1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * memscan.S: Optimized memscan for the Sparc. 4 * 5 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu) 6 */ 7 8 #include <asm/export.h> 9 10 /* In essence, this is just a fancy strlen. */ 11 12 #define LO_MAGIC 0x01010101 13 #define HI_MAGIC 0x80808080 14 15 .text 16 .align 4 17 .globl __memscan_zero, __memscan_generic 18 .globl memscan 19 EXPORT_SYMBOL(__memscan_zero) 20 EXPORT_SYMBOL(__memscan_generic) 21 __memscan_zero: 22 /* %o0 = addr, %o1 = size */ 23 cmp %o1, 0 24 bne,a 1f 25 andcc %o0, 3, %g0 26 27 retl 28 nop 29 30 1: 31 be mzero_scan_word 32 sethi %hi(HI_MAGIC), %g2 33 34 ldsb [%o0], %g3 35 mzero_still_not_word_aligned: 36 cmp %g3, 0 37 bne 1f 38 add %o0, 1, %o0 39 40 retl 41 sub %o0, 1, %o0 42 43 1: 44 subcc %o1, 1, %o1 45 bne,a 1f 46 andcc %o0, 3, %g0 47 48 retl 49 nop 50 51 1: 52 bne,a mzero_still_not_word_aligned 53 ldsb [%o0], %g3 54 55 sethi %hi(HI_MAGIC), %g2 56 mzero_scan_word: 57 or %g2, %lo(HI_MAGIC), %o3 58 sethi %hi(LO_MAGIC), %g3 59 or %g3, %lo(LO_MAGIC), %o2 60 mzero_next_word: 61 ld [%o0], %g2 62 mzero_next_word_preloaded: 63 sub %g2, %o2, %g2 64 mzero_next_word_preloaded_next: 65 andcc %g2, %o3, %g0 66 bne mzero_byte_zero 67 add %o0, 4, %o0 68 69 mzero_check_out_of_fuel: 70 subcc %o1, 4, %o1 71 bg,a 1f 72 ld [%o0], %g2 73 74 retl 75 nop 76 77 1: 78 b mzero_next_word_preloaded_next 79 sub %g2, %o2, %g2 80 81 /* Check every byte. */ 82 mzero_byte_zero: 83 ldsb [%o0 - 4], %g2 84 cmp %g2, 0 85 bne mzero_byte_one 86 sub %o0, 4, %g3 87 88 retl 89 mov %g3, %o0 90 91 mzero_byte_one: 92 ldsb [%o0 - 3], %g2 93 cmp %g2, 0 94 bne,a mzero_byte_two_and_three 95 ldsb [%o0 - 2], %g2 96 97 retl 98 sub %o0, 3, %o0 99 100 mzero_byte_two_and_three: 101 cmp %g2, 0 102 bne,a 1f 103 ldsb [%o0 - 1], %g2 104 105 retl 106 sub %o0, 2, %o0 107 108 1: 109 cmp %g2, 0 110 bne,a mzero_next_word_preloaded 111 ld [%o0], %g2 112 113 retl 114 sub %o0, 1, %o0 115 116 mzero_found_it: 117 retl 118 sub %o0, 2, %o0 119 120 memscan: 121 __memscan_generic: 122 /* %o0 = addr, %o1 = c, %o2 = size */ 123 cmp %o2, 0 124 bne,a 0f 125 ldub [%o0], %g2 126 127 b,a 2f 128 1: 129 ldub [%o0], %g2 130 0: 131 cmp %g2, %o1 132 be 2f 133 addcc %o2, -1, %o2 134 bne 1b 135 add %o0, 1, %o0 136 2: 137 retl 138 nop 139