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 EXPORT_SYMBOL(csum_partial) 42csum_partial: /* %o0=buff, %o1=len, %o2=sum */ 43 prefetch [%o0 + 0x000], #n_reads 44 clr %o4 45 prefetch [%o0 + 0x040], #n_reads 46 brz,pn %o1, csum_partial_finish 47 andcc %o0, 0x3, %g0 48 49 /* We "remember" whether the lowest bit in the address 50 * was set in %g7. Because if it is, we have to swap 51 * upper and lower 8 bit fields of the sum we calculate. 52 */ 53 bne,pn %icc, csum_partial_fix_alignment 54 andcc %o0, 0x1, %g7 55 56csum_partial_post_align: 57 prefetch [%o0 + 0x080], #n_reads 58 andncc %o1, 0x3f, %o3 59 60 prefetch [%o0 + 0x0c0], #n_reads 61 sub %o1, %o3, %o1 62 brz,pn %o3, 2f 63 prefetch [%o0 + 0x100], #n_reads 64 65 /* So that we don't need to use the non-pairing 66 * add-with-carry instructions we accumulate 32-bit 67 * values into a 64-bit register. At the end of the 68 * loop we fold it down to 32-bits and so on. 69 */ 70 prefetch [%o0 + 0x140], #n_reads 711: lduw [%o0 + 0x00], %o5 72 lduw [%o0 + 0x04], %g1 73 lduw [%o0 + 0x08], %g2 74 add %o4, %o5, %o4 75 lduw [%o0 + 0x0c], %g3 76 add %o4, %g1, %o4 77 lduw [%o0 + 0x10], %o5 78 add %o4, %g2, %o4 79 lduw [%o0 + 0x14], %g1 80 add %o4, %g3, %o4 81 lduw [%o0 + 0x18], %g2 82 add %o4, %o5, %o4 83 lduw [%o0 + 0x1c], %g3 84 add %o4, %g1, %o4 85 lduw [%o0 + 0x20], %o5 86 add %o4, %g2, %o4 87 lduw [%o0 + 0x24], %g1 88 add %o4, %g3, %o4 89 lduw [%o0 + 0x28], %g2 90 add %o4, %o5, %o4 91 lduw [%o0 + 0x2c], %g3 92 add %o4, %g1, %o4 93 lduw [%o0 + 0x30], %o5 94 add %o4, %g2, %o4 95 lduw [%o0 + 0x34], %g1 96 add %o4, %g3, %o4 97 lduw [%o0 + 0x38], %g2 98 add %o4, %o5, %o4 99 lduw [%o0 + 0x3c], %g3 100 add %o4, %g1, %o4 101 prefetch [%o0 + 0x180], #n_reads 102 add %o4, %g2, %o4 103 subcc %o3, 0x40, %o3 104 add %o0, 0x40, %o0 105 bne,pt %icc, 1b 106 add %o4, %g3, %o4 107 1082: and %o1, 0x3c, %o3 109 brz,pn %o3, 2f 110 sub %o1, %o3, %o1 1111: lduw [%o0 + 0x00], %o5 112 subcc %o3, 0x4, %o3 113 add %o0, 0x4, %o0 114 bne,pt %icc, 1b 115 add %o4, %o5, %o4 116 1172: 118 /* fold 64-->32 */ 119 srlx %o4, 32, %o5 120 srl %o4, 0, %o4 121 add %o4, %o5, %o4 122 srlx %o4, 32, %o5 123 srl %o4, 0, %o4 124 add %o4, %o5, %o4 125 126 /* fold 32-->16 */ 127 sethi %hi(0xffff0000), %g1 128 srl %o4, 16, %o5 129 andn %o4, %g1, %g2 130 add %o5, %g2, %o4 131 srl %o4, 16, %o5 132 andn %o4, %g1, %g2 133 add %o5, %g2, %o4 134 135csum_partial_end_cruft: 136 /* %o4 has the 16-bit sum we have calculated so-far. */ 137 cmp %o1, 2 138 blu,pt %icc, 1f 139 nop 140 lduh [%o0 + 0x00], %o5 141 sub %o1, 2, %o1 142 add %o0, 2, %o0 143 add %o4, %o5, %o4 1441: brz,pt %o1, 1f 145 nop 146 ldub [%o0 + 0x00], %o5 147 sub %o1, 1, %o1 148 add %o0, 1, %o0 149 sllx %o5, 8, %o5 150 add %o4, %o5, %o4 1511: 152 /* fold 32-->16 */ 153 sethi %hi(0xffff0000), %g1 154 srl %o4, 16, %o5 155 andn %o4, %g1, %g2 156 add %o5, %g2, %o4 157 srl %o4, 16, %o5 158 andn %o4, %g1, %g2 159 add %o5, %g2, %o4 160 1611: brz,pt %g7, 1f 162 nop 163 164 /* We started with an odd byte, byte-swap the result. */ 165 srl %o4, 8, %o5 166 and %o4, 0xff, %g1 167 sll %g1, 8, %g1 168 or %o5, %g1, %o4 169 1701: addcc %o2, %o4, %o2 171 addc %g0, %o2, %o2 172 173csum_partial_finish: 174 retl 175 srl %o2, 0, %o0 176