v4.0/src/MAPPER/CHDIR.ASM

   1 ;
   2 page 80,132
   3 ;
   4 title CP/DOS  DosChDir  mapper
   5 ;
   6 dosxxx  segment byte public 'dos'
   7         assume  cs:dosxxx,ds:nothing,es:nothing,ss:nothing
   8 ;
   9 ; ************************************************************************* *
  10 ; *
  11 ; *      MODULE: DosChDir
  12 ; *
  13 ; *      FUNCTION: change directory name
  14 ; *
  15 ; *      FUNCTION: This module will change the current directory for the
  16 ; *                requesting process.
  17 ; *
  18 ; *
  19 ; *      CALLING SEQUENCE:
  20 ; *
  21 ; *                PUSH@ ASCIIZ Dirname ; Directory path name
  22 ; *                PUSH  DWORD  0       ; Reserved (must be zero)  took out @
  23 ; *                                     ; 5/28 to match 3/25 spec
  24 ; *                CALL DosChDir
  25 ; *
  26 ; *
  27 ; *      RETURN SEQUENCE:
  28 ; *
  29 ; *                IF ERROR (AX NOT = 0)
  30 ; *
  31 ; *                   AX = Error Code:
  32 ; *
  33 ; *                   o   Invalid directory path
  34 ; *
  35 ; *      MODULES CALLED:
  36 ; *                     DOS int 21h   function 3Bh ; Change current directory
  37 ; *
  38 ; *************************************************************************
  39
  40         public  DosChDir
  41         .sall
  42         .xlist
  43         include macros.inc
  44         .list
  45
  46 str     struc
  47 old_bp  dw      ?
  48 return  dd      ?
  49 dtrm006 dd      0h           ;reserved  (must be zero)
  50 dnam006 dd      ?            ;address of directory path name
  51 str     ends
  52
  53 DosChDir  proc   far
  54         Enter   DosChDir                 ; push registers
  55
  56         mov     dx, word ptr [bp].dnam006    ;load directory name offset
  57         mov     ax, word ptr [bp].dnam006+2  ;load directory name segment
  58
  59         push    ax                       ; set segment in DS
  60         pop     ds
  61
  62         mov     ax,03b00h                ; load chdir op code
  63         int     21h                      ; call dos to change the directory
  64         jc      exit                     ; jump if error
  65
  66         xor     ax,ax                    ; else, good return code
  67 exit:   mexit                            ; pop registers
  68         ret     size str - 6             ; return
  69
  70 DosChDir  endp
  71
  72 dosxxx  ends
  73
  74         end