Add 0.9.7 specific comments to RC4 assembler modules.

This commit is contained in:
Andy Polyakov 2004-11-30 15:46:46 +00:00
parent e6e1f4cb5e
commit b7b46c9a87
3 changed files with 14 additions and 7 deletions

View File

@ -1,7 +1,7 @@
#!/usr/local/bin/perl
# At some point it became apparent that the original SSLeay RC4
# assembler implementation performs suboptimal on latest IA-32
# assembler implementation performs suboptimaly on latest IA-32
# microarchitectures. After re-tuning performance has changed as
# following:
#
@ -15,10 +15,12 @@
# In other words code performing further 13% faster on AMD
# would perform almost 2 times slower on Intel PIII...
# For reference! This code delivers ~80% of rc4-amd64.pl
# performance on same Opteron machine.
# performance on the same Opteron machine.
# (**) This number requires compressed key schedule set up by
# RC4_set_key, see commentary section in rc4_skey.c for
# further details.
# RC4_set_key and therefore doesn't apply to 0.9.7 [option for
# compressed key schedule is implemented in 0.9.8 and later,
# see commentary section in rc4_skey.c for further details].
#
# <appro@fy.chalmers.se>
push(@INC,"perlasm","../../perlasm");
@ -130,6 +132,8 @@ sub RC4
&add( $d, 8);
# detect compressed schedule, see commentary section in rc4_skey.c...
# in 0.9.7 context ~50 bytes below RC4_CHAR label remain redundant,
# as compressed key schedule is set up in 0.9.8 and later.
&cmp(&DWP(256,$d),-1);
&je(&label("RC4_CHAR"));
@ -190,7 +194,8 @@ sub RC4
&jmp(&label("finished"));
&align(16);
# this is essentially Intel P4 specific codepath, see rc4_skey.c...
# this is essentially Intel P4 specific codepath, see rc4_skey.c,
# and is engaged in 0.9.8 and later context...
&set_label("RC4_CHAR");
&lea ($ty,&DWP(0,$in,$ty));

View File

@ -30,7 +30,9 @@
# RC4_CHAR. Kind of ironic, huh? As it's apparently impossible to
# compose blended code, which would perform even within 30% marginal
# on either AMD and Intel platforms, I implement both cases. See
# rc4_skey.c for further details...
# rc4_skey.c for further details... This applies to 0.9.8 and later.
# In 0.9.7 context RC4_CHAR codepath is never engaged and ~70 bytes
# of code remain redundant.
$output=shift;

View File

@ -18,7 +18,7 @@
// to input and output streams. Secondly, less obvious, it's possible
// to pull up some references to elements of the key schedule itself.
// Fact is that such prior loads are not safe only for "degenerated"
// key schedule, when all elements equal to the same value, which is
// key schedule, when some elements equal to the same value, which is
// never the case [key schedule setup routine makes sure it's not].
// Furthermore. In order to compress loop body to the minimum, I chose
// to deploy deposit instruction, which substitutes for the whole