Eliminate ~3.5KB of duplicate code in des-586.pl and reserve for folded
authorAndy Polyakov <appro@openssl.org>
Tue, 25 Oct 2005 15:47:09 +0000 (15:47 +0000)
committerAndy Polyakov <appro@openssl.org>
Tue, 25 Oct 2005 15:47:09 +0000 (15:47 +0000)
loop option, which can give further 3KB code reduction.

crypto/des/asm/des-586.pl

index 72ca970..147d2ab 100644 (file)
@@ -18,8 +18,14 @@ require "desboth.pl";
 
 $L="edi";
 $R="esi";
+$trans="ebp";
+$small_footprint=1 if (grep(/\-DOPENSSL_SMALL_FOOTPRINT/,@ARGV));
+# one can discuss setting this variable to 1 unconditionally, as
+# the folded loop is only 3% slower than unrolled, but >7 times smaller
 
 &external_label("DES_SPtrans");
+&DES_encrypt_internal();
+&DES_decrypt_internal();
 &DES_encrypt("DES_encrypt1",1);
 &DES_encrypt("DES_encrypt2",0);
 &DES_encrypt3("DES_encrypt3",1);
@@ -30,6 +36,80 @@ $R="esi";
 
 &asm_finish();
 
+sub DES_encrypt_internal()
+       {
+       &function_begin_B("_x86_DES_encrypt");
+
+       if ($small_footprint)
+           {
+           &lea("edx",&DWP(128,"ecx"));
+           &push("edx");
+           &push("ecx");
+           &set_label("eloop");
+               &D_ENCRYPT(0,$L,$R,0,$trans,"eax","ebx","ecx","edx",&swtmp(0));
+               &comment("");
+               &D_ENCRYPT(1,$R,$L,2,$trans,"eax","ebx","ecx","edx",&swtmp(0));
+               &comment("");
+               &add("ecx",16);
+               &cmp("ecx",&swtmp(1));
+               &mov(&swtmp(0),"ecx");
+               &jb(&label("eloop"));
+           &add("esp",8);
+           }
+       else
+           {
+           &push("ecx");
+           for ($i=0; $i<16; $i+=2)
+               {
+               &comment("Round $i");
+               &D_ENCRYPT($i,$L,$R,$i*2,$trans,"eax","ebx","ecx","edx",&swtmp(0));
+               &comment("Round ".sprintf("%d",$i+1));
+               &D_ENCRYPT($i+1,$R,$L,($i+1)*2,$trans,"eax","ebx","ecx","edx",&swtmp(0));
+               }
+           &add("esp",4);
+       }
+       &ret();
+
+       &function_end_B("_x86_DES_encrypt");
+       }
+       
+sub DES_decrypt_internal()
+       {
+       &function_begin_B("_x86_DES_decrypt");
+
+       if ($small_footprint)
+           {
+           &push("ecx");
+           &lea("ecx",&DWP(128,"ecx"));
+           &push("ecx");
+           &set_label("dloop");
+               &D_ENCRYPT(0,$L,$R,-2,$trans,"eax","ebx","ecx","edx",&swtmp(0));
+               &comment("");
+               &D_ENCRYPT(1,$R,$L,-4,$trans,"eax","ebx","ecx","edx",&swtmp(0));
+               &comment("");
+               &sub("ecx",16);
+               &cmp("ecx",&swtmp(1));
+               &mov(&swtmp(0),"ecx");
+               &ja(&label("dloop"));
+           &add("esp",8);
+           }
+       else
+           {
+           &push("ecx");
+           for ($i=15; $i>0; $i-=2)
+               {
+               &comment("Round $i");
+               &D_ENCRYPT(15-$i,$L,$R,$i*2,$trans,"eax","ebx","ecx","edx",&swtmp(0));
+               &comment("Round ".sprintf("%d",$i-1));
+               &D_ENCRYPT(15-$i+1,$R,$L,($i-1)*2,$trans,"eax","ebx","ecx","edx",&swtmp(0));
+               }
+           &add("esp",4);
+           }
+       &ret();
+
+       &function_end_B("_x86_DES_decrypt");
+       }
+       
 sub DES_encrypt
        {
        local($name,$do_ip)=@_;
@@ -41,7 +121,6 @@ sub DES_encrypt
 
        &comment("");
        &comment("Load the 2 words");
-       $trans="ebp";
 
        if ($do_ip)
                {
@@ -75,38 +154,16 @@ sub DES_encrypt
 
        # PIC-ification:-)
        &picmeup($trans,"DES_SPtrans");
-       #if ($cpp)      { &picmeup($trans,"DES_SPtrans");   }
-       #else           { &lea($trans,&DWP("DES_SPtrans")); }
 
        &mov(   "ecx",  &wparam(1)      );
-       &cmp("ebx","0");
-       &je(&label("start_decrypt"));
 
-       for ($i=0; $i<16; $i+=2)
-               {
-               &comment("");
-               &comment("Round $i");
-               &D_ENCRYPT($i,$L,$R,$i*2,$trans,"eax","ebx","ecx","edx");
-
-               &comment("");
-               &comment("Round ".sprintf("%d",$i+1));
-               &D_ENCRYPT($i+1,$R,$L,($i+1)*2,$trans,"eax","ebx","ecx","edx");
-               }
-       &jmp(&label("end"));
-
-       &set_label("start_decrypt");
-
-       for ($i=15; $i>0; $i-=2)
-               {
-               &comment("");
-               &comment("Round $i");
-               &D_ENCRYPT(15-$i,$L,$R,$i*2,$trans,"eax","ebx","ecx","edx");
-               &comment("");
-               &comment("Round ".sprintf("%d",$i-1));
-               &D_ENCRYPT(15-$i+1,$R,$L,($i-1)*2,$trans,"eax","ebx","ecx","edx");
-               }
-
-       &set_label("end");
+       &cmp("ebx","0");
+       &je(&label("decrypt"));
+       &call("_x86_DES_encrypt");
+       &jmp(&label("done"));
+       &set_label("decrypt");
+       &call("_x86_DES_decrypt");
+       &set_label("done");
 
        if ($do_ip)
                {
@@ -140,7 +197,7 @@ sub DES_encrypt
 
 sub D_ENCRYPT
        {
-       local($r,$L,$R,$S,$trans,$u,$tmp1,$tmp2,$t)=@_;
+       local($r,$L,$R,$S,$trans,$u,$tmp1,$tmp2,$t,$wp1)=@_;
 
         &mov(  $u,             &DWP(&n2a($S*4),$tmp2,"",0));
        &xor(   $tmp1,          $tmp1);
@@ -167,7 +224,7 @@ sub D_ENCRYPT
        &and(   $t,             "0xff"  );
         &xor(  $L,             &DWP("0x600",$trans,$tmp1,0));
         &xor(  $L,             &DWP("0x700",$trans,$tmp2,0));
-       &mov(   $tmp2,          &wparam(1)      );
+       &mov(   $tmp2,          $wp1    );
         &xor(  $L,             &DWP("0x400",$trans,$u,0));
         &xor(  $L,             &DWP("0x500",$trans,$t,0));
        }