Appendix G Directpath Versus Vectorpath Instructions; Select Directpath Over Vectorpath Instructions; Directpath Instructions; Table 25. Directpath Integer Instructions - AMD Athlon Processor x86 Optimization Manual

22007E/0—November 1999

Select DirectPath Over VectorPath Instructions

DirectPath Instructions

Select DirectPath Over VectorPath Instructions
DirectPath versus
VectorPath Instructions
U s e D i r e c t Pa t h i n s t r u c t i o n s r a t h e r t h a n Ve c t o r Pa t h
instructions. DirectPath instructions are optimized for decode
and execute efficiently by minimizing the number of operations
per x86 instruction, which includes 'register ← register op
memory' as well as 'register ← register op register' forms of
instructions.
The following tables contain DirectPath instructions, which
should be used in the AMD Athlon processor wherever possible:
Table 25, "DirectPath Integer Instructions," on page 220
Table 26, "DirectPath MMX™ Instructions," on page 227
and Table 27, "DirectPath MMX™ Extensions," on page 228
Table 28, "DirectPath Floating-Point Instructions," on
page 229
All 3DNow! instructions, including the 3DNow! Extensions,
are DirectPath and are listed in Table 23, "3DNow!™
Instructions," on page 217 and Table 24, "3DNow!™ Exten-
sions," on page 218.
AMD Athlon™ Processor x86 Code Optimization
Appendix G
219