mbed official / lwip-sys

lwip operating system abstraction layer implementation based on CMSIS-RTOS

Dependents:   LwIPNetworking NetServicesMin EthernetInterface EthernetInterface_RSF ... more

arch/memcpy.c@18:8b8671ab556f, 2016-05-05 (annotated)

Committer:
mbed_official
Date:
Thu May 05 20:45:38 2016 +0100
Revision:
18:8b8671ab556f
Parent:
10:09b0951b1899 
Synchronized with git revision 860fdd282b0dc3631a6c46b39442d4ab5343e534



Full URL: https://github.com/mbedmicro/mbed/commit/860fdd282b0dc3631a6c46b39442d4ab5343e534/



rtx update to v4.79

Who changed what in which revision?

UserRevisionLine numberNew contents of line
bogdanm 10:09b0951b1899 1 /* Copyright (C) 2013 - Adam Green (https://github.com/adamgreen)
bogdanm 10:09b0951b1899 2
bogdanm 10:09b0951b1899 3 Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 10:09b0951b1899 4 you may not use this file except in compliance with the License.
bogdanm 10:09b0951b1899 5 You may obtain a copy of the License at
bogdanm 10:09b0951b1899 6
bogdanm 10:09b0951b1899 7 http://www.apache.org/licenses/LICENSE-2.0
bogdanm 10:09b0951b1899 8
bogdanm 10:09b0951b1899 9 Unless required by applicable law or agreed to in writing, software
bogdanm 10:09b0951b1899 10 distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 10:09b0951b1899 11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 10:09b0951b1899 12 See the License for the specific language governing permissions and
bogdanm 10:09b0951b1899 13 limitations under the License.
bogdanm 10:09b0951b1899 14 */
bogdanm 10:09b0951b1899 15 #if defined(TOOLCHAIN_GCC) && defined(__thumb2__)
bogdanm 10:09b0951b1899 16
bogdanm 10:09b0951b1899 17 #include <stdio.h>
bogdanm 10:09b0951b1899 18
bogdanm 10:09b0951b1899 19
bogdanm 10:09b0951b1899 20 /* This is a hand written Thumb-2 assembly language version of the
bogdanm 10:09b0951b1899 21 standard C memcpy() function that can be used by the lwIP networking
bogdanm 10:09b0951b1899 22 stack to improve its performance. It copies 4 bytes at a time and
bogdanm 10:09b0951b1899 23 unrolls the loop to perform 4 of these copies per loop iteration.
bogdanm 10:09b0951b1899 24 */
bogdanm 10:09b0951b1899 25 __attribute__((naked)) void thumb2_memcpy(void* pDest, const void* pSource, size_t length)
bogdanm 10:09b0951b1899 26 {
bogdanm 10:09b0951b1899 27 __asm (
bogdanm 10:09b0951b1899 28 ".syntax unified\n"
bogdanm 10:09b0951b1899 29 ".thumb\n"
bogdanm 10:09b0951b1899 30
bogdanm 10:09b0951b1899 31 // Copy 16 bytes at a time first.
bogdanm 10:09b0951b1899 32 " lsrs r3, r2, #4\n"
bogdanm 10:09b0951b1899 33 " beq.n 2$\n"
bogdanm 10:09b0951b1899 34 "1$: ldr r12, [r1], #4\n"
bogdanm 10:09b0951b1899 35 " str r12, [r0], #4\n"
bogdanm 10:09b0951b1899 36 " ldr r12, [r1], #4\n"
bogdanm 10:09b0951b1899 37 " str r12, [r0], #4\n"
bogdanm 10:09b0951b1899 38 " ldr r12, [r1], #4\n"
bogdanm 10:09b0951b1899 39 " str r12, [r0], #4\n"
bogdanm 10:09b0951b1899 40 " ldr r12, [r1], #4\n"
bogdanm 10:09b0951b1899 41 " str r12, [r0], #4\n"
bogdanm 10:09b0951b1899 42 " subs r3, #1\n"
bogdanm 10:09b0951b1899 43 " bne 1$\n"
bogdanm 10:09b0951b1899 44
bogdanm 10:09b0951b1899 45 // Copy byte by byte for what is left.
bogdanm 10:09b0951b1899 46 "2$:\n"
bogdanm 10:09b0951b1899 47 " ands r3, r2, #0xf\n"
bogdanm 10:09b0951b1899 48 " beq.n 4$\n"
bogdanm 10:09b0951b1899 49 "3$: ldrb r12, [r1], #1\n"
bogdanm 10:09b0951b1899 50 " strb r12, [r0], #1\n"
bogdanm 10:09b0951b1899 51 " subs r3, #1\n"
bogdanm 10:09b0951b1899 52 " bne 3$\n"
bogdanm 10:09b0951b1899 53
bogdanm 10:09b0951b1899 54 // Return to caller.
bogdanm 10:09b0951b1899 55 "4$: bx lr\n"
bogdanm 10:09b0951b1899 56 );
bogdanm 10:09b0951b1899 57 }
bogdanm 10:09b0951b1899 58
bogdanm 10:09b0951b1899 59 #endif