# FFREE — Free Floating-Point Register

Opcode |  | Mode | Leg Mode | Description
--- | --- | --- | --- | ---
DD C0+i |  |  |  | Sets tag for ST(i) to empty.

## Description ¶

Sets the tag in the FPU tag register associated with register ST(i) to empty (11B). The contents of ST(i) and the FPU stack-top pointer (TOP) are not affected.

This instruction’s operation is the same in non-64-bit modes and 64-bit mode.

## Operation ¶

    TAG(i) := 11B;

## FPU Flags Affected ¶

C0, C1, C2, C3 | undefined.

## Floating-Point Exceptions ¶

None

## Protected Mode Exceptions ¶

#NM | CR0.EM[bit 2] or CR0.TS[bit 3] = 1.
#MF | If there is a pending x87 FPU exception.
#UD | If the LOCK prefix is used.

## Real-Address Mode Exceptions ¶

Same exceptions as in protected mode.

## Virtual-8086 Mode Exceptions ¶

Same exceptions as in protected mode.

## Compatibility Mode Exceptions ¶

Same exceptions as in protected mode.

## 64-Bit Mode Exceptions ¶

Same exceptions as in protected mode.