Motorola M68060 User Manual page 407

FSAVE
The following state frames apply to the MC68060.
NULL: An FSAVE instruction that generates this state frame indicates that the
floating-point unit state has not been modified since the last hardware reset
or FRESTORE instruction with a NULL state frame. This indicates that the
programmer's model is in 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 not necessary to save the programmer's model.)
IDLE: An FSAVE instruction that generates this state frame indicates that the
floating-point unit finished in an idle condition and is without any pending
exceptions waiting for the initiation of the next instruction.
EXCP: An FSAVE instruction that generates this size state frame indicates that the
floating-point unit encountered an exception while attempting to complete
the execution of the previous floating-point instructions, or that an FRE-
STORE of an EXCP frame occurred previously.
The FSAVE does not save the programmer's model registers of the floating-point unit;
it saves only the user invisible portion of the machine. The FSAVE instruction may be
used with the FMOVEM instruction to perform a full context save of the floating-point
unit that includes the floating-point data registers and system control registers. To
accomplish a complete context save, first execute an FSAVE instruction to suspend
the current operation and save the internal state, then execute the appropriate
FMOVEM instructions to store the programmer's model.
MOTOROLA
Save Internal Floating-Point State
(MC68060 only)
M68060 USER'S MANUAL
MC68060 Instructions
FSAVE
D-17