source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/AtaGeometry.asm@ 422

Last change on this file since 422 was 422, checked in by aitotat@…, 13 years ago

Changes to XTIDE Universal BIOS:

  • Modified ROMVARS for user defined CHS translation mode.
  • Base DPT struct now includes initialization error flags again.
File size: 11.3 KB
Line 
1; Project name : XTIDE Universal BIOS
2; Description : Functions for generating L-CHS parameters for
3; drives with more than 1024 cylinders.
4;
5; These algorithms are taken from: http://www.mossywell.com/boot-sequence
6; Take a look at it for more detailed information.
7;
8; This file is shared with BIOS Drive Information Tool.
9
10;
11; XTIDE Universal BIOS and Associated Tools
12; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2012 by XTIDE Universal BIOS Team.
13;
14; This program is free software; you can redistribute it and/or modify
15; it under the terms of the GNU General Public License as published by
16; the Free Software Foundation; either version 2 of the License, or
17; (at your option) any later version.
18;
19; This program is distributed in the hope that it will be useful,
20; but WITHOUT ANY WARRANTY; without even the implied warranty of
21; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22; GNU General Public License for more details.
23; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
24;
25
26; Section containing code
27SECTION .text
28
29%ifdef MODULE_EBIOS
30;--------------------------------------------------------------------
31; AtaGeometry_GetLbaSectorCountToBXDXAXfromAtaInfoInESSI
32; Parameters:
33; ES:SI: Ptr to 512-byte ATA information read from the drive
34; Returns:
35; BX:DX:AX: 48-bit sector count
36; CL: FLGL_DPT_LBA48 if LBA48 supported
37; Zero if only LBA28 is supported
38; Corrupts registers:
39; Nothing
40;--------------------------------------------------------------------
41AtaGeometry_GetLbaSectorCountToBXDXAXfromAtaInfoInESSI:
42 mov bx, Registers_ExchangeDSSIwithESDI
43 call bx ; ATA info now in DS:DI
44 push bx ; We will return via Registers_ExchangeDSSIwithESDI
45
46 ; Check if LBA48 supported
47 test BYTE [di+ATA6.wSetSup83+1], A6_wSetSup83_LBA48>>8
48 jz SHORT .GetLba28SectorCount
49
50 ; Get LBA48 sector count
51 mov cl, FLGL_DPT_LBA48
52 mov ax, [di+ATA6.qwLBACnt]
53 mov dx, [di+ATA6.qwLBACnt+2]
54 mov bx, [di+ATA6.qwLBACnt+4]
55 ret
56
57.GetLba28SectorCount:
58 xor cl, cl
59 xor bx, bx
60 mov ax, [di+ATA1.dwLBACnt]
61 mov dx, [di+ATA1.dwLBACnt+2]
62 ret
63%endif ; MODULE_EBIOS
64
65
66;--------------------------------------------------------------------
67; AtaGeometry_GetLCHStoAXBLBHfromAtaInfoInESSIandTranslateModeInDX
68; AtaGeometry_GetLCHStoAXBLBHfromPCHSinAXBLBHandTranslateModeInDX
69; Parameters:
70; DX: Wanted translate mode or TRANSLATEMODE_AUTO to autodetect
71; ES:SI: Ptr to 512-byte ATA information read from the drive
72; Returns:
73; AX: Number of L-CHS cylinders (1...1027, yes 1027)
74; BL: Number of L-CHS heads (1...255)
75; BH: Number of L-CHS sectors per track (1...63)
76; CX: Number of bits shifted (0...3)
77; DL: CHS Translate Mode
78; Corrupts registers:
79; DH
80;--------------------------------------------------------------------
81AtaGeometry_GetLCHStoAXBLBHfromAtaInfoInESSIandTranslateModeInDX:
82 call AtaGeometry_GetPCHStoAXBLBHfromAtaInfoInESSI
83 ; Fall to AtaGeometry_GetLCHStoAXBLBHfromPCHSinAXBLBH
84
85AtaGeometry_GetLCHStoAXBLBHfromPCHSinAXBLBHandTranslateModeInDX:
86 ; Check if user defined translate mode
87 test dx, dx
88 jnz SHORT .CheckIfLargeTranslationWanted
89 MIN_U ax, MAX_LCHS_CYLINDERS ; TRANSLATEMODE_NORMAL maximum cylinders
90 inc dx
91.CheckIfLargeTranslationWanted:
92 dec dx ; Set ZF if TRANSLATEMODE_LARGE
93 jz SHORT ConvertPCHfromAXBLtoRevisedEnhancedCHinAXBL
94 dec dx ; Set ZF if TRANSLATEMODE_ASSISTED_LBA
95 jz SHORT .UseAssistedLBA
96 ; TRANSLATEMODE_AUTO set
97
98 ; Generate L-CHS using simple bit shift algorithm (ECHS) if
99 ; 8192 or less cylinders.
100 cmp ax, 8192
101 jbe SHORT ConvertPCHfromAXBLtoEnhancedCHinAXBL
102
103 ; We have 8193 or more cylinders so two algorithms are available:
104 ; Revised ECHS or Assisted LBA. The Assisted LBA provides larger
105 ; capacity but requires LBA support from drive (drives this large
106 ; always support LBA but user might have unintentionally set LBA).
107.UseAssistedLBA:
108 test BYTE [es:si+ATA1.wCaps+1], A1_wCaps_LBA>>8
109 jz SHORT ConvertPCHfromAXBLtoRevisedEnhancedCHinAXBL
110
111 ; Drive supports LBA
112 call GetSectorCountToDXAXfromCHSinAXBLBH
113 call ConvertChsSectorCountFromDXAXtoLbaAssistedLCHSinAXBLBH
114 xor cx, cx ; No bits to shift
115 mov dl, TRANSLATEMODE_ASSISTED_LBA
116 ret
117
118
119;--------------------------------------------------------------------
120; AtaGeometry_GetPCHStoAXBLBHfromAtaInfoInESSI
121; Parameters:
122; ES:SI: Ptr to 512-byte ATA information read from the drive
123; Returns:
124; AX: Number of P-CHS cylinders (1...16383)
125; BL: Number of P-CHS heads (1...16)
126; BH: Number of P-CHS sectors per track (1...63)
127; Corrupts registers:
128; Nothing
129;--------------------------------------------------------------------
130AtaGeometry_GetPCHStoAXBLBHfromAtaInfoInESSI:
131 mov ax, [es:si+ATA1.wCylCnt] ; Cylinders (1...16383)
132 mov bl, [es:si+ATA1.wHeadCnt] ; Heads (1...16)
133 mov bh, [es:si+ATA1.wSPT] ; Sectors per Track (1...63)
134 ret
135
136
137;--------------------------------------------------------------------
138; GetSectorCountToDXAXfromCHSinAXBLBH
139; Parameters:
140; ES:SI: Ptr to 512-byte ATA information read from the drive
141; AX: Number of cylinders (1...16383)
142; BL: Number of heads (1...255)
143; BH: Number of sectors per track (1...63)
144; Returns:
145; DX:AX: Total number of CHS addressable sectors
146; Corrupts registers:
147; BX
148;--------------------------------------------------------------------
149GetSectorCountToDXAXfromCHSinAXBLBH:
150 xchg ax, bx
151 mul ah ; AX = Heads * Sectors per track
152 mul bx
153 ret
154
155
156;--------------------------------------------------------------------
157; Revised Enhanced CHS calculation (Revised ECHS)
158;
159; This algorithm translates P-CHS sector count to L-CHS sector count
160; with bit shift algorithm. Since 256 heads are not allowed
161; (DOS limit), this algorithm makes translations so that maximum of
162; 240 L-CHS heads can be used. This makes the maximum addressable capacity
163; to 7,927,234,560 bytes ~ 7.38 GiB. LBA addressing needs to be used to
164; get more capacity.
165;
166; L-CHS parameters generated here require the drive to use CHS addressing.
167;
168; Here is the algorithm:
169; If cylinders > 8192 and heads = 16
170; Heads = 15
171; Cylinders = cylinders * 16 / 15 (losing the fraction component)
172; Do a standard ECHS translation
173;
174; ConvertPCHfromAXBLtoRevisedEnhancedCHinAXBL:
175; Parameters:
176; AX: Number of P-CHS cylinders (8193...16383)
177; BL: Number of P-CHS heads (1...16)
178; Returns:
179; AX: Number of L-CHS cylinders (?...1024)
180; BL: Number of L-CHS heads (?...240)
181; CX: Number of bits shifted (0...3)
182; DL: ADDRESSING_MODE_NORMAL or ADDRESSING_MODE_LARGE
183; Corrupts registers:
184; Nothing
185;--------------------------------------------------------------------
186ConvertPCHfromAXBLtoRevisedEnhancedCHinAXBL:
187 ; Generate L-CHS using simple bit shift algorithm (ECHS) if
188 ; 8192 or less cylinders
189 cmp ax, 8192
190 jbe SHORT ConvertPCHfromAXBLtoEnhancedCHinAXBL
191 cmp bl, 16 ; Drives with 8193 or more cylinders can report 15 heads
192 jb SHORT ConvertPCHfromAXBLtoEnhancedCHinAXBL
193
194 eMOVZX cx, bl ; CX = 16
195 dec bx ; Heads = 15
196 mul cx ; DX:AX = Cylinders * 16
197 dec cx ; CX = 15
198 div cx ; AX = (Cylinders * 16) / 15
199 ; Fall to ConvertPCHfromAXBXtoEnhancedCHinAXBX
200
201
202;--------------------------------------------------------------------
203; Enhanced CHS calculation (ECHS)
204;
205; This algorithm translates P-CHS sector count to L-CHS sector count
206; with simple bit shift algorithm. Since 256 heads are not allowed
207; (DOS limit), this algorithm require that there are at most 8192
208; P-CHS cylinders. This makes the maximum addressable capacity
209; to 4,227,858,432 bytes ~ 3.94 GiB. Use Revised ECHS or Assisted LBA
210; algorithms if there are more than 8192 P-CHS cylinders.
211;
212; L-CHS parameters generated here require the drive to use CHS addressing.
213;
214; Here is the algorithm:
215; Multiplier = 1
216; Cylinder = Cylinder - 1
217; Is Cylinder < 1024? If not:
218; Do a right bitwise rotation on the cylinder (i.e., divide by 2)
219; Do a left bitwise rotation on the multiplier (i.e., multiply by 2)
220; Use the multiplier on the Cylinder and Head values to obtain the translated values.
221;
222; ConvertPCHfromAXBLtoEnhancedCHinAXBL:
223; Parameters:
224; AX: Number of P-CHS cylinders (1...8192)
225; BL: Number of P-CHS heads (1...16)
226; Returns:
227; AX: Number of L-CHS cylinders (?...1024)
228; BL: Number of L-CHS heads (?...128)
229; CX: Number of bits shifted (0...3)
230; DL: TRANSLATEMODE_NORMAL or TRANSLATEMODE_LARGE
231; Corrupts registers:
232; Nothing
233;--------------------------------------------------------------------
234ConvertPCHfromAXBLtoEnhancedCHinAXBL:
235 xor cx, cx ; No bits to shift initially
236 xor dl, dl ; Assume TRANSLATEMODE_NORMAL
237.ShiftIfMoreThan1024Cylinder:
238 cmp ax, MAX_LCHS_CYLINDERS
239 jbe SHORT ReturnLCHSinAXBLBH
240 shr ax, 1 ; Halve cylinders
241 shl bl, 1 ; Double heads
242 inc cx ; Increment bit shift count
243 mov dl, TRANSLATEMODE_LARGE
244 jmp SHORT .ShiftIfMoreThan1024Cylinder
245
246
247;--------------------------------------------------------------------
248; LBA assist calculation (or Assisted LBA)
249;
250; This algorithm translates P-CHS sector count up to largest possible
251; L-CHS sector count (1024, 255, 63). Note that INT 13h interface allows
252; 256 heads but DOS supports up to 255 head. That is why BIOSes never
253; use 256 heads.
254;
255; L-CHS parameters generated here require the drive to use LBA addressing.
256;
257; Here is the algorithm:
258; If cylinders > 8192
259; Variable CH = Total CHS Sectors / 63
260; Divide (CH – 1) by 1024 and add 1
261; Round the result up to the nearest of 16, 32, 64, 128 and 255. This is the value to be used for the number of heads.
262; Divide CH by the number of heads. This is the value to be used for the number of cylinders.
263;
264; ConvertChsSectorCountFromDXAXtoLbaAssistedLCHSinAXBLBH:
265; Parameters:
266; DX:AX: Total number of P-CHS sectors for CHS addressing
267; (max = 16383 * 16 * 63 = 16,514,064)
268; Returns:
269; AX: Number of cylinders (?...1027)
270; BL: Number of heads (16, 32, 64, 128 or 255)
271; BH: Number of sectors per track (always 63)
272; Corrupts registers:
273; CX, DX
274;--------------------------------------------------------------------
275ConvertChsSectorCountFromDXAXtoLbaAssistedLCHSinAXBLBH:
276 ; Value CH = Total sector count / 63
277 ; Max = 16,514,064 / 63 = 262128
278 mov cx, LBA_ASSIST_SPT ; CX = 63
279 call Math_DivDXAXbyCX
280 push dx
281 push ax ; Value CH stored for later use
282
283 ; BX:DX:AX = Value CH - 1
284 ; Max = 262128 - 1 = 262127
285 xor bx, bx
286 sub ax, BYTE 1
287 sbb dx, bx
288
289 ; AX = Number of heads = ((Value CH - 1) / 1024) + 1
290 ; Max = (262127 / 1024) + 1 = 256
291 push si
292 call Size_DivideSizeInBXDXAXby1024andIncrementMagnitudeInCX
293 pop si
294 inc ax ; + 1
295
296 ; Heads must be 16, 32, 64, 128 or 255 (round up to the nearest)
297 ; Max = 255
298 mov cx, 16 ; Min number of heads
299.CompareNextValidNumberOfHeads:
300 cmp ax, cx
301 jbe SHORT .NumberOfHeadsNowInCX
302 shl cx, 1 ; Double number of heads
303 test ch, ch ; Reached 256 heads?
304 jz SHORT .CompareNextValidNumberOfHeads
305 dec cx ; If so, limit heads to 255
306.NumberOfHeadsNowInCX:
307 mov bx, cx ; Number of heads are returned in BL
308 mov bh, LBA_ASSIST_SPT ; Sectors per Track
309
310 ; DX:AX = Number of cylinders = Value CH (without - 1) / number of heads
311 ; Max = 262128 / 255 = 1027
312 pop ax
313 pop dx ; Value CH back to DX:AX
314 div cx
315
316 ; Return L-CHS
317ReturnLCHSinAXBLBH:
318 ret
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