MC68EC000EI10 Freescale Semiconductor, MC68EC000EI10 Datasheet - Page 511

• Manufacturer Part Number: MC68EC000EI10
• Description: IC MPU 32BIT 10MHZ 68-PLCC
• Manufacturer: Freescale Semiconductor

Specifications of MC68EC000EI10

• Processor Type: M680x0 32-Bit
• Speed: 10MHz
• Voltage: 3.3V, 5V
• Mounting Type: Surface Mount
• Package / Case: 68-PLCC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

PRESTORE
Operation:
Assembler
Syntax:
Attributes:
Description: The MC68851 aborts execution of any operation in progress. New
MOTOROLA
programmer registers and internal states are loaded from the state frame located at the
effective address. The first word at the specified address is the format word of the state
frame, specifying the size of the frame and the revision number of the MC68851 that
created it. The MC68020 writes the first word to the MC68851 restore coprocessor
interface register, initiating the restore operation. Then it reads the response
coprocessor interface register to verify that the MC68851 recognizes the format as
valid. The format is invalid if the MC68851 does not recognize the frame size or the
revision number does not match. If the format is invalid, the MC68020 takes a format
exception, and the MC68851 returns to the idle state with its user visible registers
unchanged. However, if the format is valid, then the appropriate state frame loads,
starting at the specified location and proceeding up through the higher addresses.
The PRESTORE instruction restores the nonuser visible state of the MC68851 as well
as the PMMU status register, CPU root pointer, supervisor root pointer, current access
level, valid access level, and stack change control registers of the user programming
model. In addition, if any breakpoints are enabled, all breakpoint acknowledge control
and breakpoint acknowledge data registers are restored. This instruction is the inverse
of the PSAVE instruction.
The current implementation of the MC68851 supports four state frame sizes:
NULL:
IDLE:
This state frame is 4 bytes long, with a format word of $0. A PRESTORE with
this size state frame places the MC68851 in the idle state with no coproces-
sor or module operations in progress.
This state frame is 36 ($24) bytes long. A PRESTORE with this size state
frame causes the MC68851 to place itself in an idle state with no coproces-
sor operations in progress and no breakpoints enabled. A module operation
may or may not be in progress. This state frame restores the minimal set of
MC68851 registers.
M68000 FAMILY PROGRAMMER’S REFERENCE MANUAL
If Supervisor State
Else TRAP
PRESTORE < ea >
Unsized, Privileged
Then MC68851 State Frame
Registers
PMMU Restore Function
(MC68851)
Internal State, Programmer
Supervisor (Privileged) Instructions
PRESTORE
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