Ankit Patel / Mbed 2 deprecated Robot_Control_UDP_Ethernet

Control a robot over the internet using UDP and a Ethernet interface.

Dependencies:   EthernetInterface Motor TextLCD mbed-rtos mbed Socket lwip-eth lwip-sys lwip

EthernetInterface/lwip-sys/arch/memcpy.c@0:1496281373a5, 2013-10-17 (annotated)

Committer:
apatel336
Date:
Thu Oct 17 13:26:38 2013 +0000
Revision:
0:1496281373a5
Initial Release

Who changed what in which revision?

UserRevisionLine numberNew contents of line
apatel336 0:1496281373a5 1 /* Copyright (C) 2013 - Adam Green (https://github.com/adamgreen)
apatel336 0:1496281373a5 2
apatel336 0:1496281373a5 3 Licensed under the Apache License, Version 2.0 (the "License");
apatel336 0:1496281373a5 4 you may not use this file except in compliance with the License.
apatel336 0:1496281373a5 5 You may obtain a copy of the License at
apatel336 0:1496281373a5 6
apatel336 0:1496281373a5 7 http://www.apache.org/licenses/LICENSE-2.0
apatel336 0:1496281373a5 8
apatel336 0:1496281373a5 9 Unless required by applicable law or agreed to in writing, software
apatel336 0:1496281373a5 10 distributed under the License is distributed on an "AS IS" BASIS,
apatel336 0:1496281373a5 11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
apatel336 0:1496281373a5 12 See the License for the specific language governing permissions and
apatel336 0:1496281373a5 13 limitations under the License.
apatel336 0:1496281373a5 14 */
apatel336 0:1496281373a5 15 #if defined(TOOLCHAIN_GCC) && defined(__thumb2__)
apatel336 0:1496281373a5 16
apatel336 0:1496281373a5 17 #include <stdio.h>
apatel336 0:1496281373a5 18
apatel336 0:1496281373a5 19
apatel336 0:1496281373a5 20 /* This is a hand written Thumb-2 assembly language version of the
apatel336 0:1496281373a5 21 standard C memcpy() function that can be used by the lwIP networking
apatel336 0:1496281373a5 22 stack to improve its performance. It copies 4 bytes at a time and
apatel336 0:1496281373a5 23 unrolls the loop to perform 4 of these copies per loop iteration.
apatel336 0:1496281373a5 24 */
apatel336 0:1496281373a5 25 __attribute__((naked)) void thumb2_memcpy(void* pDest, const void* pSource, size_t length)
apatel336 0:1496281373a5 26 {
apatel336 0:1496281373a5 27 __asm (
apatel336 0:1496281373a5 28 ".syntax unified\n"
apatel336 0:1496281373a5 29 ".thumb\n"
apatel336 0:1496281373a5 30
apatel336 0:1496281373a5 31 // Copy 16 bytes at a time first.
apatel336 0:1496281373a5 32 " lsrs r3, r2, #4\n"
apatel336 0:1496281373a5 33 " beq.n 2$\n"
apatel336 0:1496281373a5 34 "1$: ldr r12, [r1], #4\n"
apatel336 0:1496281373a5 35 " str r12, [r0], #4\n"
apatel336 0:1496281373a5 36 " ldr r12, [r1], #4\n"
apatel336 0:1496281373a5 37 " str r12, [r0], #4\n"
apatel336 0:1496281373a5 38 " ldr r12, [r1], #4\n"
apatel336 0:1496281373a5 39 " str r12, [r0], #4\n"
apatel336 0:1496281373a5 40 " ldr r12, [r1], #4\n"
apatel336 0:1496281373a5 41 " str r12, [r0], #4\n"
apatel336 0:1496281373a5 42 " subs r3, #1\n"
apatel336 0:1496281373a5 43 " bne 1$\n"
apatel336 0:1496281373a5 44
apatel336 0:1496281373a5 45 // Copy byte by byte for what is left.
apatel336 0:1496281373a5 46 "2$:\n"
apatel336 0:1496281373a5 47 " ands r3, r2, #0xf\n"
apatel336 0:1496281373a5 48 " beq.n 4$\n"
apatel336 0:1496281373a5 49 "3$: ldrb r12, [r1], #1\n"
apatel336 0:1496281373a5 50 " strb r12, [r0], #1\n"
apatel336 0:1496281373a5 51 " subs r3, #1\n"
apatel336 0:1496281373a5 52 " bne 3$\n"
apatel336 0:1496281373a5 53
apatel336 0:1496281373a5 54 // Return to caller.
apatel336 0:1496281373a5 55 "4$: bx lr\n"
apatel336 0:1496281373a5 56 );
apatel336 0:1496281373a5 57 }
apatel336 0:1496281373a5 58
apatel336 0:1496281373a5 59 #endif