RCL - x86-64 instruction reference

rclRotate left through carry flag 
Rotates the destination (first) operand left through the carry flag, treating CF as one extra bit in the rotation.
8086 and later
Intel's reference: RCL/RCR/ROL/ROR 
CFPFAFZFSFDFOF ●–––––?
● set from the result
? undefined afterwards
– not changed
Reads CF
OF Defined only for a count of 1.
A count of 0 leaves every flag unchanged.
Forms  rcl ,  8163264 
 rcl , 1 8163264 
 rcl , cl 8163264 
Operands r/m A general-purpose register or memory location matching the operation’s size, for example rax or qword [rbp-8]. The byte registers ah, bh, ch and dh cannot be used with a REX prefix, including when the memory address uses r8–r15. 
imm8 An 8-bit immediate, -128 to 255. Instructions that sign-extend it to a wider operand interpret the byte as -128 to 127; shift counts do not use this sign extension. 
The rotation ring has 9, 17, 33 or 65 bits for an 8-, 16-, 32- or 64-bit operand. For example, rcl al, 1 moves the old high bit into CF and the old CF into bit 0. rcr rotates in the opposite direction. OF is defined only for a count of one.
The count comes from an immediate or cl. It is masked to six bits for a 64-bit operand, or five bits for smaller operands. For byte and word operands, the masked count is then reduced modulo 9 or 17. For 32- and 64-bit operands, the mask limits the count to 31 or 63; a written count of 32 or 64 respectively masks to zero.
 global _start

section .text
_start:
        mov rax, 12
        mov rbx, 5
        mov rcx, 3
        mov rsi, 9

        rcl rax, 1

        mov rax, 60         ; syscall 60: exit
        xor rdi, rdi
        syscall