MPC561MZP56 Freescale, MPC561MZP56 Datasheet - Page 149

• Manufacturer Part Number: MPC561MZP56
• Manufacturer: Freescale

Specifications of MPC561MZP56

• Cpu Family: MPC56x
• Device Core: PowerPC
• Device Core Size: 32b
• Frequency (max): 56MHz
• Interface Type: QSPI/SCI/SPI/UART
• Total Internal Ram Size: 32KB
• # I/os (max): 56
• Number Of Timers - General Purpose: 22
• Operating Supply Voltage (typ): 2.6/5V
• Operating Supply Voltage (max): 2.7/5.25V
• Operating Supply Voltage (min): 2.5/4.75V
• On-chip Adc: 2(32-chx10-bit)
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 125C
• Operating Temperature Classification: Automotive
• Mounting: Surface Mount
• Pin Count: 388
• Package Type: BGA
• Program Memory Type: ROMLess
• Program Memory Size: Not Required
• Lead Free Status / RoHS Status: Not Compliant

The following sections describe these execution units in greater detail.
3.4.1
The BPU, located within the instruction sequencer, performs condition register look-ahead operations on
conditional branches. The BPU looks through the instruction queue for a conditional branch instruction
and attempts to resolve it early, achieving the effect of a zero-cycle branch in many cases.
The BPU uses a bit in the instruction encoding to predict the direction of the conditional branch. Therefore,
when it encounters an unresolved conditional branch instruction, the processor pre-fetches instructions
from the predicted target stream until the conditional branch is resolved.
The BPU uses a calculation feature to compute branch target addresses with three special-purpose,
user-accessible registers: the link register (LR), the count register (CTR), and the condition register (CR).
The BPU calculates the return pointer for a subroutine, then calls and saves it into the LR. The LR also
contains the branch target address for the branch conditional to link register (bclrx) instruction. The CTR
contains the branch target address for the branch conditional to count register (bcctrx) instruction. The
contents of the LR and CTR can be copied to or from any GPR. Because the BPU uses dedicated registers
rather than general-purpose or floating-point registers, execution of branch instructions is independent
from execution of integer instructions. The CR bits indicate conditions that may result from the execution
of relevant instructions.
3.4.2
The IU executes all integer processor instructions (except the integer storage access instructions)
implemented by the load/store unit. The IU contains the following subunits:
The IU also includes the integer exception register (XER) and the general-purpose register file.
IMUL–IDIV and ALU–BFU are implemented as separate execution units. The ALU–BFU unit can
execute one instruction per clock cycle. IMUL–IDIV instructions require multiple clock cycles to execute.
IMUL–IDIV is pipelined for multiply instructions, so that consecutive multiply instructions can be issued
Freescale Semiconductor
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The IMUL–IDIV unit, which implements the integer multiply and divide instructions
The Arithmetic Logic Unit (ALU)–BFU unit, which implements all integer logic, add, subtract,
and bit-field instructions
Floating-point unit (FPU)
Branch Processing Unit (BPU)
Integer Unit (IU)
Integer unit (IU)
Unit
Table 3-1. RCPU Execution Units (continued)
MPC561/MPC563 Reference Manual, Rev. 1.2
Includes implementation of all integer instructions except load/store instructions.
This module includes the GPRs (including GPR history and scoreboard) and the
following subunits: the IMUL-IDIV, which includes the implementation of the
integer multiply and divide instructions and the ALU-BFU, which includes
implementation of all integer logic, add and subtract instructions, and bit field
instructions.
Includes the FPRs (including FPR history and scoreboard) and the
implementation of all floating-point instructions except load/store floating-point
instructions.
Description
Central Processing Unit
3-5