In cortex m3 processor what is used as a temporary variable for arithmetic operations like multiplication or addition. In 8085 we have accumulator A.similarly what is used for Cortex m3 Also where is the string stored before being transmitted using uart in cortex m3 processor ?
I know the registers r0-r15.What i wanted to know is that is there any temporary register used for arithmetic operations while performing operations like Add r1,r2 in the AHB or is it done directly. p.s: I'm referring to arm cortex m3 user manual.
All processors have one or more ALU.
But most newer processors do not have any ACC - no dedicated accumulator register hard-coded as one of the inputs and hard-coded as the output.
The proceessor routes the contents from one of several general-purpose registers to the ALU and then routes the result back to one of several general-purpose registers.
And besides the "big" ALU, they can have small ALU with limited capabilities - often used for on-the-fly address computations.