199 lines
4.9 KiB
ArmAsm
199 lines
4.9 KiB
ArmAsm
/*
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* Copyright (C) 2013 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 <private/bionic_asm.h>
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.syntax unified
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.thumb
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.thumb_func
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// Get the length of src string, then get the source of the dst string.
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// Check that the two lengths together don't exceed the threshold, then
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// do a memcpy of the data.
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ENTRY(__strcat_chk)
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pld [r0, #0]
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push {r0, lr}
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.cfi_adjust_cfa_offset 8
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.cfi_rel_offset r0, 0
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.cfi_rel_offset lr, 4
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push {r4, r5}
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.cfi_adjust_cfa_offset 8
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.cfi_rel_offset r4, 0
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.cfi_rel_offset r5, 4
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mov lr, r2
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// Save the dst register to r5
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mov r5, r0
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// Zero out r4
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eor r4, r4, r4
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// r1 contains the address of the string to count.
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.L_strlen_start:
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mov r0, r1
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ands r3, r1, #7
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beq .L_mainloop
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// Align to a double word (64 bits).
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rsb r3, r3, #8
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lsls ip, r3, #31
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beq .L_align_to_32
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ldrb r2, [r1], #1
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cbz r2, .L_update_count_and_finish
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.L_align_to_32:
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bcc .L_align_to_64
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ands ip, r3, #2
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beq .L_align_to_64
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ldrb r2, [r1], #1
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cbz r2, .L_update_count_and_finish
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ldrb r2, [r1], #1
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cbz r2, .L_update_count_and_finish
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.L_align_to_64:
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tst r3, #4
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beq .L_mainloop
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ldr r3, [r1], #4
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sub ip, r3, #0x01010101
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bic ip, ip, r3
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ands ip, ip, #0x80808080
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bne .L_zero_in_second_register
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.p2align 2
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.L_mainloop:
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ldrd r2, r3, [r1], #8
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pld [r1, #64]
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sub ip, r2, #0x01010101
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bic ip, ip, r2
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ands ip, ip, #0x80808080
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bne .L_zero_in_first_register
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sub ip, r3, #0x01010101
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bic ip, ip, r3
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ands ip, ip, #0x80808080
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bne .L_zero_in_second_register
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b .L_mainloop
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.L_update_count_and_finish:
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sub r3, r1, r0
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sub r3, r3, #1
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b .L_finish
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.L_zero_in_first_register:
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sub r3, r1, r0
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lsls r2, ip, #17
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bne .L_sub8_and_finish
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bcs .L_sub7_and_finish
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lsls ip, ip, #1
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bne .L_sub6_and_finish
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sub r3, r3, #5
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b .L_finish
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.L_sub8_and_finish:
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sub r3, r3, #8
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b .L_finish
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.L_sub7_and_finish:
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sub r3, r3, #7
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b .L_finish
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.L_sub6_and_finish:
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sub r3, r3, #6
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b .L_finish
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.L_zero_in_second_register:
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sub r3, r1, r0
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lsls r2, ip, #17
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bne .L_sub4_and_finish
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bcs .L_sub3_and_finish
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lsls ip, ip, #1
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bne .L_sub2_and_finish
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sub r3, r3, #1
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b .L_finish
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.L_sub4_and_finish:
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sub r3, r3, #4
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b .L_finish
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.L_sub3_and_finish:
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sub r3, r3, #3
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b .L_finish
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.L_sub2_and_finish:
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sub r3, r3, #2
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.L_finish:
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cmp r4, #0
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bne .L_strlen_done
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// Time to get the dst string length.
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mov r1, r5
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// Save the original source address to r5.
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mov r5, r0
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// Save the current length (adding 1 for the terminator).
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add r4, r3, #1
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b .L_strlen_start
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// r0 holds the pointer to the dst string.
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// r3 holds the dst string length.
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// r4 holds the src string length + 1.
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.L_strlen_done:
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add r2, r3, r4
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cmp r2, lr
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itt hi
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movhi r0, lr
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bhi __strcat_chk_fail
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// Set up the registers for the memcpy code.
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mov r1, r5
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pld [r1, #64]
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mov r2, r4
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add r0, r0, r3
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pop {r4, r5}
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.cfi_adjust_cfa_offset -8
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.cfi_restore r4
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.cfi_restore r5
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#include "memcpy_base.S"
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// Undo the above cfi directives.
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.cfi_adjust_cfa_offset 8
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.cfi_rel_offset r4, 0
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.cfi_rel_offset r5, 4
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END(__strcat_chk)
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