// +build amd64,!appengine,!popcntgo #define POPCNTQ_DX_DX BYTE $0xf3; BYTE $0x48; BYTE $0x0f; BYTE $0xb8; BYTE $0xd2 // func Popcnt(x uint64) uint64 TEXT ·Popcnt(SB),4,$0-16 MOVQ x+0(FP), DX POPCNTQ_DX_DX MOVQ DX, ret+8(FP) RET