source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Boot/BootMenu.asm@ 243

Last change on this file since 243 was 243, checked in by aitotat@…, 13 years ago

Changes to XTIDE Universal BIOS:

  • Brought back optional "A then C" boot loader.
  • Now there is only one INT 19h handler that remains unchanged.
File size: 6.3 KB
Line 
1; Project name : XTIDE Universal BIOS
2; Description : Displays Boot Menu.
3
4; Section containing code
5SECTION .text
6
7;--------------------------------------------------------------------
8; Displays Boot Menu and returns Drive or Function number.
9;
10; BootMenu_DisplayAndReturnSelectionInDX
11; Parameters:
12; DS: RAMVARS segment
13; Returns:
14; DX: Untranslated drive number to be used for booting
15; Corrupts registers:
16; All General Purpose Registers
17;--------------------------------------------------------------------
18ALIGN JUMP_ALIGN
19BootMenu_DisplayAndReturnSelectionInDX:
20 call DriveXlate_Reset
21 call BootMenuPrint_TheBottomOfScreen
22 call BootMenu_Enter ; Get selected menuitem index to CX
23 call BootMenuPrint_ClearScreen
24 call BootMenu_GetDriveToDXforMenuitemInCX
25 jnc BootMenu_DisplayAndReturnSelectionInDX
26 ret
27
28;--------------------------------------------------------------------
29; BootMenu_GetDriveToDXforMenuitemInCX
30; Parameters:
31; CX: Index of menuitem selected from Boot Menu
32; Returns:
33; DX: Drive number to be used for booting
34; DS: RAMVARS segment
35; CF: Set: There is a selected menu item, DL is valid
36; Clear: There is no selected menu item, DL is not valid
37; Corrupts registers:
38; CX, DI
39;--------------------------------------------------------------------
40ALIGN JUMP_ALIGN
41BootMenu_GetDriveToDXforMenuitemInCX_And_RamVars_GetSegmentToDS:
42 call RamVars_GetSegmentToDS
43;;; fall-through
44
45ALIGN JUMP_ALIGN
46BootMenu_GetDriveToDXforMenuitemInCX:
47 cmp cl, NO_ITEM_HIGHLIGHTED
48 je SHORT .ReturnFloppyDriveInDX ; Clear CF if branch taken
49
50 mov dl, cl ; Copy menuitem index to DX
51 call FloppyDrive_GetCountToCX
52 cmp dl, cl ; Floppy drive?
53 jb SHORT .ReturnFloppyDriveInDX ; Set CF if branch taken
54 or cl, 80h ; Or 80h into CL before the sub
55 ; to cause CF to be set after
56 ; and result has high order bit set
57 sub dl, cl ; Remove floppy drives from index
58
59.ReturnFloppyDriveInDX:
60 ret
61
62
63;--------------------------------------------------------------------
64; Enters Boot Menu or submenu.
65;
66; BootMenu_Enter
67; Parameters:
68; Nothing
69; Returns:
70; CX: Index of selected item or NO_ITEM_SELECTED
71; Corrupts registers:
72; AX, BX, DI
73;--------------------------------------------------------------------
74ALIGN JUMP_ALIGN
75BootMenu_Enter:
76 mov bx, BootMenuEvent_Handler
77 CALL_MENU_LIBRARY DisplayWithHandlerInBXandUserDataInDXAX
78 xchg cx, ax
79 ret
80
81
82;--------------------------------------------------------------------
83; Returns number of menuitems in Boot Menu.
84;
85; BootMenu_GetMenuitemCountToAX
86; Parameters:
87; DS: RAMVARS segment
88; Returns:
89; AX: Number of boot menu items
90; Corrupts registers:
91; CX
92;--------------------------------------------------------------------
93ALIGN JUMP_ALIGN
94BootMenu_GetMenuitemCountToAX:
95 call RamVars_GetHardDiskCountFromBDAtoCX
96 xchg ax, cx
97 call FloppyDrive_GetCountToCX
98 add ax, cx
99 ret
100
101
102;--------------------------------------------------------------------
103; BootMenu_GetHeightToAHwithItemCountInAL
104; Parameters:
105; AL: Number of menuitems
106; Returns:
107; AH: Boot menu height
108; Corrupts registers:
109; AL, CX, DI
110;--------------------------------------------------------------------
111ALIGN JUMP_ALIGN
112BootMenu_GetHeightToAHwithItemCountInAL:
113 add al, BOOT_MENU_HEIGHT_WITHOUT_ITEMS
114 xchg cx, ax
115 CALL_DISPLAY_LIBRARY GetColumnsToALandRowsToAH
116 sub ah, MENU_SCREEN_BOTTOM_LINES*2 ; Leave space for bottom info
117 cmp ah, cl
118 jb SHORT .Return
119 mov ah, cl
120ALIGN JUMP_ALIGN, ret
121.Return:
122 ret
123
124
125;--------------------------------------------------------------------
126; BootMenu_GetMenuitemToAXforAsciiHotkeyInAL
127; Parameters:
128; AL: ASCII hotkey
129; Returns:
130; AX: Menuitem index
131; Corrupts registers:
132; CX
133;--------------------------------------------------------------------
134ALIGN JUMP_ALIGN
135BootMenu_GetMenuitemToAXforAsciiHotkeyInAL:
136 call Char_ALtoUpperCaseLetter
137 call BootMenu_GetLetterForFirstHardDiskToCL
138 xor ah, ah
139 cmp al, cl ; Letter is for Hard Disk?
140 jae SHORT .StartFromHardDiskLetter
141 sub al, 'A' ; Letter to Floppy Drive menuitem
142 ret
143ALIGN JUMP_ALIGN
144.StartFromHardDiskLetter:
145 sub al, cl ; Hard Disk index
146 call FloppyDrive_GetCountToCX
147 add ax, cx ; Menuitem index
148 ret
149
150
151;--------------------------------------------------------------------
152; Returns letter for first hard disk. Usually it will be 'c' but it
153; can be higher if more than two floppy drives are found.
154;
155; BootMenu_GetLetterForFirstHardDiskToCL
156; Parameters:
157; Nothing
158; Returns:
159; CL: Upper case letter for first hard disk
160; Corrupts registers:
161; CH
162;--------------------------------------------------------------------
163ALIGN JUMP_ALIGN
164BootMenu_GetLetterForFirstHardDiskToCL:
165 call FloppyDrive_GetCountToCX
166 add cl, 'A'
167 cmp cl, 'C'
168 ja .Return
169 mov cl, 'C'
170ALIGN JUMP_ALIGN, ret
171.Return:
172 ret
173
174
175;--------------------------------------------------------------------
176; BootMenu_GetMenuitemToDXforDriveInDL
177; Parameters:
178; DL: Drive number
179; Returns:
180; DX: Menuitem index (assuming drive is available)
181; Corrupts registers:
182; Nothing
183;--------------------------------------------------------------------
184ALIGN JUMP_ALIGN
185BootMenu_GetMenuitemToDXforDriveInDL:
186 xor dh, dh ; Drive number now in DX
187 test dl, dl
188 jns SHORT .ReturnItemIndexInDX ; Return if floppy drive (HD bit not set)
189 call FloppyDrive_GetCountToCX
190 and dl, ~80h ; Clear HD bit
191 add dx, cx
192.ReturnItemIndexInDX:
193 ret
194
195
196;--------------------------------------------------------------------
197; Checks is drive number valid for this system.
198;
199; BootMenu_IsDriveInSystem
200; Parameters:
201; DL: Drive number
202; DS: RAMVARS segment
203; Returns:
204; CF: Set if drive number is valid
205; Clear if drive is not present in system
206; Corrupts registers:
207; AX, CX
208;--------------------------------------------------------------------
209ALIGN JUMP_ALIGN
210BootMenu_IsDriveInSystem:
211 test dl, dl ; Floppy drive?
212 jns SHORT .IsFloppyDriveInSystem
213 call RamVars_GetHardDiskCountFromBDAtoCX ; Hard Disk count to CX
214 or cl, 80h ; Set Hard Disk bit to CX
215 jmp SHORT .CompareDriveNumberToDriveCount
216.IsFloppyDriveInSystem:
217 call FloppyDrive_GetCountToCX
218.CompareDriveNumberToDriveCount:
219 cmp dl, cl ; Set CF when DL is smaller
220 ret
Note: See TracBrowser for help on using the repository browser.