bftool

   1 #!/usr/bin/perl -sw
   2 #RE tool, decodes hex into bitfield descriptions {pos,len}
   3 #   supports disjoint bitfields
   4 #   supports mixed 64bit and 32bit (in envydis's endianness) hex words
   5 #   modes: and, or, xor (mask, diff)
   6 #Examples:
   7 #   find a diff between two OPs:
   8 #        ./bftool -op=xor 8540dc00001c0002 8540dc00001c3c02
   9 #     or ./bftool -op=xor 8540dc00001c0002 001c3c02 8540dc00
  10 #     or ./bftool -op=xor 001c0002 8540dc00 001c3c02 8540dc00
  11 #        > x: U8{0x8540dc00001c0002} U4{0x001c0002,0x8540dc00}
  12 #          y: U8{0x8540dc00001c3c02} U4{0x001c3c02,0x8540dc00}
  13 #          z: U8{0x0000000000003c00} U4{0x00003c00,0x00000000}
  14 #          {pos,len} = {10,4} = {0xa,4}
  15 #   find a match against a mask:
  16 #        ./bftool -op=and 3fc0000000000000 8540dc00001c0002
  17 #     or ./bftool -op=and 3fc0000000000000 001c0002 8540dc00
  18 #     ...
  19 #           U8{0x0540000000000000} U4{0x00000000,0x05400000}
  20 #           54,1
  21 #           56,1
  22 #           58,1
  23 use Data::Dumper;
  24 no warnings "portable";
  25 my $op = $op || "nop";
  26 sub readhex{
  27     my $A = shift;
  28     my $x = shift(@$A);
  29     return undef if not defined($x);
  30     return hex($x) if(length($x)>8 or scalar(@$A)==0 or length($A->[0])>8);
  31     my $y = shift(@$A);
  32     return hex($x)|hex($y) << 32;
  33 }
  34 my $x = readhex(\@ARGV) || undef;
  35 my $y = readhex(\@ARGV) || undef;
  36 my $z = 0;
  37 if($op eq "nop"){
  38     $z = $x;
  39 }
  40 elsif($op eq "and"){
  41     $z = $x & $y;
  42 }
  43 elsif($op eq "xor"){
  44     $z = $x ^ $y;
  45 }
  46 elsif($op eq "or"){
  47     $z = $x | $y;
  48 }
  49 print sprintf("x: U8{0x%016x} U4{0x%08x,0x%08x}\n",$x,$x&0xFFFFFFFF,($x>>32)&0xFFFFFFFF);
  50 print sprintf("y: U8{0x%016x} U4{0x%08x,0x%08x}\n",$y,$y&0xFFFFFFFF,($y>>32)&0xFFFFFFFF);
  51 print sprintf("z: U8{0x%016x} U4{0x%08x,0x%08x}\n",$z,$z&0xFFFFFFFF,($z>>32)&0xFFFFFFFF);
  52 my $pos=0;
  53 while($z!=0){
  54     while(($z&0x1) eq 0){
  55         $pos++;
  56         $z = $z >> 1;
  57     }
  58     my $len=0;
  59     while(($z&0x1) eq 1){
  60         $len++;
  61         $z = $z >> 1;
  62     }
  63     print sprintf("{pos,len} = {%d,%d} = {0x%x,%d}\n",$pos,$len,$pos,$len);
  64     $pos+=$len;
  65 }