AVR-Chat

thanks... i'll just forget about it. 

Paul Curtis <plc@rowley.co.uk> wrote:Jay,

Sorry, you can't do that in a single instruction, you do indeed need
three as TCCR1A is at an I/O location that is not reachable by SBI and
CBI instructions (only I/O addresses 0-31 are).  Not only that, SBI and
CBI take bit numbers not masks and cannot set or clear multiple bits.
Hence, the code the C compiler generates is the most compact you can
get: three instructions to set a single bit.

So to answer your final question: no, you didn't get it right.  ;-)

--
Paul Curtis, Rowley Associates Ltd http://www.rowley.co.uk
<http://www.rowley.co.uk/> 
CrossWorks for MSP430, ARM, and (soon) Atmel AVR processors 

      -----Original Message-----
      From: jay marante [mailto:jaythesis@yahoo.com] 
      Sent: 03 June 2004 13:05
      To: AVR-chat@yahoogroups.com
      Subject: [AVR-Chat] asm in ICCAVR
      
      
      i have this code with ICCAVR: 
      
      TCCR1A |= (1<<COM1A1)|(1<<COM1A0); 
      
      i wanted to replace that code with this assembly code: 
      
      asm("SBI TCCR1A,COM1A1+COM1A0\n"); 
      
      because i found out that the assembly code that the compiler
generate has three sets of instructions. i think that if i replace the C
code with the corresponding assembly code, i might optimize the flash
memory. 
      
      but i get this error when i compile it: 
      
      "absolute expression expected" 
      
      what's wring with my code? did i get it right? 
      thanks for the help.

      

      
      


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