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Optimization Guide
A.6.3
Use of PLD Instructions
The preload instruction PLD is only a hint, it does not change the architectural state of the
processor. Using or not using them will not change the behavior of your code, therefore, you should
avoid using these instructions when optimizing for space.
A.6.4
Thumb Instructions
The best opportunity for code compaction is to utilize the ARM* Thumb instructions. These
instructions are additions to the ARM* architecture primarily for the purpose of code size
reduction.
16-bit Thumb instructions have less functionality than their 32-bit equivalents, hence Thumb code
is typically slower than 32-bit ARM* code. However, in some unusual cases where Instruction
Cache size is a significant influence, being able to hold more Thumb instructions in cache may aid
performance. Whatever the performance outcome, Thumb coding significantly reduces code size.
A-32
Intel® XScale™ Microarchitecture User's Manual
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