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???
02/14/08 08:04
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#150792 - Know thy tools
Responding to: ???'s previous message
Erik Malund said:
i do not know about SDCC, but some C compilers take the easy way and go "oh this is an ISR, save and restore everything".

I don't know SDCC either, but Keil C51 makes a really huge saving on register saves/restores if you use the 'using' qualifier to specify a Register Bank for the ISR.
So, again, it's a matter of understanding the tools and using them appropriately...

I don't know if SDCC has a similar facility.

Having said all that, ISRs must always be a prime candidate for assembly in an otherwise HLL project, as they often need to be small and fast, and are always self-contained so don't need to worry about the HLL calling conventions.

List of 12 messages in thread
TopicAuthorDate
Minimum ISR time            01/01/70 00:00      
   "bible" time?            01/01/70 00:00      
      details            01/01/70 00:00      
   re-expalin            01/01/70 00:00      
   Re: Minimum ISR time            01/01/70 00:00      
   what simple ISR?            01/01/70 00:00      
      You're right, it is bloody C            01/01/70 00:00      
         C and ISRs            01/01/70 00:00      
            Know thy tools            01/01/70 00:00      
               'using' can be counterproductive in SDCC            01/01/70 00:00      
         ISRs in C            01/01/70 00:00      
            Good point            01/01/70 00:00      

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