ref: c0c0b95a971cc5da839e7453ac3c7c069b5f20cd 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