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Meaning of operator %=

vb dev over 13 years ago

Hello everybody,

I have seen the operator %= used in a code meant for Keil C. Can somebody explain me its purpose? Thanks.

www.8051projects.net/.../forum_viewtopic.php

char getchar()
   {
   volatile char c;

   while(RxInChar == RxOutChar);
   ES = 0;                         /* Disable Interrupts */
   c = RxBuffer[ RxOutChar++ ];
   RxOutChar %= BUF_SIZE;
   ES = 1;                         /* Enable Interrupts */

   return( c );
   }

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0 vb dev over 13 years ago in reply to jamil shang
Sorry but I don't think so.

RxOutChar %= BUF_SIZE;

From the code it seems that RxOutChar points to a location in receive buffer RxBuffer of size BUF_SIZE. So after incrementing RxOutChar if it exceeds BUF_SIZE it should become zero, otherwise no change.

If I am correct, what is the exact meaning of %= . What mathematical/logical operation it does?
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0 vb dev over 13 years ago in reply to jamil shang
Sorry but I don't think so.

RxOutChar %= BUF_SIZE;

From the code it seems that RxOutChar points to a location in receive buffer RxBuffer of size BUF_SIZE. So after incrementing RxOutChar if it exceeds BUF_SIZE it should become zero, otherwise no change.

If I am correct, what is the exact meaning of %= . What mathematical/logical operation it does?
Cancel
Vote up 0 Vote down

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