v4.0/src/MAPPER/SEL_DISK.ASM

   1 ;
   2 page 80,132
   3 ;
   4 title CP/DOS DosSelectDisk mapper
   5 ;
   6 dosxxx  segment byte public 'dos'
   7         assume  cs:dosxxx,ds:nothing,es:nothing,ss:nothing
   8 ;
   9 ;**********************************************************************
  10 ;*
  11 ;*   MODULE:   dosselectdisk
  12 ;*
  13 ;*   FILE NAME: dos048.asm
  14 ;*
  15 ;*   CALLING SEQUENCE:
  16 ;*
  17 ;*       push      word  drive          drive number
  18 ;*       call      dosselectdisk
  19 ;*
  20 ;*   MODULES CALLED:  PC-DOS Int 21h, ah=0eh, select disk
  21 ;*
  22 ;*********************************************************************
  23
  24             public   dosselectdisk
  25             .sall
  26             .xlist
  27             include  macros.inc
  28             .list
  29
  30 str         struc
  31 old_bp      dw       ?
  32 Return      dd       ?
  33 Drive       dw       ?       ; drive number
  34 str         ends
  35
  36 dosselectdisk  proc  far
  37         Enter   Dosselectdisk         ; push registers
  38
  39         mov     dx,[bp].drive         ; load drive number
  40         dec     dx                    ; adjust for cp/dos incompatibility
  41
  42         mov     ah,0eh
  43         int     21h                   ; select the drive
  44
  45         sub     ax,ax                 ; set good return code
  46
  47         mexit                         ; pop registers
  48         ret     size str - 6          ; return
  49
  50 dosselectdisk endp
  51
  52 dosxxx      ends
  53
  54             end