## See findcset.c and masde4.c.
        .intel_syntax noprefix

find_cset:
        mov rax, rdi    # Parsed token starts at the beginning of input.
    1:  cmp rdi, rsi    # Are we at the end of input?
        je 1f           # If so, go to end of parsing.
        mov r9b, [rdi]  # Load input character into r9l
        mov r8, rdx     # Load first delimiter pointer into r8
    2:  cmp r8, rcx     # Check for last delimiter
        je 2f           # If so, exit inner loop
        mov r10b, [r8]  # Load delimiter into r10l
        cmp r10b, r9b   # Is this delimiter found here?
        je 1f           # If so, we’re done.
        inc r8          # Otherwise, move to next delimiter
        jmp 2b          # and repeat inner loop.
    2:  inc rdi         # If no more delimiters, go to next input byte
        jmp 1b          # and repeat outer loop.
    1:  mov rdx, rdi    # End of token is beginning of remaining input.
        ret