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???
08/07/05 21:37
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 		 #98967 - CALL + RET != JUMP
Responding to: ???'s previous message
Save This Code
A_SUBROUTINE:
        CALL    SAVE_CONTEXT
; a task
        CALL    RESTORE_CONTEXT
        RET

Often, when optimizing assembly code we might substitute some flavor of JMP for a CALL immediately followed by a RET. For example:
Save This Code
A_SUBROUTINE:
        CALL    SAVE_CONTEXT
; a task
        LJMP    RESTORE_CONTEXT

Doing so when using the context save/restore subroutines would be very bad indeed.


List of 53 messages in thread
TopicAuthorDate
Week puzzle            01/01/70 00:00      
   why is one a subroutine and another a ta            01/01/70 00:00      
      no RTOS            01/01/70 00:00      
   last there was discussion, in this an an            01/01/70 00:00      
      week            01/01/70 00:00      
   Last pushed in - first popped out            01/01/70 00:00      
      come in            01/01/70 00:00      
   Will it work?            01/01/70 00:00      
      Yes it will            01/01/70 00:00      
         Mmmmm?            01/01/70 00:00      
         And another thought            01/01/70 00:00      
            it's perfectly safe...            01/01/70 00:00      
               Still not convinced            01/01/70 00:00      
                  dangers            01/01/70 00:00      
                     Choices            01/01/70 00:00      
                        the same in real life            01/01/70 00:00      
                           Smart and Neat Code            01/01/70 00:00      
                              are you a math major? :)            01/01/70 00:00      
                                 Not a maths major            01/01/70 00:00      
                        yes            01/01/70 00:00      
                  what dangerous            01/01/70 00:00      
                     If misuse is chronic...            01/01/70 00:00      
   CALL + RET != JUMP            01/01/70 00:00      
      ?????????            01/01/70 00:00      
         oops Oleg Has the code to manage it sorr            01/01/70 00:00      
            return address            01/01/70 00:00      
      you got it!            01/01/70 00:00      
         Thanks for the puzzle :-)            01/01/70 00:00      
   a question            01/01/70 00:00      
      why not            01/01/70 00:00      
         well            01/01/70 00:00      
            optimisation            01/01/70 00:00      
               I have seen that happen when the require            01/01/70 00:00      
                  it's the same than if you miss a push or            01/01/70 00:00      
         The Trick is:            01/01/70 00:00      
   the answer            01/01/70 00:00      
      you never answered            01/01/70 00:00      
         solid or intermittent problem            01/01/70 00:00      
            difference between solid or intermittent            01/01/70 00:00      
   Why Push!!!            01/01/70 00:00      
      side effect            01/01/70 00:00      
         Another SAVE_CONTEXT            01/01/70 00:00      
            Sounds like a housekeeping nightmare            01/01/70 00:00      
               Sounds like a housekeeping nightmare            01/01/70 00:00      
               it IS a housekeeping nightmare            01/01/70 00:00      
                  Erik            01/01/70 00:00      
                     Pay no attention            01/01/70 00:00      
                        Donald, if you took the time to read wha            01/01/70 00:00      
                           Reading difficulties            01/01/70 00:00      
                              sorry, used wrong word            01/01/70 00:00      
                     no problem with any post, just with stat            01/01/70 00:00      
            maybe because            01/01/70 00:00      
      eh?            01/01/70 00:00      

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