User's Manual

216 Instruction Dispatch and Execution Resources
AMD Athlon™ Processor x86 Code Optimization
22007E/0—November 1999
FSTCW [mem16] D9h mm-111-xxx VectorPath
FSTENV [mem14byte] D9h mm-110-xxx VectorPath
FSTENV [mem28byte] D9h mm-110-xxx VectorPath
FSTP [mem32real] D9h mm-011-xxx DirectPath FADD/FMUL
FSTP [mem64real] DDh mm-011-xxx DirectPath FADD/FMUL
FSTP [mem80real] D9h mm-111-xxx VectorPath
FSTP ST(i) DDh 11-011-xxx DirectPath FADD/FMUL
FSTSW AX DFh E0h VectorPath
FSTSW [mem16] DDh mm-111-xxx VectorPath FSTORE
FSUB [mem32real] D8h mm-100-xxx DirectPath FADD
FSUB [mem64real] DCh mm-100-xxx DirectPath FADD
FSUB ST, ST(i) D8h 11-100-xxx DirectPath FADD 1
FSUB ST(i), ST DCh 11-101-xxx DirectPath FADD 1
FSUBP ST, ST(i) DEh 11-101-xxx DirectPath FADD 1
FSUBR [mem32real] D8h mm-101-xxx DirectPath FADD
FSUBR [mem64real] DCh mm-101-xxx DirectPath FADD
FSUBR ST, ST(i) D8h 11-100-xxx DirectPath FADD 1
FSUBR ST(i), ST DCh 11-101-xxx DirectPath FADD 1
FSUBRP ST(i), ST DEh 11-100-xxx DirectPath FADD 1
FTST D9h E4h DirectPath FADD
FUCOM DDh 11-100-xxx DirectPath FADD
FUCOMI ST, ST(i) DB E8-EFh VectorPath FADD
FUCOMIP ST, ST(i) DF E8-EFh VectorPath FADD
FUCOMP DDh 11-101-xxx DirectPath FADD
FUCOMPP DAh E9h DirectPath FADD
FWAIT 9Bh DirectPath
FXAM D9h E5h VectorPath
FXCH D9h 11-001-xxx DirectPath FADD/FMUL/FSTORE
FXTRACT D9h F4h VectorPath
FYL2X D9h F1h VectorPath
FYL2XP1 D9h F9h VectorPath
Table 22. Floating-Point Instructions (Continued)
Instruction Mnemonic
First
Byte
Second
Byte
ModR/M
Byte
Decode
Type
FPU
Pipe(s)
Note
Notes:
1. The last three bits of the modR/M byte select the stack entry ST(i).