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chacha/asm/chacha-x86.pl: improve [backward] portability.

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(Imports upstream's d89773d659129368a341df746476da445d47ad31.)

In order to minimize dependency on assembler version a number of
post-SSE2 instructions are encoded manually. But in order to simplify
the procedure only register operands are considered. Non-register
operands are passed down to assembler. Module in question uses pshufb
with memory operands, and old [GNU] assembler can't handle it.
Fortunately in this case it's possible skip just the problematic
segment without skipping SSSE3 support altogether.

Change-Id: Ic3ba1eef14170f9922c2cc69e0d57315e99a788b
Reviewed-on: https://boringssl-review.googlesource.com/13778
Commit-Queue: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
This commit is contained in:
Adam Langley 2017-02-09 13:56:50 -08:00 committed by David Benjamin
parent 5ca18d8a47
commit b99dc55f21
1 changed files with 8 additions and 0 deletions
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8
crypto/chacha/asm/chacha-x86.pl
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@ -40,6 +40,7 @@ open STDOUT,">$output";
&asm_init($ARGV[0],"chacha-x86.pl",$ARGV[$#ARGV] eq "386");
$xmm=$ymm=1;
$gasver=999; # enable everything
$a="eax";
($b,$b_)=("ebx","ebp");
@ -436,6 +437,12 @@ my ($ap,$bp,$cp,$dp)=map(($_&~3)+(($_-1)&3),($ai,$bi,$ci,$di)); # previous
&label("pic_point"),"eax"));
&movdqu ("xmm3",&QWP(0,"ebx")); # counter and nonce
if (defined($gasver) && $gasver>=2.17) { # even though we encode
# pshufb manually, we
# handle only register
# operands, while this
# segment uses memory
# operand...
&cmp ($len,64*4);
&jb (&label("1x"));
@ -617,6 +624,7 @@ my ($ap,$bp,$cp,$dp)=map(($_&~3)+(($_-1)&3),($ai,$bi,$ci,$di)); # previous
&paddd ("xmm2",&QWP(16*6,"eax")); # +four
&pand ("xmm3",&QWP(16*7,"eax"));
&por ("xmm3","xmm2"); # counter value
}
{
my ($a,$b,$c,$d,$t,$t1,$rot16,$rot24)=map("xmm$_",(0..7));