1 /*********************************************************************** 2 * * 3 * This software is part of the ast package * 4 * Copyright (c) 1996-2009 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 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 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 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