.text
	.global	bitrev
	.type	bitrev, @function
bitrev:
    mov %rdi,%rax
    mov %rdi,%rbx
    and $0x5555555555555555,%rax
    shl $1,%rax
    and $0xAAAAAAAAAAAAAAAA,%rbx
    shr $1,%rbx
    or %rbx,%rax
    mov %rax,%rbx
    and $0x3333333333333333,%rax
    shl $2,%rax
    and $0xCCCCCCCCCCCCCCCC,%rbx
    shr $2,%rbx
    or %rbx,%rax
    mov %rax,%rbx
    and $0x0F0F0F0F0F0F0F0F,%rax
    shl $4,%rax
    and $0xF0F0F0F0F0F0F0F0,%rbx
    shr $4,%rbx
    or %rbx,%rax
    mov %rax,%rbx
    and $0x00FF00FF00FF00FF,%rax
    shl $8,%rax
    and $0xFF00FF00FF00FF00,%rbx
    shr $8,%rbx
    or %rbx,%rax
    mov %rax,%rbx
    and $0x0000FFFF0000FFFF,%rax
    shl $16,%rax
    and $0xFFFF0000FFFF0000,%rbx
    shr $16,%rbx
    or %rbx,%rax
    mov %rax,%rbx
    and $0x00000000FFFFFFFF,%rax
    shl $32,%rax
    and $0xFFFFFFFF00000000,%rbx
    shr $32,%rbx
    or %rbx,%rax
    ret

	.size	bitrev, .-bitrev