
6-12
PRELIMINARY
Instruction Set Tables
Advanci ng the S tandar ds
6.4
Instruction Set Tables
The M II CPU instruction set is presented in
three tables: Table 6-21. “M II CPU Instruction
Set Clock Count Summary” on page 6-14, Table
6-23. “M II FPU Instruction Set Summary” on
page 6-31 and the Table 6-25. “M II Processor
MMX Instruction Set Clock Count Summary” on
page 6-38. Additional information concerning
the FPU Instruction Set is presented on page
6-30, and the M II MMX instruction set on page
6-37.
6.4.1
Assumptions Made in
Determining Instruction
Clock Count
The assumptions made in determining instruc-
tion clock counts are listed below:
1.
All clock counts refer to the internal
CPU internal clock frequency.
2.
The instruction has been prefetched,
decoded and is ready for execution.
3.
Bus cycles do not require wait states.
4.
There are no local bus HOLD
requests delaying processor access to
the bus.
5.
No exceptions are detected during
instruction execution.
6.
If an effective address is calculated, it
does not use two general register
components. One register, scaling
and displacement can be used within
the clock count shown. However, if
the effective address calculation uses
two general register components,
add 1 clock to the clock count
shown.
7.
All clock counts assume aligned
32-bit memory/ IO operands.
8.
If instructions access a 32-bit
operand that crosses a 64-bit
boundary, add 1 clock for read or
write and add 2 clocks for read and
write.
9.
For non-cached memory accesses,
add two clocks (M II CPU with 2x
clock) or four clocks (M II CPU
with 3x clock). (Assumes zero wait
state memory accesses).
10. Locked cycles are not cacheable.
Therefore, using the LOCK prefix
with an instruction adds additional
clocks as specified in paragraph 9
above.
11. No parallel execution of
instructions.
6.4.2
CPU Instruction Set
Summary Table
Abbreviations
The clock counts listed in the CPU Instruction
Set Summary Table are grouped by operating
mode and whether there is a register/cache hit
or a cache miss. In some cases, more than one
clock count is shown in a column for a given
instruction, or a variable is used in the clock
count. The abbreviations used for these condi-
tions are listed in Table 6-18.