[mirror_edk2.git] / DuetPkg / BootSector / Mbr.asm

;------------------------------------------------------------------------------\r
;*\r
;*   Copyright 2006 - 2007, Intel Corporation                                                         \r
;*   All rights reserved. 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
;*    Mbr.asm\r
;*\r
;*   Abstract:\r
;*\r
;------------------------------------------------------------------------------\r
\r
    .model  small\r
;   .dosseg\r
    .stack\r
    .486p\r
    .code\r
\r
BLOCK_SIZE                EQU     0200h\r
BLOCK_MASK                EQU     01ffh\r
BLOCK_SHIFT               EQU     9\r
\r
; ****************************************************************************\r
; Code loaded by BIOS at 0x0000:0x7C00\r
; ****************************************************************************\r
\r
        org 0h\r
Start:\r
\r
; ****************************************************************************\r
; Start Print\r
; ****************************************************************************\r
\r
        mov  ax,0b800h\r
        mov  es,ax\r
        mov  ax, 07c0h\r
        mov  ds, ax\r
        lea  si, cs:[StartString]\r
        mov  cx, 10\r
        mov  di, 160\r
        rep  movsw\r
\r
; ****************************************************************************\r
; Print over\r
; ****************************************************************************\r
\r
; ****************************************************************************\r
; Initialize segment registers and copy code at 0x0000:0x7c00 to 0x0000:0x0600\r
; ****************************************************************************\r
        xor   ax, ax                              ; AX = 0x0000\r
        mov   bx, 07c00h                          ; BX = 0x7C00\r
        mov   bp, 0600h                           ; BP = 0x0600\r
        mov   si, OFFSET RelocatedStart           ; SI = Offset(RelocatedStart)\r
        mov   cx, 0200h                           ; CX = 0x0200\r
        sub   cx, si                              ; CS = 0x0200 - Offset(RelocatedStart)\r
        lea   di, [bp+si]                         ; DI = 0x0600 + Offset(RelocatedStart)\r
        lea   si, [bx+si]                         ; BX = 0x7C00 + Offset(RelocatedStart)\r
        mov   ss, ax                              ; SS = 0x0000\r
        mov   sp, bx                              ; SP = 0x7C00\r
        mov   es,ax                               ; ES = 0x0000\r
        mov   ds,ax                               ; DS = 0x0000\r
        push  ax                                  ; PUSH 0x0000\r
        push  di                                  ; PUSH 0x0600 + Offset(RelocatedStart)\r
        cld                                       ; Clear the direction flag\r
        rep   movsb                               ; Copy 0x0200 bytes from 0x7C00 to 0x0600\r
        retf                                      ; JMP 0x0000:0x0600 + Offset(RelocatedStart)\r
\r
; ****************************************************************************\r
; Code relocated to 0x0000:0x0600\r
; ****************************************************************************\r
\r
RelocatedStart:\r
; ****************************************************************************\r
; Get Driver Parameters to 0x0000:0x7BFC\r
; ****************************************************************************\r
\r
        xor   ax,ax                               ; AX = 0\r
        mov   ss,ax                               ; SS = 0\r
        add   ax,1000h\r
        mov   ds,ax\r
\r
        mov   sp,07c00h                           ; SP = 0x7c00\r
        mov   bp,sp                               ; BP = 0x7c00\r
\r
        mov   ah,8                                ; AH = 8 - Get Drive Parameters Function\r
        mov   byte ptr [bp+PhysicalDrive],dl      ; BBS defines that BIOS would pass the booting driver number to the loader through DL\r
        int   13h                                 ; Get Drive Parameters\r
        xor   ax,ax                               ; AX = 0\r
        mov   al,dh                               ; AL = DH\r
        inc   al                                  ; MaxHead = AL + 1\r
        push  ax                                  ; 0000:7bfe = MaxHead\r
        mov   al,cl                               ; AL = CL\r
        and   al,03fh                             ; MaxSector = AL & 0x3f\r
        push  ax                                  ; 0000:7bfc = MaxSector\r
\r
; ****************************************************************************\r
; Read Target DBR from hard disk to 0x0000:0x7C00\r
; ****************************************************************************\r
\r
        xor   ax, ax\r
        mov   al, byte ptr [bp+MbrPartitionIndicator]  ; AX = MbrPartitionIndex\r
        cmp   al, 0ffh                                 ; 0xFF means do legacy MBR boot\r
        jnz   EfiDbr\r
LegacyMbr:\r
        mov   eax, 00000600h                      ; Assume LegacyMBR is backuped in Sector 6\r
        jmp   StartReadTo7C00                     ; EAX = Header/Sector/Tracker/Zero\r
\r
EfiDbr:\r
        cmp   al, 4                               ; MbrPartitionIndex should < 4\r
        jae   BadDbr\r
        shl   ax, 4                               ; AX  = MBREntrySize * Index\r
        add   ax, 1beh                            ; AX  = MBREntryOffset\r
        mov   di, ax                              ; DI  = MBREntryOffset\r
\r
        ; Here we don't use the C/H/S information provided by Partition table\r
        ;  but calculate C/H/S from LBA ourselves\r
        ;       Ci: Cylinder number\r
        ;       Hi: Header number\r
        ;       Si: Sector number\r
        mov   eax, dword ptr es:[bp + di + 8]     ; Start LBA\r
        mov   edx, eax\r
        shr   edx, 16                             ; DX:AX = Start LBA\r
                                                  ;       = Ci * (H * S) + Hi * S + (Si - 1)\r
\r
        ; Calculate C/H/S according to LBA\r
        mov   bp, 7bfah\r
        div   word ptr [bp+2]                     ; AX = Hi + H*Ci\r
                                                  ; DX = Si - 1\r
        inc   dx                                  ; DX = Si\r
        push  dx                                  ; 0000:7bfa = Si  <----\r
        xor   dx, dx                              ; DX:AX = Hi + H*Ci\r
        div   word ptr [bp+4]                     ; AX = Ci         <----\r
                                                  ; DX = Hi         <----\r
\r
StartReadTo7C00:\r
\r
        mov   cl, byte ptr [bp]                   ; Si\r
        mov   ch, al                              ; Ci[0-7]\r
        or    cl, ah                              ; Ci[8,9]\r
        mov   bx, 7c00h                           ; ES:BX = 0000:7C00h\r
        mov   ah, 2h                              ; Function 02h\r
        mov   al, 1                               ; 1 Sector\r
        mov   dh, dl                              ; Hi\r
        mov   bp, 0600h\r
        mov   dl, byte ptr [bp + PhysicalDrive]   ; Drive number\r
        int   13h\r
        jc    BadDbr\r
\r
\r
\r
; ****************************************************************************\r
; Transfer control to BootSector - Jump to 0x0000:0x7C00\r
; ****************************************************************************\r
        xor   ax, ax\r
        push  ax                                  ; PUSH 0x0000 - Segment\r
        mov   di, 07c00h\r
        push  di                                  ; PUSH 0x7C00 - Offset\r
        retf                                      ; JMP 0x0000:0x7C00\r
\r
; ****************************************************************************\r
; ERROR Condition:\r
; ****************************************************************************\r
\r
BadDbr:\r
    push ax\r
    mov  ax, 0b800h\r
    mov  es, ax\r
    mov  ax, 060h\r
    mov  ds, ax\r
    lea  si, cs:[ErrorString]\r
    mov  di, 320\r
    pop  ax\r
    call A2C\r
    mov  [si+16], ah\r
    mov  [si+18], al\r
    mov  cx, 10\r
    rep  movsw\r
Halt:\r
    jmp   Halt\r
\r
StartString:\r
    db 'M', 0ch, 'B', 0ch, 'R', 0ch, ' ', 0ch, 'S', 0ch, 't', 0ch, 'a', 0ch, 'r', 0ch, 't', 0ch, '!', 0ch\r
ErrorString:\r
    db 'M', 0ch, 'B', 0ch, 'R', 0ch, ' ', 0ch, 'E', 0ch, 'r', 0ch, 'r', 0ch, ':', 0ch, '?', 0ch, '?', 0ch\r
\r
; ****************************************************************************\r
; A2C - convert Ascii code stored in AH to character stored in AX\r
; ****************************************************************************\r
A2C:\r
    mov  al, ah\r
    shr  ah, 4\r
    and  al, 0Fh\r
    add  ah, '0'\r
    add  al, '0'\r
\r
    cmp  ah, '9'\r
    jle  @f\r
    add  ah, 7\r
@@:\r
\r
    cmp al, '9'\r
    jle @f\r
    add al, 7\r
@@:\r
    ret\r
\r
\r
; ****************************************************************************\r
; PhysicalDrive - Used to indicate which disk to be boot\r
;                 Can be patched by tool\r
; ****************************************************************************\r
    org   01B6h\r
PhysicalDrive         db  80h\r
\r
; ****************************************************************************\r
; MbrPartitionIndicator - Used to indicate which MBR partition to be boot\r
;                         Can be patched by tool\r
;                         OxFF means boot to legacy MBR. (LBA OFFSET 6)\r
; ****************************************************************************\r
    org   01B7h\r
MbrPartitionIndicator db 0\r
\r
; ****************************************************************************\r
; Unique MBR signature\r
; ****************************************************************************\r
    org   01B8h\r
    db 'DUET'\r
\r
; ****************************************************************************\r
; Unknown\r
; ****************************************************************************\r
    org   01BCh\r
    dw 0\r
\r
; ****************************************************************************\r
; MBR Entry - To be patched\r
; ****************************************************************************\r
    org   01BEh\r
    dd 0, 0, 0, 0\r
    org   01CEh\r
    dd 0, 0, 0, 0\r
    org   01DEh\r
    dd 0, 0, 0, 0\r
    org   01EEh\r
    dd 0, 0, 0, 0\r
\r
; ****************************************************************************\r
; Sector Signature\r
; ****************************************************************************\r
\r
  org 01FEh\r
SectorSignature:\r
  dw        0aa55h      ; Boot Sector Signature\r
\r
  end\r
\r
Commit	Line	Data
c69dd9df	1	;------------------------------------------------------------------------------\r
	2	;*\r
	3	;* Copyright 2006 - 2007, Intel Corporation \r
	4	;* All rights reserved. This program and the accompanying materials\r
	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	;* Mbr.asm\r
	13	;*\r
	14	;* Abstract:\r
	15	;*\r
	16	;------------------------------------------------------------------------------\r
	17	\r
	18	.model small\r
	19	; .dosseg\r
	20	.stack\r
	21	.486p\r
	22	.code\r
	23	\r
	24	BLOCK_SIZE EQU 0200h\r
	25	BLOCK_MASK EQU 01ffh\r
	26	BLOCK_SHIFT EQU 9\r
	27	\r
	28	; ****************************************************************************\r
	29	; Code loaded by BIOS at 0x0000:0x7C00\r
	30	; ****************************************************************************\r
	31	\r
	32	org 0h\r
	33	Start:\r
	34	\r
	35	; ****************************************************************************\r
	36	; Start Print\r
	37	; ****************************************************************************\r
	38	\r
	39	mov ax,0b800h\r
	40	mov es,ax\r
	41	mov ax, 07c0h\r
	42	mov ds, ax\r
	43	lea si, cs:[StartString]\r
	44	mov cx, 10\r
	45	mov di, 160\r
	46	rep movsw\r
	47	\r
	48	; ****************************************************************************\r
	49	; Print over\r
	50	; ****************************************************************************\r
	51	\r
	52	; ****************************************************************************\r
	53	; Initialize segment registers and copy code at 0x0000:0x7c00 to 0x0000:0x0600\r
	54	; ****************************************************************************\r
	55	xor ax, ax ; AX = 0x0000\r
	56	mov bx, 07c00h ; BX = 0x7C00\r
	57	mov bp, 0600h ; BP = 0x0600\r
	58	mov si, OFFSET RelocatedStart ; SI = Offset(RelocatedStart)\r
	59	mov cx, 0200h ; CX = 0x0200\r
	60	sub cx, si ; CS = 0x0200 - Offset(RelocatedStart)\r
	61	lea di, [bp+si] ; DI = 0x0600 + Offset(RelocatedStart)\r
	62	lea si, [bx+si] ; BX = 0x7C00 + Offset(RelocatedStart)\r
	63	mov ss, ax ; SS = 0x0000\r
	64	mov sp, bx ; SP = 0x7C00\r
65	mov es,ax ; ES = 0x0000\r
66	mov ds,ax ; DS = 0x0000\r
67	push ax ; PUSH 0x0000\r
68	push di ; PUSH 0x0600 + Offset(RelocatedStart)\r
69	cld ; Clear the direction flag\r
70	rep movsb ; Copy 0x0200 bytes from 0x7C00 to 0x0600\r
71	retf ; JMP 0x0000:0x0600 + Offset(RelocatedStart)\r
72	\r
73	; ****************************************************************************\r
74	; Code relocated to 0x0000:0x0600\r
75	; ****************************************************************************\r
76	\r
77	RelocatedStart:\r
78	; ****************************************************************************\r
79	; Get Driver Parameters to 0x0000:0x7BFC\r
80	; ****************************************************************************\r
81	\r
82	xor ax,ax ; AX = 0\r
83	mov ss,ax ; SS = 0\r
84	add ax,1000h\r
85	mov ds,ax\r
86	\r
87	mov sp,07c00h ; SP = 0x7c00\r
88	mov bp,sp ; BP = 0x7c00\r
89	\r
90	mov ah,8 ; AH = 8 - Get Drive Parameters Function\r
91	mov byte ptr [bp+PhysicalDrive],dl ; BBS defines that BIOS would pass the booting driver number to the loader through DL\r
92	int 13h ; Get Drive Parameters\r
93	xor ax,ax ; AX = 0\r
94	mov al,dh ; AL = DH\r
95	inc al ; MaxHead = AL + 1\r
96	push ax ; 0000:7bfe = MaxHead\r
97	mov al,cl ; AL = CL\r
98	and al,03fh ; MaxSector = AL & 0x3f\r
99	push ax ; 0000:7bfc = MaxSector\r
100	\r
101	; ****************************************************************************\r
102	; Read Target DBR from hard disk to 0x0000:0x7C00\r
103	; ****************************************************************************\r
104	\r
105	xor ax, ax\r
106	mov al, byte ptr [bp+MbrPartitionIndicator] ; AX = MbrPartitionIndex\r
107	cmp al, 0ffh ; 0xFF means do legacy MBR boot\r
108	jnz EfiDbr\r
109	LegacyMbr:\r
110	mov eax, 00000600h ; Assume LegacyMBR is backuped in Sector 6\r
111	jmp StartReadTo7C00 ; EAX = Header/Sector/Tracker/Zero\r
112	\r
113	EfiDbr:\r
114	cmp al, 4 ; MbrPartitionIndex should < 4\r
115	jae BadDbr\r
116	shl ax, 4 ; AX = MBREntrySize * Index\r
117	add ax, 1beh ; AX = MBREntryOffset\r
118	mov di, ax ; DI = MBREntryOffset\r
119	\r
120	; Here we don't use the C/H/S information provided by Partition table\r
121	; but calculate C/H/S from LBA ourselves\r
122	; Ci: Cylinder number\r
123	; Hi: Header number\r
124	; Si: Sector number\r
125	mov eax, dword ptr es:[bp + di + 8] ; Start LBA\r
126	mov edx, eax\r
127	shr edx, 16 ; DX:AX = Start LBA\r
128	; = Ci * (H * S) + Hi * S + (Si - 1)\r
129	\r
130	; Calculate C/H/S according to LBA\r
131	mov bp, 7bfah\r
132	div word ptr [bp+2] ; AX = Hi + H*Ci\r
133	; DX = Si - 1\r
134	inc dx ; DX = Si\r
135	push dx ; 0000:7bfa = Si <----\r
136	xor dx, dx ; DX:AX = Hi + H*Ci\r
137	div word ptr [bp+4] ; AX = Ci <----\r
138	; DX = Hi <----\r
139	\r
140	StartReadTo7C00:\r
141	\r
142	mov cl, byte ptr [bp] ; Si\r
143	mov ch, al ; Ci[0-7]\r
144	or cl, ah ; Ci[8,9]\r
145	mov bx, 7c00h ; ES:BX = 0000:7C00h\r
146	mov ah, 2h ; Function 02h\r
147	mov al, 1 ; 1 Sector\r
148	mov dh, dl ; Hi\r
149	mov bp, 0600h\r
150	mov dl, byte ptr [bp + PhysicalDrive] ; Drive number\r
151	int 13h\r
152	jc BadDbr\r
153	\r
154	\r
155	\r
156	; ****************************************************************************\r
157	; Transfer control to BootSector - Jump to 0x0000:0x7C00\r
158	; ****************************************************************************\r
159	xor ax, ax\r
160	push ax ; PUSH 0x0000 - Segment\r
161	mov di, 07c00h\r
162	push di ; PUSH 0x7C00 - Offset\r
163	retf ; JMP 0x0000:0x7C00\r
164	\r
165	; ****************************************************************************\r
166	; ERROR Condition:\r
167	; ****************************************************************************\r
168	\r
169	BadDbr:\r
170	push ax\r
171	mov ax, 0b800h\r
172	mov es, ax\r
173	mov ax, 060h\r
174	mov ds, ax\r
175	lea si, cs:[ErrorString]\r
176	mov di, 320\r
177	pop ax\r
178	call A2C\r
179	mov [si+16], ah\r
180	mov [si+18], al\r
181	mov cx, 10\r
182	rep movsw\r
183	Halt:\r
184	jmp Halt\r
185	\r
186	StartString:\r
187	db 'M', 0ch, 'B', 0ch, 'R', 0ch, ' ', 0ch, 'S', 0ch, 't', 0ch, 'a', 0ch, 'r', 0ch, 't', 0ch, '!', 0ch\r
188	ErrorString:\r
189	db 'M', 0ch, 'B', 0ch, 'R', 0ch, ' ', 0ch, 'E', 0ch, 'r', 0ch, 'r', 0ch, ':', 0ch, '?', 0ch, '?', 0ch\r
190	\r
191	; ****************************************************************************\r
192	; A2C - convert Ascii code stored in AH to character stored in AX\r
193	; ****************************************************************************\r
194	A2C:\r
195	mov al, ah\r
196	shr ah, 4\r
197	and al, 0Fh\r
198	add ah, '0'\r
199	add al, '0'\r
200	\r
201	cmp ah, '9'\r
202	jle @f\r
203	add ah, 7\r
204	@@:\r
205	\r
206	cmp al, '9'\r
207	jle @f\r
208	add al, 7\r
209	@@:\r
210	ret\r
211	\r
212	\r
213	; ****************************************************************************\r
214	; PhysicalDrive - Used to indicate which disk to be boot\r
215	; Can be patched by tool\r
216	; ****************************************************************************\r
217	org 01B6h\r
218	PhysicalDrive db 80h\r
219	\r
220	; ****************************************************************************\r
221	; MbrPartitionIndicator - Used to indicate which MBR partition to be boot\r
222	; Can be patched by tool\r
223	; OxFF means boot to legacy MBR. (LBA OFFSET 6)\r
224	; ****************************************************************************\r
225	org 01B7h\r
226	MbrPartitionIndicator db 0\r
227	\r
228	; ****************************************************************************\r
229	; Unique MBR signature\r
230	; ****************************************************************************\r
231	org 01B8h\r
232	db 'DUET'\r
233	\r
234	; ****************************************************************************\r
235	; Unknown\r
236	; ****************************************************************************\r
237	org 01BCh\r
238	dw 0\r
239	\r
240	; ****************************************************************************\r
241	; MBR Entry - To be patched\r
242	; ****************************************************************************\r
243	org 01BEh\r
244	dd 0, 0, 0, 0\r
245	org 01CEh\r
246	dd 0, 0, 0, 0\r
247	org 01DEh\r
248	dd 0, 0, 0, 0\r
249	org 01EEh\r
250	dd 0, 0, 0, 0\r
251	\r
252	; ****************************************************************************\r
253	; Sector Signature\r
254	; ****************************************************************************\r
255	\r
256	org 01FEh\r
257	SectorSignature:\r
258	dw 0aa55h ; Boot Sector Signature\r
259	\r
260	end\r
261	\r