# CLEAR B
# REPEAT A TIMES ( INCREASE B )
##B := A
# CLEAR B INCREASE B
# REPEAT A TIMES ( CLEAR B )
##B := ISZERO A
# CLEAR B INCREASE B
# REPEAT A TIMES ( CLEAR B )
# CLEAR A
# REPEAT B TIMES ( INCREASE A )
##A := NOT A
# CLEAR C
# REPEAT A TIMES ( REPEAT B TIMES ( INCREASE C ) )
## C := A*B
## Also logical AND
# CLEAR B
# REPEAT A TIMES (
# CLEAR C INCREASE C
# REPEAT B TIMES ( CLEAR C )
# CLEAR B
# REPEAT C TIMES ( INCREASE B )
# )
##B := MOD2 A
# CLEAR B
# CLEAR C
# REPEAT A TIMES (
# CLEAR D INCREASE D
# REPEAT C TIMES (
# CLEAR D
# INCREASE B
# )
# CLEAR C
# REPEAT D TIMES ( INCREASE C )
# )
## B := HALF A
## C := MOD2 A
INCREASE A INCREASE A INCREASE A
REPEAT A TIMES ( REPEAT A TIMES ( INCREASE A INCREASE A INCREASE A ) )
# A = 192. Maximum collatz sequence has length 179.
REPEAT A TIMES ( # Basically a WHILE TRUE
# Check to terminate
CLEAR B CLEAR C
REPEAT X TIMES (
CLEAR D INCREASE D
REPEAT C TIMES ( CLEAR D INCREASE B )
CLEAR C
REPEAT D TIMES ( INCREASE C )
)
CLEAR D INCREASE D
REPEAT B TIMES ( CLEAR D )
CLEAR E INCREASE E
REPEAT D TIMES ( CLEAR E )
# B := HALF X
# C := MOD2 X
# D := ISZERO HALF X
# E := NOT ISZERO HALF X
REPEAT E TIMES ( # If we do not terminate
PRINT X
REPEAT C TIMES ( # If X is odd, Multiply by 3 and add 1.
CLEAR D INCREASE D INCREASE D
REPEAT X TIMES ( REPEAT D TIMES ( INCREASE X ) )
INCREASE X
)
CLEAR D INCREASE D
REPEAT C TIMES ( CLEAR D )
# D = NOT C
REPEAT D TIMES ( # Otherwise X is even. Divide by 2.
CLEAR X
REPEAT B TIMES ( INCREASE X )
)
)
)
PRINT X
