| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* Copyright (C) 1996-2015 Free Software Foundation, Inc. |
| 2 | This file is part of the GNU C Library. |
| 3 | Contributed by Richard Henderson (rth@tamu.edu) |
| 4 | |
| 5 | The GNU C Library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU Lesser General Public |
| 7 | License as published by the Free Software Foundation; either |
| 8 | version 2.1 of the License, or (at your option) any later version. |
| 9 | |
| 10 | The GNU C Library is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with the GNU C Library. If not, see |
| 17 | <http://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | /* Copy no more than COUNT bytes of the null-terminated string from |
| 20 | SRC to DST. If SRC does not cover all of COUNT, the balance is |
| 21 | zeroed. Return the address of the terminating null in DEST, if |
| 22 | any, else DEST + COUNT. */ |
| 23 | |
| 24 | #include <sysdep.h> |
| 25 | |
| 26 | .set noat |
| 27 | .set noreorder |
| 28 | |
| 29 | .text |
| 30 | |
| 31 | ENTRY(__stpncpy) |
| 32 | ldgp gp, 0(pv) |
| 33 | #ifdef PROF |
| 34 | lda AT, _mcount |
| 35 | jsr AT, (AT), _mcount |
| 36 | #endif |
| 37 | .prologue 1 |
| 38 | |
| 39 | beq a2, $zerocount |
| 40 | jsr t9, __stxncpy # do the work of the copy |
| 41 | |
| 42 | and t8, 0xf0, t3 # binary search for byte offset of the |
| 43 | and t8, 0xcc, t2 # last byte written. |
| 44 | and t8, 0xaa, t1 |
| 45 | andnot a0, 7, v0 |
| 46 | cmovne t3, 4, t3 |
| 47 | cmovne t2, 2, t2 |
| 48 | cmovne t1, 1, t1 |
| 49 | addq v0, t3, v0 |
| 50 | addq t1, t2, t1 |
| 51 | addq v0, t1, v0 |
| 52 | |
| 53 | bne a2, $multiword # do we have full words left? |
| 54 | |
| 55 | .align 3 |
| 56 | zapnot t0, t8, t4 # e0 : was last byte a null? |
| 57 | subq t8, 1, t2 # .. e1 : |
| 58 | addq v0, 1, t5 # e0 : |
| 59 | subq t10, 1, t3 # .. e1 : |
| 60 | or t2, t8, t2 # e0 : clear the bits between the last |
| 61 | or t3, t10, t3 # .. e1 : written byte and the last byte in |
| 62 | andnot t3, t2, t3 # e0 : COUNT |
| 63 | cmovne t4, t5, v0 # .. e1 : if last written wasnt null, inc v0 |
| 64 | zap t0, t3, t0 # e0 : |
| 65 | stq_u t0, 0(a0) # e1 : |
| 66 | ret # .. e1 : |
| 67 | |
| 68 | .align 3 |
| 69 | $multiword: |
| 70 | subq t8, 1, t7 # e0 : clear the final bits in the prev |
| 71 | or t7, t8, t7 # e1 : word |
| 72 | zapnot t0, t7, t0 # e0 : |
| 73 | subq a2, 1, a2 # .. e1 : |
| 74 | stq_u t0, 0(a0) # e0 : |
| 75 | addq a0, 8, a0 # .. e1 : |
| 76 | |
| 77 | beq a2, 1f # e1 : |
| 78 | blbc a2, 0f # e1 : |
| 79 | |
| 80 | stq_u zero, 0(a0) # e0 : zero one word |
| 81 | subq a2, 1, a2 # .. e1 : |
| 82 | addq a0, 8, a0 # e0 : |
| 83 | beq a2, 1f # .. e1 : |
| 84 | |
| 85 | 0: stq_u zero, 0(a0) # e0 : zero two words |
| 86 | subq a2, 2, a2 # .. e1 : |
| 87 | stq_u zero, 8(a0) # e0 : |
| 88 | addq a0, 16, a0 # .. e1 : |
| 89 | bne a2, 0b # e1 : |
| 90 | unop |
| 91 | |
| 92 | 1: ldq_u t0, 0(a0) # e0 : clear the leading bits in the final |
| 93 | subq t10, 1, t7 # .. e1 : word |
| 94 | or t7, t10, t7 # e0 : |
| 95 | zap t0, t7, t0 # e1 (stall) |
| 96 | stq_u t0, 0(a0) # e0 : |
| 97 | ret # .. e1 : |
| 98 | |
| 99 | $zerocount: |
| 100 | mov a0, v0 |
| 101 | ret |
| 102 | |
| 103 | END(__stpncpy) |
| 104 | |
| 105 | libc_hidden_def (__stpncpy) |
| 106 | weak_alias (__stpncpy, stpncpy) |