source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Initialization/DriveXlate.asm@ 81

Last change on this file since 81 was 35, checked in by Tomi Tilli, 14 years ago

Cleaned recent changes a bit to save few bytes.

File size: 8.3 KB
Line 
1; File name : DriveXlate.asm
2; Project name : IDE BIOS
3; Created date : 15.3.2010
4; Last update : 24.8.2010
5; Author : Tomi Tilli
6; Description : Functions for swapping drive letters.
7
8; Section containing code
9SECTION .text
10
11;--------------------------------------------------------------------
12; Translates drive number when entering INT 13h.
13;
14; DriveXlate_WhenEnteringInt13h
15; Parameters:
16; DL: Drive number to be possibly translated
17; DS: RAMVARS segment
18; Returns:
19; DL: Translated drive number
20; Corrupts registers:
21; DI
22;--------------------------------------------------------------------
23ALIGN JUMP_ALIGN
24DriveXlate_WhenEnteringInt13h:
25 inc BYTE [RAMVARS.xlateVars+XLATEVARS.bRecurCnt]
26 cmp BYTE [RAMVARS.xlateVars+XLATEVARS.bRecurCnt], 1
27 je SHORT DriveXlate_ToOrBack
28 ret
29
30
31;--------------------------------------------------------------------
32; DriveXlate_WhenLeavingInt13hWithReturnValueInDL
33; Parameters:
34; DS: RAMVARS segment
35; Returns:
36; Nothing
37; Corrupts registers:
38; DI
39;--------------------------------------------------------------------
40ALIGN JUMP_ALIGN
41DriveXlate_WhenLeavingInt13hWithReturnValueInDL:
42 dec BYTE [RAMVARS.xlateVars+XLATEVARS.bRecurCnt]
43 ret
44
45;--------------------------------------------------------------------
46; Translates drive number when leaving INT 13h.
47;
48; DriveXlate_WhenLeavingInt13h
49; Parameters:
50; DL: Drive number to be possibly translated
51; DS: RAMVARS segment
52; Returns:
53; DL: Translated drive number
54; Corrupts registers:
55; DI
56;--------------------------------------------------------------------
57ALIGN JUMP_ALIGN
58DriveXlate_WhenLeavingInt13h:
59 dec BYTE [RAMVARS.xlateVars+XLATEVARS.bRecurCnt]
60 jz SHORT DriveXlate_ToOrBack
61 ret
62
63
64;--------------------------------------------------------------------
65; Translates drive number to or back.
66;
67; DriveXlate_ToOrBack
68; Parameters:
69; DL: Drive number to be possibly translated
70; DS: RAMVARS segment
71; Returns:
72; DL: Translated drive number
73; Corrupts registers:
74; DI
75;--------------------------------------------------------------------
76ALIGN JUMP_ALIGN
77DriveXlate_ToOrBack:
78 test BYTE [cs:ROMVARS.wFlags], FLG_ROMVARS_DRVXLAT
79 jz SHORT .Return ; Return if translation disabled
80 xchg di, ax ; Backup AX
81 call DriveXlate_SwapFloppyDriveOrHardDisk
82 xchg ax, di
83.Return:
84 ret
85
86
87;--------------------------------------------------------------------
88; Swaps Floppy Drive or Hard Disk number.
89;
90; DriveXlate_SwapFloppyDriveOrHardDisk
91; Parameters:
92; DL: Drive number to be possibly swapped
93; DS: RAMVARS segment
94; Returns:
95; DL: Translated drive number
96; Corrupts registers:
97; AX
98;--------------------------------------------------------------------
99ALIGN JUMP_ALIGN
100DriveXlate_SwapFloppyDriveOrHardDisk:
101 test dl, 80h ; Hard disk?
102 jnz SHORT DriveXlate_SwapHardDisk ; If so, jump to swap
103 ; Fall to DriveXlate_SwapFloppyDrive
104
105;--------------------------------------------------------------------
106; Swaps Floppy Drive number.
107;
108; DriveXlate_SwapFloppyDrive
109; Parameters:
110; DL: Drive number to be possibly swapped
111; DS: RAMVARS segment
112; Returns:
113; DL: Translated drive number
114; Corrupts registers:
115; AX
116;--------------------------------------------------------------------
117;ALIGN JUMP_ALIGN
118DriveXlate_SwapFloppyDrive:
119 eMOVZX ax, BYTE [RAMVARS.xlateVars+XLATEVARS.bFDSwap]
120 jmp SHORT DriveXlate_SwapDrive
121
122;--------------------------------------------------------------------
123; Swaps Hard Disk number.
124;
125; DriveXlate_SwapHardDisk
126; Parameters:
127; DL: Drive number to be possibly swapped
128; DS: RAMVARS segment
129; Returns:
130; DL: Translated drive number
131; Corrupts registers:
132; AX
133;--------------------------------------------------------------------
134ALIGN JUMP_ALIGN
135DriveXlate_SwapHardDisk:
136 mov ah, 80h
137 mov al, BYTE [RAMVARS.xlateVars+XLATEVARS.bHDSwap]
138 ; Fall to DriveXlate_SwapDrive
139
140;--------------------------------------------------------------------
141; Swaps Hard Disk or Floppy Drive number.
142;
143; DriveXlate_SwapDrive
144; Parameters:
145; AL: Drive number to swap to 00h/80h
146; AH: 00h/80h to be swapped to stored drive number
147; DL: Drive number to be possibly swapped
148; Returns:
149; DL: Translated drive number
150; Corrupts registers:
151; Nothing
152;--------------------------------------------------------------------
153;ALIGN JUMP_ALIGN
154DriveXlate_SwapDrive:
155 cmp ah, dl ; Swap DL from 00h/80h to xxh?
156 je SHORT .SwapToXXhInAL
157 cmp al, dl ; Swap DL from xxh to 00h/80h?
158 je SHORT .SwapTo00hOr80hInAH
159 ret
160ALIGN JUMP_ALIGN
161.SwapTo00hOr80hInAH:
162 mov dl, ah
163 ret
164ALIGN JUMP_ALIGN
165.SwapToXXhInAL:
166 mov dl, al
167 ret
168
169
170;--------------------------------------------------------------------
171; Resets drive swapping variables to defaults (no swapping).
172;
173; DriveXlate_Reset
174; Parameters:
175; DS: RAMVARS segment
176; Returns:
177; Nothing
178; Corrupts registers:
179; AX
180;--------------------------------------------------------------------
181ALIGN JUMP_ALIGN
182DriveXlate_Reset:
183 mov WORD [RAMVARS.xlateVars], 8000h ; .bFDSwap and .bHDSwap
184 mov BYTE [RAMVARS.xlateVars+XLATEVARS.bRecurCnt], 0
185 ret
186
187
188;--------------------------------------------------------------------
189; Stores drive to be swapped.
190;
191; DriveXlate_SetDriveToSwap
192; Parameters:
193; DL: Drive to swap to 00h or 80h
194; DS: RAMVARS segment
195; Returns:
196; Nothing
197; Corrupts registers:
198; Nothing
199;--------------------------------------------------------------------
200ALIGN JUMP_ALIGN
201DriveXlate_SetDriveToSwap:
202 test dl, 80h ; Floppy drive?
203 jnz SHORT DriveXlate_SetHardDiskToSwap
204 ; Fall to DriveXlate_SetFloppyDriveToSwap
205
206;--------------------------------------------------------------------
207; Stores floppy drive to be swapped.
208;
209; DriveXlate_SetFloppyDriveToSwap
210; Parameters:
211; DL: Drive to swap to 00h
212; DS: RAMVARS segment
213; Returns:
214; Nothing
215; Corrupts registers:
216; Nothing
217;--------------------------------------------------------------------
218ALIGN JUMP_ALIGN
219DriveXlate_SetFloppyDriveToSwap:
220 mov [RAMVARS.xlateVars+XLATEVARS.bFDSwap], dl
221 ret
222
223;--------------------------------------------------------------------
224; Stores hard disk to be swapped.
225;
226; DriveXlate_SetHardDiskToSwap
227; Parameters:
228; DL: Drive to swap to 80h
229; DS: RAMVARS segment
230; Returns:
231; Nothing
232; Corrupts registers:
233; Nothing
234;--------------------------------------------------------------------
235ALIGN JUMP_ALIGN
236DriveXlate_SetHardDiskToSwap:
237 mov [RAMVARS.xlateVars+XLATEVARS.bHDSwap], dl
238 ret
239
240
241;--------------------------------------------------------------------
242; Checks if INT 13h function returns some value in DL
243; (other than the drive number that was also parameter).
244;
245; DriveXlate_DoesFunctionReturnSomethingInDL
246; Parameters:
247; AH: INT 13h BIOS Function
248; DL: Drive number
249; Returns:
250; CF: Set if something is returned in DL
251; Cleared if only drive number parameter is returned in DL
252; Corrupts registers:
253; Nothing
254;--------------------------------------------------------------------
255ALIGN JUMP_ALIGN
256DriveXlate_DoesFunctionReturnSomethingInDL:
257 cmp ah, 08h ; AH=08h, Read Disk Drive Parameters?
258 je SHORT DriveXlate_FunctionReturnsSomethingInDL
259 test dl, 80h
260 jz SHORT DriveXlate_DoesFloppyFunctionReturnSomethingInDL
261 ; Fall to DriveXlate_DoesHardDiskFunctionReturnSomethingInDL
262
263;--------------------------------------------------------------------
264; Checks if INT 13h hard disk or floppy drive function returns some
265; value in DL other than the drive number that was also parameter).
266; Some functions return different values for hard disks and floppy drives.
267;
268; DriveXlate_DoesHardDiskFunctionReturnSomethingInDL
269; DriveXlate_DoesFloppyFunctionReturnSomethingInDL
270; Parameters:
271; AH: INT 13h BIOS Function
272; DL: Hard Disk number
273; Returns:
274; CF: Set if something is returned in DL
275; Cleared if only drive number parameter is returned in DL
276; Corrupts registers:
277; Nothing
278;--------------------------------------------------------------------
279; ALIGN JUMP_ALIGN
280DriveXlate_DoesHardDiskFunctionReturnSomethingInDL:
281 cmp ah, 15h ; AH=15h, Read Disk Drive Size?
282 je SHORT DriveXlate_FunctionReturnsSomethingInDL
283DriveXlate_DoesFloppyFunctionReturnSomethingInDL:
284 clc
285 ret
286
287ALIGN JUMP_ALIGN
288DriveXlate_FunctionReturnsSomethingInDL:
289 stc
290 ret
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