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Assembly Source File  |  1988-12-12  |  5.4 KB  |  143 lines
  1.         title   SIGNAL.ASM Example signal handle
  2.         page    55,132
  3.         .286
  4. ; 
  5. ; SIGNAL.ASM  Example signal handler for OS/2.
  6. ;             Registers a signal handler then goes to
  7. ;             sleep for 10 seconds.  During the sleep
  8. ;             you can enter ^C and the signal handler
  9. ;             will display a message.
  10. ; Copyright (C) 1987 Ray Duncan
  11. ;
  12. ; Build:        MASM SIGNAL;
  13. ;               LINK SIGNAL,,,OS2,SIGNAL
  14. ;
  15. ; Usage:        SIGNAL
  16.  
  17. stdin   equ     0                       ; standard input handle
  18. stdout  equ     1                       ; standard output handle
  19. stderr  equ     2                       ; standard error handle
  20.  
  21. cr      equ     0dh                     ; ASCII carriage return
  22. lf      equ     0ah                     ; ASCII line feed
  23.  
  24.                                         ; OS/2 signal codes
  25. SIGINTR         equ     1               ; Ctrl-C
  26. SIGBROKENPIPE   equ     2               ; broken pipe
  27. SIGTERM         equ     3               ; program terminated
  28. SIGBREAK        equ     4               ; Ctrl-Break
  29. FlagA           equ     5               ; Event flag A
  30. FlagB           equ     6               ; Event flag B
  31. FlagC           equ     7               ; Event flag C
  32.  
  33.         extrn   DosExit:far             ; references to OS/2 API
  34.         extrn   DosFlagProcess:far
  35.         extrn   DosHoldSignal:far
  36.         extrn   DosSetSigHandler:far
  37.         extrn   DosSleep:far
  38.         extrn   DosWrite:far
  39.  
  40. DGROUP  group   _DATA
  41.  
  42. _DATA   segment word public 'DATA'
  43.  
  44. msg1    db      cr,lf,'Signal detected!',cr,lf
  45. msg1_len equ $-msg1
  46.  
  47. msg2    db      cr,lf 
  48.         db      'Signal handler installed.'
  49.         db      cr,lf
  50.         db      'Press Ctrl-C to demonstrate handler...'
  51.         db      cr,lf
  52. msg2_len equ $-msg2
  53.  
  54. wlen    dw      ?                       ; receives bytes written
  55.  
  56. prvact  dw      ?                       ; receives previous signal action
  57. prvhdlr dd      ?                       ; receives previous handler address
  58.  
  59. _DATA   ends
  60.  
  61.  
  62. _TEXT   segment word public 'CODE'
  63.  
  64.         assume  cs:_TEXT,ds:DGROUP
  65.  
  66. main    proc    far                     ; OS/2 entry point
  67.  
  68.                                         ; register signal handler...
  69.         push    cs                      ; address of handler
  70.         push    offset _TEXT:handler
  71.         push    ds                      ; receives previous handler address
  72.         push    offset DGROUP:prvhdlr
  73.         push    ds                      ; receives previous action
  74.         push    offset DGROUP:prvact
  75.         push    2                       ; action = 2, call handler
  76.         push    SIGINTR                 ; signal of interest= ^C
  77.         call    DosSetSigHandler        ; transfer to OS/2
  78.         or      ax,ax                   ; was set successful?
  79.         jnz     error                   ; jump if set failed.
  80.  
  81.                                         ; display message 'Press Ctrl-C
  82.                                         ; to demonstrate handler'
  83.         push    stdout                  ; standard output handle
  84.         push    ds                      ; message address
  85.         push    offset DGROUP:msg2
  86.         push    msg2_len                ; message length
  87.         push    ds                      ; receives bytes written
  88.         push    offset DGROUP:wlen
  89.         call    DosWrite                ; transfer to OS/2
  90.  
  91.         mov     cx,10                   ; delay for 10 seconds...
  92.  
  93. main1:  push    0                       ; delay for 1 second
  94.         push    1000
  95.         call    DosSleep
  96.  
  97.         loop    main1
  98.  
  99. exit:   push    1                       ; terminate all threads
  100.         push    0                       ; return success code
  101.         call    DosExit                 ; exit program
  102.  
  103. error:  push    1                       ; terminate all threads
  104.         push    1                       ; return error code
  105.         call    DosExit
  106.  
  107. main    endp
  108.  
  109.  
  110. handler proc    far                     ; this is the signal handler    
  111.                                               
  112.                                         ; display message showing
  113.                                         ; handler is active...
  114.         push    stdout                  ; standard output handle
  115.         push    ds                      ; address of data to write
  116.         push    offset DGROUP:msg1
  117.         push    msg1_len                ; length of data
  118.         push    ds                      ; receives length written
  119.         push    offset DGROUP:wlen
  120.         call    DosWrite                ; transfer to OS/2
  121.  
  122.                                         ; now reset signal...
  123.         push    cs                      ; addr of handler
  124.         push    offset _TEXT:handler
  125.         push    ds                      ; receives addr previous handler
  126.         push    offset DGROUP:prvhdlr
  127.         push    ds                      ; receives previous action
  128.         push    offset DGROUP:prvact
  129.         push    4                       ; action = 4; reset signal
  130.         push    SIGINTR                 ; signal of interest= ^C
  131.         call    DosSetSigHandler        ; transfer to OS/2
  132.         or      ax,ax                   ; handler set successfully?
  133.         jnz     error                   ; jump if set failed
  134.  
  135.         ret     4                       ; return from handler, clear stack 
  136.  
  137. handler endp
  138.  
  139. _TEXT   ends
  140.  
  141.         end     main
  142.  
  143.