16.30 BFM

Bitfield Move.

This instruction is used by the aliases:

  • BFC.
  • BFI.
  • BFXIL.

Syntax

BFM Wd, Wn, #<immr>, #<imms> ; 32-bit

BFM Xd, Xn, #<immr>, #<imms> ; 64-bit

Where:

Wd
Is the 32-bit name of the general-purpose destination register.
Wn
Is the 32-bit name of the general-purpose source register.
<immr>

Depends on the instruction variant:

32-bit general registers
Is the right rotate amount, in the range 0 to 31.
64-bit general registers
Is the right rotate amount, in the range 0 to 63.
<imms>

Depends on the instruction variant:

32-bit general registers
Is the leftmost bit number to be moved from the source, in the range 0 to 31.
64-bit general registers
Is the leftmost bit number to be moved from the source, in the range 0 to 63.
Xd
Is the 64-bit name of the general-purpose destination register.
Xn
Is the 64-bit name of the general-purpose source register.

Usage

Bitfield Move copies any number of low-order bits from a source register into the same number of adjacent bits at any position in the destination register, leaving other bits unchanged.

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