ref: 4efd6777d6644058c97db129288a4ab48fcfd92d dir: /mbld/cpufeatures+plan9-x64.s/
TEXT bld$cpufeatures+0(SB),$0 MOVL $0x1,AX CPUID MOVL CX, AX MOVL DX, DX ROLQ $32, DX ORQ DX, AX RET