Are you sure the 32-bit mix4 is correct?

Guess not

$Config{api_versionstring}:5.14.0
$Config{use64bitint}:
$Config{ivsize}:4
$Config{byteorder}:1234
$Config{i16size}:2
$Config{i32size}:4
$Config{i64size}:8
$Config{osname}:MSWin32
$Config{osvers}:5.2
$ENV{PROCESSOR_ARCHITECTURE}:X86

orig            : 11111111000000001111111111111111 ff00ffff
use integer:>>16: 11111111111111111111111100000000 ffffff00
no integer :>>16: 00000000000000001111111100000000 0000ff00

orig            : 00001111000000001111111111111111 0f00ffff
use integer:>>16: 00000000000000000000111100000000 00000f00
no integer :>>16: 00000000000000000000111100000000 00000f00
[download]

Doing low-level unsigned arithmetic can be awkward in perl.

Seems so, this needs more investigation and i dont have a C compiler for that 32bit machine

Thanks for the heads up, I will keep looking deeper

Added:

Re: How to do 'unsigned shift right' in perl? Note that both "<<" and ">>" in Perl are implemented directly using "<<" and ">>" in C. If use integer (see Integer Arithmetic) is in force then signed C integers are used, else unsigned C integers are used.

Added2:

Wow

Ive got the "fix", just like you said, but understanding why it works and "-hash hash3" still doesnt work on 32bit and how mixing IV,UV and possibly NV arithmetic between mix and hash3 is causing the difference hasnt quite gelled yet. I'll be back! Devel::Peek and perlguts will rescue me!

Doing low-level unsigned arithmetic can be awkward in perl.

yupo

ok so i developed an overly debugged version of mix and the revised mix4 and ran it on the 32 bit box

# this is inside a 'use integer;' block 
sub mix4 ($$$) {
# per http://www.perlmonks.org/?node_id=1203705 this is a revised 32bi
+t under 'use integer'; 
    $_[A] -= $_[B]; $_[A] -= $_[C]; { no integer; $_[A] ^= ($_[C]>>13)
+; }
    $_[B] -= $_[C]; $_[B] -= $_[A]; { no integer; $_[B] ^= ($_[A]<< 8)
+; } 
    $_[C] -= $_[A]; $_[C] -= $_[B]; { no integer; $_[C] ^= ($_[B]>>13)
+; } 
    $_[A] -= $_[B]; $_[A] -= $_[C]; { no integer; $_[A] ^= ($_[C]>>12)
+; } 
    $_[B] -= $_[C]; $_[B] -= $_[A]; { no integer; $_[B] ^= ($_[A]<<16)
+; } 
    $_[C] -= $_[A]; $_[C] -= $_[B]; { no integer; $_[C] ^= ($_[B]>> 5)
+; } 
    $_[A] -= $_[B]; $_[A] -= $_[C]; { no integer; $_[A] ^= ($_[C]>> 3)
+; } 
    $_[B] -= $_[C]; $_[B] -= $_[A]; { no integer; $_[B] ^= ($_[A]<<10)
+; } 
    $_[C] -= $_[A]; $_[C] -= $_[B]; { no integer; $_[C] ^= ($_[B]>>15)
+; }
}
[download]

This is mix

# there is no 'use integer;' here; 
sub mix ($$$) {
    $_[A] -= $_[B]; $_[A] -= $_[C]; $_[A] ^= ($_[C]>>13);
    $_[B] -= $_[C]; $_[B] -= $_[A]; $_[B] ^= ($_[A]<< 8);
    $_[C] -= $_[A]; $_[C] -= $_[B]; $_[C] ^= ($_[B]>>13);
    $_[A] -= $_[B]; $_[A] -= $_[C]; $_[A] ^= ($_[C]>>12);
    $_[B] -= $_[C]; $_[B] -= $_[A]; $_[B] ^= ($_[A]<<16);
    $_[C] -= $_[A]; $_[C] -= $_[B]; $_[C] ^= ($_[B]>> 5);
    $_[A] -= $_[B]; $_[A] -= $_[C]; $_[A] ^= ($_[C]>> 3);
    $_[B] -= $_[C]; $_[B] -= $_[A]; $_[B] ^= ($_[A]<<10);
    $_[C] -= $_[A]; $_[C] -= $_[B]; $_[C] ^= ($_[B]>>15);
}
[download]

during the first modification of C mix4exp shows (it is best to look at the following using download version without wrap)

     a1-x c>13  : A   :            59743          0000e95f
     b1-x a< 8  :  B  :                                    -      -162
+9499560          9edfcf58
     c1-a       :   C :                                    -          
+                          -           -59741          ffff16a3
SV = IV(0xc5f738) at 0xc5f73c
  REFCNT = 1
  FLAGS = (PADMY,IOK,pIOK)
  IV = -59741
     c1-b       :   C :                                    -          
+                          -       1629439819          611f474b
SV = IV(0xc5f738) at 0xc5f73c
  REFCNT = 1
  FLAGS = (PADMY,IOK,pIOK)
  IV = 1629439819
     c1-x b>13       : orig 1  :                                 01100
+001000111110100011101001011          611f474b
                     : orig 2  :                                 10011
+110110111111100111101011000          9edfcf58
                     : >>13    :                                 00000
+000000001001111011011111110          0004f6fe
                     : res     :                                 01100
+001000110111011000110110101          611bb1b5
     c1-x b>13  :   C :                                    -          
+                          -       1629204917          611bb1b5

while mixexp shows 


     a1-x c>13  : A   :            59743          0000e95f
     b1-x a< 8  :  B  :                                    -      -162
+9499560          9edfcf58
     c1-a       :   C :                                    -          
+                          -           -59741          ffff16a3
SV = IV(0xc5f418) at 0xc5f41c
  REFCNT = 1
  FLAGS = (PADMY,IOK,pIOK)
  IV = -59741
     c1-b       :   C :                                    -          
+                          -      -2147483648          80000000
SV = PVNV(0xc7355c) at 0xc5f41c
  REFCNT = 1
  FLAGS = (PADMY,NOK,pNOK)
  IV = -59741
  NV = -2665527477
  PV = 0
     c1-x b>13       : orig 1  :                                 10000
+000000000000000000000000000          80000000
                     : orig 2  :                                 10011
+110110111111100111101011000          9edfcf58
                     : >>13    :                                 00000
+000000001001111011011111110          0004f6fe
                     : res     :                                 10000
+000000001001111011011111110          8004f6fe
     c1-x b>13  :   C :                                    -          
+                          -      -2147158274          8004f6fe
[download]

Notice that in mix4exp the Dump shows C stays IV, and shows the proper result of mod(32) arithmetic with A and B .

But notice how in mixexp the Dump shows that after -=A C has stayed IV, with the proper result, but that after -=B C overflowed the IV creating a NV and when it comes to the shift portion it is an overflow indicator (0x80000000) that gets shifted. Of course everything goes to L in a handbasket after that.

Doing low-level unsigned arithmetic can be awkward in perl.

yupo