, ax ; add ebp, eax\r
	123	DB 66h, 0b8h ; mov eax, imm32\r
	124	SavedCr4 DD ?\r
	125	mov cr4, eax\r
	126	DB 66h\r
	127	lgdt fword ptr cs:[edi + (SavedGdt - @Base)]\r
	128	DB 66h, 0b8h ; mov eax, imm32\r
	129	SavedCr0 DD ?\r
	130	mov cr0, eax\r
	131	DB 0b8h ; mov ax, imm16\r
	132	SavedSs DW ?\r
	133	mov ss, eax\r
	134	DB 66h, 0bch ; mov esp, imm32\r
	135	SavedEsp DD ?\r
	136	DB 66h\r
	137	retf ; return to protected mode\r
	138	_BackFromUserCode ENDP\r
	139	\r
	140	_EntryPoint DD _ToUserCode - m16Start\r
	141	DW 8h\r
	142	_16Idtr FWORD (1 SHL 10) - 1\r
	143	_16Gdtr LABEL FWORD\r
	144	DW GdtEnd - _NullSegDesc - 1\r
	145	_16GdtrBase DD _NullSegDesc\r
	146	\r
	147	;------------------------------------------------------------------------------\r
	148	; _ToUserCode() takes control in real mode before passing control to user code.\r
	149	; It will be shadowed to somewhere in memory below 1MB.\r
	150	;------------------------------------------------------------------------------\r
	151	_ToUserCode PROC\r
	152	mov edx, ss\r
	153	mov ss, ecx ; set new segment selectors\r
	154	mov ds, ecx\r
	155	mov es, ecx\r
	156	mov fs, ecx\r
	157	mov gs, ecx\r
	158	mov cr0, eax\r
	159	mov cr4, ebp ; real mode starts at next instruction\r
	160	mov ss, esi ; set up 16-bit stack segment\r
	161	xchg sp, bx ; set up 16-bit stack pointer\r
	162	DB 66h\r
	163	call @Base ; push eip\r
	164	@Base:\r
	165	pop bp ; ebp <- address of @Base\r
	166	DB 67h ; address size override\r
	167	push [esp + sizeof (IA32_REGS) + 2]\r
	168	lea eax, [esi + (@RealMode - @Base)]\r
	169	push eax\r
	170	retf\r
	171	@RealMode:\r
	172	mov cs:[esi + (SavedSs - @Base)], edx\r
	173	mov cs:[esi + (SavedEsp - @Base)], bx\r
	174	DB 66h\r
	175	lidt fword ptr cs:[esi + (_16Idtr - @Base)]\r
176	popaw ; popad actually\r
177	pop ds\r
178	pop es\r
179	pop fs\r
180	pop gs\r
181	popf ; popfd\r
182	DB 66h ; Use 32-bit addressing for "retf" below\r
183	retf ; transfer control to user code\r
184	_ToUserCode ENDP\r
185	\r
186	_NullSegDesc DQ 0\r
187	_16CsDesc LABEL QWORD\r
188	DW -1\r
189	DW 0\r
190	DB 0\r
191	DB 9bh\r
192	DB 8fh ; 16-bit segment, 4GB limit\r
193	DB 0\r
194	_16DsDesc LABEL QWORD\r
195	DW -1\r
196	DW 0\r
197	DB 0\r
198	DB 93h\r
199	DB 8fh ; 16-bit segment, 4GB limit\r
200	DB 0\r
201	GdtEnd LABEL QWORD\r
202	\r
203	;------------------------------------------------------------------------------\r
204	; IA32_REGISTER_SET *\r
205	; EFIAPI\r
206	; InternalAsmThunk16 (\r
207	; IN IA32_REGISTER_SET *RegisterSet,\r
208	; IN OUT VOID *Transition\r
209	; );\r
210	;------------------------------------------------------------------------------\r
211	InternalAsmThunk16 PROC USES ebp ebx esi edi ds es fs gs\r
212	mov esi, [esp + 36] ; esi <- RegSet, the 1st parameter\r
213	movzx edx, (IA32_REGS ptr [esi])._SS\r
214	mov edi, (IA32_REGS ptr [esi])._ESP\r
215	add edi, - (sizeof (IA32_REGS) + 4) ; reserve stack space\r
216	mov ebx, edi ; ebx <- stack offset\r
217	imul eax, edx, 16 ; eax <- edx * 16\r
218	push sizeof (IA32_REGS) / 4\r
219	add edi, eax ; edi <- linear address of 16-bit stack\r
220	pop ecx\r
221	rep movsd ; copy RegSet\r
222	mov eax, [esp + 40] ; eax <- address of transition code\r
223	mov esi, edx ; esi <- 16-bit stack segment\r
224	lea edx, [eax + (SavedCr0 - m16Start)]\r
225	mov ecx, eax\r
226	and ecx, 0fh\r
227	shl eax, 12\r
228	lea ecx, [ecx + (_BackFromUserCode - m16Start)]\r
229	mov ax, cx\r
230	stosd ; [edi] <- return address of user code\r
231	sgdt fword ptr [edx + (SavedGdt - SavedCr0)]\r
232	sidt fword ptr [esp + 36] ; save IDT stack in argument space\r
233	mov eax, cr0\r
234	mov [edx], eax ; save CR0 in SavedCr0\r
235	and eax, 7ffffffeh ; clear PE, PG bits\r
236	mov ebp, cr4\r
237	mov [edx + (SavedCr4 - SavedCr0)], ebp\r
238	and ebp, 300h ; clear all but PCE and OSFXSR bits\r
239	push 10h\r
240	pop ecx ; ecx <- selector for data segments\r
241	lgdt fword ptr [edx + (_16Gdtr - SavedCr0)]\r
242	pushfd ; Save df/if indeed\r
243	call fword ptr [edx + (_EntryPoint - SavedCr0)]\r
244	popfd\r
245	lidt fword ptr [esp + 36] ; restore protected mode IDTR\r
246	lea eax, [ebp - sizeof (IA32_REGS)] ; eax <- the address of IA32_REGS\r
247	ret\r
248	InternalAsmThunk16 ENDP\r
249	\r
250	END\r