ARM base instruction -- bfxil
Bitfield Extract and Insert Low copies a bitfield of <width> bits starting from bit position <lsb> in the source register to the least significant bits of the destination register, leaving the other destination bits unchanged.
位域提取并插入低位将<width>位的位域从源寄存器中的位位置<lsb>开始复制到目标寄存器的最低有效位，保持其他目标位不变。
32-bit variant
Applies when sf == 0 && N == 0.
BFXIL <Wd>, <Wn>, #<lsb>, #<width>
is equivalent to
BFM <Wd>, <Wn>, #<lsb>, #(<lsb>+<width>-1)
and is the preferred disassembly when UInt(imms) >= UInt(immr).
64-bit variant
Applies when sf == 1 && N == 1.
BFXIL <Xd>, <Xn>, #<lsb>, #<width>
is equivalent to
BFM <Xd>, <Xn>, #<lsb>, #(<lsb>+<width>-1)
and is the preferred disassembly when UInt(imms) >= UInt(immr).
4005a0: d2800000 mov x0, #0x0 // #0
4005a4: b94023e1 ldr w1, [sp, #32]
4005a8: b3407c20 bfxil x0, x1, #0, #32