FSAVE
FSAVE
Save Internal Floating-Point State
If in Supervisor State Then
FPU Internal State => State Frame
ELSE TRAP
Assembler Syntax: FSAVE (ea)
Description:
FSAVE allows the completion of any floating-point operation in progress for
the MC68080. It saves the internal state of the floating-point unit in a state frame
located at the effective address. After the save operation, the floating-point unit is in the
idle state, waiting for the execution of the next instruction. The first word written to the
state frame is the format word specifying the size of the frame and the revision number
of the floating-point unit.
Any floating-point operations in progress when an FSAVE instruction is encountered
can be completed before the FSAVE executes, saving an IDLE state frame. Execution
of instructions already in the floating-point unit pipeline continues until completion of all
instructions in the pipeline or generation of an exception by one of the instructions. An
IDLE state frame is created by the FSAVE if no exceptions occurred; otherwise, a
BUSY or an UNIMP stack frame is created