Minor AES x86 assembler tune-up.

diff --git a/crypto/aes/asm/aes-586.pl b/crypto/aes/asm/aes-586.pl
index d728e3e661efa9694dec7384d23ebb3ecce50c3e..c61ed6bdb29df6ebc29bc0c7e29d8019b2e080b7 100755 (executable)
--- a/crypto/aes/asm/aes-586.pl
+++ b/crypto/aes/asm/aes-586.pl
@@ -24,13 +24,19 @@
 # performance improvement [as you might recall]. As AES code is hungry
 # for scaling too, I [try to] avoid the latter by favoring off-by-2
 # shifts and masking the result with 0xFF<<2 instead of "boring" 0xFF.
+#
+# As was shown by Dean Gaudet <dean@arctic.org>, the above note turned
+# void. Performance improvement with off-by-2 shifts was observed on
+# intermediate implementation, which was spilling yet another register
+# to stack... Final offset*4 code below runs just a tad faster on P4,
+# but exhibits up to 10% improvement on other cores.
 
 push(@INC,"perlasm","../../perlasm");
 require "x86asm.pl";
 
 &asm_init($ARGV[0],"aes-586.pl",$ARGV[$#ARGV] eq "386");
 
-$small_footprint=1;    # $small_footprint=1 code is 5-9% slower, but
+$small_footprint=1;    # $small_footprint=1 code is 4-6% slower, but
                        # 5 times smaller! I default to compact code.
 $s0="eax";
 $s1="ebx";
@@ -41,25 +47,27 @@ sub encstep()
 { my ($i,$te,@s) = @_;
   my $tmp,$out;
 
-       if ($i==3)  {   $out=$s[0]; &mov ("edi",&DWP(12,"esp"));}
-       else        {   $out="esi"; &mov ($out,$s[0]);          }
-                       &shr    ($out,24-2);
-                       &and    ($out,0xFF<<2);
-                       &mov    ($out,&DWP(1024*0,$te,$out));
+       # lines marked with ## denote same $sN...
+       if ($i==3)  {   &mov    ("edi",&DWP(12,"esp"));
+                       &movz   ($out=$s[0],&HB($s[0]));        }       ##
+       else        {   &mov    ($out="esi",$s[0]);
+                       &shr    ($out,24);                      }
+                       &mov    ($out,&DWP(1024*0,$te,$out,4));
 
-       if ($i==3)  {   $tmp=$s[1];                             }
-       else        {   $tmp="edi"; &mov ($tmp,$s[1]);          }
-                       &shr    ($tmp,16-2);
-                       &and    ($tmp,0xFF<<2);
-                       &xor    ($out,&DWP(1024*1,$te,$tmp));
+       if ($i==2)  {   &movz   ($tmp="edi",&LB($s[1]));        }       ##
+       else        {   $i==3?$tmp=$s[1]:&mov($tmp="edi",$s[1]);
+                       &shr    ($tmp,16);
+                       &and    ($tmp,0xFF);                    }
+                       &xor    ($out,&DWP(1024*1,$te,$tmp,4));
 
        if ($i==3)  {   $tmp=$s[2]; &mov ($s[1],&DWP(0,"esp")); }
        else        {   $tmp="edi";                             }
                        &movz   ($tmp,&HB($s[2]));
                        &xor    ($out,&DWP(1024*2,$te,$tmp,4));
+       if ($i==1)  {   &shr    ($s[2],16);                     }       ##
 
        if ($i==3)  {   $tmp=$s[3]; &mov ($s[2],&DWP(4,"esp")); }
-       else        {   $tmp="edi"; &mov ($tmp,$s[3]);          } 
+       else        {   &mov    ($tmp="edi",$s[3]);             } 
                        &and    ($tmp,0xFF);
                        &xor    ($out,&DWP(1024*3,$te,$tmp,4));
        if ($i<2)   {   &mov    (&DWP(4*$i,"esp"),$out);        }
@@ -70,30 +78,31 @@ sub enclast()
 { my ($i,$te,@s)=@_;
   my $tmp,$out;
 
-       if ($i==3)  {   $out=$s[0]; &mov ("edi",&DWP(12,"esp"));}
-       else        {   $out="esi"; &mov ($out,$s[0]);          }
-                       &shr    ($out,24-2);
-                       &and    ($out,0xFF<<2);
-                       &mov    ($out,&DWP(0,$te,$out));
+       if ($i==3)  {   &mov    ("edi",&DWP(12,"esp"));
+                       &movz   ($out=$s[0],&HB($s[0]));        }       ##
+       else        {   &mov    ($out="esi",$s[0]);
+                       &shr    ($out,24);                      }
+                       &mov    ($out,&DWP(0,$te,$out,4));
                        &and    ($out,0xff000000);
 
-       if ($i==3)  {   $tmp=$s[1];                             }
-       else        {   $tmp="edi"; &mov ($tmp,$s[1]);          }
-                       &shr    ($tmp,16-2);
-                       &and    ($tmp,0xFF<<2);
-                       &mov    ($tmp,&DWP(0,$te,$tmp));
+       if ($i==2)  {   &movz   ($tmp="edi",&LB($s[1]));        }       ##
+       else        {   $i==3?$tmp=$s[1]:&mov($tmp="edi",$s[1]);
+                       &shr    ($tmp,16);
+                       &and    ($tmp,0xFF);                    }
+                       &mov    ($tmp,&DWP(0,$te,$tmp,4));
                        &and    ($tmp,0x00ff0000);
                        &xor    ($out,$tmp);
 
        if ($i==3)  {   $tmp=$s[2]; &mov ($s[1],&DWP(0,"esp")); }
-       else        {   $tmp="edi";                             }
+       else        {   $tmp="edi";                             }
                        &movz   ($tmp,&HB($s[2]));
                        &mov    ($tmp,&DWP(0,$te,$tmp,4));
                        &and    ($tmp,0x0000ff00);
+       if ($i==1)  {   &shr    ($s[2],16);                     }       ##
                        &xor    ($out,$tmp);
 
        if ($i==3)  {   $tmp=$s[3]; &mov ($s[2],&DWP(4,"esp")); }
-       else        {   $tmp="edi"; &mov ($tmp,$s[3]);          } 
+       else        {   &mov    ($tmp="edi",$s[3]);             } 
                        &and    ($tmp,0xFF);
                        &mov    ($tmp,&DWP(0,$te,$tmp,4));
                        &and    ($tmp,0x000000ff);
@@ -565,17 +574,18 @@ sub decstep()
 { my ($i,$td,@s) = @_;
   my $tmp,$out;
 
-       if ($i==3)  {   $out=$s[0]; &mov ("edi",&DWP(12,"esp"));}
-       else        {   $out="esi"; &mov ($out,$s[0]);          }
-                       &shr    ($out,24-2);
-                       &and    ($out,0xFF<<2);
-                       &mov    ($out,&DWP(1024*0,$td,$out));
+       if ($i==2)  {   &movz   ($out="esi",&HB($s[0]));        }       ##
+       elsif($i==3){   &mov    ("edi",&DWP(12,"esp"));
+                       &shr    ($out=$s[0],24);                }
+       else        {   &mov    ($out="esi",$s[0]);
+                       &shr    ($out,24);                      }
+                       &mov    ($out,&DWP(1024*0,$td,$out,4));
 
-       if ($i==3)  {   $tmp=$s[1];                             }
-       else        {   $tmp="edi"; &mov ($tmp,$s[1]);          }
-                       &shr    ($tmp,16-2);
-                       &and    ($tmp,0xFF<<2);
-                       &xor    ($out,&DWP(1024*1,$td,$tmp));
+       if ($i==3)  {   $tmp=$s[1];                             }       ##
+       else        {   &mov    ($tmp="edi",$s[1]);
+                       &shr    ($tmp,16);                      }
+                       &and    ($tmp,0xFF);
+                       &xor    ($out,&DWP(1024*1,$td,$tmp,4));
 
        if ($i==3)  {   $tmp=$s[2]; &mov ($s[1],"esi");         }
        else        {   $tmp="edi";                             }
@@ -583,7 +593,8 @@ sub decstep()
                        &xor    ($out,&DWP(1024*2,$td,$tmp,4));
 
        if ($i==3)  {   $tmp=$s[3]; &mov ($s[2],&DWP(4,"esp")); }
-       else        {   $tmp="edi"; &mov ($tmp,$s[3]);          } 
+       else        {   &mov    ($tmp="edi",$s[3]);             }
+       if ($i==1)  {   &shr    ($s[3],16);                     }       ##
                        &and    ($tmp,0xFF);
                        &xor    ($out,&DWP(1024*3,$td,$tmp,4));
        if ($i<2)   {   &mov    (&DWP(4*$i,"esp"),$out);        }
@@ -594,18 +605,19 @@ sub declast()
 { my ($i,$td,@s)=@_;
   my $tmp,$out;
 
-       if ($i==3)  {   $out=$s[0]; &mov ("edi",&DWP(12,"esp"));}
-       else        {   $out="esi"; &mov ($out,$s[0]);          }
-                       &shr    ($out,24-2);
-                       &and    ($out,0xFF<<2);
-                       &mov    ($out,&DWP(0,$td,$out));
+       if ($i==2)  {   &movz   ($out="esi",&HB($s[0]));        }       ##
+       elsif($i==3){   &mov    ("edi",&DWP(12,"esp"));
+                       &shr    ($out=$s[0],24);                }
+       else        {   &mov    ($out="esi",$s[0]);
+                       &shr    ($out,24);                      }
+                       &mov    ($out,&DWP(0,$td,$out,4));
                        &and    ($out,0xff000000);
 
-       if ($i==3)  {   $tmp=$s[1];                             }
-       else        {   $tmp="edi"; &mov ($tmp,$s[1]);          }
-                       &shr    ($tmp,16-2);
-                       &and    ($tmp,0xFF<<2);
-                       &mov    ($tmp,&DWP(0,$td,$tmp));
+       if ($i==3)  {   $tmp=$s[1];                             }       ##
+       else        {   &mov    ($tmp="edi",$s[1]);
+                       &shr    ($tmp,16);                      }
+                       &and    ($tmp,0xFF);
+                       &mov    ($tmp,&DWP(0,$td,$tmp,4));
                        &and    ($tmp,0x00ff0000);
                        &xor    ($out,$tmp);
 
@@ -617,7 +629,8 @@ sub declast()
                        &xor    ($out,$tmp);
 
        if ($i==3)  {   $tmp=$s[3]; &mov ($s[2],&DWP(4,"esp")); }
-       else        {   $tmp="edi"; &mov ($tmp,$s[3]);          } 
+       else        {   &mov    ($tmp="edi",$s[3]);             }
+       if ($i==1)  {   &shr    ($s[3],16);                     }       ##
                        &and    ($tmp,0xFF);
                        &mov    ($tmp,&DWP(0,$td,$tmp,4));
                        &and    ($tmp,0x000000ff);