Skip to content
Unverified Commit 3d2920cf authored by Paul Burton's avatar Paul Burton
Browse files

MIPS: bitops: Only use ins for bit 16 or higher



set_bit() can set bits 0-15 using an ori instruction, rather than
loading the value -1 into a register & then using an ins instruction.

That is, rather than the following:

  li   t0, -1
  ll   t1, 0(t2)
  ins  t1, t0, 4, 1
  sc   t1, 0(t2)

We can have the simpler:

  ll   t1, 0(t2)
  ori  t1, t1, 0x10
  sc   t1, 0(t2)

The or path already allows immediates to be used, so simply restricting
the ins path to bits that don't fit in immediates is sufficient to take
advantage of this.

Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: linux-kernel@vger.kernel.org
parent fe7cd97e
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment