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/*
* FreeRTOS Kernel <DEVELOPMENT BRANCH>
* Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* SPDX-License-Identifier: MIT
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* https://www.FreeRTOS.org
* https://github.com/FreeRTOS
*
*/
/* Standard includes. */
#include <stdint.h>
/* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE ensures that PRIVILEGED_FUNCTION
* is defined correctly and privileged functions are placed in correct sections. */
#define MPU_WRAPPERS_INCLUDED_FROM_API_FILE
/* Portasm includes. */
#include "portasm.h"
/* System call numbers includes. */
#include "mpu_syscall_numbers.h"
/* MPU_WRAPPERS_INCLUDED_FROM_API_FILE is needed to be defined only for the
* header files. */
#undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE
#if ( configENABLE_FPU == 1 )
#error Cortex-M23 does not have a Floating Point Unit (FPU) and therefore configENABLE_FPU must be set to 0.
#endif
#if ( configENABLE_MPU == 1 )
void vRestoreContextOfFirstTask( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */
{
__asm volatile
(
" .syntax unified \n"
" \n"
" program_mpu_first_task: \n"
" ldr r3, pxCurrentTCBConst2 \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r0, [r3] \n" /* r0 = pxCurrentTCB.*/
" \n"
" dmb \n" /* Complete outstanding transfers before disabling MPU. */
" ldr r1, xMPUCTRLConst2 \n" /* r1 = 0xe000ed94 [Location of MPU_CTRL]. */
" ldr r2, [r1] \n" /* Read the value of MPU_CTRL. */
" movs r3, #1 \n" /* r3 = 1. */
" bics r2, r3 \n" /* r2 = r2 & ~r3 i.e. Clear the bit 0 in r2. */
" str r2, [r1] \n" /* Disable MPU. */
" \n"
" adds r0, #4 \n" /* r0 = r0 + 4. r0 now points to MAIR0 in TCB. */
" ldr r1, [r0] \n" /* r1 = *r0 i.e. r1 = MAIR0. */
" ldr r2, xMAIR0Const2 \n" /* r2 = 0xe000edc0 [Location of MAIR0]. */
" str r1, [r2] \n" /* Program MAIR0. */
" \n"
" adds r0, #4 \n" /* r0 = r0 + 4. r0 now points to first RBAR in TCB. */
" ldr r1, xRNRConst2 \n" /* r1 = 0xe000ed98 [Location of RNR]. */
" \n"
" movs r3, #4 \n" /* r3 = 4. */
" str r3, [r1] \n" /* Program RNR = 4. */
" ldmia r0!, {r4-r5} \n" /* Read first set of RBAR/RLAR registers from TCB. */
" ldr r2, xRBARConst2 \n" /* r2 = 0xe000ed9c [Location of RBAR]. */
" stmia r2!, {r4-r5} \n" /* Write first set of RBAR/RLAR registers. */
" movs r3, #5 \n" /* r3 = 5. */
" str r3, [r1] \n" /* Program RNR = 5. */
" ldmia r0!, {r4-r5} \n" /* Read second set of RBAR/RLAR registers from TCB. */
" ldr r2, xRBARConst2 \n" /* r2 = 0xe000ed9c [Location of RBAR]. */
" stmia r2!, {r4-r5} \n" /* Write second set of RBAR/RLAR registers. */
" movs r3, #6 \n" /* r3 = 6. */
" str r3, [r1] \n" /* Program RNR = 6. */
" ldmia r0!, {r4-r5} \n" /* Read third set of RBAR/RLAR registers from TCB. */
" ldr r2, xRBARConst2 \n" /* r2 = 0xe000ed9c [Location of RBAR]. */
" stmia r2!, {r4-r5} \n" /* Write third set of RBAR/RLAR registers. */
" movs r3, #7 \n" /* r3 = 6. */
" str r3, [r1] \n" /* Program RNR = 7. */
" ldmia r0!, {r4-r5} \n" /* Read fourth set of RBAR/RLAR registers from TCB. */
" ldr r2, xRBARConst2 \n" /* r2 = 0xe000ed9c [Location of RBAR]. */
" stmia r2!, {r4-r5} \n" /* Write fourth set of RBAR/RLAR registers. */
" \n"
" ldr r1, xMPUCTRLConst2 \n" /* r1 = 0xe000ed94 [Location of MPU_CTRL]. */
" ldr r2, [r1] \n" /* Read the value of MPU_CTRL. */
" movs r3, #1 \n" /* r3 = 1. */
" orrs r2, r3 \n" /* r2 = r2 | r3 i.e. Set the bit 0 in r2. */
" str r2, [r1] \n" /* Enable MPU. */
" dsb \n" /* Force memory writes before continuing. */
" \n"
" restore_context_first_task: \n"
" ldr r2, pxCurrentTCBConst2 \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r0, [r2] \n" /* r0 = pxCurrentTCB.*/
" ldr r1, [r0] \n" /* r1 = Location of saved context in TCB. */
" \n"
" restore_special_regs_first_task: \n"
" subs r1, #16 \n"
" ldmia r1!, {r2-r5} \n" /* r2 = original PSP, r3 = PSPLIM, r4 = CONTROL, r5 = LR. */
" subs r1, #16 \n"
" msr psp, r2 \n"
#if ( configRUN_FREERTOS_SECURE_ONLY == 1 )
" msr psplim, r3 \n"
#endif
" msr control, r4 \n"
" mov lr, r5 \n"
" \n"
" restore_general_regs_first_task: \n"
" subs r1, #32 \n"
" ldmia r1!, {r4-r7} \n" /* r4-r7 contain half of the hardware saved context. */
" stmia r2!, {r4-r7} \n" /* Copy half of the the hardware saved context on the task stack. */
" ldmia r1!, {r4-r7} \n" /* r4-r7 contain rest half of the hardware saved context. */
" stmia r2!, {r4-r7} \n" /* Copy rest half of the the hardware saved context on the task stack. */
" subs r1, #48 \n"
" ldmia r1!, {r4-r7} \n" /* Restore r8-r11. */
" mov r8, r4 \n" /* r8 = r4. */
" mov r9, r5 \n" /* r9 = r5. */
" mov r10, r6 \n" /* r10 = r6. */
" mov r11, r7 \n" /* r11 = r7. */
" subs r1, #32 \n"
" ldmia r1!, {r4-r7} \n" /* Restore r4-r7. */
" subs r1, #16 \n"
" \n"
" restore_context_done_first_task: \n"
" str r1, [r0] \n" /* Save the location where the context should be saved next as the first member of TCB. */
" bx lr \n"
" \n"
" .align 4 \n"
" pxCurrentTCBConst2: .word pxCurrentTCB \n"
" xMPUCTRLConst2: .word 0xe000ed94 \n"
" xMAIR0Const2: .word 0xe000edc0 \n"
" xRNRConst2: .word 0xe000ed98 \n"
" xRBARConst2: .word 0xe000ed9c \n"
);
}
#else /* configENABLE_MPU */
void vRestoreContextOfFirstTask( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */
{
__asm volatile
(
" .syntax unified \n"
" \n"
" ldr r2, pxCurrentTCBConst2 \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r1, [r2] \n" /* Read pxCurrentTCB. */
" ldr r0, [r1] \n" /* Read top of stack from TCB - The first item in pxCurrentTCB is the task top of stack. */
" \n"
" ldm r0!, {r1-r2} \n" /* Read from stack - r1 = PSPLIM and r2 = EXC_RETURN. */
#if ( configRUN_FREERTOS_SECURE_ONLY == 1 )
" msr psplim, r1 \n" /* Set this task's PSPLIM value. */
#endif
" movs r1, #2 \n" /* r1 = 2. */
" msr CONTROL, r1 \n" /* Switch to use PSP in the thread mode. */
" adds r0, #32 \n" /* Discard everything up to r0. */
" msr psp, r0 \n" /* This is now the new top of stack to use in the task. */
" isb \n"
" bx r2 \n" /* Finally, branch to EXC_RETURN. */
" \n"
" .align 4 \n"
"pxCurrentTCBConst2: .word pxCurrentTCB \n"
);
}
#endif /* configENABLE_MPU */
/*-----------------------------------------------------------*/
BaseType_t xIsPrivileged( void ) /* __attribute__ (( naked )) */
{
__asm volatile
(
" .syntax unified \n"
" \n"
" mrs r0, control \n" /* r0 = CONTROL. */
" movs r1, #1 \n" /* r1 = 1. */
" tst r0, r1 \n" /* Perform r0 & r1 (bitwise AND) and update the conditions flag. */
" beq running_privileged \n" /* If the result of previous AND operation was 0, branch. */
" movs r0, #0 \n" /* CONTROL[0]!=0. Return false to indicate that the processor is not privileged. */
" bx lr \n" /* Return. */
" running_privileged: \n"
" movs r0, #1 \n" /* CONTROL[0]==0. Return true to indicate that the processor is privileged. */
" bx lr \n" /* Return. */
" \n"
" .align 4 \n"
::: "r0", "r1", "memory"
);
}
/*-----------------------------------------------------------*/
void vRaisePrivilege( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */
{
__asm volatile
(
" .syntax unified \n"
" \n"
" mrs r0, control \n" /* Read the CONTROL register. */
" movs r1, #1 \n" /* r1 = 1. */
" bics r0, r1 \n" /* Clear the bit 0. */
" msr control, r0 \n" /* Write back the new CONTROL value. */
" bx lr \n" /* Return to the caller. */
::: "r0", "r1", "memory"
);
}
/*-----------------------------------------------------------*/
void vResetPrivilege( void ) /* __attribute__ (( naked )) */
{
__asm volatile
(
" .syntax unified \n"
" \n"
" mrs r0, control \n" /* r0 = CONTROL. */
" movs r1, #1 \n" /* r1 = 1. */
" orrs r0, r1 \n" /* r0 = r0 | r1. */
" msr control, r0 \n" /* CONTROL = r0. */
" bx lr \n" /* Return to the caller. */
::: "r0", "r1", "memory"
);
}
/*-----------------------------------------------------------*/
void vStartFirstTask( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */
{
__asm volatile
(
" .syntax unified \n"
" \n"
" ldr r0, xVTORConst \n" /* Use the NVIC offset register to locate the stack. */
" ldr r0, [r0] \n" /* Read the VTOR register which gives the address of vector table. */
" ldr r0, [r0] \n" /* The first entry in vector table is stack pointer. */
" msr msp, r0 \n" /* Set the MSP back to the start of the stack. */
" cpsie i \n" /* Globally enable interrupts. */
" dsb \n"
" isb \n"
" svc %0 \n" /* System call to start the first task. */
" nop \n"
" \n"
" .align 4 \n"
"xVTORConst: .word 0xe000ed08 \n"
::"i" ( portSVC_START_SCHEDULER ) : "memory"
);
}
/*-----------------------------------------------------------*/
uint32_t ulSetInterruptMask( void ) /* __attribute__(( naked )) PRIVILEGED_FUNCTION */
{
__asm volatile
(
" .syntax unified \n"
" \n"
" mrs r0, PRIMASK \n"
" cpsid i \n"
" bx lr \n"
::: "memory"
);
}
/*-----------------------------------------------------------*/
void vClearInterruptMask( __attribute__( ( unused ) ) uint32_t ulMask ) /* __attribute__(( naked )) PRIVILEGED_FUNCTION */
{
__asm volatile
(
" .syntax unified \n"
" \n"
" msr PRIMASK, r0 \n"
" bx lr \n"
::: "memory"
);
}
/*-----------------------------------------------------------*/
#if ( configENABLE_MPU == 1 )
void PendSV_Handler( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */
{
__asm volatile
(
" .syntax unified \n"
" \n"
" ldr r2, pxCurrentTCBConst \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r0, [r2] \n" /* r0 = pxCurrentTCB. */
" ldr r1, [r0] \n" /* r1 = Location in TCB where the context should be saved. */
" mrs r2, psp \n" /* r2 = PSP. */
" \n"
" save_general_regs: \n"
" stmia r1!, {r4-r7} \n" /* Store r4-r7. */
" mov r4, r8 \n" /* r4 = r8. */
" mov r5, r9 \n" /* r5 = r9. */
" mov r6, r10 \n" /* r6 = r10. */
" mov r7, r11 \n" /* r7 = r11. */
" stmia r1!, {r4-r7} \n" /* Store r8-r11. */
" ldmia r2!, {r4-r7} \n" /* Copy half of the hardware saved context into r4-r7. */
" stmia r1!, {r4-r7} \n" /* Store the hardware saved context. */
" ldmia r2!, {r4-r7} \n" /* Copy rest half of the hardware saved context into r4-r7. */
" stmia r1!, {r4-r7} \n" /* Store the hardware saved context. */
" \n"
" save_special_regs: \n"
" mrs r2, psp \n" /* r2 = PSP. */
#if ( configRUN_FREERTOS_SECURE_ONLY == 1 )
" mrs r3, psplim \n" /* r3 = PSPLIM. */
#else
" movs r3, #0 \n" /* r3 = 0. 0 is stored in the PSPLIM slot. */
#endif
" mrs r4, control \n" /* r4 = CONTROL. */
" mov r5, lr \n" /* r5 = LR. */
" stmia r1!, {r2-r5} \n" /* Store original PSP (after hardware has saved context), PSPLIM, CONTROL and LR. */
" str r1, [r0] \n" /* Save the location from where the context should be restored as the first member of TCB. */
" \n"
" select_next_task: \n"
" cpsid i \n"
" bl vTaskSwitchContext \n"
" cpsie i \n"
" \n"
" program_mpu: \n"
" ldr r3, pxCurrentTCBConst \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r0, [r3] \n" /* r0 = pxCurrentTCB.*/
" \n"
" dmb \n" /* Complete outstanding transfers before disabling MPU. */
" ldr r1, xMPUCTRLConst \n" /* r1 = 0xe000ed94 [Location of MPU_CTRL]. */
" ldr r2, [r1] \n" /* Read the value of MPU_CTRL. */
" movs r3, #1 \n" /* r3 = 1. */
" bics r2, r3 \n" /* r2 = r2 & ~r3 i.e. Clear the bit 0 in r2. */
" str r2, [r1] \n" /* Disable MPU. */
" \n"
" adds r0, #4 \n" /* r0 = r0 + 4. r0 now points to MAIR0 in TCB. */
" ldr r1, [r0] \n" /* r1 = *r0 i.e. r1 = MAIR0. */
" ldr r2, xMAIR0Const \n" /* r2 = 0xe000edc0 [Location of MAIR0]. */
" str r1, [r2] \n" /* Program MAIR0. */
" \n"
" adds r0, #4 \n" /* r0 = r0 + 4. r0 now points to first RBAR in TCB. */
" ldr r1, xRNRConst \n" /* r1 = 0xe000ed98 [Location of RNR]. */
" \n"
" movs r3, #4 \n" /* r3 = 4. */
" str r3, [r1] \n" /* Program RNR = 4. */
" ldmia r0!, {r4-r5} \n" /* Read first set of RBAR/RLAR registers from TCB. */
" ldr r2, xRBARConst \n" /* r2 = 0xe000ed9c [Location of RBAR]. */
" stmia r2!, {r4-r5} \n" /* Write first set of RBAR/RLAR registers. */
" movs r3, #5 \n" /* r3 = 5. */
" str r3, [r1] \n" /* Program RNR = 5. */
" ldmia r0!, {r4-r5} \n" /* Read second set of RBAR/RLAR registers from TCB. */
" ldr r2, xRBARConst \n" /* r2 = 0xe000ed9c [Location of RBAR]. */
" stmia r2!, {r4-r5} \n" /* Write second set of RBAR/RLAR registers. */
" movs r3, #6 \n" /* r3 = 6. */
" str r3, [r1] \n" /* Program RNR = 6. */
" ldmia r0!, {r4-r5} \n" /* Read third set of RBAR/RLAR registers from TCB. */
" ldr r2, xRBARConst \n" /* r2 = 0xe000ed9c [Location of RBAR]. */
" stmia r2!, {r4-r5} \n" /* Write third set of RBAR/RLAR registers. */
" movs r3, #7 \n" /* r3 = 6. */
" str r3, [r1] \n" /* Program RNR = 7. */
" ldmia r0!, {r4-r5} \n" /* Read fourth set of RBAR/RLAR registers from TCB. */
" ldr r2, xRBARConst \n" /* r2 = 0xe000ed9c [Location of RBAR]. */
" stmia r2!, {r4-r5} \n" /* Write fourth set of RBAR/RLAR registers. */
" \n"
" ldr r1, xMPUCTRLConst \n" /* r1 = 0xe000ed94 [Location of MPU_CTRL]. */
" ldr r2, [r1] \n" /* Read the value of MPU_CTRL. */
" movs r3, #1 \n" /* r3 = 1. */
" orrs r2, r3 \n" /* r2 = r2 | r3 i.e. Set the bit 0 in r2. */
" str r2, [r1] \n" /* Enable MPU. */
" dsb \n" /* Force memory writes before continuing. */
" \n"
" restore_context: \n"
" ldr r2, pxCurrentTCBConst \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r0, [r2] \n" /* r0 = pxCurrentTCB.*/
" ldr r1, [r0] \n" /* r1 = Location of saved context in TCB. */
" \n"
" restore_special_regs: \n"
" subs r1, #16 \n"
" ldmia r1!, {r2-r5} \n" /* r2 = original PSP, r3 = PSPLIM, r4 = CONTROL, r5 = LR. */
" subs r1, #16 \n"
" msr psp, r2 \n"
#if ( configRUN_FREERTOS_SECURE_ONLY == 1 )
" msr psplim, r3 \n"
#endif
" msr control, r4 \n"
" mov lr, r5 \n"
" \n"
" restore_general_regs: \n"
" subs r1, #32 \n"
" ldmia r1!, {r4-r7} \n" /* r4-r7 contain half of the hardware saved context. */
" stmia r2!, {r4-r7} \n" /* Copy half of the the hardware saved context on the task stack. */
" ldmia r1!, {r4-r7} \n" /* r4-r7 contain rest half of the hardware saved context. */
" stmia r2!, {r4-r7} \n" /* Copy rest half of the the hardware saved context on the task stack. */
" subs r1, #48 \n"
" ldmia r1!, {r4-r7} \n" /* Restore r8-r11. */
" mov r8, r4 \n" /* r8 = r4. */
" mov r9, r5 \n" /* r9 = r5. */
" mov r10, r6 \n" /* r10 = r6. */
" mov r11, r7 \n" /* r11 = r7. */
" subs r1, #32 \n"
" ldmia r1!, {r4-r7} \n" /* Restore r4-r7. */
" subs r1, #16 \n"
" \n"
" restore_context_done: \n"
" str r1, [r0] \n" /* Save the location where the context should be saved next as the first member of TCB. */
" bx lr \n"
" \n"
" .align 4 \n"
" pxCurrentTCBConst: .word pxCurrentTCB \n"
" xMPUCTRLConst: .word 0xe000ed94 \n"
" xMAIR0Const: .word 0xe000edc0 \n"
" xRNRConst: .word 0xe000ed98 \n"
" xRBARConst: .word 0xe000ed9c \n"
);
}
#else /* configENABLE_MPU */
void PendSV_Handler( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */
{
__asm volatile
(
" .syntax unified \n"
" \n"
" mrs r0, psp \n" /* Read PSP in r0. */
" ldr r2, pxCurrentTCBConst \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r1, [r2] \n" /* Read pxCurrentTCB. */
" subs r0, r0, #40 \n" /* Make space for PSPLIM, LR and the remaining registers on the stack. */
" str r0, [r1] \n" /* Save the new top of stack in TCB. */
#if ( configRUN_FREERTOS_SECURE_ONLY == 1 )
" mrs r2, psplim \n" /* r2 = PSPLIM. */
#else
" movs r2, #0 \n" /* r2 = 0. 0 is stored in the PSPLIM slot. */
#endif
" mov r3, lr \n" /* r3 = LR/EXC_RETURN. */
" stmia r0!, {r2-r7} \n" /* Store on the stack - PSPLIM, LR and low registers that are not automatically saved. */
" mov r4, r8 \n" /* r4 = r8. */
" mov r5, r9 \n" /* r5 = r9. */
" mov r6, r10 \n" /* r6 = r10. */
" mov r7, r11 \n" /* r7 = r11. */
" stmia r0!, {r4-r7} \n" /* Store the high registers that are not saved automatically. */
" \n"
" cpsid i \n"
" bl vTaskSwitchContext \n"
" cpsie i \n"
" \n"
" ldr r2, pxCurrentTCBConst \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r1, [r2] \n" /* Read pxCurrentTCB. */
" ldr r0, [r1] \n" /* The first item in pxCurrentTCB is the task top of stack. r0 now points to the top of stack. */
" \n"
" adds r0, r0, #24 \n" /* Move to the high registers. */
" ldmia r0!, {r4-r7} \n" /* Restore the high registers that are not automatically restored. */
" mov r8, r4 \n" /* r8 = r4. */
" mov r9, r5 \n" /* r9 = r5. */
" mov r10, r6 \n" /* r10 = r6. */
" mov r11, r7 \n" /* r11 = r7. */
" msr psp, r0 \n" /* Remember the new top of stack for the task. */
" subs r0, r0, #40 \n" /* Move to the starting of the saved context. */
" ldmia r0!, {r2-r7} \n" /* Read from stack - r2 = PSPLIM, r3 = LR and r4-r7 restored. */
#if ( configRUN_FREERTOS_SECURE_ONLY == 1 )
" msr psplim, r2 \n" /* Restore the PSPLIM register value for the task. */
#endif
" bx r3 \n"
" \n"
" .align 4 \n"
"pxCurrentTCBConst: .word pxCurrentTCB \n"
);
}
#endif /* configENABLE_MPU */
/*-----------------------------------------------------------*/
#if ( ( configENABLE_MPU == 1 ) && ( configUSE_MPU_WRAPPERS_V1 == 0 ) )
void SVC_Handler( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */
{
__asm volatile
(
".syntax unified \n"
".extern vPortSVCHandler_C \n"
".extern vSystemCallEnter \n"
".extern vSystemCallExit \n"
" \n"
"movs r0, #4 \n"
"mov r1, lr \n"
"tst r0, r1 \n"
"beq stack_on_msp \n"
"stack_on_psp: \n"
" mrs r0, psp \n"
" b route_svc \n"
"stack_on_msp: \n"
" mrs r0, msp \n"
" b route_svc \n"
" \n"
"route_svc: \n"
" ldr r3, [r0, #24] \n"
" subs r3, #2 \n"
" ldrb r2, [r3, #0] \n"
" cmp r2, %0 \n"
" blt system_call_enter \n"
" cmp r2, %1 \n"
" beq system_call_exit \n"
" b vPortSVCHandler_C \n"
" \n"
"system_call_enter: \n"
" b vSystemCallEnter \n"
"system_call_exit: \n"
" b vSystemCallExit \n"
" \n"
: /* No outputs. */
: "i" ( NUM_SYSTEM_CALLS ), "i" ( portSVC_SYSTEM_CALL_EXIT )
: "r0", "r1", "r2", "r3", "memory"
);
}
#else /* ( configENABLE_MPU == 1 ) && ( configUSE_MPU_WRAPPERS_V1 == 0 ) */
void SVC_Handler( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */
{
__asm volatile
(
" .syntax unified \n"
" \n"
" movs r0, #4 \n"
" mov r1, lr \n"
" tst r0, r1 \n"
" beq stacking_used_msp \n"
" mrs r0, psp \n"
" ldr r2, svchandler_address_const \n"
" bx r2 \n"
" stacking_used_msp: \n"
" mrs r0, msp \n"
" ldr r2, svchandler_address_const \n"
" bx r2 \n"
" \n"
" .align 4 \n"
"svchandler_address_const: .word vPortSVCHandler_C \n"
);
}
#endif /* ( configENABLE_MPU == 1 ) && ( configUSE_MPU_WRAPPERS_V1 == 0 ) */
/*-----------------------------------------------------------*/