AN2203 Freescale Semiconductor / Motorola, AN2203 Datasheet - Page 65

• Manufacturer Part Number: AN2203
• Description: MPC7450 RISC Microprocessor Family Software Optimization Guide
• Manufacturer: Freescale Semiconductor / Motorola

Table A-6 shows latencies for FPU instructions. Instructions with a single entry in the cycles column are not
pipelined; all FPU stages are busy for the full duration of instruction execution and are unavailable to
subsequent instructions. Floating-point arithmetic instructions execute in the FPU; floating-point loads and
stores execute in the LSU.
For pipelined instructions, two numbers are shown separated by a colon. The first shows the number of
cycles required to fill the pipeline. The second is the throughput once the pipeline is full. For example,
fabs[.] passes through five stages with a 1-cycle throughput.
MOTOROLA
1
2
3
xori
xoris
xor[.]
MPC7450 RISC Microprocessor Family Software Optimization Guide
If the record bit is set, the GPR result is available in 1 cycle while the CR result is
available in the second cycle.
32*32-bit multiplication has an early exit condition. If the 15 most-significant bits
of the B operand are either all set or all cleared, the multiply finishes with a
latency of 3 and a throughput of 1.
srawi[.] and sraw[.] produce a GPR result in 1 cycle, but the full results,
including the CA, OV, CR results, are available in 2 cycles.
Mnemonic
fabs[.]
fadds[.]
fadd[.]
fcmpo
fcmpu
fctiwz[.]
fctiw[.]
fdivs[.]
fdiv[.]
fmadds[.]
fmadd[.]
fmr[.]
fmsubs[.]
fmsub[.]
fmuls[.]
fmul[.]
Mnemonic
Table A-6. Floating-Point Unit (FPU) Execution Latencies
Table A-5. Integer Unit Execution Latencies (continued)
Freescale Semiconductor, Inc.
For More Information On This Product,
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
Unit
IU1/IU2
IU1/IU2
IU1/IU2
Unit
MPC750/MPC7400
MPC750
Go to: www.freescale.com
Cycles
3:1
3:1
3:1
3:1
3:1
3:1
3:1
4:2
3:1
3:1
4:2
3:1
4:2
3:1
17
31
Cycles
Unit
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
1
1
1
MPC7400
Cycles
3:1
3:1
3:1
3:1
3:1
3:1
3:1
3:1
3:1
3:1
3:1
3:1
3:1
3:1
17
31
Unit
IU1
IU1
IU1
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
FPU
Unit
MPC7450
MPC7450
MPC7450 Execution Latencies
Cycles
5:1
5:1
5:1
5:1
5:1
5:1
5:1
5:1
5:1
5:1
5:1
5:1
5:1
5:1
Cycles
21
35
1
1
1
65