Question

Are there any techniques to optimize code in order to ensure lesser power consumption.Architecture is ARM.language is C

Answer 1

From the ARM technical reference site:

The features of the ARM11 MPCore
processor that improve energy
efficiency include:

• accurate branch and sub-routine return prediction, reducing the number
  of incorrect instruction fetch and
  decode operations
• use of physically addressed caches, which reduces the number of cache
  flushes and refills, saving energy in
  the system
• the use of MicroTLBs reduces the power consumed in translation and
  protection lookups each cycle
• the caches use sequential access information to reduce the number of
  accesses to the tag RAMs and to
  unwanted data RAMs.

In the ARM11 MPCore processor
extensive use is also made of gated
clocks and gates to disable inputs to
unused functional blocks. Only the
logic actively in use to perform a
calculation consumes any dynamic
power.

Based on this information, I’d say that the processor does a lot of work for you to save power. Any power wastage would come from poorly written code that does more processing than necessary, which you wouldn’t want anyway. If you’re looking to save power, the overall design of your application will have more effect. Network access, screen rendering, and other power-hungry operations will be of more concern for power consumption.