420878c690
Add a macro to annotate function end and start using both ENTRY and END for each function. This allows valgrind (and presumably other debugging tools) to use the debug symbols to trace the functions. Change-Id: I5f09cef8e22fb356eb6f5cee952b031e567599b6
283 lines
8.3 KiB
ArmAsm
283 lines
8.3 KiB
ArmAsm
/*
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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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#include <machine/cpu-features.h>
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#include <machine/asm.h>
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/*
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* Optimized memcmp() for ARM9.
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* This would not be optimal on XScale or ARM11, where more prefetching
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* and use of PLD will be needed.
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* The 2 major optimzations here are
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* (1) The main loop compares 16 bytes at a time
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* (2) The loads are scheduled in a way they won't stall
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*/
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ENTRY(memcmp)
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PLD (r0, #0)
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PLD (r1, #0)
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/* take of the case where length is 0 or the buffers are the same */
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cmp r0, r1
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cmpne r2, #0
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moveq r0, #0
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bxeq lr
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.save {r4, lr}
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/* save registers */
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stmfd sp!, {r4, lr}
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PLD (r0, #32)
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PLD (r1, #32)
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/* since r0 hold the result, move the first source
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* pointer somewhere else
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*/
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mov r4, r0
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/* make sure we have at least 8+4 bytes, this simplify things below
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* and avoid some overhead for small blocks
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*/
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cmp r2, #(8+4)
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bmi 8f
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/* align first pointer to word boundary
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* offset = -src & 3
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*/
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rsb r3, r4, #0
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ands r3, r3, #3
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beq 0f
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/* align first pointer */
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sub r2, r2, r3
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1: ldrb r0, [r4], #1
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ldrb ip, [r1], #1
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subs r0, r0, ip
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bne 9f
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subs r3, r3, #1
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bne 1b
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0: /* here the first pointer is aligned, and we have at least 4 bytes
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* to process.
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*/
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/* see if the pointers are congruent */
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eor r0, r4, r1
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ands r0, r0, #3
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bne 5f
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/* congruent case, 32 bytes per iteration
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* We need to make sure there are at least 32+4 bytes left
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* because we effectively read ahead one word, and we could
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* read past the buffer (and segfault) if we're not careful.
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*/
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ldr ip, [r1]
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subs r2, r2, #(32 + 4)
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bmi 1f
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0: PLD (r4, #64)
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PLD (r1, #64)
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ldr r0, [r4], #4
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ldr lr, [r1, #4]!
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eors r0, r0, ip
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ldreq r0, [r4], #4
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ldreq ip, [r1, #4]!
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eoreqs r0, r0, lr
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ldreq r0, [r4], #4
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ldreq lr, [r1, #4]!
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eoreqs r0, r0, ip
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ldreq r0, [r4], #4
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ldreq ip, [r1, #4]!
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eoreqs r0, r0, lr
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ldreq r0, [r4], #4
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ldreq lr, [r1, #4]!
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eoreqs r0, r0, ip
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ldreq r0, [r4], #4
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ldreq ip, [r1, #4]!
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eoreqs r0, r0, lr
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ldreq r0, [r4], #4
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ldreq lr, [r1, #4]!
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eoreqs r0, r0, ip
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ldreq r0, [r4], #4
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ldreq ip, [r1, #4]!
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eoreqs r0, r0, lr
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bne 2f
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subs r2, r2, #32
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bhs 0b
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/* do we have at least 4 bytes left? */
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1: adds r2, r2, #(32 - 4 + 4)
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bmi 4f
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/* finish off 4 bytes at a time */
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3: ldr r0, [r4], #4
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ldr ip, [r1], #4
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eors r0, r0, ip
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bne 2f
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subs r2, r2, #4
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bhs 3b
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/* are we done? */
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4: adds r2, r2, #4
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moveq r0, #0
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beq 9f
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/* finish off the remaining bytes */
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b 8f
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2: /* the last 4 bytes are different, restart them */
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sub r4, r4, #4
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sub r1, r1, #4
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mov r2, #4
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/* process the last few bytes */
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8: ldrb r0, [r4], #1
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ldrb ip, [r1], #1
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// stall
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subs r0, r0, ip
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bne 9f
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subs r2, r2, #1
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bne 8b
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9: /* restore registers and return */
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ldmfd sp!, {r4, lr}
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bx lr
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END(memcmp)
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5: /*************** non-congruent case ***************/
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and r0, r1, #3
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cmp r0, #2
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bne 4f
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/* here, offset is 2 (16-bits aligned, special cased) */
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/* make sure we have at least 16 bytes to process */
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subs r2, r2, #16
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addmi r2, r2, #16
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bmi 8b
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/* align the unaligned pointer */
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bic r1, r1, #3
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ldr lr, [r1], #4
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6: PLD (r1, #64)
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PLD (r4, #64)
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mov ip, lr, lsr #16
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ldr lr, [r1], #4
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ldr r0, [r4], #4
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orr ip, ip, lr, lsl #16
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eors r0, r0, ip
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moveq ip, lr, lsr #16
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ldreq lr, [r1], #4
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ldreq r0, [r4], #4
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orreq ip, ip, lr, lsl #16
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eoreqs r0, r0, ip
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moveq ip, lr, lsr #16
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ldreq lr, [r1], #4
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ldreq r0, [r4], #4
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orreq ip, ip, lr, lsl #16
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eoreqs r0, r0, ip
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moveq ip, lr, lsr #16
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ldreq lr, [r1], #4
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ldreq r0, [r4], #4
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orreq ip, ip, lr, lsl #16
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eoreqs r0, r0, ip
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bne 7f
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subs r2, r2, #16
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bhs 6b
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sub r1, r1, #2
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/* are we done? */
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adds r2, r2, #16
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moveq r0, #0
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beq 9b
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/* finish off the remaining bytes */
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b 8b
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7: /* fix up the 2 pointers and fallthrough... */
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sub r1, r1, #(4+2)
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sub r4, r4, #4
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mov r2, #4
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b 8b
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4: /*************** offset is 1 or 3 (less optimized) ***************/
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stmfd sp!, {r5, r6, r7}
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// r5 = rhs
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// r6 = lhs
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// r7 = scratch
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mov r5, r0, lsl #3 /* r5 = right shift */
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rsb r6, r5, #32 /* r6 = left shift */
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/* align the unaligned pointer */
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bic r1, r1, #3
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ldr r7, [r1], #4
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sub r2, r2, #8
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6: mov ip, r7, lsr r5
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ldr r7, [r1], #4
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ldr r0, [r4], #4
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orr ip, ip, r7, lsl r6
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eors r0, r0, ip
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moveq ip, r7, lsr r5
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ldreq r7, [r1], #4
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ldreq r0, [r4], #4
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orreq ip, ip, r7, lsl r6
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eoreqs r0, r0, ip
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bne 7f
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subs r2, r2, #8
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bhs 6b
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sub r1, r1, r6, lsr #3
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ldmfd sp!, {r5, r6, r7}
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/* are we done? */
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adds r2, r2, #8
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moveq r0, #0
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beq 9b
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/* finish off the remaining bytes */
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b 8b
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7: /* fix up the 2 pointers and fallthrough... */
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sub r1, r1, #4
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sub r1, r1, r6, lsr #3
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sub r4, r4, #4
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mov r2, #4
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ldmfd sp!, {r5, r6, r7}
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b 8b
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