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37 #include <machine/endian.h>
39 typedef const void *cvp;
40 typedef const unsigned char *ustring;
41 typedef unsigned long ul;
42 typedef const unsigned long *culp;
45 * bcmp -- vax cmpc3 instruction
50 register size_t length;
52 #if BYTE_ORDER == LITTLE_ENDIAN
54 * The following code is endian specific. Changing it from
55 * little-endian to big-endian is fairly trivial, but making
56 * it do both is more difficult.
58 * Note that this code will reference the entire longword which
59 * includes the final byte to compare. I don't believe this is
60 * a problem since AFAIK, objects are not protected at smaller
61 * than longword boundaries.
63 int shl, shr, len = length;
64 ustring p1 = b1, p2 = b2;
71 * align p1 to a longword boundary
73 while ((long)p1 & (sizeof(long) - 1)) {
81 * align p2 to longword boundary and calculate the shift required to
84 shr = (long)p2 & (sizeof(long) - 1);
86 p2 -= shr; /* p2 now longword aligned */
87 shr <<= 3; /* offset in bits */
88 shl = (sizeof(long) << 3) - shr;
93 while ((len -= sizeof(long)) >= 0) {
96 if (*(culp)p1 != (va >> shr | vb << shl))
102 * At this point, len is between -sizeof(long) and -1,
103 * representing 0 .. sizeof(long)-1 bytes remaining.
105 if (!(len += sizeof(long)))
108 len <<= 3; /* remaining length in bits */
110 * The following is similar to the `if' condition
111 * inside the above while loop. The ?: is necessary
112 * to avoid accessing the longword after the longword
113 * containing the last byte to be compared.
115 return ((((va >> shr | ((shl < len) ? *(culp)p2 << shl : 0)) ^
116 *(culp)p1) & ((1L << len) - 1)) != 0);
118 /* p1 and p2 have common alignment so no shifting needed */
119 while ((len -= sizeof(long)) >= 0) {
120 if (*(culp)p1 != *(culp)p2)
127 * At this point, len is between -sizeof(long) and -1,
128 * representing 0 .. sizeof(long)-1 bytes remaining.
130 if (!(len += sizeof(long)))
133 return (((*(culp)p1 ^ *(culp)p2)
134 & ((1L << (len << 3)) - 1)) != 0);
137 register char *p1, *p2;