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/ ProfitPress Mega CDROM2 …eeware (MSDOS)(1992)(Eng) / ProfitPress-MegaCDROM2.B6I / PROG / ASSEMBLY / NOR_ASMB.ZIP / DISK_I17.ASM < prev    next >
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Assembly Source File  |  1989-05-16  |  802 b   |  38 lines
  1. .MODEL    SMALL
  2.  
  3. .DATA
  4.  
  5.     EXTRN    SECTOR:BYTE
  6.     EXTRN    DISK_DRIVE_NO:BYTE
  7.     EXTRN    CURRENT_SECTOR_NO:WORD
  8.  
  9. .CODE
  10.  
  11.     PUBLIC    READ_SECTOR
  12. ;-----------------------------------------------------------------------;
  13. ; This procedure reads one sector (512 bytes) into SECTOR.        ;
  14. ;                                    ;
  15. ; Reads:    CURRENT_SECTOR_NO, DISK_DRIVE_NO            ;
  16. ; Writes:    SECTOR                            ;
  17. ;-----------------------------------------------------------------------;
  18. READ_SECTOR    PROC
  19.     PUSH    AX
  20.     PUSH    BX
  21.     PUSH    CX
  22.     PUSH    DX
  23.     MOV    AL,DISK_DRIVE_NO    ;Drive number
  24.     MOV    CX,1            ;Read only 1 sector
  25.     MOV    DX,CURRENT_SECTOR_NO    ;Logical sector number
  26.     LEA    BX,SECTOR        ;Where to store this sector
  27.     INT    25h            ;Read the sector
  28.     POPF                ;Discard flags put on stack by DOS
  29.     POP    DX
  30.     POP    CX
  31.     POP    BX
  32.     POP    AX
  33.     RET
  34. READ_SECTOR    ENDP
  35.  
  36.  
  37.     END
  38.