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by Michael Hope
Pulled in the initial versions |
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/*
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* Copyright (C) 2008 The Android Open Source Project |
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* All rights reserved. |
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*
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* * Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* * Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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*/
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.text
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.global memset |
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.type memset, %function |
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.global bzero
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.type bzero, %function |
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.align
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/*
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* Optimized memset() for ARM. |
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*
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* memset() returns its first argument. |
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*/
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bzero: |
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mov r2, r1 |
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mov r1, #0 |
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memset: |
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/* compute the offset to align the destination |
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* offset = (4-(src&3))&3 = -src & 3 |
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*/
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.fnstart
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.save {r0, r4-r7, lr} |
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stmfd sp!, {r0, r4-r7, lr} |
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rsb r3, r0, #0 |
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ands r3, r3, #3 |
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cmp r3, r2 |
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movhi r3, r2 |
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/* splat r1 */ |
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mov r1, r1, lsl #24 |
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orr r1, r1, r1, lsr #8 |
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orr r1, r1, r1, lsr #16 |
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movs r12, r3, lsl #31 |
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strcsb r1, [r0], #1 /* can't use strh (alignment unknown) */ |
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strcsb r1, [r0], #1 |
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strmib r1, [r0], #1 |
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subs r2, r2, r3 |
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ldmlsfd sp!, {r0, r4-r7, lr} /* return */ |
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bxls lr |
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/* align the destination to a cache-line */ |
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mov r12, r1 |
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mov lr, r1 |
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mov r4, r1 |
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mov r5, r1 |
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mov r6, r1 |
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mov r7, r1 |
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rsb r3, r0, #0 |
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ands r3, r3, #0x1C |
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beq 3f |
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cmp r3, r2 |
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andhi r3, r2, #0x1C |
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sub r2, r2, r3 |
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/* conditionnaly writes 0 to 7 words (length in r3) */ |
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movs r3, r3, lsl #28 |
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stmcsia r0!, {r1, lr} |
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stmcsia r0!, {r1, lr} |
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stmmiia r0!, {r1, lr} |
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movs r3, r3, lsl #2 |
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strcs r1, [r0], #4 |
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3: |
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subs r2, r2, #32 |
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mov r3, r1 |
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bmi 2f |
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1: subs r2, r2, #32 |
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stmia r0!, {r1,r3,r4,r5,r6,r7,r12,lr} |
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bhs 1b |
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2: add r2, r2, #32 |
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/* conditionnaly stores 0 to 31 bytes */ |
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movs r2, r2, lsl #28 |
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stmcsia r0!, {r1,r3,r12,lr} |
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stmmiia r0!, {r1, lr} |
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movs r2, r2, lsl #2 |
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strcs r1, [r0], #4 |
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strmih r1, [r0], #2 |
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movs r2, r2, lsl #2 |
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strcsb r1, [r0] |
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ldmfd sp!, {r0, r4-r7, lr} |
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bx lr |
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.fnend
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