130 lines
4.3 KiB
ArmAsm
130 lines
4.3 KiB
ArmAsm
/****************************************************************************
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* arch/arm/src/armv7-r/arm_saveusercontext.S
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <arch/irq.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Public Symbols
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****************************************************************************/
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.file "arm_saveusercontext.S"
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/****************************************************************************
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* Macros
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: arm_saveusercontext
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*
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* Description:
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* Save the current thread context. Full prototype is:
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*
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* int arm_saveusercontext(uint32_t *saveregs);
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*
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* Returned Value:
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* 0: Normal return
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* 1: Context switch return
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*
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****************************************************************************/
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.globl arm_saveusercontext
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.type arm_saveusercontext, function
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arm_saveusercontext:
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/* On entry, a1 (r0) holds address of struct xcptcontext */
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/* Make sure that the return value will be non-zero (the value of the
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* other volatile registers don't matter -- r1-r3, ip). This function
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* is called through the normal C calling conventions and the values of
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* these registers cannot be assumed at the point of setjmp return.
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*/
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mov ip, #1
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str ip, [r0, #(4*REG_R0)]
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/* Save the volatile registers (plus r12 which really
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* doesn't need to be saved)
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*/
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add r1, r0, #(4*REG_R4)
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stmia r1, {r4-r14}
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/* Save the current cpsr */
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mrs r2, cpsr /* R2 = CPSR value */
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add r1, r0, #(4*REG_CPSR)
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str r2, [r1]
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/* Save the return address as the PC so that we return to the exit from
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* this function.
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*/
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add r1, r0, #(4*REG_PC)
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str lr, [r1]
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/* Save the floating point registers.
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* REVISIT: Not all of the floating point registers need to be saved.
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* Some are volatile and need not be preserved across functions calls.
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* But right now, I can't find the definitive list of the volatile
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* floating point registers.
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*/
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#ifdef CONFIG_ARCH_FPU
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add r1, r0, #(4*REG_S0) /* R1=Address of FP register storage */
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/* Store all floating point registers. Registers are stored in numeric order,
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* s0, s1, ... in increasing address order.
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*/
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#ifdef CONFIG_ARM_HAVE_FPU_D32
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vstmia.64 r1!, {d0-d15} /* Save the full FP context */
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vstmia.64 r1!, {d16-d31}
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#else
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vstmia r1!, {s0-s31} /* Save the full FP context */
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#endif
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/* Store the floating point control and status register. At the end of the
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* vstmia, r1 will point to the FPSCR storage location.
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*/
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vmrs r2, fpscr /* Fetch the FPSCR */
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str r2, [r1], #4 /* Save the floating point control and status register */
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#endif
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/* Return 0 now indicating that this return is not a context switch */
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mov r0, #0 /* Return value == 0 */
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bx lr /* Return */
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.size arm_saveusercontext, .-arm_saveusercontext
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.end
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