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author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2009-10-25 02:24:40 +0000 |
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committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2009-10-25 02:24:40 +0000 |
commit | efc8d580b339a7c741e8f134c9fbb8a834ee3179 (patch) | |
tree | 4e68d0859d8a8ee180e7819e7f8cb35e9dfac4f3 /nuttx/arch/arm/src/cortexm3/up_switchcontext.S | |
parent | 5e5bc7a64b05d06510c8989165759368ad6cc8fc (diff) | |
download | px4-nuttx-efc8d580b339a7c741e8f134c9fbb8a834ee3179.tar.gz px4-nuttx-efc8d580b339a7c741e8f134c9fbb8a834ee3179.tar.bz2 px4-nuttx-efc8d580b339a7c741e8f134c9fbb8a834ee3179.zip |
Improved certain Cortex-M3 context switch times
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2177 42af7a65-404d-4744-a932-0658087f49c3
Diffstat (limited to 'nuttx/arch/arm/src/cortexm3/up_switchcontext.S')
-rwxr-xr-x | nuttx/arch/arm/src/cortexm3/up_switchcontext.S | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/nuttx/arch/arm/src/cortexm3/up_switchcontext.S b/nuttx/arch/arm/src/cortexm3/up_switchcontext.S new file mode 100755 index 000000000..055a7a268 --- /dev/null +++ b/nuttx/arch/arm/src/cortexm3/up_switchcontext.S @@ -0,0 +1,95 @@ +/************************************************************************************ + * arch/arm/src/cortexm3/up_switchcontext.S + * + * Copyright (C) 2009 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ************************************************************************************/ + +/************************************************************************************ + * Included Files + ************************************************************************************/ + +#include <nuttx/config.h> +#include <arch/irq.h> +#include "nvic.h" + +/************************************************************************************ + * Preprocessor Definitions + ************************************************************************************/ + +/************************************************************************************ + * Global Symbols + ************************************************************************************/ + + .syntax unified + .thumb + .file "up_context.S" + +/************************************************************************************ + * Macros + ************************************************************************************/ + +/************************************************************************************ + * Public Functions + ************************************************************************************/ + +/************************************************************************** + * Name: up_switchcontext + * + * Description: + * Save the current thread context and restore the specified context. + * Full prototype is: + * + * void up_switchcontext(uint32 *saveregs, uint32 *restoreregs); + * + * Return: + * None + * + **************************************************************************/ + + .thumb_func + .globl up_switchcontext + .type up_switchcontext, function +up_switchcontext: + + /* Perform the System call with R0=1, R1=saveregs, R2=restoreregs */ + + mov r2, r1 /* R2: restoreregs */ + mov r1, r0 /* R1: saveregs */ + mov r0, #2 /* R0: 2 means context switch */ + svc 0 /* Force synchronous SVCall (or Hard Fault) */ + + /* This call should not return */ + + bx lr /* Unnecessary ... will not return */ + .size up_switchcontext, .-up_switchcontext + .end + |