| 1 | /* strncpy - copy at most n characters from a string from source to |
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| 2 | destination. For IBM S390 |
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| 3 | This file is part of the GNU C Library. |
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| 4 | Copyright (C) 2000-2024 Free Software Foundation, Inc. |
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| 5 | |
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| 6 | The GNU C Library is free software; you can redistribute it and/or |
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| 7 | modify it under the terms of the GNU Lesser General Public |
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| 8 | License as published by the Free Software Foundation; either |
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| 9 | version 2.1 of the License, or (at your option) any later version. |
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| 10 | |
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| 11 | The GNU C Library is distributed in the hope that it will be useful, |
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| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 14 | Lesser General Public License for more details. |
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| 15 | |
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| 16 | You should have received a copy of the GNU Lesser General Public |
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| 17 | License along with the GNU C Library; if not, see |
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| 18 | <https://www.gnu.org/licenses/>. */ |
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| 19 | |
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| 20 | /* |
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| 21 | * R2 = address of destination (dst) |
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| 22 | * R3 = address of source (src) |
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| 23 | * R4 = max of bytes to copy |
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| 24 | */ |
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| 25 | |
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| 26 | #include <ifunc-strncpy.h> |
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| 27 | #include "sysdep.h" |
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| 28 | #include "asm-syntax.h" |
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| 29 | |
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| 30 | #if HAVE_STRNCPY_Z900_G5 |
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| 31 | ENTRY(STRNCPY_Z900_G5) |
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| 32 | .text |
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| 33 | st %r2,24(%r15) # save dst pointer |
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| 34 | slr %r2,%r3 # %r3 points to src, %r2+%r3 to dst |
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| 35 | lhi %r1,3 |
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| 36 | nr %r1,%r4 # last 2 bits of # bytes |
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| 37 | srl %r4,2 |
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| 38 | ltr %r4,%r4 # less than 4 bytes to copy ? |
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| 39 | jz .L1 |
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| 40 | bras %r5,.L0 # enter loop & load address of a 0 |
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| 41 | .long 0 |
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| 42 | .L0: icm %r0,8,0(%r3) # first byte |
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| 43 | jz .L3 |
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| 44 | icm %r0,4,1(%r3) # second byte |
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| 45 | jz .L4 |
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| 46 | icm %r0,2,2(%r3) # third byte |
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| 47 | jz .L5 |
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| 48 | icm %r0,1,3(%r3) # fourth byte |
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| 49 | jz .L6 |
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| 50 | st %r0,0(%r2,%r3) # store all four to dest. |
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| 51 | la %r3,4(%r3) |
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| 52 | brct %r4,.L0 |
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| 53 | .L1: ltr %r1,%r1 |
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| 54 | jz .Lexit |
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| 55 | .L2: icm %r0,1,0(%r3) |
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| 56 | stc %r0,0(%r2,%r3) |
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| 57 | la %r3,1(%r3) |
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| 58 | jz .L7 |
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| 59 | brct %r1,.L2 |
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| 60 | j .Lexit |
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| 61 | .L3: icm %r0,4,0(%r5) |
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| 62 | .L4: icm %r0,2,0(%r5) |
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| 63 | .L5: icm %r0,1,0(%r5) |
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| 64 | .L6: st %r0,0(%r2,%r3) |
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| 65 | la %r3,4(%r3) |
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| 66 | ahi %r4,-1 |
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| 67 | j .L8 |
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| 68 | .L7: ahi %r1,-1 |
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| 69 | .L8: sll %r4,2 |
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| 70 | alr %r4,%r1 |
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| 71 | alr %r2,%r3 # start of dst area to be zeroed |
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| 72 | lr %r3,%r4 |
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| 73 | slr %r4,%r4 |
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| 74 | slr %r5,%r5 |
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| 75 | .L9: mvcle %r2,%r4,0 # pad dst with zeroes |
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| 76 | jo .L9 |
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| 77 | .Lexit: l %r2,24(%r15) # return dst pointer |
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| 78 | br %r14 |
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| 79 | END(STRNCPY_Z900_G5) |
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| 80 | |
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| 81 | # if ! HAVE_STRNCPY_IFUNC |
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| 82 | strong_alias (STRNCPY_Z900_G5, strncpy) |
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| 83 | # endif |
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| 84 | |
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| 85 | # if defined SHARED && IS_IN (libc) |
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| 86 | strong_alias (STRNCPY_Z900_G5, __GI_strncpy) |
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| 87 | # endif |
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| 88 | #endif |
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| 89 | |
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