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AMD Athlon™ Processor x86 Code Optimization
Dependencies
Register Operands
Stack Allocation
128
Spread out true dependencies to increase the opportunities for
p a ra l l e l e x e c u t i o n . A n t i -d e p e n d e n c i e s a n d o u t p u t
dependencies do not impact performance.
Maintain frequently used values in registers rather than in
memory. This technique avoids the comparatively long latencies
for accessing memory.
When allocating space for local variables and/or outgoing
parameters within a procedure, adjust the stack pointer and
use moves rather than pushes. This method of allocation allows
random access to the outgoing parameters so that they can be
set up when they are calculated instead of being held
somewhere else until the procedure call. In addition, this
method reduces ESP dependencies and uses fewer execution
resources.
22007E/0—November 1999
Dependencies
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