Restore Restore The Floating-Point Registers - Texas Instruments TMS320C28 series Reference Manual

Instructions
RESTORE
Restore the Floating-Point Registers
Operands
none
Opcode
LSW: 1110 0101
Restore the floating-point register set (R0H - R7H and STF) from their shadow registers.
Description
The SAVE and RESTORE instructions should be used in high-priority interrupts. That is
interrupts that cannot themselves be interrupted. In low-priority interrupt routines the
floating-point registers should be pushed onto the stack.
The RESTORE instruction cannot be used in any delay slots for pipelined operations.
Restrictions
Doing so will yield invalid results. To avoid this, the proper number of NOPs or
non-pipelined instructions must be inserted before the RESTORE operation.
; The following is INVALID
; The following is VALID
Restoring the status register will overwrite all flags:
Flags
Flag
Modified
This is a single-cycle instruction.
Pipeline
114 Instruction Set
This instruction does not have any operands
0110 0010
MPYF32 R2H, R1H, R0H
RESTORE
MPYF32 R2H, R1H, R0H
NOP
RESTORE
TF ZI
Yes Yes
; 2 pipeline-cycle instruction (2p)
; INVALID, do not use RESTORE in a delay slot
; 2 pipeline-cycle instruction (2p)
; 1 delay cycle, R2H updated after this instruction
; VALID
NI ZF NF
Yes Yes Yes
SPRUEO2A – June 2007 – Revised August 2008
www.ti.com
LUF LVF
Yes Yes
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