crypto/bn/asm/x86_64-mont.pl: minor optimization.
[openssl.git] / crypto / bn / asm / x86_64-mont.pl
index 84fea1a059bd5f5eec03fa19c427a1d0912ebb32..ba938d6ccdddfb9f6fe384ac3197a28830a6b3e6 100755 (executable)
@@ -1,7 +1,7 @@
 #!/usr/bin/env perl
 
 # ====================================================================
-# Written by Andy Polyakov <appro@fy.chalmers.se> for the OpenSSL
+# Written by Andy Polyakov <appro@openssl.org> for the OpenSSL
 # project. The module is, however, dual licensed under OpenSSL and
 # CRYPTOGAMS licenses depending on where you obtain it. For further
 # details see http://www.openssl.org/~appro/cryptogams/.
 # respectful 50%. It remains to be seen if loop unrolling and
 # dedicated squaring routine can provide further improvement...
 
-$output=shift;
-open STDOUT,"| $^X ../perlasm/x86_64-xlate.pl $output";
+# July 2011.
+#
+# Add dedicated squaring procedure. Performance improvement varies
+# from platform to platform, but in average it's ~5%/15%/25%/33%
+# for 512-/1024-/2048-/4096-bit RSA *sign* benchmarks respectively.
+
+# August 2011.
+#
+# Unroll and modulo-schedule inner loops in such manner that they
+# are "fallen through" for input lengths of 8, which is critical for
+# 1024-bit RSA *sign*. Average performance improvement in comparison
+# to *initial* version of this module from 2005 is ~0%/30%/40%/45%
+# for 512-/1024-/2048-/4096-bit RSA *sign* benchmarks respectively.
+
+# June 2013.
+#
+# Optmize reduction in squaring procedure and improve 1024+-bit RSA
+# sign performance by 10-16% on Intel Sandy Bridge and later
+# (virtually same on non-Intel processors).
+
+$flavour = shift;
+$output  = shift;
+if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }
+
+$win64=0; $win64=1 if ($flavour =~ /[nm]asm|mingw64/ || $output =~ /\.asm$/);
+
+$0 =~ m/(.*[\/\\])[^\/\\]+$/; $dir=$1;
+( $xlate="${dir}x86_64-xlate.pl" and -f $xlate ) or
+( $xlate="${dir}../../perlasm/x86_64-xlate.pl" and -f $xlate) or
+die "can't locate x86_64-xlate.pl";
+
+open OUT,"| \"$^X\" $xlate $flavour $output";
+*STDOUT=*OUT;
 
 # int bn_mul_mont(
 $rp="%rdi";    # BN_ULONG *rp,
@@ -27,7 +58,6 @@ $n0="%r8";    # const BN_ULONG *n0,
 $num="%r9";    # int num);
 $lo0="%r10";
 $hi0="%r11";
-$bp="%r12";    # reassign $bp
 $hi1="%r13";
 $i="%r14";
 $j="%r15";
@@ -41,6 +71,18 @@ $code=<<___;
 .type  bn_mul_mont,\@function,6
 .align 16
 bn_mul_mont:
+       test    \$3,${num}d
+       jnz     .Lmul_enter
+       cmp     \$8,${num}d
+       jb      .Lmul_enter
+       cmp     $ap,$bp
+       jne     .Lmul4x_enter
+       test    \$7,${num}d
+       jz      .Lsqr8x_enter
+       jmp     .Lmul4x_enter
+
+.align 16
+.Lmul_enter:
        push    %rbx
        push    %rbp
        push    %r12
@@ -48,53 +90,74 @@ bn_mul_mont:
        push    %r14
        push    %r15
 
-       lea     2($num),%rax
-       mov     %rsp,%rbp
-       neg     %rax
-       lea     (%rsp,%rax,8),%rsp      # tp=alloca(8*(num+2))
+       mov     ${num}d,${num}d
+       lea     2($num),%r10
+       mov     %rsp,%r11
+       neg     %r10
+       lea     (%rsp,%r10,8),%rsp      # tp=alloca(8*(num+2))
        and     \$-1024,%rsp            # minimize TLB usage
-       mov     %rbp,8(%rsp,$num,8)     # tp[num+1]=%rsp
-       mov     %rdx,$bp                # $bp reassigned, remember?
 
+       mov     %r11,8(%rsp,$num,8)     # tp[num+1]=%rsp
+.Lmul_body:
+       mov     $bp,%r12                # reassign $bp
+___
+               $bp="%r12";
+$code.=<<___;
        mov     ($n0),$n0               # pull n0[0] value
+       mov     ($bp),$m0               # m0=bp[0]
+       mov     ($ap),%rax
 
        xor     $i,$i                   # i=0
        xor     $j,$j                   # j=0
 
-       mov     ($bp),$m0               # m0=bp[0]
-       mov     ($ap),%rax
+       mov     $n0,$m1
        mulq    $m0                     # ap[0]*bp[0]
        mov     %rax,$lo0
-       mov     %rdx,$hi0
+       mov     ($np),%rax
 
-       imulq   $n0,%rax                # "tp[0]"*n0
-       mov     %rax,$m1
+       imulq   $lo0,$m1                # "tp[0]"*n0
+       mov     %rdx,$hi0
 
-       mulq    ($np)                   # np[0]*m1
-       add     $lo0,%rax               # discarded
+       mulq    $m1                     # np[0]*m1
+       add     %rax,$lo0               # discarded
+       mov     8($ap),%rax
        adc     \$0,%rdx
        mov     %rdx,$hi1
 
        lea     1($j),$j                # j++
+       jmp     .L1st_enter
+
+.align 16
 .L1st:
+       add     %rax,$hi1
        mov     ($ap,$j,8),%rax
-       mulq    $m0                     # ap[j]*bp[0]
-       add     $hi0,%rax
        adc     \$0,%rdx
-       mov     %rax,$lo0
+       add     $hi0,$hi1               # np[j]*m1+ap[j]*bp[0]
+       mov     $lo0,$hi0
+       adc     \$0,%rdx
+       mov     $hi1,-16(%rsp,$j,8)     # tp[j-1]
+       mov     %rdx,$hi1
+
+.L1st_enter:
+       mulq    $m0                     # ap[j]*bp[0]
+       add     %rax,$hi0
        mov     ($np,$j,8),%rax
-       mov     %rdx,$hi0
+       adc     \$0,%rdx
+       lea     1($j),$j                # j++
+       mov     %rdx,$lo0
 
        mulq    $m1                     # np[j]*m1
-       add     $hi1,%rax
-       lea     1($j),$j                # j++
+       cmp     $num,$j
+       jne     .L1st
+
+       add     %rax,$hi1
+       mov     ($ap),%rax              # ap[0]
        adc     \$0,%rdx
-       add     $lo0,%rax               # np[j]*m1+ap[j]*bp[0]
+       add     $hi0,$hi1               # np[j]*m1+ap[j]*bp[0]
        adc     \$0,%rdx
-       mov     %rax,-16(%rsp,$j,8)     # tp[j-1]
-       cmp     $num,$j
+       mov     $hi1,-16(%rsp,$j,8)     # tp[j-1]
        mov     %rdx,$hi1
-       jl      .L1st
+       mov     $lo0,$hi0
 
        xor     %rdx,%rdx
        add     $hi0,$hi1
@@ -103,50 +166,64 @@ bn_mul_mont:
        mov     %rdx,(%rsp,$num,8)      # store upmost overflow bit
 
        lea     1($i),$i                # i++
-.align 4
+       jmp     .Louter
+.align 16
 .Louter:
-       xor     $j,$j                   # j=0
-
        mov     ($bp,$i,8),$m0          # m0=bp[i]
-       mov     ($ap),%rax              # ap[0]
+       xor     $j,$j                   # j=0
+       mov     $n0,$m1
+       mov     (%rsp),$lo0
        mulq    $m0                     # ap[0]*bp[i]
-       add     (%rsp),%rax             # ap[0]*bp[i]+tp[0]
+       add     %rax,$lo0               # ap[0]*bp[i]+tp[0]
+       mov     ($np),%rax
        adc     \$0,%rdx
-       mov     %rax,$lo0
-       mov     %rdx,$hi0
 
-       imulq   $n0,%rax                # tp[0]*n0
-       mov     %rax,$m1
+       imulq   $lo0,$m1                # tp[0]*n0
+       mov     %rdx,$hi0
 
-       mulq    ($np,$j,8)              # np[0]*m1
-       add     $lo0,%rax               # discarded
-       mov     8(%rsp),$lo0            # tp[1]
+       mulq    $m1                     # np[0]*m1
+       add     %rax,$lo0               # discarded
+       mov     8($ap),%rax
        adc     \$0,%rdx
+       mov     8(%rsp),$lo0            # tp[1]
        mov     %rdx,$hi1
 
        lea     1($j),$j                # j++
-.align 4
+       jmp     .Linner_enter
+
+.align 16
 .Linner:
+       add     %rax,$hi1
        mov     ($ap,$j,8),%rax
-       mulq    $m0                     # ap[j]*bp[i]
-       add     $hi0,%rax
        adc     \$0,%rdx
-       add     %rax,$lo0               # ap[j]*bp[i]+tp[j]
+       add     $lo0,$hi1               # np[j]*m1+ap[j]*bp[i]+tp[j]
+       mov     (%rsp,$j,8),$lo0
+       adc     \$0,%rdx
+       mov     $hi1,-16(%rsp,$j,8)     # tp[j-1]
+       mov     %rdx,$hi1
+
+.Linner_enter:
+       mulq    $m0                     # ap[j]*bp[i]
+       add     %rax,$hi0
        mov     ($np,$j,8),%rax
        adc     \$0,%rdx
+       add     $hi0,$lo0               # ap[j]*bp[i]+tp[j]
        mov     %rdx,$hi0
+       adc     \$0,$hi0
+       lea     1($j),$j                # j++
 
        mulq    $m1                     # np[j]*m1
-       add     $hi1,%rax
-       lea     1($j),$j                # j++
-       adc     \$0,%rdx
-       add     $lo0,%rax               # np[j]*m1+ap[j]*bp[i]+tp[j]
+       cmp     $num,$j
+       jne     .Linner
+
+       add     %rax,$hi1
+       mov     ($ap),%rax              # ap[0]
        adc     \$0,%rdx
+       add     $lo0,$hi1               # np[j]*m1+ap[j]*bp[i]+tp[j]
        mov     (%rsp,$j,8),$lo0
-       cmp     $num,$j
-       mov     %rax,-16(%rsp,$j,8)     # tp[j-1]
+       adc     \$0,%rdx
+       mov     $hi1,-16(%rsp,$j,8)     # tp[j-1]
        mov     %rdx,$hi1
-       jl      .Linner
 
        xor     %rdx,%rdx
        add     $hi0,$hi1
@@ -160,50 +237,1572 @@ bn_mul_mont:
        cmp     $num,$i
        jl      .Louter
 
+       xor     $i,$i                   # i=0 and clear CF!
+       mov     (%rsp),%rax             # tp[0]
+       lea     (%rsp),$ap              # borrow ap for tp
+       mov     $num,$j                 # j=num
+       jmp     .Lsub
+.align 16
+.Lsub: sbb     ($np,$i,8),%rax
+       mov     %rax,($rp,$i,8)         # rp[i]=tp[i]-np[i]
+       mov     8($ap,$i,8),%rax        # tp[i+1]
+       lea     1($i),$i                # i++
+       dec     $j                      # doesnn't affect CF!
+       jnz     .Lsub
+
+       sbb     \$0,%rax                # handle upmost overflow bit
+       xor     $i,$i
+       and     %rax,$ap
+       not     %rax
+       mov     $rp,$np
+       and     %rax,$np
+       mov     $num,$j                 # j=num
+       or      $np,$ap                 # ap=borrow?tp:rp
+.align 16
+.Lcopy:                                        # copy or in-place refresh
+       mov     ($ap,$i,8),%rax
+       mov     $i,(%rsp,$i,8)          # zap temporary vector
+       mov     %rax,($rp,$i,8)         # rp[i]=tp[i]
+       lea     1($i),$i
+       sub     \$1,$j
+       jnz     .Lcopy
+
+       mov     8(%rsp,$num,8),%rsi     # restore %rsp
+       mov     \$1,%rax
+       mov     (%rsi),%r15
+       mov     8(%rsi),%r14
+       mov     16(%rsi),%r13
+       mov     24(%rsi),%r12
+       mov     32(%rsi),%rbp
+       mov     40(%rsi),%rbx
+       lea     48(%rsi),%rsp
+.Lmul_epilogue:
+       ret
+.size  bn_mul_mont,.-bn_mul_mont
+___
+{{{
+my @A=("%r10","%r11");
+my @N=("%r13","%rdi");
+$code.=<<___;
+.type  bn_mul4x_mont,\@function,6
+.align 16
+bn_mul4x_mont:
+.Lmul4x_enter:
+       push    %rbx
+       push    %rbp
+       push    %r12
+       push    %r13
+       push    %r14
+       push    %r15
+
+       mov     ${num}d,${num}d
+       lea     4($num),%r10
+       mov     %rsp,%r11
+       neg     %r10
+       lea     (%rsp,%r10,8),%rsp      # tp=alloca(8*(num+4))
+       and     \$-1024,%rsp            # minimize TLB usage
+
+       mov     %r11,8(%rsp,$num,8)     # tp[num+1]=%rsp
+.Lmul4x_body:
+       mov     $rp,16(%rsp,$num,8)     # tp[num+2]=$rp
+       mov     %rdx,%r12               # reassign $bp
+___
+               $bp="%r12";
+$code.=<<___;
+       mov     ($n0),$n0               # pull n0[0] value
+       mov     ($bp),$m0               # m0=bp[0]
+       mov     ($ap),%rax
+
        xor     $i,$i                   # i=0
-       lea     -1($num),$j             # j=num-1
-       cmp     \$0,%rdx                # %rdx still holds upmost overflow bit
-       jnz     .Lsub                   # CF is cleared by compare with 0
-       mov     (%rsp,$j,8),%rax
-       cmp     ($np,$j,8),%rax         # tp[num-1]-np[num-1]
-       jae     .Lsub                   # if taken CF was cleared by above cmp
+       xor     $j,$j                   # j=0
+
+       mov     $n0,$m1
+       mulq    $m0                     # ap[0]*bp[0]
+       mov     %rax,$A[0]
+       mov     ($np),%rax
+
+       imulq   $A[0],$m1               # "tp[0]"*n0
+       mov     %rdx,$A[1]
+
+       mulq    $m1                     # np[0]*m1
+       add     %rax,$A[0]              # discarded
+       mov     8($ap),%rax
+       adc     \$0,%rdx
+       mov     %rdx,$N[1]
+
+       mulq    $m0
+       add     %rax,$A[1]
+       mov     8($np),%rax
+       adc     \$0,%rdx
+       mov     %rdx,$A[0]
+
+       mulq    $m1
+       add     %rax,$N[1]
+       mov     16($ap),%rax
+       adc     \$0,%rdx
+       add     $A[1],$N[1]
+       lea     4($j),$j                # j++
+       adc     \$0,%rdx
+       mov     $N[1],(%rsp)
+       mov     %rdx,$N[0]
+       jmp     .L1st4x
+.align 16
+.L1st4x:
+       mulq    $m0                     # ap[j]*bp[0]
+       add     %rax,$A[0]
+       mov     -16($np,$j,8),%rax
+       adc     \$0,%rdx
+       mov     %rdx,$A[1]
+
+       mulq    $m1                     # np[j]*m1
+       add     %rax,$N[0]
+       mov     -8($ap,$j,8),%rax
+       adc     \$0,%rdx
+       add     $A[0],$N[0]             # np[j]*m1+ap[j]*bp[0]
+       adc     \$0,%rdx
+       mov     $N[0],-24(%rsp,$j,8)    # tp[j-1]
+       mov     %rdx,$N[1]
+
+       mulq    $m0                     # ap[j]*bp[0]
+       add     %rax,$A[1]
+       mov     -8($np,$j,8),%rax
+       adc     \$0,%rdx
+       mov     %rdx,$A[0]
+
+       mulq    $m1                     # np[j]*m1
+       add     %rax,$N[1]
+       mov     ($ap,$j,8),%rax
+       adc     \$0,%rdx
+       add     $A[1],$N[1]             # np[j]*m1+ap[j]*bp[0]
+       adc     \$0,%rdx
+       mov     $N[1],-16(%rsp,$j,8)    # tp[j-1]
+       mov     %rdx,$N[0]
+
+       mulq    $m0                     # ap[j]*bp[0]
+       add     %rax,$A[0]
+       mov     ($np,$j,8),%rax
+       adc     \$0,%rdx
+       mov     %rdx,$A[1]
+
+       mulq    $m1                     # np[j]*m1
+       add     %rax,$N[0]
+       mov     8($ap,$j,8),%rax
+       adc     \$0,%rdx
+       add     $A[0],$N[0]             # np[j]*m1+ap[j]*bp[0]
+       adc     \$0,%rdx
+       mov     $N[0],-8(%rsp,$j,8)     # tp[j-1]
+       mov     %rdx,$N[1]
+
+       mulq    $m0                     # ap[j]*bp[0]
+       add     %rax,$A[1]
+       mov     8($np,$j,8),%rax
+       adc     \$0,%rdx
+       lea     4($j),$j                # j++
+       mov     %rdx,$A[0]
+
+       mulq    $m1                     # np[j]*m1
+       add     %rax,$N[1]
+       mov     -16($ap,$j,8),%rax
+       adc     \$0,%rdx
+       add     $A[1],$N[1]             # np[j]*m1+ap[j]*bp[0]
+       adc     \$0,%rdx
+       mov     $N[1],-32(%rsp,$j,8)    # tp[j-1]
+       mov     %rdx,$N[0]
+       cmp     $num,$j
+       jl      .L1st4x
+
+       mulq    $m0                     # ap[j]*bp[0]
+       add     %rax,$A[0]
+       mov     -16($np,$j,8),%rax
+       adc     \$0,%rdx
+       mov     %rdx,$A[1]
+
+       mulq    $m1                     # np[j]*m1
+       add     %rax,$N[0]
+       mov     -8($ap,$j,8),%rax
+       adc     \$0,%rdx
+       add     $A[0],$N[0]             # np[j]*m1+ap[j]*bp[0]
+       adc     \$0,%rdx
+       mov     $N[0],-24(%rsp,$j,8)    # tp[j-1]
+       mov     %rdx,$N[1]
+
+       mulq    $m0                     # ap[j]*bp[0]
+       add     %rax,$A[1]
+       mov     -8($np,$j,8),%rax
+       adc     \$0,%rdx
+       mov     %rdx,$A[0]
+
+       mulq    $m1                     # np[j]*m1
+       add     %rax,$N[1]
+       mov     ($ap),%rax              # ap[0]
+       adc     \$0,%rdx
+       add     $A[1],$N[1]             # np[j]*m1+ap[j]*bp[0]
+       adc     \$0,%rdx
+       mov     $N[1],-16(%rsp,$j,8)    # tp[j-1]
+       mov     %rdx,$N[0]
+
+       xor     $N[1],$N[1]
+       add     $A[0],$N[0]
+       adc     \$0,$N[1]
+       mov     $N[0],-8(%rsp,$j,8)
+       mov     $N[1],(%rsp,$j,8)       # store upmost overflow bit
+
+       lea     1($i),$i                # i++
 .align 4
-.Lcopy:
-       mov     (%rsp,$j,8),%rax
-       mov     %rax,($rp,$j,8)         # rp[i]=tp[i]
-       mov     $i,(%rsp,$j,8)          # zap temporary vector
+.Louter4x:
+       mov     ($bp,$i,8),$m0          # m0=bp[i]
+       xor     $j,$j                   # j=0
+       mov     (%rsp),$A[0]
+       mov     $n0,$m1
+       mulq    $m0                     # ap[0]*bp[i]
+       add     %rax,$A[0]              # ap[0]*bp[i]+tp[0]
+       mov     ($np),%rax
+       adc     \$0,%rdx
+
+       imulq   $A[0],$m1               # tp[0]*n0
+       mov     %rdx,$A[1]
+
+       mulq    $m1                     # np[0]*m1
+       add     %rax,$A[0]              # "$N[0]", discarded
+       mov     8($ap),%rax
+       adc     \$0,%rdx
+       mov     %rdx,$N[1]
+
+       mulq    $m0                     # ap[j]*bp[i]
+       add     %rax,$A[1]
+       mov     8($np),%rax
+       adc     \$0,%rdx
+       add     8(%rsp),$A[1]           # +tp[1]
+       adc     \$0,%rdx
+       mov     %rdx,$A[0]
+
+       mulq    $m1                     # np[j]*m1
+       add     %rax,$N[1]
+       mov     16($ap),%rax
+       adc     \$0,%rdx
+       add     $A[1],$N[1]             # np[j]*m1+ap[j]*bp[i]+tp[j]
+       lea     4($j),$j                # j+=2
+       adc     \$0,%rdx
+       mov     $N[1],(%rsp)            # tp[j-1]
+       mov     %rdx,$N[0]
+       jmp     .Linner4x
+.align 16
+.Linner4x:
+       mulq    $m0                     # ap[j]*bp[i]
+       add     %rax,$A[0]
+       mov     -16($np,$j,8),%rax
+       adc     \$0,%rdx
+       add     -16(%rsp,$j,8),$A[0]    # ap[j]*bp[i]+tp[j]
+       adc     \$0,%rdx
+       mov     %rdx,$A[1]
+
+       mulq    $m1                     # np[j]*m1
+       add     %rax,$N[0]
+       mov     -8($ap,$j,8),%rax
+       adc     \$0,%rdx
+       add     $A[0],$N[0]
+       adc     \$0,%rdx
+       mov     $N[0],-24(%rsp,$j,8)    # tp[j-1]
+       mov     %rdx,$N[1]
+
+       mulq    $m0                     # ap[j]*bp[i]
+       add     %rax,$A[1]
+       mov     -8($np,$j,8),%rax
+       adc     \$0,%rdx
+       add     -8(%rsp,$j,8),$A[1]
+       adc     \$0,%rdx
+       mov     %rdx,$A[0]
+
+       mulq    $m1                     # np[j]*m1
+       add     %rax,$N[1]
+       mov     ($ap,$j,8),%rax
+       adc     \$0,%rdx
+       add     $A[1],$N[1]
+       adc     \$0,%rdx
+       mov     $N[1],-16(%rsp,$j,8)    # tp[j-1]
+       mov     %rdx,$N[0]
+
+       mulq    $m0                     # ap[j]*bp[i]
+       add     %rax,$A[0]
+       mov     ($np,$j,8),%rax
+       adc     \$0,%rdx
+       add     (%rsp,$j,8),$A[0]       # ap[j]*bp[i]+tp[j]
+       adc     \$0,%rdx
+       mov     %rdx,$A[1]
+
+       mulq    $m1                     # np[j]*m1
+       add     %rax,$N[0]
+       mov     8($ap,$j,8),%rax
+       adc     \$0,%rdx
+       add     $A[0],$N[0]
+       adc     \$0,%rdx
+       mov     $N[0],-8(%rsp,$j,8)     # tp[j-1]
+       mov     %rdx,$N[1]
+
+       mulq    $m0                     # ap[j]*bp[i]
+       add     %rax,$A[1]
+       mov     8($np,$j,8),%rax
+       adc     \$0,%rdx
+       add     8(%rsp,$j,8),$A[1]
+       adc     \$0,%rdx
+       lea     4($j),$j                # j++
+       mov     %rdx,$A[0]
+
+       mulq    $m1                     # np[j]*m1
+       add     %rax,$N[1]
+       mov     -16($ap,$j,8),%rax
+       adc     \$0,%rdx
+       add     $A[1],$N[1]
+       adc     \$0,%rdx
+       mov     $N[1],-32(%rsp,$j,8)    # tp[j-1]
+       mov     %rdx,$N[0]
+       cmp     $num,$j
+       jl      .Linner4x
+
+       mulq    $m0                     # ap[j]*bp[i]
+       add     %rax,$A[0]
+       mov     -16($np,$j,8),%rax
+       adc     \$0,%rdx
+       add     -16(%rsp,$j,8),$A[0]    # ap[j]*bp[i]+tp[j]
+       adc     \$0,%rdx
+       mov     %rdx,$A[1]
+
+       mulq    $m1                     # np[j]*m1
+       add     %rax,$N[0]
+       mov     -8($ap,$j,8),%rax
+       adc     \$0,%rdx
+       add     $A[0],$N[0]
+       adc     \$0,%rdx
+       mov     $N[0],-24(%rsp,$j,8)    # tp[j-1]
+       mov     %rdx,$N[1]
+
+       mulq    $m0                     # ap[j]*bp[i]
+       add     %rax,$A[1]
+       mov     -8($np,$j,8),%rax
+       adc     \$0,%rdx
+       add     -8(%rsp,$j,8),$A[1]
+       adc     \$0,%rdx
+       lea     1($i),$i                # i++
+       mov     %rdx,$A[0]
+
+       mulq    $m1                     # np[j]*m1
+       add     %rax,$N[1]
+       mov     ($ap),%rax              # ap[0]
+       adc     \$0,%rdx
+       add     $A[1],$N[1]
+       adc     \$0,%rdx
+       mov     $N[1],-16(%rsp,$j,8)    # tp[j-1]
+       mov     %rdx,$N[0]
+
+       xor     $N[1],$N[1]
+       add     $A[0],$N[0]
+       adc     \$0,$N[1]
+       add     (%rsp,$num,8),$N[0]     # pull upmost overflow bit
+       adc     \$0,$N[1]
+       mov     $N[0],-8(%rsp,$j,8)
+       mov     $N[1],(%rsp,$j,8)       # store upmost overflow bit
+
+       cmp     $num,$i
+       jl      .Louter4x
+___
+{
+my @ri=("%rax","%rdx",$m0,$m1);
+$code.=<<___;
+       mov     16(%rsp,$num,8),$rp     # restore $rp
+       mov     0(%rsp),@ri[0]          # tp[0]
+       pxor    %xmm0,%xmm0
+       mov     8(%rsp),@ri[1]          # tp[1]
+       shr     \$2,$num                # num/=4
+       lea     (%rsp),$ap              # borrow ap for tp
+       xor     $i,$i                   # i=0 and clear CF!
+
+       sub     0($np),@ri[0]
+       mov     16($ap),@ri[2]          # tp[2]
+       mov     24($ap),@ri[3]          # tp[3]
+       sbb     8($np),@ri[1]
+       lea     -1($num),$j             # j=num/4-1
+       jmp     .Lsub4x
+.align 16
+.Lsub4x:
+       mov     @ri[0],0($rp,$i,8)      # rp[i]=tp[i]-np[i]
+       mov     @ri[1],8($rp,$i,8)      # rp[i]=tp[i]-np[i]
+       sbb     16($np,$i,8),@ri[2]
+       mov     32($ap,$i,8),@ri[0]     # tp[i+1]
+       mov     40($ap,$i,8),@ri[1]
+       sbb     24($np,$i,8),@ri[3]
+       mov     @ri[2],16($rp,$i,8)     # rp[i]=tp[i]-np[i]
+       mov     @ri[3],24($rp,$i,8)     # rp[i]=tp[i]-np[i]
+       sbb     32($np,$i,8),@ri[0]
+       mov     48($ap,$i,8),@ri[2]
+       mov     56($ap,$i,8),@ri[3]
+       sbb     40($np,$i,8),@ri[1]
+       lea     4($i),$i                # i++
+       dec     $j                      # doesnn't affect CF!
+       jnz     .Lsub4x
+
+       mov     @ri[0],0($rp,$i,8)      # rp[i]=tp[i]-np[i]
+       mov     32($ap,$i,8),@ri[0]     # load overflow bit
+       sbb     16($np,$i,8),@ri[2]
+       mov     @ri[1],8($rp,$i,8)      # rp[i]=tp[i]-np[i]
+       sbb     24($np,$i,8),@ri[3]
+       mov     @ri[2],16($rp,$i,8)     # rp[i]=tp[i]-np[i]
+
+       sbb     \$0,@ri[0]              # handle upmost overflow bit
+       mov     @ri[3],24($rp,$i,8)     # rp[i]=tp[i]-np[i]
+       xor     $i,$i                   # i=0
+       and     @ri[0],$ap
+       not     @ri[0]
+       mov     $rp,$np
+       and     @ri[0],$np
+       lea     -1($num),$j
+       or      $np,$ap                 # ap=borrow?tp:rp
+
+       movdqu  ($ap),%xmm1
+       movdqa  %xmm0,(%rsp)
+       movdqu  %xmm1,($rp)
+       jmp     .Lcopy4x
+.align 16
+.Lcopy4x:                                      # copy or in-place refresh
+       movdqu  16($ap,$i),%xmm2
+       movdqu  32($ap,$i),%xmm1
+       movdqa  %xmm0,16(%rsp,$i)
+       movdqu  %xmm2,16($rp,$i)
+       movdqa  %xmm0,32(%rsp,$i)
+       movdqu  %xmm1,32($rp,$i)
+       lea     32($i),$i
        dec     $j
-       jge     .Lcopy
-.align 4
-.Lexit:
-       mov     8(%rsp,$num,8),%rsp     # restore %rsp
+       jnz     .Lcopy4x
+
+       shl     \$2,$num
+       movdqu  16($ap,$i),%xmm2
+       movdqa  %xmm0,16(%rsp,$i)
+       movdqu  %xmm2,16($rp,$i)
+___
+}
+$code.=<<___;
+       mov     8(%rsp,$num,8),%rsi     # restore %rsp
+       mov     \$1,%rax
+       mov     (%rsi),%r15
+       mov     8(%rsi),%r14
+       mov     16(%rsi),%r13
+       mov     24(%rsi),%r12
+       mov     32(%rsi),%rbp
+       mov     40(%rsi),%rbx
+       lea     48(%rsi),%rsp
+.Lmul4x_epilogue:
+       ret
+.size  bn_mul4x_mont,.-bn_mul4x_mont
+___
+}}}
+\f{{{
+######################################################################
+# void bn_sqr8x_mont(
+my $rptr="%rdi";       # const BN_ULONG *rptr,
+my $aptr="%rsi";       # const BN_ULONG *aptr,
+my $bptr="%rdx";       # not used
+my $nptr="%rcx";       # const BN_ULONG *nptr,
+my $n0  ="%r8";                # const BN_ULONG *n0);
+my $num ="%r9";                # int num, has to be divisible by 8
+
+my ($i,$j,$tptr)=("%rbp","%rcx",$rptr);
+my @A0=("%r10","%r11");
+my @A1=("%r12","%r13");
+my ($a0,$a1,$ai)=("%r14","%r15","%rbx");
+
+$code.=<<___;
+.type  bn_sqr8x_mont,\@function,6
+.align 32
+bn_sqr8x_mont:
+.Lsqr8x_enter:
+       push    %rbx
+       push    %rbp
+       push    %r12
+       push    %r13
+       push    %r14
+       push    %r15
+
+       shl     \$3,${num}d             # convert $num to bytes
+       xor     %r10,%r10
+       mov     %rsp,%r11               # put aside %rsp
+       sub     $num,%r10               # -$num
+       mov     ($n0),$n0               # *n0
+       lea     -72(%rsp,%r10,2),%rsp   # alloca(frame+2*$num)
+       and     \$-1024,%rsp            # minimize TLB usage
+       ##############################################################
+       # Stack layout
+       #
+       # +0    saved $num, used in reduction section
+       # +8    &t[2*$num], used in reduction section
+       # +32   saved $rptr
+       # +40   saved $nptr
+       # +48   saved *n0
+       # +56   saved %rsp
+       # +64   t[2*$num]
+       #
+       mov     $rptr,32(%rsp)          # save $rptr
+       mov     $nptr,40(%rsp)
+       mov     $n0,  48(%rsp)
+       mov     %r11, 56(%rsp)          # save original %rsp
+.Lsqr8x_body:
+       ##############################################################
+       # Squaring part:
+       #
+       # a) multiply-n-add everything but a[i]*a[i];
+       # b) shift result of a) by 1 to the left and accumulate
+       #    a[i]*a[i] products;
+       #
+       ##############################################################
+       #                                                     a[1]a[0]
+       #                                                 a[2]a[0]
+       #                                             a[3]a[0]
+       #                                             a[2]a[1]
+       #                                         a[4]a[0]
+       #                                         a[3]a[1]
+       #                                     a[5]a[0]
+       #                                     a[4]a[1]
+       #                                     a[3]a[2]
+       #                                 a[6]a[0]
+       #                                 a[5]a[1]
+       #                                 a[4]a[2]
+       #                             a[7]a[0]
+       #                             a[6]a[1]
+       #                             a[5]a[2]
+       #                             a[4]a[3]
+       #                         a[7]a[1]
+       #                         a[6]a[2]
+       #                         a[5]a[3]
+       #                     a[7]a[2]
+       #                     a[6]a[3]
+       #                     a[5]a[4]
+       #                 a[7]a[3]
+       #                 a[6]a[4]
+       #             a[7]a[4]
+       #             a[6]a[5]
+       #         a[7]a[5]
+       #     a[7]a[6]
+       #                                                     a[1]a[0]
+       #                                                 a[2]a[0]
+       #                                             a[3]a[0]
+       #                                         a[4]a[0]
+       #                                     a[5]a[0]
+       #                                 a[6]a[0]
+       #                             a[7]a[0]
+       #                                             a[2]a[1]
+       #                                         a[3]a[1]
+       #                                     a[4]a[1]
+       #                                 a[5]a[1]
+       #                             a[6]a[1]
+       #                         a[7]a[1]
+       #                                     a[3]a[2]
+       #                                 a[4]a[2]
+       #                             a[5]a[2]
+       #                         a[6]a[2]
+       #                     a[7]a[2]
+       #                             a[4]a[3]
+       #                         a[5]a[3]
+       #                     a[6]a[3]
+       #                 a[7]a[3]
+       #                     a[5]a[4]
+       #                 a[6]a[4]
+       #             a[7]a[4]
+       #             a[6]a[5]
+       #         a[7]a[5]
+       #     a[7]a[6]
+       #                                                         a[0]a[0]
+       #                                                 a[1]a[1]
+       #                                         a[2]a[2]
+       #                                 a[3]a[3]
+       #                         a[4]a[4]
+       #                 a[5]a[5]
+       #         a[6]a[6]
+       # a[7]a[7]
+
+       lea     32(%r10),$i             # $i=-($num-32)
+       lea     ($aptr,$num),$aptr      # end of a[] buffer, ($aptr,$i)=&ap[2]
+
+       mov     $num,$j                 # $j=$num
+
+                                       # comments apply to $num==8 case
+       mov     -32($aptr,$i),$a0       # a[0]
+       lea     64(%rsp,$num,2),$tptr   # end of tp[] buffer, &tp[2*$num]
+       mov     -24($aptr,$i),%rax      # a[1]
+       lea     -32($tptr,$i),$tptr     # end of tp[] window, &tp[2*$num-"$i"]
+       mov     -16($aptr,$i),$ai       # a[2]
+       mov     %rax,$a1
+
+       mul     $a0                     # a[1]*a[0]
+       mov     %rax,$A0[0]             # a[1]*a[0]
+        mov    $ai,%rax                # a[2]
+       mov     %rdx,$A0[1]
+       mov     $A0[0],-24($tptr,$i)    # t[1]
+
+       mul     $a0                     # a[2]*a[0]
+       add     %rax,$A0[1]
+        mov    $ai,%rax
+       adc     \$0,%rdx
+       mov     $A0[1],-16($tptr,$i)    # t[2]
+       mov     %rdx,$A0[0]
+
+       lea     -16($i),$j              # j=-16
+
+
+        mov    8($aptr,$j),$ai         # a[3]
+       mul     $a1                     # a[2]*a[1]
+       mov     %rax,$A1[0]             # a[2]*a[1]+t[3]
+        mov    $ai,%rax
+       mov     %rdx,$A1[1]
+
+        lea    16($j),$j
+       mul     $a0                     # a[3]*a[0]
+       add     %rax,$A0[0]             # a[3]*a[0]+a[2]*a[1]+t[3]
+        mov    $ai,%rax
+       mov     %rdx,$A0[1]
+       adc     \$0,$A0[1]
+       add     $A1[0],$A0[0]
+       adc     \$0,$A0[1]
+       mov     $A0[0],-8($tptr,$j)     # t[3]
+       jmp     .Lsqr4x_1st
+
+.align 32
+.Lsqr4x_1st:
+        mov    ($aptr,$j),$ai          # a[4]
+       mul     $a1                     # a[3]*a[1]
+       add     %rax,$A1[1]             # a[3]*a[1]+t[4]
+        mov    $ai,%rax
+       mov     %rdx,$A1[0]
+       adc     \$0,$A1[0]
+
+       mul     $a0                     # a[4]*a[0]
+       add     %rax,$A0[1]             # a[4]*a[0]+a[3]*a[1]+t[4]
+        mov    $ai,%rax                # a[3]
+        mov    8($aptr,$j),$ai         # a[5]
+       mov     %rdx,$A0[0]
+       adc     \$0,$A0[0]
+       add     $A1[1],$A0[1]
+       adc     \$0,$A0[0]
+
+
+       mul     $a1                     # a[4]*a[3]
+       add     %rax,$A1[0]             # a[4]*a[3]+t[5]
+        mov    $ai,%rax
+        mov    $A0[1],($tptr,$j)       # t[4]
+       mov     %rdx,$A1[1]
+       adc     \$0,$A1[1]
+
+       mul     $a0                     # a[5]*a[2]
+       add     %rax,$A0[0]             # a[5]*a[2]+a[4]*a[3]+t[5]
+        mov    $ai,%rax
+        mov    16($aptr,$j),$ai        # a[6]
+       mov     %rdx,$A0[1]
+       adc     \$0,$A0[1]
+       add     $A1[0],$A0[0]
+       adc     \$0,$A0[1]
+
+       mul     $a1                     # a[5]*a[3]
+       add     %rax,$A1[1]             # a[5]*a[3]+t[6]
+        mov    $ai,%rax
+        mov    $A0[0],8($tptr,$j)      # t[5]
+       mov     %rdx,$A1[0]
+       adc     \$0,$A1[0]
+
+       mul     $a0                     # a[6]*a[2]
+       add     %rax,$A0[1]             # a[6]*a[2]+a[5]*a[3]+t[6]
+        mov    $ai,%rax                # a[3]
+        mov    24($aptr,$j),$ai        # a[7]
+       mov     %rdx,$A0[0]
+       adc     \$0,$A0[0]
+       add     $A1[1],$A0[1]
+       adc     \$0,$A0[0]
+
+
+       mul     $a1                     # a[6]*a[5]
+       add     %rax,$A1[0]             # a[6]*a[5]+t[7]
+        mov    $ai,%rax
+        mov    $A0[1],16($tptr,$j)     # t[6]
+       mov     %rdx,$A1[1]
+       adc     \$0,$A1[1]
+
+       mul     $a0                     # a[7]*a[4]
+       add     %rax,$A0[0]             # a[7]*a[4]+a[6]*a[5]+t[6]
+        mov    $ai,%rax
+        lea    32($j),$j
+       mov     %rdx,$A0[1]
+       adc     \$0,$A0[1]
+       add     $A1[0],$A0[0]
+       adc     \$0,$A0[1]
+       mov     $A0[0],-8($tptr,$j)     # t[7]
+
+       cmp     \$0,$j
+       jne     .Lsqr4x_1st
+
+       mul     $a1                     # a[7]*a[5]
+       add     %rax,$A1[1]
+       lea     16($i),$i
+       adc     \$0,%rdx
+       add     $A0[1],$A1[1]
+       adc     \$0,%rdx
+
+       mov     $A1[1],($tptr)          # t[8]
+       mov     %rdx,$A1[0]
+       mov     %rdx,8($tptr)           # t[9]
+       jmp     .Lsqr4x_outer
+
+.align 32
+.Lsqr4x_outer:                         # comments apply to $num==6 case
+       mov     -32($aptr,$i),$a0       # a[0]
+       lea     64(%rsp,$num,2),$tptr   # end of tp[] buffer, &tp[2*$num]
+       mov     -24($aptr,$i),%rax      # a[1]
+       lea     -32($tptr,$i),$tptr     # end of tp[] window, &tp[2*$num-"$i"]
+       mov     -16($aptr,$i),$ai       # a[2]
+       mov     %rax,$a1
+
+       mov     -24($tptr,$i),$A0[0]    # t[1]
+       mul     $a0                     # a[1]*a[0]
+       add     %rax,$A0[0]             # a[1]*a[0]+t[1]
+        mov    $ai,%rax                # a[2]
+       adc     \$0,%rdx
+       mov     $A0[0],-24($tptr,$i)    # t[1]
+       mov     %rdx,$A0[1]
+
+       mul     $a0                     # a[2]*a[0]
+       add     %rax,$A0[1]
+        mov    $ai,%rax
+       adc     \$0,%rdx
+       add     -16($tptr,$i),$A0[1]    # a[2]*a[0]+t[2]
+       mov     %rdx,$A0[0]
+       adc     \$0,$A0[0]
+       mov     $A0[1],-16($tptr,$i)    # t[2]
+
+       lea     -16($i),$j              # j=-16
+       xor     $A1[0],$A1[0]
+
+
+        mov    8($aptr,$j),$ai         # a[3]
+       mul     $a1                     # a[2]*a[1]
+       add     %rax,$A1[0]             # a[2]*a[1]+t[3]
+        mov    $ai,%rax
+       adc     \$0,%rdx
+       add     8($tptr,$j),$A1[0]
+       mov     %rdx,$A1[1]
+       adc     \$0,$A1[1]
+
+       mul     $a0                     # a[3]*a[0]
+       add     %rax,$A0[0]             # a[3]*a[0]+a[2]*a[1]+t[3]
+        mov    $ai,%rax
+       adc     \$0,%rdx
+       add     $A1[0],$A0[0]
+       mov     %rdx,$A0[1]
+       adc     \$0,$A0[1]
+       mov     $A0[0],8($tptr,$j)      # t[3]
+
+       lea     16($j),$j
+       jmp     .Lsqr4x_inner
+
+.align 32
+.Lsqr4x_inner:
+        mov    ($aptr,$j),$ai          # a[4]
+       mul     $a1                     # a[3]*a[1]
+       add     %rax,$A1[1]             # a[3]*a[1]+t[4]
+        mov    $ai,%rax
+       mov     %rdx,$A1[0]
+       adc     \$0,$A1[0]
+       add     ($tptr,$j),$A1[1]
+       adc     \$0,$A1[0]
+
+       mul     $a0                     # a[4]*a[0]
+       add     %rax,$A0[1]             # a[4]*a[0]+a[3]*a[1]+t[4]
+        mov    $ai,%rax                # a[3]
+        mov    8($aptr,$j),$ai         # a[5]
+       mov     %rdx,$A0[0]
+       adc     \$0,$A0[0]
+       add     $A1[1],$A0[1]
+       adc     \$0,$A0[0]
+
+       mul     $a1                     # a[4]*a[3]
+       add     %rax,$A1[0]             # a[4]*a[3]+t[5]
+       mov     $A0[1],($tptr,$j)       # t[4]
+        mov    $ai,%rax
+       mov     %rdx,$A1[1]
+       adc     \$0,$A1[1]
+       add     8($tptr,$j),$A1[0]
+       lea     16($j),$j               # j++
+       adc     \$0,$A1[1]
+
+       mul     $a0                     # a[5]*a[2]
+       add     %rax,$A0[0]             # a[5]*a[2]+a[4]*a[3]+t[5]
+        mov    $ai,%rax
+       adc     \$0,%rdx
+       add     $A1[0],$A0[0]
+       mov     %rdx,$A0[1]
+       adc     \$0,$A0[1]
+       mov     $A0[0],-8($tptr,$j)     # t[5], "preloaded t[1]" below
+
+       cmp     \$0,$j
+       jne     .Lsqr4x_inner
+
+       mul     $a1                     # a[5]*a[3]
+       add     %rax,$A1[1]
+       adc     \$0,%rdx
+       add     $A0[1],$A1[1]
+       adc     \$0,%rdx
+
+       mov     $A1[1],($tptr)          # t[6], "preloaded t[2]" below
+       mov     %rdx,$A1[0]
+       mov     %rdx,8($tptr)           # t[7], "preloaded t[3]" below
+
+       add     \$16,$i
+       jnz     .Lsqr4x_outer
+
+                                       # comments apply to $num==4 case
+       mov     -32($aptr),$a0          # a[0]
+       lea     64(%rsp,$num,2),$tptr   # end of tp[] buffer, &tp[2*$num]
+       mov     -24($aptr),%rax         # a[1]
+       lea     -32($tptr,$i),$tptr     # end of tp[] window, &tp[2*$num-"$i"]
+       mov     -16($aptr),$ai          # a[2]
+       mov     %rax,$a1
+
+       mul     $a0                     # a[1]*a[0]
+       add     %rax,$A0[0]             # a[1]*a[0]+t[1], preloaded t[1]
+        mov    $ai,%rax                # a[2]
+       mov     %rdx,$A0[1]
+       adc     \$0,$A0[1]
+
+       mul     $a0                     # a[2]*a[0]
+       add     %rax,$A0[1]
+        mov    $ai,%rax
+        mov    $A0[0],-24($tptr)       # t[1]
+       mov     %rdx,$A0[0]
+       adc     \$0,$A0[0]
+       add     $A1[1],$A0[1]           # a[2]*a[0]+t[2], preloaded t[2]
+        mov    -8($aptr),$ai           # a[3]
+       adc     \$0,$A0[0]
+
+       mul     $a1                     # a[2]*a[1]
+       add     %rax,$A1[0]             # a[2]*a[1]+t[3], preloaded t[3]
+        mov    $ai,%rax
+        mov    $A0[1],-16($tptr)       # t[2]
+       mov     %rdx,$A1[1]
+       adc     \$0,$A1[1]
+
+       mul     $a0                     # a[3]*a[0]
+       add     %rax,$A0[0]             # a[3]*a[0]+a[2]*a[1]+t[3]
+        mov    $ai,%rax
+       mov     %rdx,$A0[1]
+       adc     \$0,$A0[1]
+       add     $A1[0],$A0[0]
+       adc     \$0,$A0[1]
+       mov     $A0[0],-8($tptr)        # t[3]
+
+       mul     $a1                     # a[3]*a[1]
+       add     %rax,$A1[1]
+        mov    -16($aptr),%rax         # a[2]
+       adc     \$0,%rdx
+       add     $A0[1],$A1[1]
+       adc     \$0,%rdx
+
+       mov     $A1[1],($tptr)          # t[4]
+       mov     %rdx,$A1[0]
+       mov     %rdx,8($tptr)           # t[5]
+
+       mul     $ai                     # a[2]*a[3]
+___
+{
+my ($shift,$carry)=($a0,$a1);
+my @S=(@A1,$ai,$n0);
+$code.=<<___;
+        add    \$16,$i
+        xor    $shift,$shift
+        sub    $num,$i                 # $i=16-$num
+        xor    $carry,$carry
+
+       add     $A1[0],%rax             # t[5]
+       adc     \$0,%rdx
+       mov     %rax,8($tptr)           # t[5]
+       mov     %rdx,16($tptr)          # t[6]
+       mov     $carry,24($tptr)        # t[7]
+
+        mov    -16($aptr,$i),%rax      # a[0]
+       lea     64(%rsp,$num,2),$tptr
+        xor    $A0[0],$A0[0]           # t[0]
+        mov    -24($tptr,$i,2),$A0[1]  # t[1]
+
+       lea     ($shift,$A0[0],2),$S[0] # t[2*i]<<1 | shift
+       shr     \$63,$A0[0]
+       lea     ($j,$A0[1],2),$S[1]     # t[2*i+1]<<1 |
+       shr     \$63,$A0[1]
+       or      $A0[0],$S[1]            # | t[2*i]>>63
+        mov    -16($tptr,$i,2),$A0[0]  # t[2*i+2]      # prefetch
+       mov     $A0[1],$shift           # shift=t[2*i+1]>>63
+       mul     %rax                    # a[i]*a[i]
+       neg     $carry                  # mov $carry,cf
+        mov    -8($tptr,$i,2),$A0[1]   # t[2*i+2+1]    # prefetch
+       adc     %rax,$S[0]
+        mov    -8($aptr,$i),%rax       # a[i+1]        # prefetch
+       mov     $S[0],-32($tptr,$i,2)
+       adc     %rdx,$S[1]
+
+       lea     ($shift,$A0[0],2),$S[2] # t[2*i]<<1 | shift
+        mov    $S[1],-24($tptr,$i,2)
+        sbb    $carry,$carry           # mov cf,$carry
+       shr     \$63,$A0[0]
+       lea     ($j,$A0[1],2),$S[3]     # t[2*i+1]<<1 |
+       shr     \$63,$A0[1]
+       or      $A0[0],$S[3]            # | t[2*i]>>63
+        mov    0($tptr,$i,2),$A0[0]    # t[2*i+2]      # prefetch
+       mov     $A0[1],$shift           # shift=t[2*i+1]>>63
+       mul     %rax                    # a[i]*a[i]
+       neg     $carry                  # mov $carry,cf
+        mov    8($tptr,$i,2),$A0[1]    # t[2*i+2+1]    # prefetch
+       adc     %rax,$S[2]
+        mov    0($aptr,$i),%rax        # a[i+1]        # prefetch
+       mov     $S[2],-16($tptr,$i,2)
+       adc     %rdx,$S[3]
+       lea     16($i),$i
+       mov     $S[3],-40($tptr,$i,2)
+       sbb     $carry,$carry           # mov cf,$carry
+       jmp     .Lsqr4x_shift_n_add
+
+.align 32
+.Lsqr4x_shift_n_add:
+       lea     ($shift,$A0[0],2),$S[0] # t[2*i]<<1 | shift
+       shr     \$63,$A0[0]
+       lea     ($j,$A0[1],2),$S[1]     # t[2*i+1]<<1 |
+       shr     \$63,$A0[1]
+       or      $A0[0],$S[1]            # | t[2*i]>>63
+        mov    -16($tptr,$i,2),$A0[0]  # t[2*i+2]      # prefetch
+       mov     $A0[1],$shift           # shift=t[2*i+1]>>63
+       mul     %rax                    # a[i]*a[i]
+       neg     $carry                  # mov $carry,cf
+        mov    -8($tptr,$i,2),$A0[1]   # t[2*i+2+1]    # prefetch
+       adc     %rax,$S[0]
+        mov    -8($aptr,$i),%rax       # a[i+1]        # prefetch
+       mov     $S[0],-32($tptr,$i,2)
+       adc     %rdx,$S[1]
+
+       lea     ($shift,$A0[0],2),$S[2] # t[2*i]<<1 | shift
+        mov    $S[1],-24($tptr,$i,2)
+        sbb    $carry,$carry           # mov cf,$carry
+       shr     \$63,$A0[0]
+       lea     ($j,$A0[1],2),$S[3]     # t[2*i+1]<<1 |
+       shr     \$63,$A0[1]
+       or      $A0[0],$S[3]            # | t[2*i]>>63
+        mov    0($tptr,$i,2),$A0[0]    # t[2*i+2]      # prefetch
+       mov     $A0[1],$shift           # shift=t[2*i+1]>>63
+       mul     %rax                    # a[i]*a[i]
+       neg     $carry                  # mov $carry,cf
+        mov    8($tptr,$i,2),$A0[1]    # t[2*i+2+1]    # prefetch
+       adc     %rax,$S[2]
+        mov    0($aptr,$i),%rax        # a[i+1]        # prefetch
+       mov     $S[2],-16($tptr,$i,2)
+       adc     %rdx,$S[3]
+
+       lea     ($shift,$A0[0],2),$S[0] # t[2*i]<<1 | shift
+        mov    $S[3],-8($tptr,$i,2)
+        sbb    $carry,$carry           # mov cf,$carry
+       shr     \$63,$A0[0]
+       lea     ($j,$A0[1],2),$S[1]     # t[2*i+1]<<1 |
+       shr     \$63,$A0[1]
+       or      $A0[0],$S[1]            # | t[2*i]>>63
+        mov    16($tptr,$i,2),$A0[0]   # t[2*i+2]      # prefetch
+       mov     $A0[1],$shift           # shift=t[2*i+1]>>63
+       mul     %rax                    # a[i]*a[i]
+       neg     $carry                  # mov $carry,cf
+        mov    24($tptr,$i,2),$A0[1]   # t[2*i+2+1]    # prefetch
+       adc     %rax,$S[0]
+        mov    8($aptr,$i),%rax        # a[i+1]        # prefetch
+       mov     $S[0],0($tptr,$i,2)
+       adc     %rdx,$S[1]
+
+       lea     ($shift,$A0[0],2),$S[2] # t[2*i]<<1 | shift
+        mov    $S[1],8($tptr,$i,2)
+        sbb    $carry,$carry           # mov cf,$carry
+       shr     \$63,$A0[0]
+       lea     ($j,$A0[1],2),$S[3]     # t[2*i+1]<<1 |
+       shr     \$63,$A0[1]
+       or      $A0[0],$S[3]            # | t[2*i]>>63
+        mov    32($tptr,$i,2),$A0[0]   # t[2*i+2]      # prefetch
+       mov     $A0[1],$shift           # shift=t[2*i+1]>>63
+       mul     %rax                    # a[i]*a[i]
+       neg     $carry                  # mov $carry,cf
+        mov    40($tptr,$i,2),$A0[1]   # t[2*i+2+1]    # prefetch
+       adc     %rax,$S[2]
+        mov    16($aptr,$i),%rax       # a[i+1]        # prefetch
+       mov     $S[2],16($tptr,$i,2)
+       adc     %rdx,$S[3]
+       mov     $S[3],24($tptr,$i,2)
+       sbb     $carry,$carry           # mov cf,$carry
+       add     \$32,$i
+       jnz     .Lsqr4x_shift_n_add
+
+       lea     ($shift,$A0[0],2),$S[0] # t[2*i]<<1 | shift
+       shr     \$63,$A0[0]
+       lea     ($j,$A0[1],2),$S[1]     # t[2*i+1]<<1 |
+       shr     \$63,$A0[1]
+       or      $A0[0],$S[1]            # | t[2*i]>>63
+        mov    -16($tptr),$A0[0]       # t[2*i+2]      # prefetch
+       mov     $A0[1],$shift           # shift=t[2*i+1]>>63
+       mul     %rax                    # a[i]*a[i]
+       neg     $carry                  # mov $carry,cf
+        mov    -8($tptr),$A0[1]        # t[2*i+2+1]    # prefetch
+       adc     %rax,$S[0]
+        mov    -8($aptr),%rax          # a[i+1]        # prefetch
+       mov     $S[0],-32($tptr)
+       adc     %rdx,$S[1]
+
+       lea     ($shift,$A0[0],2),$S[2] # t[2*i]<<1|shift
+        mov    $S[1],-24($tptr)
+        sbb    $carry,$carry           # mov cf,$carry
+       shr     \$63,$A0[0]
+       lea     ($j,$A0[1],2),$S[3]     # t[2*i+1]<<1 |
+       shr     \$63,$A0[1]
+       or      $A0[0],$S[3]            # | t[2*i]>>63
+       mul     %rax                    # a[i]*a[i]
+       neg     $carry                  # mov $carry,cf
+       adc     %rax,$S[2]
+       adc     %rdx,$S[3]
+       mov     $S[2],-16($tptr)
+       mov     $S[3],-8($tptr)
+___
+}\f
+######################################################################
+# Montgomery reduction part, "word-by-word" algorithm.
+#
+# This new path is inspired by multiple submissions from Intel, by
+# Shay Gueron, Vlad Krasnov, Erdinc Ozturk, James Guilford,
+# Vinodh Gopal...
+{
+my ($nptr,$tptr,$carry,$m0)=("%rbp","%rdi","%rsi","%rbx");
+
+$code.=<<___;
+       mov     40(%rsp),$nptr          # pull $nptr
+       xor     %rax,%rax
+       lea     ($nptr,$num),%rdx       # end of n[]
+       lea     64(%rsp,$num,2),$tptr   # end of t[] buffer
+       mov     %rdx,0(%rsp)
+       mov     $tptr,8(%rsp)
+       mov     %rax,($tptr)            # clear top-most carry bit
+       lea     64(%rsp,$num),$tptr     # end of initial t[] window
+       neg     $num
+       jmp     .L8x_reduction_loop
+
+.align 32
+.L8x_reduction_loop:
+       lea     ($tptr,$num),$tptr      # start of current t[] window
+       mov     8*0($tptr),$m0
+       mov     8*1($tptr),%r9
+       mov     8*2($tptr),%r10
+       mov     8*3($tptr),%r11
+       mov     8*4($tptr),%r12
+       mov     8*5($tptr),%r13
+       mov     8*6($tptr),%r14
+       mov     8*7($tptr),%r15
+       lea     8*8($tptr),$tptr
+
+       mov     $m0,%r8
+       imulq   48(%rsp),$m0            # n0*a[0]
+       mov     8*0($nptr),%rax         # n[0]
+       mov     \$8,%ecx
+       jmp     .L8x_reduce
+
+.align 32
+.L8x_reduce:
+       mulq    $m0
+        mov    8*1($nptr),%rax         # n[1]
+       neg     %r8
+       mov     %rdx,%r8
+       adc     \$0,%r8
+
+       mulq    $m0
+       add     %rax,%r9
+        mov    8*2($nptr),%rax
+       adc     \$0,%rdx
+       add     %r9,%r8
+        mov    $m0,64-8(%rsp,%rcx,8)   # put aside n0*a[i]
+       mov     %rdx,%r9
+       adc     \$0,%r9
+
+       mulq    $m0
+       add     %rax,%r10
+        mov    8*3($nptr),%rax
+       adc     \$0,%rdx
+       add     %r10,%r9
+        mov    48(%rsp),$carry         # pull n0, borrow $carry
+       mov     %rdx,%r10
+       adc     \$0,%r10
+
+       mulq    $m0
+       add     %rax,%r11
+        mov    8*4($nptr),%rax
+       adc     \$0,%rdx
+        imulq  %r8,$carry              # modulo-scheduled
+       add     %r11,%r10
+       mov     %rdx,%r11
+       adc     \$0,%r11
+
+       mulq    $m0
+       add     %rax,%r12
+        mov    8*5($nptr),%rax
+       adc     \$0,%rdx
+       add     %r12,%r11
+       mov     %rdx,%r12
+       adc     \$0,%r12
+
+       mulq    $m0
+       add     %rax,%r13
+        mov    8*6($nptr),%rax
+       adc     \$0,%rdx
+       add     %r13,%r12
+       mov     %rdx,%r13
+       adc     \$0,%r13
+
+       mulq    $m0
+       add     %rax,%r14
+        mov    8*7($nptr),%rax
+       adc     \$0,%rdx
+       add     %r14,%r13
+       mov     %rdx,%r14
+       adc     \$0,%r14
+
+       mulq    $m0
+        mov    $carry,$m0              # n0*a[i]
+       add     %rax,%r15
+        mov    8*0($nptr),%rax         # n[0]
+       adc     \$0,%rdx
+       add     %r15,%r14
+       mov     %rdx,%r15
+       adc     \$0,%r15
+
+       dec     %ecx
+       jnz     .L8x_reduce
+
+       lea     8*8($nptr),$nptr
+       xor     %rax,%rax
+       mov     8(%rsp),%rdx            # pull end of t[]
+       cmp     0(%rsp),$nptr           # end of n[]?
+       jae     .L8x_no_tail
+
+       add     8*0($tptr),%r8
+       adc     8*1($tptr),%r9
+       adc     8*2($tptr),%r10
+       adc     8*3($tptr),%r11
+       adc     8*4($tptr),%r12
+       adc     8*5($tptr),%r13
+       adc     8*6($tptr),%r14
+       adc     8*7($tptr),%r15
+       sbb     $carry,$carry           # top carry
+
+       mov     64+56(%rsp),$m0         # pull n0*a[0]
+       mov     \$8,%ecx
+       mov     8*0($nptr),%rax
+       jmp     .L8x_tail
+
+.align 32
+.L8x_tail:
+       mulq    $m0
+       add     %rax,%r8
+        mov    8*1($nptr),%rax
+        mov    %r8,($tptr)             # save result
+       mov     %rdx,%r8
+       adc     \$0,%r8
+
+       mulq    $m0
+       add     %rax,%r9
+        mov    8*2($nptr),%rax
+       adc     \$0,%rdx
+       add     %r9,%r8
+        lea    8($tptr),$tptr          # $tptr++
+       mov     %rdx,%r9
+       adc     \$0,%r9
+
+       mulq    $m0
+       add     %rax,%r10
+        mov    8*3($nptr),%rax
+       adc     \$0,%rdx
+       add     %r10,%r9
+       mov     %rdx,%r10
+       adc     \$0,%r10
+
+       mulq    $m0
+       add     %rax,%r11
+        mov    8*4($nptr),%rax
+       adc     \$0,%rdx
+       add     %r11,%r10
+       mov     %rdx,%r11
+       adc     \$0,%r11
+
+       mulq    $m0
+       add     %rax,%r12
+        mov    8*5($nptr),%rax
+       adc     \$0,%rdx
+       add     %r12,%r11
+       mov     %rdx,%r12
+       adc     \$0,%r12
+
+       mulq    $m0
+       add     %rax,%r13
+        mov    8*6($nptr),%rax
+       adc     \$0,%rdx
+       add     %r13,%r12
+       mov     %rdx,%r13
+       adc     \$0,%r13
+
+       mulq    $m0
+       add     %rax,%r14
+        mov    8*7($nptr),%rax
+       adc     \$0,%rdx
+       add     %r14,%r13
+       mov     %rdx,%r14
+       adc     \$0,%r14
+
+       mulq    $m0
+        mov    64-16(%rsp,%rcx,8),$m0  # pull n0*a[i]
+       add     %rax,%r15
+       adc     \$0,%rdx
+       add     %r15,%r14
+        mov    8*0($nptr),%rax         # pull n[0]
+       mov     %rdx,%r15
+       adc     \$0,%r15
+
+       dec     %ecx
+       jnz     .L8x_tail
+
+       lea     8*8($nptr),$nptr
+       mov     8(%rsp),%rdx            # pull end of t[]
+       cmp     0(%rsp),$nptr           # end of n[]?
+       jae     .L8x_tail_done          # break out of loop
+
+        mov    64+56(%rsp),$m0         # pull n0*a[0]
+       neg     $carry
+        mov    8*0($nptr),%rax         # pull n[0]
+       adc     8*0($tptr),%r8
+       adc     8*1($tptr),%r9
+       adc     8*2($tptr),%r10
+       adc     8*3($tptr),%r11
+       adc     8*4($tptr),%r12
+       adc     8*5($tptr),%r13
+       adc     8*6($tptr),%r14
+       adc     8*7($tptr),%r15
+       sbb     $carry,$carry           # top carry
+
+       mov     \$8,%ecx
+       jmp     .L8x_tail
+
+.align 32
+.L8x_tail_done:
+       add     (%rdx),%r8              # can this overflow?
+       xor     %rax,%rax
+
+       neg     $carry
+.L8x_no_tail:
+       adc     8*0($tptr),%r8
+       adc     8*1($tptr),%r9
+       adc     8*2($tptr),%r10
+       adc     8*3($tptr),%r11
+       adc     8*4($tptr),%r12
+       adc     8*5($tptr),%r13
+       adc     8*6($tptr),%r14
+       adc     8*7($tptr),%r15
+       adc     \$0,%rax                # top-most carry
+
+       mov     40(%rsp),$nptr          # restore $nptr
+
+       mov     %r8,8*0($tptr)          # store top 512 bits
+       mov     %r9,8*1($tptr)
+        mov    $nptr,$num              # $num is %r9, can't be moved upwards
+       mov     %r10,8*2($tptr)
+        sub    0(%rsp),$num            # -$num
+       mov     %r11,8*3($tptr)
+       mov     %r12,8*4($tptr)
+       mov     %r13,8*5($tptr)
+       mov     %r14,8*6($tptr)
+       mov     %r15,8*7($tptr)
+       lea     8*8($tptr),$tptr
+       mov     %rax,(%rdx)             # store top-most carry
+
+       cmp     %rdx,$tptr              # end of t[]?
+       jb      .L8x_reduction_loop
+
+       neg     $num                    # restore $num
+___
+}\f
+##############################################################
+# Post-condition, 4x unrolled copy from bn_mul_mont
+#
+{
+my ($tptr,$nptr)=("%rbx",$aptr);
+my @ri=("%rax","%rdx","%r10","%r11");
+$code.=<<___;
+       mov     64(%rsp,$num),@ri[0]    # tp[0]
+       lea     64(%rsp,$num),$tptr     # upper half of t[2*$num] holds result
+       mov     40(%rsp),$nptr          # restore $nptr
+       shr     \$5,$num                # num/4
+       mov     8($tptr),@ri[1]         # t[1]
+       xor     $i,$i                   # i=0 and clear CF!
+
+       mov     32(%rsp),$rptr          # restore $rptr
+       sub     0($nptr),@ri[0]
+       mov     16($tptr),@ri[2]        # t[2]
+       mov     24($tptr),@ri[3]        # t[3]
+       sbb     8($nptr),@ri[1]
+       lea     -1($num),$j             # j=num/4-1
+       jmp     .Lsqr4x_sub
+.align 32
+.Lsqr4x_sub:
+       mov     @ri[0],0($rptr,$i,8)    # rp[i]=tp[i]-np[i]
+       mov     @ri[1],8($rptr,$i,8)    # rp[i]=tp[i]-np[i]
+       sbb     16($nptr,$i,8),@ri[2]
+       mov     32($tptr,$i,8),@ri[0]   # tp[i+1]
+       mov     40($tptr,$i,8),@ri[1]
+       sbb     24($nptr,$i,8),@ri[3]
+       mov     @ri[2],16($rptr,$i,8)   # rp[i]=tp[i]-np[i]
+       mov     @ri[3],24($rptr,$i,8)   # rp[i]=tp[i]-np[i]
+       sbb     32($nptr,$i,8),@ri[0]
+       mov     48($tptr,$i,8),@ri[2]
+       mov     56($tptr,$i,8),@ri[3]
+       sbb     40($nptr,$i,8),@ri[1]
+       lea     4($i),$i                # i++
+       dec     $j                      # doesn't affect CF!
+       jnz     .Lsqr4x_sub
+
+       mov     @ri[0],0($rptr,$i,8)    # rp[i]=tp[i]-np[i]
+       mov     32($tptr,$i,8),@ri[0]   # load overflow bit
+       sbb     16($nptr,$i,8),@ri[2]
+       mov     @ri[1],8($rptr,$i,8)    # rp[i]=tp[i]-np[i]
+       sbb     24($nptr,$i,8),@ri[3]
+       mov     @ri[2],16($rptr,$i,8)   # rp[i]=tp[i]-np[i]
+
+       sbb     \$0,@ri[0]              # handle upmost overflow bit
+       mov     @ri[3],24($rptr,$i,8)   # rp[i]=tp[i]-np[i]
+       xor     $i,$i                   # i=0
+       and     @ri[0],$tptr
+       not     @ri[0]
+       mov     $rptr,$nptr
+       and     @ri[0],$nptr
+       lea     -1($num),$j
+       or      $nptr,$tptr             # tp=borrow?tp:rp
+
+       pxor    %xmm0,%xmm0
+       lea     64(%rsp,$num,8),$nptr
+       movdqu  ($tptr),%xmm1
+       lea     ($nptr,$num,8),$nptr
+       movdqa  %xmm0,64(%rsp)          # zap lower half of temporary vector
+       movdqa  %xmm0,($nptr)           # zap upper half of temporary vector
+       movdqu  %xmm1,($rptr)
+       jmp     .Lsqr4x_copy
+.align 32
+.Lsqr4x_copy:                          # copy or in-place refresh
+       movdqu  16($tptr,$i),%xmm2
+       movdqu  32($tptr,$i),%xmm1
+       movdqa  %xmm0,80(%rsp,$i)       # zap lower half of temporary vector
+       movdqa  %xmm0,96(%rsp,$i)       # zap lower half of temporary vector
+       movdqa  %xmm0,16($nptr,$i)      # zap upper half of temporary vector
+       movdqa  %xmm0,32($nptr,$i)      # zap upper half of temporary vector
+       movdqu  %xmm2,16($rptr,$i)
+       movdqu  %xmm1,32($rptr,$i)
+       lea     32($i),$i
+       dec     $j
+       jnz     .Lsqr4x_copy
+
+       movdqu  16($tptr,$i),%xmm2
+       movdqa  %xmm0,80(%rsp,$i)       # zap lower half of temporary vector
+       movdqa  %xmm0,16($nptr,$i)      # zap upper half of temporary vector
+       movdqu  %xmm2,16($rptr,$i)
+___
+}
+$code.=<<___;
+       mov     56(%rsp),%rsi           # restore %rsp
        mov     \$1,%rax
+       mov     0(%rsi),%r15
+       mov     8(%rsi),%r14
+       mov     16(%rsi),%r13
+       mov     24(%rsi),%r12
+       mov     32(%rsi),%rbp
+       mov     40(%rsi),%rbx
+       lea     48(%rsi),%rsp
+.Lsqr8x_epilogue:
+       ret
+.size  bn_sqr8x_mont,.-bn_sqr8x_mont
+___
+}}}
+$code.=<<___;
+.asciz "Montgomery Multiplication for x86_64, CRYPTOGAMS by <appro\@openssl.org>"
+.align 16
+___
+
+# EXCEPTION_DISPOSITION handler (EXCEPTION_RECORD *rec,ULONG64 frame,
+#              CONTEXT *context,DISPATCHER_CONTEXT *disp)
+if ($win64) {
+$rec="%rcx";
+$frame="%rdx";
+$context="%r8";
+$disp="%r9";
+
+$code.=<<___;
+.extern        __imp_RtlVirtualUnwind
+.type  mul_handler,\@abi-omnipotent
+.align 16
+mul_handler:
+       push    %rsi
+       push    %rdi
+       push    %rbx
+       push    %rbp
+       push    %r12
+       push    %r13
+       push    %r14
+       push    %r15
+       pushfq
+       sub     \$64,%rsp
+
+       mov     120($context),%rax      # pull context->Rax
+       mov     248($context),%rbx      # pull context->Rip
+
+       mov     8($disp),%rsi           # disp->ImageBase
+       mov     56($disp),%r11          # disp->HandlerData
+
+       mov     0(%r11),%r10d           # HandlerData[0]
+       lea     (%rsi,%r10),%r10        # end of prologue label
+       cmp     %r10,%rbx               # context->Rip<end of prologue label
+       jb      .Lcommon_seh_tail
+
+       mov     152($context),%rax      # pull context->Rsp
+
+       mov     4(%r11),%r10d           # HandlerData[1]
+       lea     (%rsi,%r10),%r10        # epilogue label
+       cmp     %r10,%rbx               # context->Rip>=epilogue label
+       jae     .Lcommon_seh_tail
+
+       mov     192($context),%r10      # pull $num
+       mov     8(%rax,%r10,8),%rax     # pull saved stack pointer
+       lea     48(%rax),%rax
+
+       mov     -8(%rax),%rbx
+       mov     -16(%rax),%rbp
+       mov     -24(%rax),%r12
+       mov     -32(%rax),%r13
+       mov     -40(%rax),%r14
+       mov     -48(%rax),%r15
+       mov     %rbx,144($context)      # restore context->Rbx
+       mov     %rbp,160($context)      # restore context->Rbp
+       mov     %r12,216($context)      # restore context->R12
+       mov     %r13,224($context)      # restore context->R13
+       mov     %r14,232($context)      # restore context->R14
+       mov     %r15,240($context)      # restore context->R15
+
+       jmp     .Lcommon_seh_tail
+.size  mul_handler,.-mul_handler
+
+.type  sqr_handler,\@abi-omnipotent
+.align 16
+sqr_handler:
+       push    %rsi
+       push    %rdi
+       push    %rbx
+       push    %rbp
+       push    %r12
+       push    %r13
+       push    %r14
+       push    %r15
+       pushfq
+       sub     \$64,%rsp
+
+       mov     120($context),%rax      # pull context->Rax
+       mov     248($context),%rbx      # pull context->Rip
+
+       lea     .Lsqr8x_body(%rip),%r10
+       cmp     %r10,%rbx               # context->Rip<.Lsqr_body
+       jb      .Lcommon_seh_tail
+
+       mov     152($context),%rax      # pull context->Rsp
+
+       lea     .Lsqr8x_epilogue(%rip),%r10
+       cmp     %r10,%rbx               # context->Rip>=.Lsqr_epilogue
+       jae     .Lcommon_seh_tail
+
+       mov     56(%rax),%rax           # pull saved stack pointer
+       lea     48(%rax),%rax
+
+       mov     -8(%rax),%rbx
+       mov     -16(%rax),%rbp
+       mov     -24(%rax),%r12
+       mov     -32(%rax),%r13
+       mov     -40(%rax),%r14
+       mov     -48(%rax),%r15
+       mov     %rbx,144($context)      # restore context->Rbx
+       mov     %rbp,160($context)      # restore context->Rbp
+       mov     %r12,216($context)      # restore context->R12
+       mov     %r13,224($context)      # restore context->R13
+       mov     %r14,232($context)      # restore context->R14
+       mov     %r15,240($context)      # restore context->R15
+
+.Lcommon_seh_tail:
+       mov     8(%rax),%rdi
+       mov     16(%rax),%rsi
+       mov     %rax,152($context)      # restore context->Rsp
+       mov     %rsi,168($context)      # restore context->Rsi
+       mov     %rdi,176($context)      # restore context->Rdi
+
+       mov     40($disp),%rdi          # disp->ContextRecord
+       mov     $context,%rsi           # context
+       mov     \$154,%ecx              # sizeof(CONTEXT)
+       .long   0xa548f3fc              # cld; rep movsq
+
+       mov     $disp,%rsi
+       xor     %rcx,%rcx               # arg1, UNW_FLAG_NHANDLER
+       mov     8(%rsi),%rdx            # arg2, disp->ImageBase
+       mov     0(%rsi),%r8             # arg3, disp->ControlPc
+       mov     16(%rsi),%r9            # arg4, disp->FunctionEntry
+       mov     40(%rsi),%r10           # disp->ContextRecord
+       lea     56(%rsi),%r11           # &disp->HandlerData
+       lea     24(%rsi),%r12           # &disp->EstablisherFrame
+       mov     %r10,32(%rsp)           # arg5
+       mov     %r11,40(%rsp)           # arg6
+       mov     %r12,48(%rsp)           # arg7
+       mov     %rcx,56(%rsp)           # arg8, (NULL)
+       call    *__imp_RtlVirtualUnwind(%rip)
+
+       mov     \$1,%eax                # ExceptionContinueSearch
+       add     \$64,%rsp
+       popfq
        pop     %r15
        pop     %r14
        pop     %r13
        pop     %r12
        pop     %rbp
        pop     %rbx
+       pop     %rdi
+       pop     %rsi
        ret
+.size  sqr_handler,.-sqr_handler
 
-.align 16
-.Lsub: mov     (%rsp,$i,8),%rax
-       sbb     ($np,$i,8),%rax
-       mov     %rax,($rp,$i,8)         # rp[i]=tp[i]-np[j]
-       lea     1($i),$i                # i++
-       dec     $j                      # doesn't affect CF!
-       jge     .Lsub
-       lea     -1($num),$j             # j=num-1
-       sbb     \$0,%rdx
-       jc      .Lcopy                  # tp was less than np
+.section       .pdata
 .align 4
-.Lzap: mov     $i,(%rsp,$j,8)          # zap temporary vector
-       dec     $j
-       jge     .Lzap
-       jmp     .Lexit
-.size  bn_mul_mont,.-bn_mul_mont
-.asciz "Montgomery Multiplication for x86_64, CRYPTOGAMS by <appro\@openssl.org>"
+       .rva    .LSEH_begin_bn_mul_mont
+       .rva    .LSEH_end_bn_mul_mont
+       .rva    .LSEH_info_bn_mul_mont
+
+       .rva    .LSEH_begin_bn_mul4x_mont
+       .rva    .LSEH_end_bn_mul4x_mont
+       .rva    .LSEH_info_bn_mul4x_mont
+
+       .rva    .LSEH_begin_bn_sqr8x_mont
+       .rva    .LSEH_end_bn_sqr8x_mont
+       .rva    .LSEH_info_bn_sqr8x_mont
+
+.section       .xdata
+.align 8
+.LSEH_info_bn_mul_mont:
+       .byte   9,0,0,0
+       .rva    mul_handler
+       .rva    .Lmul_body,.Lmul_epilogue       # HandlerData[]
+.LSEH_info_bn_mul4x_mont:
+       .byte   9,0,0,0
+       .rva    mul_handler
+       .rva    .Lmul4x_body,.Lmul4x_epilogue   # HandlerData[]
+.LSEH_info_bn_sqr8x_mont:
+       .byte   9,0,0,0
+       .rva    sqr_handler
 ___
+}
 
 print $code;
 close STDOUT;