v4.0/src/MAPPER/SETINT24.ASM

   1 ;\e0\ f
   2 page 80,132
   3
   4 ;**********************************************************************
   5 ;*
   6 ;*   MODULE:   set_int24_vector
   7 ;*
   8 ;*   Critical error handler for C programs BACKUP and RESTORE
   9 ;*
  10 ;*********************************************************************
  11 ;------------------------------------------------------------;;;;AN000;
  12 databuff  segment   public  'databuff'                       ;;;;AN000;
  13 databuff   ends                                              ;;;;AN000;
  14 ;------------------------------------------------------------;;;;AN000;
  15
  16
  17 dosxxx  segment byte public 'dos'                               ;AN000;
  18         assume  cs:dosxxx,ds:nothing,es:nothing,ss:nothing      ;AN000;
  19
  20
  21             public   set_int24_vector                           ;AN000;
  22             .sall                                               ;AN000;
  23             .xlist                                              ;AN000;
  24             include  macros.inc                                 ;AN000;
  25             .list                                               ;AN000;
  26
  27 str         struc                                               ;AN000;
  28 old_bp      dw       ?                                          ;AN000;
  29 Return      dd       ?                                          ;AN000;
  30 Flag        dw       ?                                          ;AN000;
  31 str         ends                                                ;AN000;
  32
  33
  34 set_int24_vector   proc  far                                    ;AN000;
  35         Enter   set_int24_vector                                ;AN000;
  36
  37         mov     ax,seg databuff                                 ;AN000;
  38         mov     ds,ax                                           ;AN000;
  39         assume  ds:databuff                                     ;AN000;
  40
  41         mov     ax,03524h               ;Get Int24 Vector       ;AN000;
  42         int     21h                                             ;AN000;
  43                                         ;Save it
  44         mov     word ptr cs:OldInt24,bx                         ;AN000;
  45         mov     word ptr cs:OldInt24+2,es                       ;AN000;
  46
  47                                         ;Get address of my Int24 Handler
  48         mov     dx,cs                                           ;AN000;
  49         mov     ds,dx                                           ;AN000;
  50         mov     dx,offset AppErrorHandler                       ;AN000;
  51
  52         mov     ax,02524H              ;Set new INT24 vector    ;AN000;
  53         int     21h                                             ;AN000;
  54
  55         xor     ax,ax                  ;Set good error return   ;AN000;
  56
  57 exit:   mexit                          ; pop all registers      ;AN000;
  58         ret     size str - 6           ; return                 ;AN000;
  59
  60 set_int24_vector    endp                                        ;AN000;
  61
  62
  63
  64
  65
  66 ;-------------------------------------------------------
  67 ;
  68 ;           ****   Error Handler  ******
  69 ;
  70 ;-------------------------------------------------------
  71 Ignore          equ     0               ;AN000;
  72 Retry           equ     1               ;AN000;
  73 Abort           equ     2               ;AN000;
  74 Fail            equ     3               ;AN000;
  75
  76 OldInt24   dd   ?                       ;AN000; ;save old interrupt handler address  ;;;
  77
  78 AppErrorHandler    proc    near         ;AN000;
  79         pushf                           ;AN000;
  80         call    dword ptr cs:OldInt24   ;AN000; Get user to respond
  81         cmp     al,Abort                ;AN000; For any resonse other than Abort
  82         jne     rett                    ;AN000;  retry the operation
  83
  84         int     023h                    ;AN000;
  85
  86 rett:                                   ;AN000;
  87         iret                            ;AN000; return to caller
  88 AppErrorHandler         endp            ;AN000;
  89 ;-------------------------------------------------------
  90 ;-------------------------------------------------------
  91
  92 dosxxx      ends                        ;AN000;
  93            end                          ;AN000;
  94 \1a