/****************************************************************************
* arch/arm/src/armv7-a/arm_saveusercontext.S
*
* Copyright (C) 2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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/irq.h>
#include "up_internal.h"
.file "arm_saveusercontext.S"
/****************************************************************************
* Preprocessor Definitions
****************************************************************************/
/****************************************************************************
* Public Symbols
****************************************************************************/
.globl up_saveusercontext
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
.text
/****************************************************************************
* Name: up_saveusercontext
****************************************************************************/
.globl up_saveusercontext
.type up_saveusercontext, function
up_saveusercontext:
/* On entry, a1 (r0) holds address of struct xcptcontext */
/* Make sure that the return value will be non-zero (the value of the
* other volatile registers don't matter -- r1-r3, ip). This function
* is called through the normal C calling conventions and the values of
* these registers cannot be assumed at the point of setjmp return.
*/
mov ip, #1
str ip, [r0, #(4*REG_R0)]
/* Save the volatile registers (plus r12 which really
* doesn't need to be saved)
*/
add r1, r0, #(4*REG_R4)
stmia r1, {r4-r14}
/* Save the current cpsr */
mrs r2, cpsr /* R3 = CPSR value */
add r1, r0, #(4*REG_CPSR)
str r2, [r1]
/* Save the return address as the PC so that we return to the exit from
* this function.
*/
add r1, r0, #(4*REG_PC)
str lr, [r1]
/* Save the floating point registers.
* REVISIT: Not all of the floating point registers need to be saved.
* Some are volatile and need not be preserved across functions calls.
* But right now, I can't find the definitive list of the volatile
* floating point registers.
*/
#ifdef CONFIG_ARCH_FPU
add r1, r0, #(4*REG_S0) /* R1=Address of FP register storage */
/* Store all floating point registers. Registers are stored in numeric order,
* s0, s1, ... in increasing address order.
*/
vstmia r1!, {s0-s31} /* Save the full FP context */
/* Store the floating point control and status register. At the end of the
* vstmia, r1 will point to the FPCSR storage location.
*/
vmrs r2, fpscr /* Fetch the FPCSR */
str r2, [r1], #4 /* Save the floating point control and status register */
#endif
/* Return 0 now indicating that this return is not a context switch */
mov r0, #0 /* Return value == 0 */
mov pc, lr /* Return */
.size up_saveusercontext, . - up_saveusercontext
.end
