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1
by Michael Hope
Pulled in the initial versions |
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/* Copyright (C) 1998, 2003 Free Software Foundation, Inc. |
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This file is part of the GNU C Library. |
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Code contributed by Matthew Wilcox <willy@odie.barnet.ac.uk> |
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The GNU C Library is free software; you can redistribute it and/or |
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modify it under the terms of the GNU Lesser General Public |
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License as published by the Free Software Foundation; either |
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version 2.1 of the License, or (at your option) any later version. |
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The GNU C Library is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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Lesser General Public License for more details. |
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||
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You should have received a copy of the GNU Lesser General Public |
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License along with the GNU C Library; if not, write to the Free |
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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02111-1307 USA. */ |
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/* size_t strlen(const char *S) |
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* entry: r0 -> string |
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* exit: r0 = len |
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*/
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77
by Michael Hope
Added function type attributes to all reference assembly versions. |
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.text
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72
by Michael Hope
Updated the GLIBC routines and shifted the C only routines out. |
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.globl strlen |
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77
by Michael Hope
Added function type attributes to all reference assembly versions. |
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.type strlen, %function |
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72
by Michael Hope
Updated the GLIBC routines and shifted the C only routines out. |
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2
by Michael Hope
Made the different routines compile. Expanded the tests. |
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strlen: |
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1
by Michael Hope
Pulled in the initial versions |
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bic r1, r0, $3 @ addr of word containing first byte |
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ldr r2, [r1], $4 @ get the first word |
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ands r3, r0, $3 @ how many bytes are duff? |
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rsb r0, r3, $0 @ get - that number into counter. |
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beq Laligned @ skip into main check routine if no |
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@ more |
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#ifdef __ARMEB__
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orr r2, r2, $0xff000000 @ set this byte to non-zero |
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subs r3, r3, $1 @ any more to do? |
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orrgt r2, r2, $0x00ff0000 @ if so, set this byte |
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subs r3, r3, $1 @ more? |
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orrgt r2, r2, $0x0000ff00 @ then set. |
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#else
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orr r2, r2, $0x000000ff @ set this byte to non-zero |
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subs r3, r3, $1 @ any more to do? |
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orrgt r2, r2, $0x0000ff00 @ if so, set this byte |
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subs r3, r3, $1 @ more? |
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orrgt r2, r2, $0x00ff0000 @ then set. |
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#endif
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Laligned: @ here, we have a word in r2. Does it |
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tst r2, $0x000000ff @ contain any zeroes? |
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tstne r2, $0x0000ff00 @ |
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tstne r2, $0x00ff0000 @ |
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tstne r2, $0xff000000 @ |
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addne r0, r0, $4 @ if not, the string is 4 bytes longer |
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ldrne r2, [r1], $4 @ and we continue to the next word |
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bne Laligned @ |
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Llastword: @ drop through to here once we find a |
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#ifdef __ARMEB__
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tst r2, $0xff000000 @ word that has a zero byte in it |
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addne r0, r0, $1 @ |
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tstne r2, $0x00ff0000 @ and add up to 3 bytes on to it |
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addne r0, r0, $1 @ |
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tstne r2, $0x0000ff00 @ (if first three all non-zero, 4th |
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addne r0, r0, $1 @ must be zero) |
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#else
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tst r2, $0x000000ff @ word that has a zero byte in it |
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addne r0, r0, $1 @ |
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tstne r2, $0x0000ff00 @ and add up to 3 bytes on to it |
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addne r0, r0, $1 @ |
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tstne r2, $0x00ff0000 @ (if first three all non-zero, 4th |
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addne r0, r0, $1 @ must be zero) |
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#endif
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2
by Michael Hope
Made the different routines compile. Expanded the tests. |
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bx lr |
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