* Date: Wed, 14 Sep 1994 06:35:31 GMT
*/
-void RC4(RC4_KEY *key, unsigned long len, unsigned char *indata,
+void RC4(RC4_KEY *key, unsigned long len, const unsigned char *indata,
unsigned char *outdata)
{
register RC4_INT *d;
y=key->y;
d=key->data;
-#if defined(RC4_CHUNK) && (defined(L_ENDIAN) || defined(B_ENDIAN))
+#if defined(RC4_CHUNK)
/*
* The original reason for implementing this(*) was the fact that
* pre-21164a Alpha CPUs don't have byte load/store instructions
* at natural word size made it possible to reduce amount of
* instructions as well as to perform early read-ahead without
* suffering from RAW (read-after-write) hazard. This resulted
- * in >40%(**) performance improvement (on 21064 box with gcc).
+ * in ~40%(**) performance improvement on 21064 box with gcc.
* But it's not only Alpha users who win here:-) Thanks to the
* early-n-wide read-ahead this implementation also exhibits
- * >40% speed-up on SPARC and almost 20% on MIPS.
+ * >40% speed-up on SPARC and 20-30% on 64-bit MIPS (depending
+ * on sizeof(RC4_INT)).
*
* (*) "this" means code which recognizes the case when input
* and output pointers appear to be aligned at natural CPU
- * word boundary.
+ * word boundary
* (**) i.e. according to 'apps/openssl speed rc4' benchmark,
- * crypto/rc4/rc4speed.c exhibits almost 70% speed-up.
+ * crypto/rc4/rc4speed.c exhibits almost 70% speed-up...
+ *
+ * Cavets.
+ *
+ * - RC4_CHUNK="unsigned long long" should be a #1 choice for
+ * UltraSPARC. Unfortunately gcc generates very slow code
+ * (2.5-3 times slower than one generated by Sun's WorkShop
+ * C) and therefore gcc (at least 2.95 and earlier) should
+ * always be told that RC4_CHUNK="unsigned long".
*
* <appro@fy.chalmers.se>
*/
-#define RC4_STEP ( \
+# define RC4_STEP ( \
x=(x+1) &0xff, \
tx=d[x], \
y=(tx+y)&0xff, \
(RC4_CHUNK)d[(tx+ty)&0xff]\
)
-#if defined(L_ENDIAN)
-# define SHFT(c) ((c)*8)
-# define MASK(i) (((RC4_CHUNK)-1)>>((sizeof(RC4_CHUNK)-(i))<<3))
-# define SHINC 8
-#elif defined(B_ENDIAN)
-# define SHFT(c) ((sizeof(RC4_CHUNK)-(c)-1)*8)
-# define MASK(i) (((RC4_CHUNK)-1)<<((sizeof(RC4_CHUNK)-(i))<<3))
-# define SHINC -8
-#else
-# error "L_ENDIAN or B_ENDIAN *must* be defined!"
-#endif
-
if ( ( ((unsigned long)indata & (sizeof(RC4_CHUNK)-1)) |
- ((unsigned long)outdata & (sizeof(RC4_CHUNK)-1)) ) == 0
- ) {
- RC4_CHUNK ichunk,cipher;
+ ((unsigned long)outdata & (sizeof(RC4_CHUNK)-1)) ) == 0 )
+ {
+ RC4_CHUNK ichunk,otp;
+ const union { long one; char little; } is_endian = {1};
- for (;len&-sizeof(RC4_CHUNK);len-=sizeof(RC4_CHUNK)) {
- ichunk = *(RC4_CHUNK *)indata;
- cipher = RC4_STEP<<SHFT(0);
- cipher |= RC4_STEP<<SHFT(1);
- cipher |= RC4_STEP<<SHFT(2);
- cipher |= RC4_STEP<<SHFT(3);
-#ifdef RC4_CHUNK_IS_64_BIT
- cipher |= RC4_STEP<<SHFT(4);
- cipher |= RC4_STEP<<SHFT(5);
- cipher |= RC4_STEP<<SHFT(6);
- cipher |= RC4_STEP<<SHFT(7);
-#endif
- *(RC4_CHUNK *)outdata = cipher^ichunk;
- indata += sizeof(RC4_CHUNK);
- outdata += sizeof(RC4_CHUNK);
- }
- if (len) {
- RC4_CHUNK mask,ochunk;
+ /*
+ * I reckon we can afford to implement both endian
+ * cases and to decide which way to take at run-time
+ * because the machine code appears to be very compact
+ * and redundant 1-2KB is perfectly tolerable (i.e.
+ * in case the compiler fails to eliminate it:-). By
+ * suggestion from Terrel Larson <terr@terralogic.net>
+ * who also stands for the is_endian union:-)
+ *
+ * Special notes.
+ *
+ * - is_endian is declared automatic as doing otherwise
+ * (declaring static) prevents gcc from eliminating
+ * the redundant code;
+ * - compilers (those I've tried) don't seem to have
+ * problems eliminating either the operators guarded
+ * by "if (sizeof(RC4_CHUNK)==8)" or the condition
+ * expressions themselves so I've got 'em to replace
+ * corresponding #ifdefs from the previous version;
+ * - I chose to let the redundant switch cases when
+ * sizeof(RC4_CHUNK)!=8 be (were also #ifdefed
+ * before);
+ * - in case you wonder "&(sizeof(RC4_CHUNK)*8-1)" in
+ * [LB]ESHFT guards against "shift is out of range"
+ * warnings when sizeof(RC4_CHUNK)!=8
+ *
+ * <appro@fy.chalmers.se>
+ */
+ if (!is_endian.little)
+ { /* BIG-ENDIAN CASE */
+# define BESHFT(c) (((sizeof(RC4_CHUNK)-(c)-1)*8)&(sizeof(RC4_CHUNK)*8-1))
+ for (;len&-sizeof(RC4_CHUNK);len-=sizeof(RC4_CHUNK))
+ {
+ ichunk = *(RC4_CHUNK *)indata;
+ otp = RC4_STEP<<BESHFT(0);
+ otp |= RC4_STEP<<BESHFT(1);
+ otp |= RC4_STEP<<BESHFT(2);
+ otp |= RC4_STEP<<BESHFT(3);
+ if (sizeof(RC4_CHUNK)==8)
+ {
+ otp |= RC4_STEP<<BESHFT(4);
+ otp |= RC4_STEP<<BESHFT(5);
+ otp |= RC4_STEP<<BESHFT(6);
+ otp |= RC4_STEP<<BESHFT(7);
+ }
+ *(RC4_CHUNK *)outdata = otp^ichunk;
+ indata += sizeof(RC4_CHUNK);
+ outdata += sizeof(RC4_CHUNK);
+ }
+ if (len)
+ {
+ RC4_CHUNK mask=(RC4_CHUNK)-1, ochunk;
- ichunk = *(RC4_CHUNK *)indata;
- ochunk = *(RC4_CHUNK *)outdata;
- cipher = 0;
- i = SHFT(0);
- mask = MASK(len);
- switch (len) {
-#ifdef RC4_CHUNK_IS_64_BIT
- case 7: cipher = RC4_STEP<<SHFT(0), i+=SHINC;
- case 6: cipher |= RC4_STEP<<i, i+=SHINC;
- case 5: cipher |= RC4_STEP<<i, i+=SHINC;
- case 4: cipher |= RC4_STEP<<i, i+=SHINC;
- case 3: cipher |= RC4_STEP<<i, i+=SHINC;
-#else
- case 3: cipher = RC4_STEP<<SHFT(0), i+=SHINC;
-#endif
- case 2: cipher |= RC4_STEP<<i, i+=SHINC;
- case 1: cipher |= RC4_STEP<<i, i+=SHINC;
- case 0: ; /* it's never the case, but it
- has to be here for ultrix? */
+ ichunk = *(RC4_CHUNK *)indata;
+ ochunk = *(RC4_CHUNK *)outdata;
+ otp = 0;
+ i = BESHFT(0);
+ mask <<= (sizeof(RC4_CHUNK)-len)<<3;
+ switch (len&(sizeof(RC4_CHUNK)-1))
+ {
+ case 7: otp = RC4_STEP<<i, i-=8;
+ case 6: otp |= RC4_STEP<<i, i-=8;
+ case 5: otp |= RC4_STEP<<i, i-=8;
+ case 4: otp |= RC4_STEP<<i, i-=8;
+ case 3: otp |= RC4_STEP<<i, i-=8;
+ case 2: otp |= RC4_STEP<<i, i-=8;
+ case 1: otp |= RC4_STEP<<i, i-=8;
+ case 0: ; /*
+ * it's never the case,
+ * but it has to be here
+ * for ultrix?
+ */
+ }
+ ochunk &= ~mask;
+ ochunk |= (otp^ichunk) & mask;
+ *(RC4_CHUNK *)outdata = ochunk;
+ }
+ key->x=x;
+ key->y=y;
+ return;
+ }
+ else
+ { /* LITTLE-ENDIAN CASE */
+# define LESHFT(c) (((c)*8)&(sizeof(RC4_CHUNK)*8-1))
+ for (;len&-sizeof(RC4_CHUNK);len-=sizeof(RC4_CHUNK))
+ {
+ ichunk = *(RC4_CHUNK *)indata;
+ otp = RC4_STEP;
+ otp |= RC4_STEP<<8;
+ otp |= RC4_STEP<<16;
+ otp |= RC4_STEP<<24;
+ if (sizeof(RC4_CHUNK)==8)
+ {
+ otp |= RC4_STEP<<LESHFT(4);
+ otp |= RC4_STEP<<LESHFT(5);
+ otp |= RC4_STEP<<LESHFT(6);
+ otp |= RC4_STEP<<LESHFT(7);
+ }
+ *(RC4_CHUNK *)outdata = otp^ichunk;
+ indata += sizeof(RC4_CHUNK);
+ outdata += sizeof(RC4_CHUNK);
+ }
+ if (len)
+ {
+ RC4_CHUNK mask=(RC4_CHUNK)-1, ochunk;
+
+ ichunk = *(RC4_CHUNK *)indata;
+ ochunk = *(RC4_CHUNK *)outdata;
+ otp = 0;
+ i = 0;
+ mask >>= (sizeof(RC4_CHUNK)-len)<<3;
+ switch (len&(sizeof(RC4_CHUNK)-1))
+ {
+ case 7: otp = RC4_STEP, i+=8;
+ case 6: otp |= RC4_STEP<<i, i+=8;
+ case 5: otp |= RC4_STEP<<i, i+=8;
+ case 4: otp |= RC4_STEP<<i, i+=8;
+ case 3: otp |= RC4_STEP<<i, i+=8;
+ case 2: otp |= RC4_STEP<<i, i+=8;
+ case 1: otp |= RC4_STEP<<i, i+=8;
+ case 0: ; /*
+ * it's never the case,
+ * but it has to be here
+ * for ultrix?
+ */
+ }
+ ochunk &= ~mask;
+ ochunk |= (otp^ichunk) & mask;
+ *(RC4_CHUNK *)outdata = ochunk;
+ }
+ key->x=x;
+ key->y=y;
+ return;
}
- ochunk &= ~mask;
- ochunk |= (cipher^ichunk) & mask;
- *(RC4_CHUNK *)outdata = ochunk;
}
- }
- else
#endif
- {
#define LOOP(in,out) \
x=((x+1)&0xff); \
tx=d[x]; \
RC4_LOOP(indata,outdata,6); if (--i == 0) break;
}
}
- }
key->x=x;
key->y=y;
}
projects / openssl.git / blobdiff