#!/usr/bin/env tclsh9.0

proc run {A} {
    set B 0; set C 0; set out 0
    while {$A} {
        set B [expr {($A & 7) ^ 5}]
        set C [expr {$A >> $B}]
        set A [expr {$A >> 3}]
        set B [expr {$B ^ 6 ^ $C}]
        set out [expr {($out << 3) | ($B & 7)}]
    }
    return $out
}

proc runp {A} {
    puts [format "%llo (%lld) -> %llo" $A $A [run $A]]
}

proc try {prefix} {
    global target
    set t [expr {$target % 2**(3*(1 + [llength $prefix]))}]
    # puts [format "try t=%llo $prefix" $t]
    set n 0
    foreach d $prefix {set n [expr {$n << 3 | $d}]}
    for {set d 0} {$d <= 7} {incr d} {
        set A [expr {$n << 3 | $d}]
        set out [run $A]
        if {$out == $target} {
            runp $A
            exit
        }
        if {$out == $t} {
            try [list {*}$prefix $d]
        }
    }
}

# runp 0o1000000000000371
# runp 0o3710000000000000
set target 0o2415750316435530
try [list]

# B := A mod 8    # 2,4
# B := B ^ 5      # 1,5
# C := A / 2**B   # 7,5
# A := A / 8      # 0,3
# B := B ^ 6      # 1,6
# B := B ^ C      # 4,3
# out B mod 8     # 5,5
# JMP 0 if A      # 3,0