user manual

128 Dependencies
AMD Athlon™ Processor x86 Code Optimization
22007E/0—November 1999
Dependencies
Spread out true dependencies to increase the opportunities for
parallel execution. Anti-dependencies and output
dependencies do not impact performance.
Register Operands
Maintain frequently used values in registers rather than in
memory. This technique avoids the comparatively long latencies
for accessing memory.
Stack Allocation
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.