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Text File  |  1993-10-06  |  640 b   |  42 lines
  1. Interrupt Processing Sequence.
  2.  
  3. -start
  4. Complete current instruction.
  5. Interval interrupt ?
  6.     (yes) >pushflags
  7.     (no) NMI ?
  8.         (yes) >pushflags
  9.         (no) INTR ?
  10.             (yes) IF ?
  11.                 (1)Acknowledge interrupt.
  12.                 Read type code.
  13.                 >pushflags
  14.                 (0) >tf
  15.             (no)
  16.             -tf
  17.             TF ?
  18.                 (1) >pushflags
  19.                 (0)
  20.                 -next
  21.                 Execute next instruction.
  22.                 >start
  23. -pushflags
  24. Push flags.
  25. Let TEMP = TF.
  26. Clear IF & TF.
  27. Push CS & IP.
  28. Call interrupt service routine.
  29. NMI ?
  30.     (yes)
  31.     >pushflags
  32.     (no)
  33.     TEMP ?
  34.         (1)
  35.         >pushflags
  36.         (0)
  37.         Execute interrupt procedure.
  38. Pop IP & CS.
  39. Pop flags.
  40. Resume interrupted procedure.
  41. >next
  42.