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<?php for($i=0; $i<256; $i++) echo !ord(chr($i)) == $i;
Finding entry points
Branch analysis from position: 0
1 jumps found. (Code = 42) Position 1 = 13
Branch analysis from position: 13
2 jumps found. (Code = 44) Position 1 = 15, Position 2 = 2
Branch analysis from position: 15
1 jumps found. (Code = 62) Position 1 = -2
Branch analysis from position: 2
2 jumps found. (Code = 44) Position 1 = 15, Position 2 = 2
Branch analysis from position: 15
Branch analysis from position: 2
filename:       /in/ARjnd
function name:  (null)
number of ops:  16
compiled vars:  !0 = $i
line     #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
   3     0  E >   ASSIGN                                                   !0, 0
         1      > JMP                                                      ->13
         2    >   INIT_FCALL                                               'ord'
         3        INIT_FCALL                                               'chr'
         4        SEND_VAR                                                 !0
         5        DO_ICALL                                         $2      
         6        SEND_VAR                                                 $2
         7        DO_ICALL                                         $3      
         8        BOOL_NOT                                         ~4      $3
         9        IS_EQUAL                                         ~5      !0, ~4
        10        ECHO                                                     ~5
        11        POST_INC                                         ~6      !0
        12        FREE                                                     ~6
        13    >   IS_SMALLER                                       ~7      !0, 256
        14      > JMPNZ                                                    ~7, ->2
   4    15    > > RETURN                                                   1

Generated using Vulcan Logic Dumper, using php 7.3.0