MC68EC000EI16 Freescale Semiconductor, MC68EC000EI16 Datasheet - Page 466

• Manufacturer Part Number: MC68EC000EI16
• Description: IC MPU 32BIT 16MHZ 68-PLCC
• Manufacturer: Freescale Semiconductor

Specifications of MC68EC000EI16

• Processor Type: M680x0 32-Bit
• Speed: 16MHz
• Voltage: 3.3V, 5V
• Mounting Type: Surface Mount
• Package / Case: 68-PLCC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

Supervisor (Privileged) Instructions
FRESTORE
Floating-Point Status Register: Cleared if the state size is NULL; otherwise, not affected.
6-12
The current implementation supports the following four state frames:
NULL:
IDLE:
UNIMP: This state frame is generated only by the MC68040. It is 48 ($30) bytes long.
BUSY:
This state frame is 4 bytes long, with a format word of $0000. An FRE-
STORE operation with this size state frame is equivalent to a hardware reset
of the floating-point unit. The programmer’s model is set to the reset state,
with nonsignaling NANs in the floating-point data registers and zeros in the
floating-point control register, floating-point status register, and floating-
point instruction address register. (Thus, it is unnecessary to load the pro-
grammer’s model before this operation.)
This state frame is 4 bytes long in the MC68040, 28 ($1C) bytes long in the
MC68881, and 60 ($3C) bytes long in the MC68882. An FRESTORE oper-
ation with this state frame causes the floating-point unit to be restored to the
idle state, waiting for the initiation of the next instruction, with no exceptions
pending. The programmer’s model is not affected by loading this type of
state frame.
An FSAVE that generates this size frame indicates either an unimplemented
floating-point instruction or only an E1 exception is pending. This frame is
never generated when an unsupported data type exception is pending or an
E3 exception is pending. If both E1 and E3 exceptions are pending, a BUSY
frame is generated.
This state frame is 96 ($60) bytes long in the MC68040, 184 ($B8) bytes long
in the MC68881, and 216 ($D8) bytes long in the MC68882. An FRESTORE
operation with this size state frame causes the floating-point unit to be
restored to the busy state, executing the instructions that were suspended
by a previous FSAVE operation. The programmer’s model is not affected by
loading this type of state frame; however, the completion of the suspended
instructions after the restore is executed may modify the programmer’s
model.
M68000 FAMILY PROGRAMMER’S REFERENCE MANUAL
(MC68881, MC68882, MC68040 only)
Floating-Point State
Restore Internal
FRESTORE
MOTOROLA