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can i RET in the interrupt insted of RETI

kt venkatesh

Hi! i use p89v51rd2fa microcontroller and microversion 3 C51 compiler. if i write an interrupt function in c the compiler create a asm code like

push ACC
push PSW

a=b;

pop PSW
pop ACC
RETI


can i change the RETI to RET.
regrads,
venkatesh.

Parents Reply Children
  • 0 in reply to erik malund

    why bother with some very convoluted C code (C was never intended for absolute addresses) when some extremely simple assembly code will do?

    Yes! you are correct but i am not familiar with asm coading also most part of the program was also done by c language.Since i have one more asm file [iap.a51] for the IAP calls so i can use asm coading in this file.

    regards,
    venkatesh.

  • 0 in reply to kt venkatesh

    when you use RET instead RETI the code will still be
    executet at interruptlevel. So at some point there has
    to be a RETI. see my solution:
    http://www.keil.com/forum/docs/thread129.asp

    but before use that you should first fully understand
    it. I use this code to change interrupt functions at
    runtime. works perfect here

    Thomas

  • 0 in reply to Thomas

    Hi! it works with RETI also when i make the changes denoted by Erik.Thanks Erik and Thanks Thomas.here is the code.

                     CSEG at 0x0B
                JB    FLAG,?appT0x ; in app mode
                ljmp  02456H
?appT0x:
                ljmp  0400BH
                RET

                CSEG at 0x23
                JB    FLAG,?appT4x ; in app mode
                ljmp  2468H
?appT4x:
                ljmp  04023h
                RET


    there is no change in interrupt [RETI].
    regards,
    venkatesh.