source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/FindDPT.asm@ 261

Last change on this file since 261 was 259, checked in by gregli@…, 13 years ago

For function int13/0h, restored the code to only reset the floppy drives if a floppy drive was passed in for reset. Other minor optimizations. Better create new floppy support in Serial Server.
File size: 7.1 KB
Line 
1; Project name : XTIDE Universal BIOS
2; Description : Functions for finding Disk Parameter Table.
3
4; Section containing code
5SECTION .text
6
7;--------------------------------------------------------------------
8; Finds pointer to first unused Disk Parameter Table.
9;
10; FindDPT_ForNewDriveToDSDI
11; Parameters:
12; DS: RAMVARS segment
13; Returns:
14; DS:DI: Ptr to first unused DPT
15; Corrupts registers:
16; DX
17;--------------------------------------------------------------------
18ALIGN JUMP_ALIGN
19FindDPT_ForNewDriveToDSDI:
20 mov ax, [RAMVARS.wDrvCntAndFirst]
21 add al, ah
22%ifdef MODULE_SERIAL_FLOPPY
23 add al, [RAMVARS.xlateVars+XLATEVARS.bFlopCreateCnt]
24%endif
25 xchg ax, dx
26 ; fall-through to FindDPT_ForDriveNumber
27
28;--------------------------------------------------------------------
29; Finds Disk Parameter Table for drive number.
30; IDE Base Port address will be stored to RAMVARS if correct DPT is found.
31;
32; FindDPT_ForDriveNumber
33; Parameters:
34; DL: Drive number
35; DS: RAMVARS segment
36; Returns:
37; DS:DI: Ptr to DPT
38; Corrupts registers:
39; Nothing
40;--------------------------------------------------------------------
41ALIGN JUMP_ALIGN
42FindDPT_ForDriveNumber:
43 push dx
44 xchg di, ax ; Save the contents of AX in DI
45
46%ifdef MODULE_SERIAL_FLOPPY
47 mov ax, [RAMVARS.wDrvCntAndFirst]
48
49 test dl, dl
50 js .harddisk
51
52 call RamVars_UnpackFlopCntAndFirstToAL
53 add dl, ah ; add in end of hard disk DPT list, floppies start immediately after
54.harddisk:
55 sub dl, al ; subtract off beginning of either hard disk or floppy list (as appropriate)
56%else
57 sub dl, [RAMVARS.bFirstDrv] ; subtract off beginning of hard disk list
58%endif
59
60 mov al, LARGEST_DPT_SIZE
61
62 mul dl
63 add ax, BYTE RAMVARS_size
64
65 xchg di, ax ; Restore AX and put result in DI
66 pop dx
67
68 ret
69
70;--------------------------------------------------------------------
71; Consolidator for checking the result from RamVars_IsDriveHandledByThisBIOS
72; and then if it is our drive, getting the DPT with FindDPT_ForDriveNumber
73;
74; RamVars_IsDriveHandledByThisBIOS_And_FindDPT_ForDriveNumber
75; Parameters:
76; DL: Drive number
77; DS: RAMVARS segment
78; Returns:
79; DS:DI: Ptr to DPT, if it is our drive
80; CF: Set if not our drive, clear if it is our drive
81; Corrupts registers:
82; Nothing
83;--------------------------------------------------------------------
84ALIGN JUMP_ALIGN
85RamVars_IsDriveHandledByThisBIOS_And_FindDPT_ForDriveNumber:
86 call RamVars_IsDriveHandledByThisBIOS
87 jnc FindDPT_ForDriveNumber
88 ret
89
90
91;--------------------------------------------------------------------
92; Finds Disk Parameter Table for
93; Master or Slave drive at wanted port.
94;
95; FindDPT_ToDSDIForIdeMasterAtPortDX
96; FindDPT_ToDSDIForIdeSlaveAtPortDX
97; Parameters:
98; DX: IDE Base Port address
99; DS: RAMVARS segment
100; Returns:
101; DL: Drive number (if DPT found)
102; DS:DI: Ptr to DPT
103; CF: Set if wanted DPT found
104; Cleared if DPT not found
105; Corrupts registers:
106; SI
107;
108; Converted to macros since there is only once call site for each of these
109;
110;--------------------------------------------------------------------
111
112%macro FindDPT_ToDSDIForIdeMasterAtPortDX 0
113 mov si, IterateToMasterAtPortCallback
114 call IterateAllDPTs
115%endmacro
116
117%macro FindDPT_ToDSDIForIdeSlaveAtPortDX 0
118 mov si, IterateToSlaveAtPortCallback
119 call IterateAllDPTs
120%endmacro
121
122
123;--------------------------------------------------------------------
124; Iteration callback for finding DPT using
125; IDE base port for Master or Slave drive.
126;
127; IterateToSlaveAtPortCallback
128; IterateToMasterAtPortCallback
129; Parameters:
130; DX: IDE Base Port address
131; DS:DI: Ptr to DPT to examine
132; Returns:
133; CF: Set if wanted DPT found
134; Cleared if wrong DPT
135; Corrupts registers:
136; Nothing
137;--------------------------------------------------------------------
138ALIGN JUMP_ALIGN
139IterateToSlaveAtPortCallback:
140 test BYTE [di+DPT.bFlagsLow], FLGL_DPT_SLAVE ; Clears CF
141 jnz SHORT CompareBasePortAddress
142 ret ; Wrong DPT
143
144ALIGN JUMP_ALIGN
145IterateToMasterAtPortCallback:
146 test BYTE [di+DPT.bFlagsLow], FLGL_DPT_SLAVE
147 jnz SHORT ReturnWrongDPT ; Return if slave drive
148
149CompareBasePortAddress:
150 push bx
151 eMOVZX bx, BYTE [di+DPT.bIdevarsOffset] ; CS:BX now points to IDEVARS
152 cmp dx, [cs:bx+IDEVARS.wPort] ; Wanted port?
153 pop bx
154 jne SHORT ReturnWrongDPT
155
156ReturnRightDPT:
157 stc ; Set CF since wanted DPT
158 ret
159
160
161;--------------------------------------------------------------------
162; IterateToDptWithFlagsHighInBL
163; Parameters:
164; DS:DI: Ptr to DPT to examine
165; BL: Bit(s) to test in DPT.bFlagsHigh
166; Returns:
167; CF: Set if wanted DPT found
168; Cleared if wrong DPT
169; Corrupts registers:
170; Nothing
171;--------------------------------------------------------------------
172ALIGN JUMP_ALIGN
173IterateToDptWithFlagsHighInBL:
174 test BYTE [di+DPT.bFlagsHigh], bl ; Clears CF (but we need the clc
175 ; below anyway for callers above)
176 jnz SHORT ReturnRightDPT
177
178ReturnWrongDPT:
179 clc ; Clear CF since wrong DPT
180 ret
181
182;--------------------------------------------------------------------
183; FindDPT_ToDSDIforSerialDevice
184; Parameters:
185; DS: RAMVARS segment
186; Returns:
187; DS:DI: Ptr to DPT
188; CF: Set if wanted DPT found
189; Cleared if DPT not found
190; Corrupts registers:
191; SI
192;--------------------------------------------------------------------
193ALIGN JUMP_ALIGN
194FindDPT_ToDSDIforSerialDevice:
195 mov bl, FLGH_DPT_SERIAL_DEVICE
196; fall-through
197
198;--------------------------------------------------------------------
199; FindDPT_ToDSDIforFlagsHigh
200; Parameters:
201; DS: RAMVARS segment
202; BL: Bit(s) to test in DPT.bFlagsHigh
203; Returns:
204; DS:DI: Ptr to DPT
205; CF: Set if wanted DPT found
206; Cleared if DPT not found
207; Corrupts registers:
208; SI
209;--------------------------------------------------------------------
210ALIGN JUMP_ALIGN
211FindDPT_ToDSDIforFlagsHighInBL:
212 mov si, IterateToDptWithFlagsHighInBL
213 ; Fall to IterateAllDPTs
214
215;--------------------------------------------------------------------
216; Iterates all Disk Parameter Tables.
217;
218; IterateAllDPTs
219; Parameters:
220; AX,BX,DX: Parameters to callback function
221; CS:SI: Ptr to callback function
222; DS: RAMVARS segment
223; Returns:
224; DS:DI: Ptr to wanted DPT (if found)
225; If not found, points to first empty DPT
226; CF: Set if wanted DPT found
227; Cleared if DPT not found, or no DPTs present
228; Corrupts registers:
229; Nothing unless corrupted by callback function
230;--------------------------------------------------------------------
231ALIGN JUMP_ALIGN
232IterateAllDPTs:
233 push cx
234
235 mov di, RAMVARS_size ; Point DS:DI to first DPT
236
237 mov cl, [RAMVARS.bDrvCnt]
238 xor ch, ch ; Clears CF
239
240 jcxz .AllDptsIterated ; Return if no drives, CF will be clear from xor above
241
242ALIGN JUMP_ALIGN
243.LoopWhileDPTsLeft:
244 call si ; Is wanted DPT?
245 jc SHORT .AllDptsIterated ; If so, return
246 add di, BYTE LARGEST_DPT_SIZE ; Point to next DPT, clears CF
247 loop .LoopWhileDPTsLeft
248
249 ; fall-through: DPT was not found, CF is already clear from ADD di inside the loop
250
251ALIGN JUMP_ALIGN
252.AllDptsIterated:
253 pop cx
254 ret
255
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