v4.0/src/MAPPER/WRITE.ASM

   1 page 80,132
   2
   3 title CP/DOS DosWrite mapper
   4
   5 dosxxx  segment byte public 'dos'
   6         assume  cs:dosxxx,ds:nothing,es:nothing,ss:nothing
   7
   8 ;**********************************************************************
   9 ;*
  10 ;*   MODULE:   doswrite
  11 ;*
  12 ;*   FUNCTION:  Write a specified number of bytes to a file
  13 ;*
  14 ;*   CALLING SEQUENCE:
  15 ;*
  16 ;*       push      word     file handle
  17 ;*       push@     other    buffer area
  18 ;*       push      word     buffer length
  19 ;*       push@     word     bytes written
  20 ;*       call      doswrite
  21 ;*
  22 ;*   MODULES CALLED:  PC-DOS Int 21h, ah=40h, write
  23 ;*
  24 ;*********************************************************************
  25
  26             public   doswrite
  27             .sall
  28             .xlist
  29             include  macros.inc
  30             .list
  31
  32 str         struc
  33 old_bp      dw       ?
  34 return      dd       ?
  35 Written     dd       ?       ; number of bytes actually written
  36 Bufflng     dw       ?       ; number of bytes to be written
  37 Buffer      dd       ?       ; write buffer address
  38 Handle      dw       ?       ; file handle
  39 str         ends
  40
  41 doswrite    proc     far
  42
  43             Enter    doswrite            ; push registers
  44
  45             mov      bx,[bp].handle      ; get handle
  46             lds      dx,[bp].buffer      ; set write buffer
  47             mov      cx,[bp].bufflng     ; number of bytes to be written
  48
  49             mov      ah,40h              ; load opcode
  50             int      21h                 ; write bytes to the file
  51             jc       exit                ; jump if error
  52
  53             lds      si,[bp].written     ; pointer to return data
  54             mov      word ptr [si],ax    ; save actual number of bytes written
  55             sub      ax,ax               ; set good return code
  56
  57 exit:       mexit                        ; pop registers
  58             ret      size str - 6        ; return
  59
  60 doswrite    endp
  61
  62 dosxxx      ends
  63
  64             end