If i<j then the algorithm for `Add i j' is

   FindReg i                  Find least significant end of register i
   L5
   Write 1                    Leave a mark
   R
   Rto 2 1
   ...     (j-i+1 times)      Find least significant end of register j
   Rto 2 1
   L4                         Move to actual bit
:L0:                          Henceforth c=0
   `0 0 0 L 1; 0 1 1 L :L2:'  Read b -- henceforth b=0
   Write 1                    Leave mark
   L2
   `0 0 0 L 1; 0 1 1 R :L6:'  If this is the last bit, go to :L6:
   Lto 2 1
   ...     (j-i+1 times)      If not, find mark in register i
   Lto 2 1
   R4                         Move to bit
   `0 0 0 L 1; 0 1 1 L 1'     and add in b(=0) and c(=0)
:L1:
   L2                         Move to mark
   Write 0                    and erase it
   L4
   Write 1                    Mark next bit
   R
   Rto 2 1
   ...     (j-i+1 times)      Find mark in register j
   Rto 2 1
   L
   Write 0                    Remove it
   L3                         Move to next bit
   Goto :L0:                  and loop round
:L2:                          Henceforth b=1
   Write 1
   L2
   `0 0 0 L 1; 0 1 1 R :L7:'
   Lto 2 1
   ...     (j-i+1 times)
   Lto 2 1
   R4
   `0 0 1 L :L1:; 0 1 0 L :L4:'  Add in b(=1) and c(=0); find new carry
:L3:                          Henceforth c=1
   `0 0 0 L 1; 0 1 1 L :L5:'  Read b -- henceforth b=0
   Write 1
   L2
   `0 0 0 L 1; 0 1 1 R :L7:'
   Lto 2 1
   ...     (j-i+1 times)
   Lto 2 1
   R4
   `0 0 1 L :L1:; 0 1 0 L 1'  Add in b(=0) and c(=1); find new carry
:L4:
   L2
   Write 0
   L4
   Write 1
   R
   Rto 2 1
   ...     (j-i+1 times)
   Rto 2 1
   L
   Write 0
   L3
   Goto :L3:
:L5:
   Write 1
   L2
   `0 0 0 L 1; 0 1 1 R :L6:'
   Lto 2 1
   ...     (j-i+1 times)
   Lto 2 1
   R4
   `0 0 0 L :L4:; 0 1 1 L :L4:'  Add in b(=1) and c(=1); find new carry
:L6:
   R
   Write 0                    Remove mark
   Lto 2 1
   ...     (j-i+1 times)      Find last bit of register i
   Lto 2 1
   R4                         Move to actual bit
   `0 0 0 L :L8:; 0 1 1 L :L8:'   and add (b+c=0)
:L7:
   R
   Write 0
   Lto 2 1
   ...     (j-i+1 times)
   Lto 2 1
   R4
   `0 0 1 L 1; 0 1 0 L 1'     Add (b+c=1)
:L8:
   FindStart                  Return to home position

If i>j then it is

   FindReg i                  Move to register i
   L3
   Write 1                    Leave mark
   Lto 2 1
   ...     (i-j times)        Move to register j
   Lto 2 1
   L                          Move to actual bit
:L0:                          Henceforth c=0
   `0 0 0 L 1; 0 1 1 L :L2:'  Read b -- henceforth b=0
   L2
   Write 1                    Leave mark
   R
   Rto 2 1
   ...     (i-j times)        Find delimiter at start of register i
   Rto 2 1
   `0 0 0 R 1; 0 1 1 R :L6:'  If this is the last bit, go to :L6:
   Rto 2 1                    If not, find mark
   `0 0 0 L 1; 0 1 1 L 1'     and add in b(=0) and c(=0); find new carry
:L1:
   Write 0                    Remove old mark
   L4
   Write 1                    and write new one
   L
   Lto 2 1
   ...     (i-j+1 times)      Find mark left in register j
   Lto 2 1
   R
   Write 0                    Remove it
   L                          Move to next bit
   Goto :L0:                  and loop round
:L2:                          Henceforth b=1
   L2
   Write 1
   R
   Rto 2 1
   ...     (i-j times)
   Rto 2 1
   `0 0 0 R 1; 0 1 1 R :L7:'
   Rto 2 1
   `0 0 1 L 1; 0 1 0 L :L4:'  Add in b(=1) and c(=0); find new carry
   Goto :L1:
:L3:                          Henceforth c=1
   `0 0 0 L 1; 0 1 1 L :L5:'  Read b -- henceforth b=0
   L2
   Write 1
   R
   Rto 2 1
   ...     (i-j times)
   Rto 2 1
   `0 0 0 R 1; 0 1 1 R :L7:'
   Rto 2 1
   `0 0 1 L :L1:; 0 1 0 L 1'  Add in b(=0) and c(=1); find new carry
:L4:
   Write 0
   L4
   Write 1
   L
   Lto 2 1
   ...     (i-j+1 times)
   Lto 2 1
   R
   Write 0
   L
   Goto :L3:
:L5:                          Henceforth b=1
   L2
   Write 1
   R
   Rto 2 1
   ...     (i-j times)
   Rto 2 1
   `0 0 0 R 1; 0 1 1 R :L6:'
   Rto 2 1
   `0 0 0 L 1; 0 1 1 L 1'     Add in b(=1) and c(=1); find new carry
   Goto :L4:
:L6:
   `0 0 0 L :L8:; 0 1 1 L :L8:'    Add final bit (b+c=0)
:L7:
   `0 0 1 L 1; 0 1 0 L 1'          Add final bit (b+c=1)
:L8:
   Write 0                    Remove mark
   L
   FindStart                  Return to home position