source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h/AHCh_HSeek.asm@ 137

Last change on this file since 137 was 116, checked in by krille_n_@…, 14 years ago

Changes to all parts of the project:

  • Removed a redundant macro (HPIO_NORMALIZE_PTR)
  • Deleted XTIDE_Universal_BIOS/Inc/BiosData.inc since that was also redundant.
  • Size optimization: Changed the LOAD_BDA_SEGMENT_TO macro to use the stack on 186+ processors (the old behaviour can still be used where needed).
  • Made other minor size optimizations and cleanups to various functions, mostly in the Int13h handler.
File size: 1.9 KB
Line 
1; Project name : XTIDE Universal BIOS
2; Description : Int 13h function AH=Ch, Seek.
3
4; Section containing code
5SECTION .text
6
7;--------------------------------------------------------------------
8; Int 13h function AH=Ch, Seek.
9;
10; AHCh_HandlerForSeek
11; Parameters:
12; AH: Bios function Ch
13; CH: Cylinder number, bits 7...0
14; CL: Bits 7...6: Cylinder number bits 9 and 8
15; Bits 5...0: Starting sector number (1...63)
16; DH: Starting head number (0...255)
17; DL: Drive number
18; Parameters loaded by Int13h_Jump:
19; DS: RAMVARS segment
20; Returns:
21; AH: BIOS Error code
22; CF: 0 if succesfull, 1 if error
23; IF: 1
24; Corrupts registers:
25; Flags
26;--------------------------------------------------------------------
27ALIGN JUMP_ALIGN
28AHCh_HandlerForSeek:
29 push dx
30 push cx
31 push bx
32 push ax
33%ifndef USE_186
34 call AHCh_SeekToCylinder
35 jmp Int13h_PopXRegsAndReturn
36%else
37 push Int13h_PopXRegsAndReturn
38 ; Fall through to AHCh_SeekToCylinder
39%endif
40
41
42;--------------------------------------------------------------------
43; Seeks to a cylinder.
44;
45; AHCh_SeekToCylinder
46; Parameters:
47; CH: Cylinder number, bits 7...0
48; CL: Bits 7...6: Cylinder number bits 9 and 8
49; Bits 5...0: Starting sector number (1...63)
50; DH: Starting head number (0...255)
51; DL: Drive Number
52; DS: RAMVARS segment
53; Returns:
54; DS:DI: Ptr to DPT
55; AH: BIOS Error code
56; CF: 0 if succesfull, 1 if error
57; Corrupts registers:
58; AL, BX, CX, DX
59;--------------------------------------------------------------------
60ALIGN JUMP_ALIGN
61AHCh_SeekToCylinder:
62 call FindDPT_ForDriveNumber ; DS:DI now points to DPT
63 mov ax, HCMD_SEEK<<8 ; Load cmd to AH, AL=zero sector cnt
64 call HCommand_OutputCountAndLCHSandCommand
65 jc SHORT .Return ; Return if error
66 mov bx, di ; DS:BX now points to DPT
67 jmp HStatus_WaitIrqOrRdy ; Wait for IRQ or RDY
68.Return:
69 ret
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