146
Floating-Point Pipeline Stages
AMD Athlon™ Processor x86 Code Optimization
22007E/0—November 1999
Floating-Point Pipeline Stages
The floating-point unit (FPU) is implemented as a coprocessor
that has its own out-of-order control in addition to the data
p at h . The FP U h a n d le s all reg iste r o p eratio n s for x 87
instructions, all 3DNow! operations, and all MMX operations.
The FPU consists of a stack renaming unit, a register renaming
unit, a scheduler, a register file, and three parallel execution
units. Figure 9 shows a block diagram of the dataflow through
the FPU.
Figure 9. Floating-Point Unit Block Diagram
The floating-point pipeline stages 7–15 are shown in Figure 10
and de scribed in the follow ing sections. N ote that the
floating-point pipe and integer pipe separates at cycle 7.
Figure 10. Floating-Point Pipeline Stages
Instruction Control Unit
Instruction Control Unit
FADD
• MMX™ ALU
• 3DNow!™
FADD
• MMX™ ALU
• 3DNow!™
FSTORE
FSTORE
FMUL
• MMX ALU
• MMX Mul
• 3DNow!
FMUL
• MMX ALU
• MMX Mul
• 3DNow!
Stack Map
Stack Map
Register Rename
Register Rename
Scheduler (36-entry)
Scheduler (36-entry)
FPU Register File (88-entry)
FPU Register File (88-entry)
Pipeline
Pipeline
Stage
Stage
7
7
8
8
11
11
9
9
10
10
12
12
to
to
15
15
STKREN
REGREN
SCHEDW
SCHED
FREG
7
8
9
10
11
FEXE1
12
FEXE4
15
Summary of Contents for Athlon Processor x86
Page 1: ...AMD Athlon Processor x86 Code Optimization Guide TM...
Page 12: ...xii List of Figures AMD Athlon Processor x86 Code Optimization 22007E 0 November 1999...
Page 16: ...xvi Revision History AMD Athlon Processor x86 Code Optimization 22007E 0 November 1999...
Page 202: ...186 Page Attribute Table PAT AMD Athlon Processor x86 Code Optimization 22007E 0 November 1999...
Page 252: ...236 VectorPath Instructions AMD Athlon Processor x86 Code Optimization 22007E 0 November 1999...
Page 256: ...240 Index AMD Athlon Processor x86 Code Optimization 22007E 0 November 1999...