xref: /onnv-gate/usr/src/common/openssl/crypto/md32_common.h (revision 2139:6243c3338933)
1 /* crypto/md32_common.h */
2 /* ====================================================================
3  * Copyright (c) 1999-2002 The OpenSSL Project.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  *
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in
14  *    the documentation and/or other materials provided with the
15  *    distribution.
16  *
17  * 3. All advertising materials mentioning features or use of this
18  *    software must display the following acknowledgment:
19  *    "This product includes software developed by the OpenSSL Project
20  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
21  *
22  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
23  *    endorse or promote products derived from this software without
24  *    prior written permission. For written permission, please contact
25  *    licensing@OpenSSL.org.
26  *
27  * 5. Products derived from this software may not be called "OpenSSL"
28  *    nor may "OpenSSL" appear in their names without prior written
29  *    permission of the OpenSSL Project.
30  *
31  * 6. Redistributions of any form whatsoever must retain the following
32  *    acknowledgment:
33  *    "This product includes software developed by the OpenSSL Project
34  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
35  *
36  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
37  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
39  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
40  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
42  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
43  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
44  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
45  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
46  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
47  * OF THE POSSIBILITY OF SUCH DAMAGE.
48  * ====================================================================
49  *
50  * This product includes cryptographic software written by Eric Young
51  * (eay@cryptsoft.com).  This product includes software written by Tim
52  * Hudson (tjh@cryptsoft.com).
53  *
54  */
55 
56 /*
57  * This is a generic 32 bit "collector" for message digest algorithms.
58  * Whenever needed it collects input character stream into chunks of
59  * 32 bit values and invokes a block function that performs actual hash
60  * calculations.
61  *
62  * Porting guide.
63  *
64  * Obligatory macros:
65  *
66  * DATA_ORDER_IS_BIG_ENDIAN or DATA_ORDER_IS_LITTLE_ENDIAN
67  *	this macro defines byte order of input stream.
68  * HASH_CBLOCK
69  *	size of a unit chunk HASH_BLOCK operates on.
70  * HASH_LONG
71  *	has to be at lest 32 bit wide, if it's wider, then
72  *	HASH_LONG_LOG2 *has to* be defined along
73  * HASH_CTX
74  *	context structure that at least contains following
75  *	members:
76  *		typedef struct {
77  *			...
78  *			HASH_LONG	Nl,Nh;
79  *			HASH_LONG	data[HASH_LBLOCK];
80  *			unsigned int	num;
81  *			...
82  *			} HASH_CTX;
83  * HASH_UPDATE
84  *	name of "Update" function, implemented here.
85  * HASH_TRANSFORM
86  *	name of "Transform" function, implemented here.
87  * HASH_FINAL
88  *	name of "Final" function, implemented here.
89  * HASH_BLOCK_HOST_ORDER
90  *	name of "block" function treating *aligned* input message
91  *	in host byte order, implemented externally.
92  * HASH_BLOCK_DATA_ORDER
93  *	name of "block" function treating *unaligned* input message
94  *	in original (data) byte order, implemented externally (it
95  *	actually is optional if data and host are of the same
96  *	"endianess").
97  * HASH_MAKE_STRING
98  *	macro convering context variables to an ASCII hash string.
99  *
100  * Optional macros:
101  *
102  * B_ENDIAN or L_ENDIAN
103  *	defines host byte-order.
104  * HASH_LONG_LOG2
105  *	defaults to 2 if not states otherwise.
106  * HASH_LBLOCK
107  *	assumed to be HASH_CBLOCK/4 if not stated otherwise.
108  * HASH_BLOCK_DATA_ORDER_ALIGNED
109  *	alternative "block" function capable of treating
110  *	aligned input message in original (data) order,
111  *	implemented externally.
112  *
113  * MD5 example:
114  *
115  *	#define DATA_ORDER_IS_LITTLE_ENDIAN
116  *
117  *	#define HASH_LONG		MD5_LONG
118  *	#define HASH_LONG_LOG2		MD5_LONG_LOG2
119  *	#define HASH_CTX		MD5_CTX
120  *	#define HASH_CBLOCK		MD5_CBLOCK
121  *	#define HASH_LBLOCK		MD5_LBLOCK
122  *	#define HASH_UPDATE		MD5_Update
123  *	#define HASH_TRANSFORM		MD5_Transform
124  *	#define HASH_FINAL		MD5_Final
125  *	#define HASH_BLOCK_HOST_ORDER	md5_block_host_order
126  *	#define HASH_BLOCK_DATA_ORDER	md5_block_data_order
127  *
128  *					<appro@fy.chalmers.se>
129  */
130 
131 #if !defined(DATA_ORDER_IS_BIG_ENDIAN) && !defined(DATA_ORDER_IS_LITTLE_ENDIAN)
132 #error "DATA_ORDER must be defined!"
133 #endif
134 
135 #ifndef HASH_CBLOCK
136 #error "HASH_CBLOCK must be defined!"
137 #endif
138 #ifndef HASH_LONG
139 #error "HASH_LONG must be defined!"
140 #endif
141 #ifndef HASH_CTX
142 #error "HASH_CTX must be defined!"
143 #endif
144 
145 #ifndef HASH_UPDATE
146 #error "HASH_UPDATE must be defined!"
147 #endif
148 #ifndef HASH_TRANSFORM
149 #error "HASH_TRANSFORM must be defined!"
150 #endif
151 #ifndef HASH_FINAL
152 #error "HASH_FINAL must be defined!"
153 #endif
154 
155 #ifndef HASH_BLOCK_HOST_ORDER
156 #error "HASH_BLOCK_HOST_ORDER must be defined!"
157 #endif
158 
159 #if 0
160 /*
161  * Moved below as it's required only if HASH_BLOCK_DATA_ORDER_ALIGNED
162  * isn't defined.
163  */
164 #ifndef HASH_BLOCK_DATA_ORDER
165 #error "HASH_BLOCK_DATA_ORDER must be defined!"
166 #endif
167 #endif
168 
169 #ifndef HASH_LBLOCK
170 #define HASH_LBLOCK	(HASH_CBLOCK/4)
171 #endif
172 
173 #ifndef HASH_LONG_LOG2
174 #define HASH_LONG_LOG2	2
175 #endif
176 
177 /*
178  * Engage compiler specific rotate intrinsic function if available.
179  */
180 #undef ROTATE
181 #ifndef PEDANTIC
182 # if defined(_MSC_VER) || defined(__ICC)
183 #  define ROTATE(a,n)	_lrotl(a,n)
184 # elif defined(__MWERKS__)
185 #  if defined(__POWERPC__)
186 #   define ROTATE(a,n)	__rlwinm(a,n,0,31)
187 #  elif defined(__MC68K__)
188     /* Motorola specific tweak. <appro@fy.chalmers.se> */
189 #   define ROTATE(a,n)	( n<24 ? __rol(a,n) : __ror(a,32-n) )
190 #  else
191 #   define ROTATE(a,n)	__rol(a,n)
192 #  endif
193 # elif defined(__GNUC__) && __GNUC__>=2 && !defined(OPENSSL_NO_ASM) && !defined(OPENSSL_NO_INLINE_ASM)
194   /*
195    * Some GNU C inline assembler templates. Note that these are
196    * rotates by *constant* number of bits! But that's exactly
197    * what we need here...
198    * 					<appro@fy.chalmers.se>
199    */
200 #  if defined(__i386) || defined(__i386__) || defined(__x86_64) || defined(__x86_64__)
201 #   define ROTATE(a,n)	({ register unsigned int ret;	\
202 				__asm__ (			\
203 				"roll %1,%0"		\
204 				: "=r"(ret)		\
205 				: "I"(n), "0"(a)	\
206 				: "cc");		\
207 			   ret;				\
208 			})
209 #  elif defined(__powerpc) || defined(__ppc__) || defined(__powerpc64__)
210 #   define ROTATE(a,n)	({ register unsigned int ret;	\
211 				__asm__ (			\
212 				"rlwinm %0,%1,%2,0,31"	\
213 				: "=r"(ret)		\
214 				: "r"(a), "I"(n));	\
215 			   ret;				\
216 			})
217 #  endif
218 # endif
219 #endif /* PEDANTIC */
220 
221 #if HASH_LONG_LOG2==2	/* Engage only if sizeof(HASH_LONG)== 4 */
222 /* A nice byte order reversal from Wei Dai <weidai@eskimo.com> */
223 #ifdef ROTATE
224 /* 5 instructions with rotate instruction, else 9 */
225 #define REVERSE_FETCH32(a,l)	(					\
226 		l=*(const HASH_LONG *)(a),				\
227 		((ROTATE(l,8)&0x00FF00FF)|(ROTATE((l&0x00FF00FF),24)))	\
228 				)
229 #else
230 /* 6 instructions with rotate instruction, else 8 */
231 #define REVERSE_FETCH32(a,l)	(				\
232 		l=*(const HASH_LONG *)(a),			\
233 		l=(((l>>8)&0x00FF00FF)|((l&0x00FF00FF)<<8)),	\
234 		ROTATE(l,16)					\
235 				)
236 /*
237  * Originally the middle line started with l=(((l&0xFF00FF00)>>8)|...
238  * It's rewritten as above for two reasons:
239  *	- RISCs aren't good at long constants and have to explicitely
240  *	  compose 'em with several (well, usually 2) instructions in a
241  *	  register before performing the actual operation and (as you
242  *	  already realized:-) having same constant should inspire the
243  *	  compiler to permanently allocate the only register for it;
244  *	- most modern CPUs have two ALUs, but usually only one has
245  *	  circuitry for shifts:-( this minor tweak inspires compiler
246  *	  to schedule shift instructions in a better way...
247  *
248  *				<appro@fy.chalmers.se>
249  */
250 #endif
251 #endif
252 
253 #ifndef ROTATE
254 #define ROTATE(a,n)     (((a)<<(n))|(((a)&0xffffffff)>>(32-(n))))
255 #endif
256 
257 /*
258  * Make some obvious choices. E.g., HASH_BLOCK_DATA_ORDER_ALIGNED
259  * and HASH_BLOCK_HOST_ORDER ought to be the same if input data
260  * and host are of the same "endianess". It's possible to mask
261  * this with blank #define HASH_BLOCK_DATA_ORDER though...
262  *
263  *				<appro@fy.chalmers.se>
264  */
265 #if defined(B_ENDIAN)
266 #  if defined(DATA_ORDER_IS_BIG_ENDIAN)
267 #    if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED) && HASH_LONG_LOG2==2
268 #      define HASH_BLOCK_DATA_ORDER_ALIGNED	HASH_BLOCK_HOST_ORDER
269 #    endif
270 #  endif
271 #elif defined(L_ENDIAN)
272 #  if defined(DATA_ORDER_IS_LITTLE_ENDIAN)
273 #    if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED) && HASH_LONG_LOG2==2
274 #      define HASH_BLOCK_DATA_ORDER_ALIGNED	HASH_BLOCK_HOST_ORDER
275 #    endif
276 #  endif
277 #endif
278 
279 #if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
280 #ifndef HASH_BLOCK_DATA_ORDER
281 #error "HASH_BLOCK_DATA_ORDER must be defined!"
282 #endif
283 #endif
284 
285 #if defined(DATA_ORDER_IS_BIG_ENDIAN)
286 
287 #ifndef PEDANTIC
288 # if defined(__GNUC__) && __GNUC__>=2 && !defined(OPENSSL_NO_ASM) && !defined(OPENSSL_NO_INLINE_ASM)
289 #  if ((defined(__i386) || defined(__i386__)) && !defined(I386_ONLY)) || \
290       (defined(__x86_64) || defined(__x86_64__))
291     /*
292      * This gives ~30-40% performance improvement in SHA-256 compiled
293      * with gcc [on P4]. Well, first macro to be frank. We can pull
294      * this trick on x86* platforms only, because these CPUs can fetch
295      * unaligned data without raising an exception.
296      */
297 #   define HOST_c2l(c,l)	({ unsigned int r=*((const unsigned int *)(c));	\
298 				   __asm__ ("bswapl %0":"=r"(r):"0"(r));	\
299 				   (c)+=4; (l)=r;			})
300 #   define HOST_l2c(l,c)	({ unsigned int r=(l);			\
301 				   __asm__ ("bswapl %0":"=r"(r):"0"(r));	\
302 				   *((unsigned int *)(c))=r; (c)+=4; r;	})
303 #  endif
304 # endif
305 #endif
306 
307 #ifndef HOST_c2l
308 #define HOST_c2l(c,l)	(l =(((unsigned long)(*((c)++)))<<24),		\
309 			 l|=(((unsigned long)(*((c)++)))<<16),		\
310 			 l|=(((unsigned long)(*((c)++)))<< 8),		\
311 			 l|=(((unsigned long)(*((c)++)))    ),		\
312 			 l)
313 #endif
314 #define HOST_p_c2l(c,l,n)	{					\
315 			switch (n) {					\
316 			case 0: l =((unsigned long)(*((c)++)))<<24;	\
317 			case 1: l|=((unsigned long)(*((c)++)))<<16;	\
318 			case 2: l|=((unsigned long)(*((c)++)))<< 8;	\
319 			case 3: l|=((unsigned long)(*((c)++)));		\
320 				} }
321 #define HOST_p_c2l_p(c,l,sc,len) {					\
322 			switch (sc) {					\
323 			case 0: l =((unsigned long)(*((c)++)))<<24;	\
324 				if (--len == 0) break;			\
325 			case 1: l|=((unsigned long)(*((c)++)))<<16;	\
326 				if (--len == 0) break;			\
327 			case 2: l|=((unsigned long)(*((c)++)))<< 8;	\
328 				} }
329 /* NOTE the pointer is not incremented at the end of this */
330 #define HOST_c2l_p(c,l,n)	{					\
331 			l=0; (c)+=n;					\
332 			switch (n) {					\
333 			case 3: l =((unsigned long)(*(--(c))))<< 8;	\
334 			case 2: l|=((unsigned long)(*(--(c))))<<16;	\
335 			case 1: l|=((unsigned long)(*(--(c))))<<24;	\
336 				} }
337 #ifndef HOST_l2c
338 #define HOST_l2c(l,c)	(*((c)++)=(unsigned char)(((l)>>24)&0xff),	\
339 			 *((c)++)=(unsigned char)(((l)>>16)&0xff),	\
340 			 *((c)++)=(unsigned char)(((l)>> 8)&0xff),	\
341 			 *((c)++)=(unsigned char)(((l)    )&0xff),	\
342 			 l)
343 #endif
344 
345 #elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)
346 
347 #if defined(__i386) || defined(__i386__) || defined(__x86_64) || defined(__x86_64__)
348 # ifndef B_ENDIAN
349    /* See comment in DATA_ORDER_IS_BIG_ENDIAN section. */
350 #  define HOST_c2l(c,l)	((l)=*((const unsigned int *)(c)), (c)+=4, l)
351 #  define HOST_l2c(l,c)	(*((unsigned int *)(c))=(l), (c)+=4, l)
352 # endif
353 #endif
354 
355 #ifndef HOST_c2l
356 #define HOST_c2l(c,l)	(l =(((unsigned long)(*((c)++)))    ),		\
357 			 l|=(((unsigned long)(*((c)++)))<< 8),		\
358 			 l|=(((unsigned long)(*((c)++)))<<16),		\
359 			 l|=(((unsigned long)(*((c)++)))<<24),		\
360 			 l)
361 #endif
362 #define HOST_p_c2l(c,l,n)	{					\
363 			switch (n) {					\
364 			case 0: l =((unsigned long)(*((c)++)));		\
365 			case 1: l|=((unsigned long)(*((c)++)))<< 8;	\
366 			case 2: l|=((unsigned long)(*((c)++)))<<16;	\
367 			case 3: l|=((unsigned long)(*((c)++)))<<24;	\
368 				} }
369 #define HOST_p_c2l_p(c,l,sc,len) {					\
370 			switch (sc) {					\
371 			case 0: l =((unsigned long)(*((c)++)));		\
372 				if (--len == 0) break;			\
373 			case 1: l|=((unsigned long)(*((c)++)))<< 8;	\
374 				if (--len == 0) break;			\
375 			case 2: l|=((unsigned long)(*((c)++)))<<16;	\
376 				} }
377 /* NOTE the pointer is not incremented at the end of this */
378 #define HOST_c2l_p(c,l,n)	{					\
379 			l=0; (c)+=n;					\
380 			switch (n) {					\
381 			case 3: l =((unsigned long)(*(--(c))))<<16;	\
382 			case 2: l|=((unsigned long)(*(--(c))))<< 8;	\
383 			case 1: l|=((unsigned long)(*(--(c))));		\
384 				} }
385 #ifndef HOST_l2c
386 #define HOST_l2c(l,c)	(*((c)++)=(unsigned char)(((l)    )&0xff),	\
387 			 *((c)++)=(unsigned char)(((l)>> 8)&0xff),	\
388 			 *((c)++)=(unsigned char)(((l)>>16)&0xff),	\
389 			 *((c)++)=(unsigned char)(((l)>>24)&0xff),	\
390 			 l)
391 #endif
392 
393 #endif
394 
395 /*
396  * Time for some action:-)
397  */
398 
HASH_UPDATE(HASH_CTX * c,const void * data_,size_t len)399 int HASH_UPDATE (HASH_CTX *c, const void *data_, size_t len)
400 	{
401 	const unsigned char *data=data_;
402 	register HASH_LONG * p;
403 	register HASH_LONG l;
404 	size_t sw,sc,ew,ec;
405 
406 	if (len==0) return 1;
407 
408 	l=(c->Nl+(((HASH_LONG)len)<<3))&0xffffffffUL;
409 	/* 95-05-24 eay Fixed a bug with the overflow handling, thanks to
410 	 * Wei Dai <weidai@eskimo.com> for pointing it out. */
411 	if (l < c->Nl) /* overflow */
412 		c->Nh++;
413 	c->Nh+=(len>>29);	/* might cause compiler warning on 16-bit */
414 	c->Nl=l;
415 
416 	if (c->num != 0)
417 		{
418 		p=c->data;
419 		sw=c->num>>2;
420 		sc=c->num&0x03;
421 
422 		if ((c->num+len) >= HASH_CBLOCK)
423 			{
424 			l=p[sw]; HOST_p_c2l(data,l,sc); p[sw++]=l;
425 			for (; sw<HASH_LBLOCK; sw++)
426 				{
427 				HOST_c2l(data,l); p[sw]=l;
428 				}
429 			HASH_BLOCK_HOST_ORDER (c,p,1);
430 			len-=(HASH_CBLOCK-c->num);
431 			c->num=0;
432 			/* drop through and do the rest */
433 			}
434 		else
435 			{
436 			c->num+=(unsigned int)len;
437 			if ((sc+len) < 4) /* ugly, add char's to a word */
438 				{
439 				l=p[sw]; HOST_p_c2l_p(data,l,sc,len); p[sw]=l;
440 				}
441 			else
442 				{
443 				ew=(c->num>>2);
444 				ec=(c->num&0x03);
445 				if (sc)
446 					l=p[sw];
447 				HOST_p_c2l(data,l,sc);
448 				p[sw++]=l;
449 				for (; sw < ew; sw++)
450 					{
451 					HOST_c2l(data,l); p[sw]=l;
452 					}
453 				if (ec)
454 					{
455 					HOST_c2l_p(data,l,ec); p[sw]=l;
456 					}
457 				}
458 			return 1;
459 			}
460 		}
461 
462 	sw=len/HASH_CBLOCK;
463 	if (sw > 0)
464 		{
465 #if defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
466 		/*
467 		 * Note that HASH_BLOCK_DATA_ORDER_ALIGNED gets defined
468 		 * only if sizeof(HASH_LONG)==4.
469 		 */
470 		if ((((size_t)data)%4) == 0)
471 			{
472 			/* data is properly aligned so that we can cast it: */
473 			HASH_BLOCK_DATA_ORDER_ALIGNED (c,(const HASH_LONG *)data,sw);
474 			sw*=HASH_CBLOCK;
475 			data+=sw;
476 			len-=sw;
477 			}
478 		else
479 #if !defined(HASH_BLOCK_DATA_ORDER)
480 			while (sw--)
481 				{
482 				memcpy (p=c->data,data,HASH_CBLOCK);
483 				HASH_BLOCK_DATA_ORDER_ALIGNED(c,p,1);
484 				data+=HASH_CBLOCK;
485 				len-=HASH_CBLOCK;
486 				}
487 #endif
488 #endif
489 #if defined(HASH_BLOCK_DATA_ORDER)
490 			{
491 			HASH_BLOCK_DATA_ORDER(c,data,sw);
492 			sw*=HASH_CBLOCK;
493 			data+=sw;
494 			len-=sw;
495 			}
496 #endif
497 		}
498 
499 	if (len!=0)
500 		{
501 		p = c->data;
502 		c->num = len;
503 		ew=len>>2;	/* words to copy */
504 		ec=len&0x03;
505 		for (; ew; ew--,p++)
506 			{
507 			HOST_c2l(data,l); *p=l;
508 			}
509 		HOST_c2l_p(data,l,ec);
510 		*p=l;
511 		}
512 	return 1;
513 	}
514 
515 
HASH_TRANSFORM(HASH_CTX * c,const unsigned char * data)516 void HASH_TRANSFORM (HASH_CTX *c, const unsigned char *data)
517 	{
518 #if defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
519 	if ((((size_t)data)%4) == 0)
520 		/* data is properly aligned so that we can cast it: */
521 		HASH_BLOCK_DATA_ORDER_ALIGNED (c,(const HASH_LONG *)data,1);
522 	else
523 #if !defined(HASH_BLOCK_DATA_ORDER)
524 		{
525 		memcpy (c->data,data,HASH_CBLOCK);
526 		HASH_BLOCK_DATA_ORDER_ALIGNED (c,c->data,1);
527 		}
528 #endif
529 #endif
530 #if defined(HASH_BLOCK_DATA_ORDER)
531 	HASH_BLOCK_DATA_ORDER (c,data,1);
532 #endif
533 	}
534 
535 
HASH_FINAL(unsigned char * md,HASH_CTX * c)536 int HASH_FINAL (unsigned char *md, HASH_CTX *c)
537 	{
538 	register HASH_LONG *p;
539 	register unsigned long l;
540 	register int i,j;
541 	static const unsigned char end[4]={0x80,0x00,0x00,0x00};
542 	const unsigned char *cp=end;
543 
544 	/* c->num should definitly have room for at least one more byte. */
545 	p=c->data;
546 	i=c->num>>2;
547 	j=c->num&0x03;
548 
549 #if 0
550 	/* purify often complains about the following line as an
551 	 * Uninitialized Memory Read.  While this can be true, the
552 	 * following p_c2l macro will reset l when that case is true.
553 	 * This is because j&0x03 contains the number of 'valid' bytes
554 	 * already in p[i].  If and only if j&0x03 == 0, the UMR will
555 	 * occur but this is also the only time p_c2l will do
556 	 * l= *(cp++) instead of l|= *(cp++)
557 	 * Many thanks to Alex Tang <altitude@cic.net> for pickup this
558 	 * 'potential bug' */
559 #ifdef PURIFY
560 	if (j==0) p[i]=0; /* Yeah, but that's not the way to fix it:-) */
561 #endif
562 	l=p[i];
563 #else
564 	l = (j==0) ? 0 : p[i];
565 #endif
566 	HOST_p_c2l(cp,l,j); p[i++]=l; /* i is the next 'undefined word' */
567 
568 	if (i>(HASH_LBLOCK-2)) /* save room for Nl and Nh */
569 		{
570 		if (i<HASH_LBLOCK) p[i]=0;
571 		HASH_BLOCK_HOST_ORDER (c,p,1);
572 		i=0;
573 		}
574 	for (; i<(HASH_LBLOCK-2); i++)
575 		p[i]=0;
576 
577 #if   defined(DATA_ORDER_IS_BIG_ENDIAN)
578 	p[HASH_LBLOCK-2]=c->Nh;
579 	p[HASH_LBLOCK-1]=c->Nl;
580 #elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)
581 	p[HASH_LBLOCK-2]=c->Nl;
582 	p[HASH_LBLOCK-1]=c->Nh;
583 #endif
584 	HASH_BLOCK_HOST_ORDER (c,p,1);
585 
586 #ifndef HASH_MAKE_STRING
587 #error "HASH_MAKE_STRING must be defined!"
588 #else
589 	HASH_MAKE_STRING(c,md);
590 #endif
591 
592 	c->num=0;
593 	/* clear stuff, HASH_BLOCK may be leaving some stuff on the stack
594 	 * but I'm not worried :-)
595 	OPENSSL_cleanse((void *)c,sizeof(HASH_CTX));
596 	 */
597 	return 1;
598 	}
599 
600 #ifndef MD32_REG_T
601 #define MD32_REG_T long
602 /*
603  * This comment was originaly written for MD5, which is why it
604  * discusses A-D. But it basically applies to all 32-bit digests,
605  * which is why it was moved to common header file.
606  *
607  * In case you wonder why A-D are declared as long and not
608  * as MD5_LONG. Doing so results in slight performance
609  * boost on LP64 architectures. The catch is we don't
610  * really care if 32 MSBs of a 64-bit register get polluted
611  * with eventual overflows as we *save* only 32 LSBs in
612  * *either* case. Now declaring 'em long excuses the compiler
613  * from keeping 32 MSBs zeroed resulting in 13% performance
614  * improvement under SPARC Solaris7/64 and 5% under AlphaLinux.
615  * Well, to be honest it should say that this *prevents*
616  * performance degradation.
617  *				<appro@fy.chalmers.se>
618  * Apparently there're LP64 compilers that generate better
619  * code if A-D are declared int. Most notably GCC-x86_64
620  * generates better code.
621  *				<appro@fy.chalmers.se>
622  */
623 #endif
624