58e97e521c
Add the `LIBC_PREVENT_STRING_KERNEL` and `LIBC_PREVENT_STRING_USER` that are meant to be selected by the chip if no libc implementation is going to be built. If selected, neither NuttX's software version of the libc nor any architecture-specific implementation will be built in the kernel or in the userspace, respectively. In this case, the linker may provide a ROM-defined version of the libc functions instead.
138 lines
3.0 KiB
ArmAsm
138 lines
3.0 KiB
ArmAsm
/****************************************************************************
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* libs/libc/machine/arm/armv8-m/gnu/arch_memset.S
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*
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* Copyright (c) 2015 ARM Ltd
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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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* 1. 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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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the company may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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#include "libc.h"
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#ifdef LIBC_BUILD_STRING
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#include "arm_asm.h"
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.thumb
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.syntax unified
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.global memset
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.type memset, %function
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.fnstart
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.cfi_startproc
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memset:
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prologue 4 6
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#ifdef __ARM_FEATURE_MVE
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vdup.8 q0, r1
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mov r3, lr
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mov r1, r0
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wlstp.8 lr, r2, 2f
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1:
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vstrb.8 q0, [r1], #16
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letp lr, 1b
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2:
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.cfi_remember_state
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epilogue 4 6
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.cfi_restore_state
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bx r3
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#else
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lsls r4, r0, #30
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beq 10f
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subs r4, r2, #1
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cmp r2, #0
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beq 9f
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uxtb r5, r1
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mov r3, r0
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b 2f
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1:
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subs r2, r4, #1
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cbz r4, 9f
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mov r4, r2
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2:
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strb r5, [r3], #1
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lsls r2, r3, #30
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bne 1b
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3:
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cmp r4, #3
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bls 7f
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uxtb r5, r1
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orr r5, r5, r5, lsl #8
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cmp r4, #15
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orr r5, r5, r5, lsl #16
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bls 5f
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mov r6, r4
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add r2, r3, #16
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4:
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subs r6, r6, #16
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cmp r6, #15
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str r5, [r2, #-16]
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str r5, [r2, #-12]
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str r5, [r2, #-8]
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str r5, [r2, #-4]
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add r2, r2, #16
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bhi 4b
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sub r2, r4, #16
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bic r2, r2, #15
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and r4, r4, #15
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adds r2, r2, #16
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cmp r4, #3
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add r3, r3, r2
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bls 7f
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5:
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mov r6, r3
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mov r2, r4
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6:
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subs r2, r2, #4
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cmp r2, #3
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str r5, [r6], #4
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bhi 6b
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subs r2, r4, #4
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bic r2, r2, #3
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adds r2, r2, #4
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add r3, r3, r2
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and r4, r4, #3
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7:
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cbz r4, 9f
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uxtb r1, r1
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add r4, r4, r3
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8:
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strb r1, [r3], #1
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cmp r3, r4
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bne 8b
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9:
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.cfi_remember_state
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epilogue 4 6
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10:
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.cfi_restore_state
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mov r4, r2
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mov r3, r0
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b 3b
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#endif
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.cfi_endproc
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.cantunwind
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.fnend
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.size memset, . - memset
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#endif
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