1 /***********************************************************************
2 * *
3 * This software is part of the ast package *
4 * Copyright (c) 1996-2010 AT&T Intellectual Property *
5 * and is licensed under the *
6 * Common Public License, Version 1.0 *
7 * by AT&T Intellectual Property *
8 * *
9 * A copy of the License is available at *
10 * http://www.opensource.org/licenses/cpl1.0.txt *
11 * (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
12 * *
13 * Information and Software Systems Research *
14 * AT&T Research *
15 * Florham Park NJ *
16 * *
17 * Glenn Fowler <gsf@research.att.com> *
18 * *
19 ***********************************************************************/
20 #pragma prototyped
21
22 /*
23 * att
24 */
25
26 #define att_description \
27 "The system 5 release 4 checksum. This is the default for \bsum\b \
28 when \bgetconf UNIVERSE\b is \batt\b. This is the only true sum; \
29 all of the other methods are order dependent."
30 #define att_options 0
31 #define att_match "att|sys5|s5|default"
32 #define att_open long_open
33 #define att_init long_init
34 #define att_print long_print
35 #define att_data long_data
36 #define att_scale 512
37
38 #if defined(__SUNPRO_C) || defined(__GNUC__)
39
40 #if defined(__SUNPRO_C)
41 # include <sun_prefetch.h>
42 # define sum_prefetch(addr) sun_prefetch_read_many((void *)(addr))
43 #elif defined(__GNUC__)
44 # define sum_prefetch(addr) __builtin_prefetch((addr), 0, 3)
45 #else
46 # error Unknown compiler
47 #endif
48
49 #define CBLOCK_SIZE (64)
50 #pragma unroll(16)
51
52 /* Inmos transputer would love this algorithm */
53 static int
att_block(register Sum_t * p,const void * s,size_t n)54 att_block(register Sum_t* p, const void* s, size_t n)
55 {
56 register uint32_t c = ((Integral_t*)p)->sum;
57 register const unsigned char* b = (const unsigned char*)s;
58 register const unsigned char* e = b + n;
59 register uint32_t s0, s1, s2, s3, s4, s5, s6, s7;
60 register unsigned int i;
61
62 s0=s1=s2=s3=s4=s5=s6=s7=0U;
63
64 sum_prefetch((void *)b);
65
66 while (n > CBLOCK_SIZE)
67 {
68 sum_prefetch((b+CBLOCK_SIZE));
69
70 /* Compiler will unroll for() loops per #pragma unroll */
71 for (i=0 ; i < (CBLOCK_SIZE/8) ; i++)
72 {
73 /*
74 * use s0-s7 to decouple calculations (this improves pipelining)
75 * because each operation is completely independent from it's
76 * siblings
77 */
78 s0+=b[0];
79 s1+=b[1];
80 s2+=b[2];
81 s3+=b[3];
82 s4+=b[4];
83 s5+=b[5];
84 s6+=b[6];
85 s7+=b[7];
86
87 b+=8;
88 n-=8;
89 }
90 }
91
92 c+=s0+s1+s2+s3+s4+s5+s6+s7;
93
94 while (b < e)
95 c += *b++;
96 ((Integral_t*)p)->sum = c;
97 return 0;
98 }
99
100 #else
101 static int
att_block(register Sum_t * p,const void * s,size_t n)102 att_block(register Sum_t* p, const void* s, size_t n)
103 {
104 register uint32_t c = ((Integral_t*)p)->sum;
105 register unsigned char* b = (unsigned char*)s;
106 register unsigned char* e = b + n;
107
108 while (b < e)
109 c += *b++;
110 ((Integral_t*)p)->sum = c;
111 return 0;
112 }
113 #endif /* defined(__SUNPRO_C) || defined(__GNUC__) */
114
115 static int
att_done(Sum_t * p)116 att_done(Sum_t* p)
117 {
118 register uint32_t c = ((Integral_t*)p)->sum;
119
120 c = (c & 0xffff) + ((c >> 16) & 0xffff);
121 c = (c & 0xffff) + (c >> 16);
122 ((Integral_t*)p)->sum = c & 0xffff;
123 return short_done(p);
124 }
125