| 1 | /* SPDX-License-Identifier: GPL-2.0-only */
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| 2 | /*
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| 3 | * linux/arch/arm/lib/memset.S
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| 4 | *
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| 5 | * Copyright (C) 1995-2000 Russell King
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| 6 | *
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| 7 | * ASM optimised string functions
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| 8 | */
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| 9 | |
| 10 | |
| 11 | |
| 12 |
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| 13 | .text
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| 14 | .align 5
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| 15 |
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| 16 | ENTRY(__memset)
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| 17 | ENTRY(mmioset)
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| 18 | WEAK(memset)
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| 19 | UNWIND( .fnstart )
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| 20 | and r1, r1, |
| 21 | ands r3, r0, |
| 22 | mov ip, r0 @ preserve r0 as return value
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| 23 | bne 6f @ 1
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| 24 | /*
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| 25 | * we know that the pointer in ip is aligned to a word boundary.
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| 26 | */
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| 27 | 1: orr r1, r1, r1, lsl |
| 28 | orr r1, r1, r1, lsl |
| 29 | mov r3, r1
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| 30 | 7: cmp r2, |
| 31 | blt 4f
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| 32 | UNWIND( .fnend )
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| 33 |
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| 34 | |
| 35 |
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| 36 | /*
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| 37 | * We need 2 extra registers for this loop - use r8 and the LR
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| 38 | */
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| 39 | UNWIND( .fnstart )
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| 40 | UNWIND( .save {r8, lr} )
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| 41 | stmfd sp!, {r8, lr}
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| 42 | mov r8, r1
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| 43 | mov lr, r3
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| 44 |
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| 45 | 2: subs r2, r2, |
| 46 | stmiage ip!, {r1, r3, r8, lr} @ 64 bytes at a time.
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| 47 | stmiage ip!, {r1, r3, r8, lr}
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| 48 | stmiage ip!, {r1, r3, r8, lr}
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| 49 | stmiage ip!, {r1, r3, r8, lr}
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| 50 | bgt 2b
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| 51 | ldmfdeq sp!, {r8, pc} @ Now <64 bytes to go.
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| 52 | /*
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| 53 | * No need to correct the count; we're only testing bits from now on
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| 54 | */
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| 55 | tst r2, #32
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| 56 | stmiane ip!, {r1, r3, r8, lr}
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| 57 | stmiane ip!, {r1, r3, r8, lr}
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| 58 | tst r2, #16
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| 59 | stmiane ip!, {r1, r3, r8, lr}
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| 60 | ldmfd sp!, {r8, lr}
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| 61 | UNWIND( .fnend )
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| 62 |
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| 63 | #else
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| 64 |
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| 65 | /*
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| 66 | * This version aligns the destination pointer in order to write
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| 67 | * whole cache lines at once.
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| 68 | */
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| 69 |
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| 70 | UNWIND( .fnstart )
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| 71 | UNWIND( .save {r4-r8, lr} )
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| 72 | stmfd sp!, {r4-r8, lr}
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| 73 | mov r4, r1
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| 74 | mov r5, r3
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| 75 | mov r6, r1
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| 76 | mov r7, r3
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| 77 | mov r8, r1
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| 78 | mov lr, r3
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| 79 |
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| 80 | cmp r2, #96
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| 81 | tstgt ip, #31
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| 82 | ble 3f
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| 83 |
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| 84 | and r8, ip, #31
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| 85 | rsb r8, r8, #32
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| 86 | sub r2, r2, r8
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| 87 | movs r8, r8, lsl #(32 - 4)
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| 88 | stmiacs ip!, {r4, r5, r6, r7}
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| 89 | stmiami ip!, {r4, r5}
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| 90 | tst r8, #(1 << 30)
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| 91 | mov r8, r1
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| 92 | strne r1, [ip], #4
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| 93 |
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| 94 | 3: subs r2, r2, #64
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| 95 | stmiage ip!, {r1, r3-r8, lr}
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| 96 | stmiage ip!, {r1, r3-r8, lr}
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| 97 | bgt 3b
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| 98 | ldmfdeq sp!, {r4-r8, pc}
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| 99 |
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| 100 | tst r2, #32
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| 101 | stmiane ip!, {r1, r3-r8, lr}
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| 102 | tst r2, #16
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| 103 | stmiane ip!, {r4-r7}
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| 104 | ldmfd sp!, {r4-r8, lr}
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| 105 | UNWIND( .fnend )
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| 106 |
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| 107 | #endif
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| 108 |
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| 109 | UNWIND( .fnstart )
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| 110 | 4: tst r2, #8
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| 111 | stmiane ip!, {r1, r3}
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| 112 | tst r2, #4
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| 113 | strne r1, [ip], #4
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| 114 | /*
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| 115 | * When we get here, we've got less than 4 bytes to set. We
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| 116 | * may have an unaligned pointer as well.
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| 117 | */
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| 118 | 5: tst r2, |
| 119 | strbne r1, [ip], |
| 120 | strbne r1, [ip], |
| 121 | tst r2, |
| 122 | strbne r1, [ip], |
| 123 | ret lr
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| 124 |
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| 125 | 6: subs r2, r2, |
| 126 | blt 5b @ 1 bytes to align with?
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| 127 | cmp r3, |
| 128 | strblt r1, [ip], |
| 129 | strble r1, [ip], |
| 130 | strb r1, [ip], |
| 131 | add r2, r2, r3 @ 1 (r2 = r2 - (4 - r3))
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| 132 | b 1b
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| 133 | UNWIND( .fnend )
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| 134 | ENDPROC(memset)
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| 135 | ENDPROC(mmioset)
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| 136 | ENDPROC(__memset)
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| 137 |
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| 138 | ENTRY(__memset32)
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| 139 | UNWIND( .fnstart )
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| 140 | mov r3, r1 @ copy r1 to r3 and fall into memset64
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| 141 | UNWIND( .fnend )
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| 142 | ENDPROC(__memset32)
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| 143 | ENTRY(__memset64)
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| 144 | UNWIND( .fnstart )
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| 145 | mov ip, r0 @ preserve r0 as return value
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| 146 | b 7b @ jump into the middle of memset
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| 147 | UNWIND( .fnend )
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| 148 | ENDPROC(__memset64)
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