1#!/usr/bin/env perl
2#
3# ====================================================================
4# Written by Andy Polyakov <appro@fy.chalmers.se> for the OpenSSL
5# project. The module is, however, dual licensed under OpenSSL and
6# CRYPTOGAMS licenses depending on where you obtain it. For further
7# details see http://www.openssl.org/~appro/cryptogams/.
8# ====================================================================
9#
10# July 2004
11#
12# 2.22x RC4 tune-up:-) It should be noted though that my hand [as in
13# "hand-coded assembler"] doesn't stand for the whole improvement
14# coefficient. It turned out that eliminating RC4_CHAR from config
15# line results in ~40% improvement (yes, even for C implementation).
16# Presumably it has everything to do with AMD cache architecture and
17# RAW or whatever penalties. Once again! The module *requires* config
18# line *without* RC4_CHAR! As for coding "secret," I bet on partial
19# register arithmetics. For example instead of 'inc %r8; and $255,%r8'
20# I simply 'inc %r8b'. Even though optimization manual discourages
21# to operate on partial registers, it turned out to be the best bet.
22# At least for AMD... How IA32E would perform remains to be seen...
23
24# November 2004
25#
26# As was shown by Marc Bevand reordering of couple of load operations
27# results in even higher performance gain of 3.3x:-) At least on
28# Opteron... For reference, 1x in this case is RC4_CHAR C-code
29# compiled with gcc 3.3.2, which performs at ~54MBps per 1GHz clock.
30# Latter means that if you want to *estimate* what to expect from
31# *your* Opteron, then multiply 54 by 3.3 and clock frequency in GHz.
32
33# November 2004
34#
35# Intel P4 EM64T core was found to run the AMD64 code really slow...
36# The only way to achieve comparable performance on P4 was to keep
37# RC4_CHAR. Kind of ironic, huh? As it's apparently impossible to
38# compose blended code, which would perform even within 30% marginal
39# on either AMD and Intel platforms, I implement both cases. See
40# rc4_skey.c for further details...
41
42# April 2005
43#
44# P4 EM64T core appears to be "allergic" to 64-bit inc/dec. Replacing
45# those with add/sub results in 50% performance improvement of folded
46# loop...
47
48# May 2005
49#
50# As was shown by Zou Nanhai loop unrolling can improve Intel EM64T
51# performance by >30% [unlike P4 32-bit case that is]. But this is
52# provided that loads are reordered even more aggressively! Both code
53# pathes, AMD64 and EM64T, reorder loads in essentially same manner
54# as my IA-64 implementation. On Opteron this resulted in modest 5%
55# improvement [I had to test it], while final Intel P4 performance
56# achieves respectful 432MBps on 2.8GHz processor now. For reference.
57# If executed on Xeon, current RC4_CHAR code-path is 2.7x faster than
58# RC4_INT code-path. While if executed on Opteron, it's only 25%
59# slower than the RC4_INT one [meaning that if CPU �-arch detection
60# is not implemented, then this final RC4_CHAR code-path should be
61# preferred, as it provides better *all-round* performance].
62
63# March 2007
64#
65# Intel Core2 was observed to perform poorly on both code paths:-( It
66# apparently suffers from some kind of partial register stall, which
67# occurs in 64-bit mode only [as virtually identical 32-bit loop was
68# observed to outperform 64-bit one by almost 50%]. Adding two movzb to
69# cloop1 boosts its performance by 80%! This loop appears to be optimal
70# fit for Core2 and therefore the code was modified to skip cloop8 on
71# this CPU.
72
73# May 2010
74#
75# Intel Westmere was observed to perform suboptimally. Adding yet
76# another movzb to cloop1 improved performance by almost 50%! Core2
77# performance is improved too, but nominally...
78
79# May 2011
80#
81# The only code path that was not modified is P4-specific one. Non-P4
82# Intel code path optimization is heavily based on submission by Maxim
83# Perminov, Maxim Locktyukhin and Jim Guilford of Intel. I've used
84# some of the ideas even in attempt to optmize the original RC4_INT
85# code path... Current performance in cycles per processed byte (less
86# is better) and improvement coefficients relative to previous
87# version of this module are:
88#
89# Opteron	5.3/+0%(*)
90# P4		6.5
91# Core2		6.2/+15%(**)
92# Westmere	4.2/+60%
93# Sandy Bridge	4.2/+120%
94# Atom		9.3/+80%
95#
96# (*)	But corresponding loop has less instructions, which should have
97#	positive effect on upcoming Bulldozer, which has one less ALU.
98#	For reference, Intel code runs at 6.8 cpb rate on Opteron.
99# (**)	Note that Core2 result is ~15% lower than corresponding result
100#	for 32-bit code, meaning that it's possible to improve it,
101#	but more than likely at the cost of the others (see rc4-586.pl
102#	to get the idea)...
103
104$flavour = shift;
105$output  = shift;
106if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }
107
108$win64=0; $win64=1 if ($flavour =~ /[nm]asm|mingw64/ || $output =~ /\.asm$/);
109
110$0 =~ m/(.*[\/\\])[^\/\\]+$/; $dir=$1;
111( $xlate="${dir}x86_64-xlate.pl" and -f $xlate ) or
112( $xlate="${dir}../../perlasm/x86_64-xlate.pl" and -f $xlate) or
113die "can't locate x86_64-xlate.pl";
114
115open OUT,"| \"$^X\" $xlate $flavour $output";
116*STDOUT=*OUT;
117
118$dat="%rdi";	    # arg1
119$len="%rsi";	    # arg2
120$inp="%rdx";	    # arg3
121$out="%rcx";	    # arg4
122
123{
124$code=<<___;
125.text
126.extern	OPENSSL_ia32cap_P
127
128.globl	asm_RC4
129.type	asm_RC4,\@function,4
130.align	16
131asm_RC4:
132	or	$len,$len
133	jne	.Lentry
134	ret
135.Lentry:
136	push	%rbx
137	push	%r12
138	push	%r13
139.Lprologue:
140	mov	$len,%r11
141	mov	$inp,%r12
142	mov	$out,%r13
143___
144my $len="%r11";		# reassign input arguments
145my $inp="%r12";
146my $out="%r13";
147
148my @XX=("%r10","%rsi");
149my @TX=("%rax","%rbx");
150my $YY="%rcx";
151my $TY="%rdx";
152
153$code.=<<___;
154	xor	$XX[0],$XX[0]
155	xor	$YY,$YY
156
157	lea	8($dat),$dat
158	mov	-8($dat),$XX[0]#b
159	mov	-4($dat),$YY#b
160	cmpl	\$-1,256($dat)
161	je	.LRC4_CHAR
162	mov	OPENSSL_ia32cap_P(%rip),%r8d
163	xor	$TX[1],$TX[1]
164	inc	$XX[0]#b
165	sub	$XX[0],$TX[1]
166	sub	$inp,$out
167	movl	($dat,$XX[0],4),$TX[0]#d
168	test	\$-16,$len
169	jz	.Lloop1
170	bt	\$30,%r8d	# Intel CPU?
171	jc	.Lintel
172	and	\$7,$TX[1]
173	lea	1($XX[0]),$XX[1]
174	jz	.Loop8
175	sub	$TX[1],$len
176.Loop8_warmup:
177	add	$TX[0]#b,$YY#b
178	movl	($dat,$YY,4),$TY#d
179	movl	$TX[0]#d,($dat,$YY,4)
180	movl	$TY#d,($dat,$XX[0],4)
181	add	$TY#b,$TX[0]#b
182	inc	$XX[0]#b
183	movl	($dat,$TX[0],4),$TY#d
184	movl	($dat,$XX[0],4),$TX[0]#d
185	xorb	($inp),$TY#b
186	movb	$TY#b,($out,$inp)
187	lea	1($inp),$inp
188	dec	$TX[1]
189	jnz	.Loop8_warmup
190
191	lea	1($XX[0]),$XX[1]
192	jmp	.Loop8
193.align	16
194.Loop8:
195___
196for ($i=0;$i<8;$i++) {
197$code.=<<___ if ($i==7);
198	add	\$8,$XX[1]#b
199___
200$code.=<<___;
201	add	$TX[0]#b,$YY#b
202	movl	($dat,$YY,4),$TY#d
203	movl	$TX[0]#d,($dat,$YY,4)
204	movl	`4*($i==7?-1:$i)`($dat,$XX[1],4),$TX[1]#d
205	ror	\$8,%r8				# ror is redundant when $i=0
206	movl	$TY#d,4*$i($dat,$XX[0],4)
207	add	$TX[0]#b,$TY#b
208	movb	($dat,$TY,4),%r8b
209___
210push(@TX,shift(@TX)); #push(@XX,shift(@XX));	# "rotate" registers
211}
212$code.=<<___;
213	add	\$8,$XX[0]#b
214	ror	\$8,%r8
215	sub	\$8,$len
216
217	xor	($inp),%r8
218	mov	%r8,($out,$inp)
219	lea	8($inp),$inp
220
221	test	\$-8,$len
222	jnz	.Loop8
223	cmp	\$0,$len
224	jne	.Lloop1
225	jmp	.Lexit
226
227.align	16
228.Lintel:
229	test	\$-32,$len
230	jz	.Lloop1
231	and	\$15,$TX[1]
232	jz	.Loop16_is_hot
233	sub	$TX[1],$len
234.Loop16_warmup:
235	add	$TX[0]#b,$YY#b
236	movl	($dat,$YY,4),$TY#d
237	movl	$TX[0]#d,($dat,$YY,4)
238	movl	$TY#d,($dat,$XX[0],4)
239	add	$TY#b,$TX[0]#b
240	inc	$XX[0]#b
241	movl	($dat,$TX[0],4),$TY#d
242	movl	($dat,$XX[0],4),$TX[0]#d
243	xorb	($inp),$TY#b
244	movb	$TY#b,($out,$inp)
245	lea	1($inp),$inp
246	dec	$TX[1]
247	jnz	.Loop16_warmup
248
249	mov	$YY,$TX[1]
250	xor	$YY,$YY
251	mov	$TX[1]#b,$YY#b
252
253.Loop16_is_hot:
254	lea	($dat,$XX[0],4),$XX[1]
255___
256sub RC4_loop {
257  my $i=shift;
258  my $j=$i<0?0:$i;
259  my $xmm="%xmm".($j&1);
260
261    $code.="	add	\$16,$XX[0]#b\n"		if ($i==15);
262    $code.="	movdqu	($inp),%xmm2\n"			if ($i==15);
263    $code.="	add	$TX[0]#b,$YY#b\n"		if ($i<=0);
264    $code.="	movl	($dat,$YY,4),$TY#d\n";
265    $code.="	pxor	%xmm0,%xmm2\n"			if ($i==0);
266    $code.="	psllq	\$8,%xmm1\n"			if ($i==0);
267    $code.="	pxor	$xmm,$xmm\n"			if ($i<=1);
268    $code.="	movl	$TX[0]#d,($dat,$YY,4)\n";
269    $code.="	add	$TY#b,$TX[0]#b\n";
270    $code.="	movl	`4*($j+1)`($XX[1]),$TX[1]#d\n"	if ($i<15);
271    $code.="	movz	$TX[0]#b,$TX[0]#d\n";
272    $code.="	movl	$TY#d,4*$j($XX[1])\n";
273    $code.="	pxor	%xmm1,%xmm2\n"			if ($i==0);
274    $code.="	lea	($dat,$XX[0],4),$XX[1]\n"	if ($i==15);
275    $code.="	add	$TX[1]#b,$YY#b\n"		if ($i<15);
276    $code.="	pinsrw	\$`($j>>1)&7`,($dat,$TX[0],4),$xmm\n";
277    $code.="	movdqu	%xmm2,($out,$inp)\n"		if ($i==0);
278    $code.="	lea	16($inp),$inp\n"		if ($i==0);
279    $code.="	movl	($XX[1]),$TX[1]#d\n"		if ($i==15);
280}
281	RC4_loop(-1);
282$code.=<<___;
283	jmp	.Loop16_enter
284.align	16
285.Loop16:
286___
287
288for ($i=0;$i<16;$i++) {
289    $code.=".Loop16_enter:\n"		if ($i==1);
290	RC4_loop($i);
291	push(@TX,shift(@TX)); 		# "rotate" registers
292}
293$code.=<<___;
294	mov	$YY,$TX[1]
295	xor	$YY,$YY			# keyword to partial register
296	sub	\$16,$len
297	mov	$TX[1]#b,$YY#b
298	test	\$-16,$len
299	jnz	.Loop16
300
301	psllq	\$8,%xmm1
302	pxor	%xmm0,%xmm2
303	pxor	%xmm1,%xmm2
304	movdqu	%xmm2,($out,$inp)
305	lea	16($inp),$inp
306
307	cmp	\$0,$len
308	jne	.Lloop1
309	jmp	.Lexit
310
311.align	16
312.Lloop1:
313	add	$TX[0]#b,$YY#b
314	movl	($dat,$YY,4),$TY#d
315	movl	$TX[0]#d,($dat,$YY,4)
316	movl	$TY#d,($dat,$XX[0],4)
317	add	$TY#b,$TX[0]#b
318	inc	$XX[0]#b
319	movl	($dat,$TX[0],4),$TY#d
320	movl	($dat,$XX[0],4),$TX[0]#d
321	xorb	($inp),$TY#b
322	movb	$TY#b,($out,$inp)
323	lea	1($inp),$inp
324	dec	$len
325	jnz	.Lloop1
326	jmp	.Lexit
327
328.align	16
329.LRC4_CHAR:
330	add	\$1,$XX[0]#b
331	movzb	($dat,$XX[0]),$TX[0]#d
332	test	\$-8,$len
333	jz	.Lcloop1
334	jmp	.Lcloop8
335.align	16
336.Lcloop8:
337	mov	($inp),%r8d
338	mov	4($inp),%r9d
339___
340# unroll 2x4-wise, because 64-bit rotates kill Intel P4...
341for ($i=0;$i<4;$i++) {
342$code.=<<___;
343	add	$TX[0]#b,$YY#b
344	lea	1($XX[0]),$XX[1]
345	movzb	($dat,$YY),$TY#d
346	movzb	$XX[1]#b,$XX[1]#d
347	movzb	($dat,$XX[1]),$TX[1]#d
348	movb	$TX[0]#b,($dat,$YY)
349	cmp	$XX[1],$YY
350	movb	$TY#b,($dat,$XX[0])
351	jne	.Lcmov$i			# Intel cmov is sloooow...
352	mov	$TX[0],$TX[1]
353.Lcmov$i:
354	add	$TX[0]#b,$TY#b
355	xor	($dat,$TY),%r8b
356	ror	\$8,%r8d
357___
358push(@TX,shift(@TX)); push(@XX,shift(@XX));	# "rotate" registers
359}
360for ($i=4;$i<8;$i++) {
361$code.=<<___;
362	add	$TX[0]#b,$YY#b
363	lea	1($XX[0]),$XX[1]
364	movzb	($dat,$YY),$TY#d
365	movzb	$XX[1]#b,$XX[1]#d
366	movzb	($dat,$XX[1]),$TX[1]#d
367	movb	$TX[0]#b,($dat,$YY)
368	cmp	$XX[1],$YY
369	movb	$TY#b,($dat,$XX[0])
370	jne	.Lcmov$i			# Intel cmov is sloooow...
371	mov	$TX[0],$TX[1]
372.Lcmov$i:
373	add	$TX[0]#b,$TY#b
374	xor	($dat,$TY),%r9b
375	ror	\$8,%r9d
376___
377push(@TX,shift(@TX)); push(@XX,shift(@XX));	# "rotate" registers
378}
379$code.=<<___;
380	lea	-8($len),$len
381	mov	%r8d,($out)
382	lea	8($inp),$inp
383	mov	%r9d,4($out)
384	lea	8($out),$out
385
386	test	\$-8,$len
387	jnz	.Lcloop8
388	cmp	\$0,$len
389	jne	.Lcloop1
390	jmp	.Lexit
391___
392$code.=<<___;
393.align	16
394.Lcloop1:
395	add	$TX[0]#b,$YY#b
396	movzb	$YY#b,$YY#d
397	movzb	($dat,$YY),$TY#d
398	movb	$TX[0]#b,($dat,$YY)
399	movb	$TY#b,($dat,$XX[0])
400	add	$TX[0]#b,$TY#b
401	add	\$1,$XX[0]#b
402	movzb	$TY#b,$TY#d
403	movzb	$XX[0]#b,$XX[0]#d
404	movzb	($dat,$TY),$TY#d
405	movzb	($dat,$XX[0]),$TX[0]#d
406	xorb	($inp),$TY#b
407	lea	1($inp),$inp
408	movb	$TY#b,($out)
409	lea	1($out),$out
410	sub	\$1,$len
411	jnz	.Lcloop1
412	jmp	.Lexit
413
414.align	16
415.Lexit:
416	sub	\$1,$XX[0]#b
417	movl	$XX[0]#d,-8($dat)
418	movl	$YY#d,-4($dat)
419
420	mov	(%rsp),%r13
421	mov	8(%rsp),%r12
422	mov	16(%rsp),%rbx
423	add	\$24,%rsp
424.Lepilogue:
425	ret
426.size	asm_RC4,.-asm_RC4
427___
428}
429
430$idx="%r8";
431$ido="%r9";
432
433$code.=<<___;
434.globl	asm_RC4_set_key
435.type	asm_RC4_set_key,\@function,3
436.align	16
437asm_RC4_set_key:
438	lea	8($dat),$dat
439	lea	($inp,$len),$inp
440	neg	$len
441	mov	$len,%rcx
442	xor	%eax,%eax
443	xor	$ido,$ido
444	xor	%r10,%r10
445	xor	%r11,%r11
446
447	mov	OPENSSL_ia32cap_P(%rip),$idx#d
448	bt	\$20,$idx#d	# RC4_CHAR?
449	jc	.Lc1stloop
450	jmp	.Lw1stloop
451
452.align	16
453.Lw1stloop:
454	mov	%eax,($dat,%rax,4)
455	add	\$1,%al
456	jnc	.Lw1stloop
457
458	xor	$ido,$ido
459	xor	$idx,$idx
460.align	16
461.Lw2ndloop:
462	mov	($dat,$ido,4),%r10d
463	add	($inp,$len,1),$idx#b
464	add	%r10b,$idx#b
465	add	\$1,$len
466	mov	($dat,$idx,4),%r11d
467	cmovz	%rcx,$len
468	mov	%r10d,($dat,$idx,4)
469	mov	%r11d,($dat,$ido,4)
470	add	\$1,$ido#b
471	jnc	.Lw2ndloop
472	jmp	.Lexit_key
473
474.align	16
475.Lc1stloop:
476	mov	%al,($dat,%rax)
477	add	\$1,%al
478	jnc	.Lc1stloop
479
480	xor	$ido,$ido
481	xor	$idx,$idx
482.align	16
483.Lc2ndloop:
484	mov	($dat,$ido),%r10b
485	add	($inp,$len),$idx#b
486	add	%r10b,$idx#b
487	add	\$1,$len
488	mov	($dat,$idx),%r11b
489	jnz	.Lcnowrap
490	mov	%rcx,$len
491.Lcnowrap:
492	mov	%r10b,($dat,$idx)
493	mov	%r11b,($dat,$ido)
494	add	\$1,$ido#b
495	jnc	.Lc2ndloop
496	movl	\$-1,256($dat)
497
498.align	16
499.Lexit_key:
500	xor	%eax,%eax
501	mov	%eax,-8($dat)
502	mov	%eax,-4($dat)
503	ret
504.size	asm_RC4_set_key,.-asm_RC4_set_key
505___
506
507# EXCEPTION_DISPOSITION handler (EXCEPTION_RECORD *rec,ULONG64 frame,
508#		CONTEXT *context,DISPATCHER_CONTEXT *disp)
509if ($win64) {
510$rec="%rcx";
511$frame="%rdx";
512$context="%r8";
513$disp="%r9";
514
515$code.=<<___;
516.extern	__imp_RtlVirtualUnwind
517.type	stream_se_handler,\@abi-omnipotent
518.align	16
519stream_se_handler:
520	push	%rsi
521	push	%rdi
522	push	%rbx
523	push	%rbp
524	push	%r12
525	push	%r13
526	push	%r14
527	push	%r15
528	pushfq
529	sub	\$64,%rsp
530
531	mov	120($context),%rax	# pull context->Rax
532	mov	248($context),%rbx	# pull context->Rip
533
534	lea	.Lprologue(%rip),%r10
535	cmp	%r10,%rbx		# context->Rip<prologue label
536	jb	.Lin_prologue
537
538	mov	152($context),%rax	# pull context->Rsp
539
540	lea	.Lepilogue(%rip),%r10
541	cmp	%r10,%rbx		# context->Rip>=epilogue label
542	jae	.Lin_prologue
543
544	lea	24(%rax),%rax
545
546	mov	-8(%rax),%rbx
547	mov	-16(%rax),%r12
548	mov	-24(%rax),%r13
549	mov	%rbx,144($context)	# restore context->Rbx
550	mov	%r12,216($context)	# restore context->R12
551	mov	%r13,224($context)	# restore context->R13
552
553.Lin_prologue:
554	mov	8(%rax),%rdi
555	mov	16(%rax),%rsi
556	mov	%rax,152($context)	# restore context->Rsp
557	mov	%rsi,168($context)	# restore context->Rsi
558	mov	%rdi,176($context)	# restore context->Rdi
559
560	jmp	.Lcommon_seh_exit
561.size	stream_se_handler,.-stream_se_handler
562
563.type	key_se_handler,\@abi-omnipotent
564.align	16
565key_se_handler:
566	push	%rsi
567	push	%rdi
568	push	%rbx
569	push	%rbp
570	push	%r12
571	push	%r13
572	push	%r14
573	push	%r15
574	pushfq
575	sub	\$64,%rsp
576
577	mov	152($context),%rax	# pull context->Rsp
578	mov	8(%rax),%rdi
579	mov	16(%rax),%rsi
580	mov	%rsi,168($context)	# restore context->Rsi
581	mov	%rdi,176($context)	# restore context->Rdi
582
583.Lcommon_seh_exit:
584
585	mov	40($disp),%rdi		# disp->ContextRecord
586	mov	$context,%rsi		# context
587	mov	\$154,%ecx		# sizeof(CONTEXT)
588	.long	0xa548f3fc		# cld; rep movsq
589
590	mov	$disp,%rsi
591	xor	%rcx,%rcx		# arg1, UNW_FLAG_NHANDLER
592	mov	8(%rsi),%rdx		# arg2, disp->ImageBase
593	mov	0(%rsi),%r8		# arg3, disp->ControlPc
594	mov	16(%rsi),%r9		# arg4, disp->FunctionEntry
595	mov	40(%rsi),%r10		# disp->ContextRecord
596	lea	56(%rsi),%r11		# &disp->HandlerData
597	lea	24(%rsi),%r12		# &disp->EstablisherFrame
598	mov	%r10,32(%rsp)		# arg5
599	mov	%r11,40(%rsp)		# arg6
600	mov	%r12,48(%rsp)		# arg7
601	mov	%rcx,56(%rsp)		# arg8, (NULL)
602	call	*__imp_RtlVirtualUnwind(%rip)
603
604	mov	\$1,%eax		# ExceptionContinueSearch
605	add	\$64,%rsp
606	popfq
607	pop	%r15
608	pop	%r14
609	pop	%r13
610	pop	%r12
611	pop	%rbp
612	pop	%rbx
613	pop	%rdi
614	pop	%rsi
615	ret
616.size	key_se_handler,.-key_se_handler
617
618.section	.pdata
619.align	4
620	.rva	.LSEH_begin_asm_RC4
621	.rva	.LSEH_end_asm_RC4
622	.rva	.LSEH_info_asm_RC4
623
624	.rva	.LSEH_begin_asm_RC4_set_key
625	.rva	.LSEH_end_asm_RC4_set_key
626	.rva	.LSEH_info_asm_RC4_set_key
627
628.section	.xdata
629.align	8
630.LSEH_info_asm_RC4:
631	.byte	9,0,0,0
632	.rva	stream_se_handler
633.LSEH_info_asm_RC4_set_key:
634	.byte	9,0,0,0
635	.rva	key_se_handler
636___
637}
638
639sub reg_part {
640my ($reg,$conv)=@_;
641    if ($reg =~ /%r[0-9]+/)	{ $reg .= $conv; }
642    elsif ($conv eq "b")	{ $reg =~ s/%[er]([^x]+)x?/%$1l/;	}
643    elsif ($conv eq "w")	{ $reg =~ s/%[er](.+)/%$1/;		}
644    elsif ($conv eq "d")	{ $reg =~ s/%[er](.+)/%e$1/;		}
645    return $reg;
646}
647
648$code =~ s/(%[a-z0-9]+)#([bwd])/reg_part($1,$2)/gem;
649$code =~ s/\`([^\`]*)\`/eval $1/gem;
650
651print $code;
652
653close STDOUT;
654