source: xtideuniversalbios/tags/v2.0.0_beta_3/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/AtaGeometry.asm@ 624

Last change on this file since 624 was 491, checked in by krille_n_@…, 12 years ago

Changes:

  • Added a new define (USE_UNDOC_INTEL) that enables optimizations possible by using undocumented instructions available on all Intel processors and truly compatible clones. AFAIK the only exceptions are the NEC V-series and the Sony CXQ70108 processors so this option should be safe for use on the AT builds.
  • Building BIOSDRVS or the BIOS without MODULE_STRINGS_COMPRESSED would fail due to the recent code exclusions so I changed them a bit. Also fixed the mistaken change to Main.asm
  • Changed the Tandy specific info in Configuration_FullMode.txt so it matches the info in the Wiki.
  • Optimizations and fixes in general.
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_GetLCHStoAXBLBHfromPCHSinAXBLBHandTranslateModeInDX
84
85AtaGeometry_GetLCHStoAXBLBHfromPCHSinAXBLBHandTranslateModeInDX:
86 ; Check if user defined translate mode
87 dec dx ; Set ZF if TRANSLATEMODE_LARGE, SF if TRANSLATEMODE_NORMAL
88 jns SHORT .CheckIfLargeTranslationWanted
89 MIN_U ax, MAX_LCHS_CYLINDERS ; TRANSLATEMODE_NORMAL maximum cylinders
90 inc dx
91.CheckIfLargeTranslationWanted:
92 jz SHORT ConvertPCHfromAXBLtoRevisedEnhancedCHinAXBL
93 dec dx ; Set ZF if TRANSLATEMODE_ASSISTED_LBA
94 jz SHORT .UseAssistedLBA
95 ; TRANSLATEMODE_AUTO set
96
97 ; Generate L-CHS using simple bit shift algorithm (ECHS) if
98 ; 8192 or less cylinders.
99 cmp ax, 8192
100 jbe SHORT ConvertPCHfromAXBLtoEnhancedCHinAXBL
101
102 ; We have 8193 or more cylinders so two algorithms are available:
103 ; Revised ECHS or Assisted LBA. The Assisted LBA provides larger
104 ; capacity but requires LBA support from drive (drives this large
105 ; always support LBA but user might have unintentionally set LBA).
106.UseAssistedLBA:
107 test BYTE [es:si+ATA1.wCaps+1], A1_wCaps_LBA>>8
108 jz SHORT ConvertPCHfromAXBLtoRevisedEnhancedCHinAXBL
109
110 ; Drive supports LBA
111 call GetSectorCountToDXAXfromCHSinAXBLBH
112 call ConvertChsSectorCountFromDXAXtoLbaAssistedLCHSinAXBLBH
113 xor cx, cx ; No bits to shift
114 mov dl, TRANSLATEMODE_ASSISTED_LBA
115 ret
116
117
118;--------------------------------------------------------------------
119; AtaGeometry_GetPCHStoAXBLBHfromAtaInfoInESSI
120; Parameters:
121; ES:SI: Ptr to 512-byte ATA information read from the drive
122; Returns:
123; AX: Number of P-CHS cylinders (1...16383)
124; BL: Number of P-CHS heads (1...16)
125; BH: Number of P-CHS sectors per track (1...63)
126; Corrupts registers:
127; Nothing
128;--------------------------------------------------------------------
129AtaGeometry_GetPCHStoAXBLBHfromAtaInfoInESSI:
130 mov ax, [es:si+ATA1.wCylCnt] ; Cylinders (1...16383)
131 mov bl, [es:si+ATA1.wHeadCnt] ; Heads (1...16)
132 mov bh, [es:si+ATA1.wSPT] ; Sectors per Track (1...63)
133 ret
134
135
136;--------------------------------------------------------------------
137; GetSectorCountToDXAXfromCHSinAXBLBH
138; Parameters:
139; ES:SI: Ptr to 512-byte ATA information read from the drive
140; AX: Number of cylinders (1...16383)
141; BL: Number of heads (1...255)
142; BH: Number of sectors per track (1...63)
143; Returns:
144; DX:AX: Total number of CHS addressable sectors
145; Corrupts registers:
146; BX
147;--------------------------------------------------------------------
148GetSectorCountToDXAXfromCHSinAXBLBH:
149 xchg ax, bx
150 mul ah ; AX = Heads * Sectors per track
151 mul bx
152 ret
153
154
155;--------------------------------------------------------------------
156; Revised Enhanced CHS calculation (Revised ECHS)
157;
158; This algorithm translates P-CHS sector count to L-CHS sector count
159; with bit shift algorithm. Since 256 heads are not allowed
160; (DOS limit), this algorithm makes translations so that maximum of
161; 240 L-CHS heads can be used. This makes the maximum addressable capacity
162; to 7,927,234,560 bytes ~ 7.38 GiB. LBA addressing needs to be used to
163; get more capacity.
164;
165; L-CHS parameters generated here require the drive to use CHS addressing.
166;
167; Here is the algorithm:
168; If cylinders > 8192 and heads = 16
169; Heads = 15
170; Cylinders = cylinders * 16 / 15 (losing the fraction component)
171; Do a standard ECHS translation
172;
173; ConvertPCHfromAXBLtoRevisedEnhancedCHinAXBL:
174; Parameters:
175; AX: Number of P-CHS cylinders (8193...16383)
176; BL: Number of P-CHS heads (1...16)
177; Returns:
178; AX: Number of L-CHS cylinders (?...1024)
179; BL: Number of L-CHS heads (?...240)
180; CX: Number of bits shifted (0...3)
181; DL: ADDRESSING_MODE_NORMAL or ADDRESSING_MODE_LARGE
182; Corrupts registers:
183; Nothing
184;--------------------------------------------------------------------
185ConvertPCHfromAXBLtoRevisedEnhancedCHinAXBL:
186 ; Generate L-CHS using simple bit shift algorithm (ECHS) if
187 ; 8192 or less cylinders
188 cmp ax, 8192
189 jbe SHORT ConvertPCHfromAXBLtoEnhancedCHinAXBL
190 cmp bl, 16 ; Drives with 8193 or more cylinders can report 15 heads
191 jb SHORT ConvertPCHfromAXBLtoEnhancedCHinAXBL
192
193 eMOVZX cx, bl ; CX = 16
194 dec bx ; Heads = 15
195 mul cx ; DX:AX = Cylinders * 16
196 dec cx ; CX = 15
197 div cx ; AX = (Cylinders * 16) / 15
198 ; Fall to ConvertPCHfromAXBXtoEnhancedCHinAXBX
199
200
201;--------------------------------------------------------------------
202; Enhanced CHS calculation (ECHS)
203;
204; This algorithm translates P-CHS sector count to L-CHS sector count
205; with simple bit shift algorithm. Since 256 heads are not allowed
206; (DOS limit), this algorithm require that there are at most 8192
207; P-CHS cylinders. This makes the maximum addressable capacity
208; to 4,227,858,432 bytes ~ 3.94 GiB. Use Revised ECHS or Assisted LBA
209; algorithms if there are more than 8192 P-CHS cylinders.
210;
211; L-CHS parameters generated here require the drive to use CHS addressing.
212;
213; Here is the algorithm:
214; Multiplier = 1
215; Cylinder = Cylinder - 1
216; Is Cylinder < 1024? If not:
217; Do a right bitwise rotation on the cylinder (i.e., divide by 2)
218; Do a left bitwise rotation on the multiplier (i.e., multiply by 2)
219; Use the multiplier on the Cylinder and Head values to obtain the translated values.
220;
221; ConvertPCHfromAXBLtoEnhancedCHinAXBL:
222; Parameters:
223; AX: Number of P-CHS cylinders (1...8192)
224; BL: Number of P-CHS heads (1...16)
225; Returns:
226; AX: Number of L-CHS cylinders (?...1024)
227; BL: Number of L-CHS heads (?...128)
228; CX: Number of bits shifted (0...3)
229; DL: TRANSLATEMODE_NORMAL or TRANSLATEMODE_LARGE
230; Corrupts registers:
231; Nothing
232;--------------------------------------------------------------------
233ConvertPCHfromAXBLtoEnhancedCHinAXBL:
234 xor cx, cx ; No bits to shift initially
235 xor dl, dl ; Assume TRANSLATEMODE_NORMAL
236.ShiftIfMoreThan1024Cylinder:
237 cmp ax, MAX_LCHS_CYLINDERS
238 jbe SHORT ReturnLCHSinAXBLBH
239 shr ax, 1 ; Halve cylinders
240 eSHL_IM bl, 1 ; Double heads
241 inc cx ; Increment bit shift count
242 mov dl, TRANSLATEMODE_LARGE
243 jmp SHORT .ShiftIfMoreThan1024Cylinder
244
245
246;--------------------------------------------------------------------
247; LBA assist calculation (or Assisted LBA)
248;
249; This algorithm translates P-CHS sector count up to largest possible
250; L-CHS sector count (1024, 255, 63). Note that INT 13h interface allows
251; 256 heads but DOS supports up to 255 head. That is why BIOSes never
252; use 256 heads.
253;
254; L-CHS parameters generated here require the drive to use LBA addressing.
255;
256; Here is the algorithm:
257; If cylinders > 8192
258; Variable CH = Total CHS Sectors / 63
259; Divide (CH – 1) by 1024 and add 1
260; 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.
261; Divide CH by the number of heads. This is the value to be used for the number of cylinders.
262;
263; ConvertChsSectorCountFromDXAXtoLbaAssistedLCHSinAXBLBH:
264; Parameters:
265; DX:AX: Total number of P-CHS sectors for CHS addressing
266; (max = 16383 * 16 * 63 = 16,514,064)
267; Returns:
268; AX: Number of cylinders (?...1027)
269; BL: Number of heads (16, 32, 64, 128 or 255)
270; BH: Number of sectors per track (always 63)
271; Corrupts registers:
272; CX, DX
273;--------------------------------------------------------------------
274ConvertChsSectorCountFromDXAXtoLbaAssistedLCHSinAXBLBH:
275 ; Value CH = Total sector count / 63
276 ; Max = 16,514,064 / 63 = 262128
277 mov cx, LBA_ASSIST_SPT ; CX = 63
278 call Math_DivDXAXbyCX
279 push dx
280 push ax ; Value CH stored for later use
281
282 ; BX:DX:AX = Value CH - 1
283 ; Max = 262128 - 1 = 262127
284 xor bx, bx
285 sub ax, BYTE 1
286 sbb dx, bx
287
288 ; AX = Number of heads = ((Value CH - 1) / 1024) + 1
289 ; Max = (262127 / 1024) + 1 = 256
290 push si
291 call Size_DivideSizeInBXDXAXby1024andIncrementMagnitudeInCX
292 pop si
293 inc ax ; + 1
294
295 ; Heads must be 16, 32, 64, 128 or 255 (round up to the nearest)
296 ; Max = 255
297 mov cx, 16 ; Min number of heads
298.CompareNextValidNumberOfHeads:
299 cmp ax, cx
300 jbe SHORT .NumberOfHeadsNowInCX
301 eSHL_IM cl, 1 ; Double number of heads
302 jnz SHORT .CompareNextValidNumberOfHeads ; Reached 256 heads?
303 dec cl ; If so, limit heads to 255
304.NumberOfHeadsNowInCX:
305 mov bx, cx ; Number of heads are returned in BL
306 mov bh, LBA_ASSIST_SPT ; Sectors per Track
307
308 ; DX:AX = Number of cylinders = Value CH (without - 1) / number of heads
309 ; Max = 262128 / 255 = 1027
310 pop ax
311 pop dx ; Value CH back to DX:AX
312 div cx
313
314 ; Return L-CHS
315ReturnLCHSinAXBLBH:
316 ret
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