1/* checksum.S: Sparc V9 optimized checksum code. 2 * 3 * Copyright(C) 1995 Linus Torvalds 4 * Copyright(C) 1995 Miguel de Icaza 5 * Copyright(C) 1996, 2000 David S. Miller 6 * Copyright(C) 1997 Jakub Jelinek 7 * 8 * derived from: 9 * Linux/Alpha checksum c-code 10 * Linux/ix86 inline checksum assembly 11 * RFC1071 Computing the Internet Checksum (esp. Jacobsons m68k code) 12 * David Mosberger-Tang for optimized reference c-code 13 * BSD4.4 portable checksum routine 14 */ 15 16#include <asm/export.h> 17 .text 18 19csum_partial_fix_alignment: 20 /* We checked for zero length already, so there must be 21 * at least one byte. 22 */ 23 be,pt %icc, 1f 24 nop 25 ldub [%o0 + 0x00], %o4 26 add %o0, 1, %o0 27 sub %o1, 1, %o1 281: andcc %o0, 0x2, %g0 29 be,pn %icc, csum_partial_post_align 30 cmp %o1, 2 31 blu,pn %icc, csum_partial_end_cruft 32 nop 33 lduh [%o0 + 0x00], %o5 34 add %o0, 2, %o0 35 sub %o1, 2, %o1 36 ba,pt %xcc, csum_partial_post_align 37 add %o5, %o4, %o4 38 39 .align 32 40 .globl csum_partial 41 .type csum_partial,#function 42 EXPORT_SYMBOL(csum_partial) 43csum_partial: /* %o0=buff, %o1=len, %o2=sum */ 44 prefetch [%o0 + 0x000], #n_reads 45 clr %o4 46 prefetch [%o0 + 0x040], #n_reads 47 brz,pn %o1, csum_partial_finish 48 andcc %o0, 0x3, %g0 49 50 /* We "remember" whether the lowest bit in the address 51 * was set in %g7. Because if it is, we have to swap 52 * upper and lower 8 bit fields of the sum we calculate. 53 */ 54 bne,pn %icc, csum_partial_fix_alignment 55 andcc %o0, 0x1, %g7 56 57csum_partial_post_align: 58 prefetch [%o0 + 0x080], #n_reads 59 andncc %o1, 0x3f, %o3 60 61 prefetch [%o0 + 0x0c0], #n_reads 62 sub %o1, %o3, %o1 63 brz,pn %o3, 2f 64 prefetch [%o0 + 0x100], #n_reads 65 66 /* So that we don't need to use the non-pairing 67 * add-with-carry instructions we accumulate 32-bit 68 * values into a 64-bit register. At the end of the 69 * loop we fold it down to 32-bits and so on. 70 */ 71 prefetch [%o0 + 0x140], #n_reads 721: lduw [%o0 + 0x00], %o5 73 lduw [%o0 + 0x04], %g1 74 lduw [%o0 + 0x08], %g2 75 add %o4, %o5, %o4 76 lduw [%o0 + 0x0c], %g3 77 add %o4, %g1, %o4 78 lduw [%o0 + 0x10], %o5 79 add %o4, %g2, %o4 80 lduw [%o0 + 0x14], %g1 81 add %o4, %g3, %o4 82 lduw [%o0 + 0x18], %g2 83 add %o4, %o5, %o4 84 lduw [%o0 + 0x1c], %g3 85 add %o4, %g1, %o4 86 lduw [%o0 + 0x20], %o5 87 add %o4, %g2, %o4 88 lduw [%o0 + 0x24], %g1 89 add %o4, %g3, %o4 90 lduw [%o0 + 0x28], %g2 91 add %o4, %o5, %o4 92 lduw [%o0 + 0x2c], %g3 93 add %o4, %g1, %o4 94 lduw [%o0 + 0x30], %o5 95 add %o4, %g2, %o4 96 lduw [%o0 + 0x34], %g1 97 add %o4, %g3, %o4 98 lduw [%o0 + 0x38], %g2 99 add %o4, %o5, %o4 100 lduw [%o0 + 0x3c], %g3 101 add %o4, %g1, %o4 102 prefetch [%o0 + 0x180], #n_reads 103 add %o4, %g2, %o4 104 subcc %o3, 0x40, %o3 105 add %o0, 0x40, %o0 106 bne,pt %icc, 1b 107 add %o4, %g3, %o4 108 1092: and %o1, 0x3c, %o3 110 brz,pn %o3, 2f 111 sub %o1, %o3, %o1 1121: lduw [%o0 + 0x00], %o5 113 subcc %o3, 0x4, %o3 114 add %o0, 0x4, %o0 115 bne,pt %icc, 1b 116 add %o4, %o5, %o4 117 1182: 119 /* fold 64-->32 */ 120 srlx %o4, 32, %o5 121 srl %o4, 0, %o4 122 add %o4, %o5, %o4 123 srlx %o4, 32, %o5 124 srl %o4, 0, %o4 125 add %o4, %o5, %o4 126 127 /* fold 32-->16 */ 128 sethi %hi(0xffff0000), %g1 129 srl %o4, 16, %o5 130 andn %o4, %g1, %g2 131 add %o5, %g2, %o4 132 srl %o4, 16, %o5 133 andn %o4, %g1, %g2 134 add %o5, %g2, %o4 135 136csum_partial_end_cruft: 137 /* %o4 has the 16-bit sum we have calculated so-far. */ 138 cmp %o1, 2 139 blu,pt %icc, 1f 140 nop 141 lduh [%o0 + 0x00], %o5 142 sub %o1, 2, %o1 143 add %o0, 2, %o0 144 add %o4, %o5, %o4 1451: brz,pt %o1, 1f 146 nop 147 ldub [%o0 + 0x00], %o5 148 sub %o1, 1, %o1 149 add %o0, 1, %o0 150 sllx %o5, 8, %o5 151 add %o4, %o5, %o4 1521: 153 /* fold 32-->16 */ 154 sethi %hi(0xffff0000), %g1 155 srl %o4, 16, %o5 156 andn %o4, %g1, %g2 157 add %o5, %g2, %o4 158 srl %o4, 16, %o5 159 andn %o4, %g1, %g2 160 add %o5, %g2, %o4 161 1621: brz,pt %g7, 1f 163 nop 164 165 /* We started with an odd byte, byte-swap the result. */ 166 srl %o4, 8, %o5 167 and %o4, 0xff, %g1 168 sll %g1, 8, %g1 169 or %o5, %g1, %o4 170 1711: addcc %o2, %o4, %o2 172 addc %g0, %o2, %o2 173 174csum_partial_finish: 175 retl 176 srl %o2, 0, %o0 177