source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Boot/BootMenuInfo.asm@ 314

Last change on this file since 314 was 269, checked in by gregli@…, 13 years ago

Fixed a bug with reporting the number of hard disks when there were only foreign disks (none managed by this bios). Also a few small optimizations.

File size: 2.5 KB
RevLine 
[88]1; Project name : XTIDE Universal BIOS
[3]2; Description : Functions for generating and accessing drive
3; information to be displayed on boot menu.
4
5; Section containing code
6SECTION .text
7
8;--------------------------------------------------------------------
[254]9; Creates new BOOTMENUINFO struct for detected hard disk.
[3]10;
[254]11; BootMenuInfo_CreateForHardDisk
[3]12; Parameters:
13; DL: Drive number
14; DS:DI: Ptr to Disk Parameter Table
15; ES:SI: Ptr to 512-byte ATA information read from the drive
16; Returns:
[254]17; ES:BX: Ptr to BOOTMENUINFO (if successful)
[3]18; Corrupts registers:
[254]19; AX, BX, CX, DX, DI
[3]20;--------------------------------------------------------------------
[254]21BootMenuInfo_CreateForHardDisk:
22 call BootMenuInfo_ConvertDPTtoBX ; ES:BX now points to new BOOTMENUINFO
[3]23
[254]24 ; Store Drive Name
25 push ds ; Preserve RAMVARS
26 push si
[3]27
[254]28 push es ; ES copied to DS
[3]29 pop ds
[241]30
[254]31 add si, BYTE ATA1.strModel ; DS:SI now points drive name
32 lea di, [bx+BOOTMENUINFO.szDrvName] ; ES:DI now points to name destination
33 mov cx, MAX_HARD_DISK_NAME_LENGTH / 2 ; Max number of WORDs allowed
[121]34.CopyNextWord:
35 lodsw
[254]36 xchg al, ah ; Change endianness
[121]37 stosw
38 loop .CopyNextWord
[254]39 xor ax, ax ; Zero AX and clear CF
40 stosw ; Terminate with NULL
[3]41
42 pop si
43 pop ds
[241]44
[3]45 ret
46
[252]47
[3]48;--------------------------------------------------------------------
[254]49; BootMenuInfo_GetTotalSectorCount
[3]50; Parameters:
[241]51; DS:DI: DPT Pointer
[3]52; Returns:
53; BX:DX:AX: 48-bit sector count
54; Corrupts registers:
[252]55; CX
[128]56;--------------------------------------------------------------------
[3]57ALIGN JUMP_ALIGN
[254]58BootMenuInfo_GetTotalSectorCount:
[252]59 test BYTE [di+DPT.bFlagsLow], FLG_DRVNHEAD_LBA
60 jnz SHORT .ReturnFullCapacity
61 jmp AH15h_GetSectorCountToBXDXAX
62.ReturnFullCapacity:
63 jmp AccessDPT_GetLbaSectorCountToBXDXAX
[100]64
65
66;--------------------------------------------------------------------
[254]67; Returns offset to BOOTMENUINFO based on DPT pointer.
[100]68;
[254]69; BootMenuInfo_ConvertDPTtoBX
[100]70; Parameters:
[241]71; DS:DI: DPT Pointer
[100]72; Returns:
[254]73; BX: Offset to BOOTMENUINFO struct
[100]74; Corrupts registers:
75; AX
76;--------------------------------------------------------------------
77ALIGN JUMP_ALIGN
[254]78BootMenuInfo_ConvertDPTtoBX:
[241]79 mov ax, di
[254]80 sub ax, RAMVARS_size ; subtract off base of DPTs
81 mov bl, DPT_BOOTMENUINFO_SIZE_MULTIPLIER ; BOOTMENUINFO's are a whole number multiple of DPT size
[241]82 mul bl
[254]83 add ax, BOOTVARS.rgBootNfo ; add base of BOOTMENUINFO
[241]84 xchg ax, bx
85 ret
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