source: rtems/c/src/lib/libbsp/arm/shared/startup/bsp-start-memcpy.S @ f0c564c

/**
 * @file
 *
 * @brief bsp_start_memcpy() implementation.
 */

/*
 * Copyright (c) 2008-2011 embedded brains GmbH.  All rights reserved.
 *
 *  embedded brains GmbH
 *  Obere Lagerstr. 30
 *  82178 Puchheim
 *  Germany
 *  <rtems@embedded-brains.de>
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rtems.org/license/LICENSE.
 */

#include <rtems/asm.h>
#include <rtems/system.h>
#include <rtems/score/cpu.h>

        .section        ".bsp_start_text", "ax"

#if defined(ARM_MULTILIB_ARCH_V4)

DEFINE_FUNCTION_ARM(bsp_start_memcpy)

        /* Return if dest == src */
        cmp     r0, r1
#ifdef __thumb__
        bxeq    lr
#else
        moveq   pc, lr
#endif

        /* Return if length is zero */
        mov     r3, #0
        cmp     r3, r2
#ifdef __thumb__
        bxeq    lr
#else
        moveq   pc, lr
#endif

        /* Save non-volatile registers */
        push    {r4-r8, lr}

        /* Copy worker routine to stack */
        adr     ip, worker_begin
        ldm     ip, {r3-r8}
        push    {r3-r8}

        /* Execute worker routine */
        mov     r3, #0
        mov     ip, sp
        mov     lr, pc
#ifdef __thumb__
        bx      ip
#else
        mov     pc, ip
#endif

        /* Restore stack and non-volatile registers */
        add     sp, sp, #24
        pop     {r4-r8, lr}

        /* Return */
#ifdef __thumb__
        bx      lr
#else
        mov     pc, lr
#endif

worker_begin:

        /* Worker routine */
        ldr     ip, [r1, r3]
        str     ip, [r0, r3]
        add     r3, r3, #4
        cmp     r3, r2
        bcc     worker_begin
#ifdef __thumb__
        bx      lr
#else
        mov     pc, lr
#endif

#elif defined(ARM_MULTILIB_ARCH_V7M)

        .syntax unified

        .align  2
        .globl  bsp_start_memcpy
        .thumb
        .thumb_func
        .type   bsp_start_memcpy, %function

bsp_start_memcpy:

        /* Return if dest == src */
        cmp     r0, r1
        beq     return

        /* Return if length is zero */
        movs    r3, #0
        cmp     r3, r2
        beq     return

        /* Save non-volatile registers */
        push    {r4-r7, lr}

        /* Copy worker routine to stack */
        adr     r3, worker_begin
        ldm     r3, {r4-r7}
        push    {r4-r7}

        /* Execute worker routine */
        add     r3, sp, #1
        adds    r2, r2, #3
        bic     r2, r2, #3
        adds    r2, r2, r1
        blx     r3

        /* Restore stack and non-volatile registers */
        add     sp, sp, #16
        pop     {r4-r7, lr}

return:

        /* Return */
        bx      lr

        .align  2

worker_begin:

        /* Worker routine */
        ldr     r3, [r1], #4
        cmp     r2, r1
        str     r3, [r0], #4
        bne     worker_begin
        bx      lr

#endif /* defined(ARM_MULTILIB_ARCH_V7M) */