MC7457RX1267LC Datasheet, PDF (9/71 Pages) Freescale Semiconductor, Inc – Microprocessor

Comparison with the MPC7455, MPC7445, MPC7450, MPC7451, and MPC7441
3 Comparison with the MPC7455, MPC7445, MPC7450,
MPC7451, and MPC7441
Table 1 compares the key features of the MPC7457 with the key features of the earlier MPC7455,
MPC7445, MPC7450, MPC7451, and MPC7441. To achieve a higher frequency, the number of logic
levels per cycle is reduced. Also, to achieve this higher frequency, the pipeline of the MPC7457 is
extended (compared to the MPC7400), while maintaining the same level of performance as measured by
the number of instructions executed per cycle (IPC).
Table 1. Microarchitecture Comparison
Microarchitectural Specs
MPC7457/MPC7447
MPC7455/MPC7445
MPC7450/MPC7451/
MPC7441
Basic Pipeline Functions
Logic inversions per cycle
Pipeline stages up to execute
Total pipeline stages (minimum)
Pipeline maximum instruction throughput
18
5
7
3 + Branch
18
5
7
3 + Branch
Pipeline Resources
Instruction buffer size
Completion buffer size
Renames (integer, float, vector)
12
16
16, 16, 16
12
16
16, 16, 16
Maximum Execution Throughput
SFX
Vector
Scalar floating-point
3
2 (any 2 of 4 units)
1
3
2 (any 2 of 4 units)
1
Out-of-Order Window Size in Execution Queues
SFX integer units
Vector units
Scalar floating-point unit
1 entry × 3 queues
In order, 4 queues
In order
1 entry × 3 queues
In order, 4 queues
In order
Branch Processing Resources
Prediction structures
BTIC size, associativity
BHT size
Link stack depth
Unresolved branches supported
Branch taken penalty (BTIC hit)
BTIC, BHT, link stack
128-entry, 4-way
2K-entry
8
3
1
BTIC, BHT, link stack
128-entry, 4-way
2K-entry
8
3
1
18
5
7
3 + Branch
12
16
16, 16, 16
3
2 (any 2 of 4 units)
1
1 entry × 3 queues
In order, 4 queues
In order
BTIC, BHT, link stack
128-entry, 4-way
2K-entry
8
3
1
MPC7457 RISC Microprocessor Hardware Specifications, Rev. 8
Freescale Semiconductor
9