329 lines
10 KiB
ArmAsm
329 lines
10 KiB
ArmAsm
/*----------------------------------------------------------------------------
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* RL-ARM - RTX
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*----------------------------------------------------------------------------
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* Name: HAL_CM0.S
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* Purpose: Hardware Abstraction Layer for ARM7TDMI
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* Rev.: V1.0
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*----------------------------------------------------------------------------
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*
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* Copyright (c) 1999-2009 KEIL, 2009-2015 ARM Germany GmbH
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* All rights reserved.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* - Neither the name of ARM nor the names of its contributors may be used
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* to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDERS AND CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*---------------------------------------------------------------------------*/
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.file "HAL_CM0.S"
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.syntax unified
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.equ TCB_TSTACK, 40
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/*----------------------------------------------------------------------------
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* Functions
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*---------------------------------------------------------------------------*/
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.arm
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.section ".text"
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.align 2
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/*-------------------------- Save Context --------------------------------*/
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/* MUST be called the first */
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.macro SaveContext
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/* Push R0 as we are going to use the register. */ \
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STMDB SP!, {R0}
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/* Set R0 to SP(user) */
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STMDB SP,{SP}^
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NOP
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SUB SP, SP, #4
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LDMIA SP!,{R0}
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/* Push the LR return address onto the user stack. */
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STMDB R0!, {LR}
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/* Now we have saved LR we can use it instead of R0. */
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MOV LR, R0
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/* Pop R0 so we can save it onto the system mode stack. */
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LDMIA SP!, {R0}
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/* Push all the system mode registers onto the task stack. */
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STMDB LR,{R0-R12,LR}^ /* LR can not be changed because user's LR is used*/
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NOP /* pass 1 cycle before changing LR */
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SUB LR, LR, #14*4 /* change LR now -15 dwords (R0-R14)*/
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/* Push the SPSR onto the task stack. */
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MRS R0, SPSR
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STMDB LR!, {R0}
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/* Store the new top of stack for the task. */
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LDR R0,=os_tsk
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LDR R0, [R0] /* R0 = (tcb) os_tsk.run */
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STR LR, [R0, TCB_TSTACK] /* tcb.tsk_stack = SP(user) */
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.endm
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/*-------------------------- Restore Context --------------------------------*/
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.type RestoreContext, %function
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.global RestoreContext
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RestoreContext:
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.fnstart
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.cantunwind
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/* Set the LR to the task stack. */
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LDR R0,=os_tsk
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LDR R1, [R0, 4] /* R1 = (tcb) os_tsk.new */
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STR R1, [R0] /* os_tsk.run = os_tsk_newk */
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LDR LR, [R1, TCB_TSTACK] /* LR = tcb.tsk_stack */
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/* Get the SPSR from the stack. */
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LDMFD LR!, {R0} /* SPSR */
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MSR SPSR, R0
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/* Restore all system mode registers for the task. */
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LDMFD LR, {R0-R12,LR}^
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NOP
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ADD LR, LR, 15*4 /* increase starck pointer */
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/* Set SP(user) to LR */
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STMDB SP!,{LR}
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LDMIA SP,{SP}^
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NOP
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ADD SP, SP, #4
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/* Restore the return address. */
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LDR LR, [LR,#-4] /* last dword is task's PC register */
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/* And return - correcting the offset in the LR to obtain the */
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/* correct address. */
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SUBS PC, LR, #4
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/*-------------------------- End --------------------------------*/
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.fnend
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.size RestoreContext, .-RestoreContext
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/*--------------------------- rt_set_PSP ------------------------------------*/
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# void rt_set_PSP (U32 stack);
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.type rt_set_PSP, %function
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.global rt_set_PSP
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rt_set_PSP:
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.fnstart
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.cantunwind
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MOV SP,R0
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BX LR
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.fnend
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.size rt_set_PSP, .-rt_set_PSP
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/*--------------------------- rt_get_PSP ------------------------------------*/
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# U32 rt_get_PSP (void);
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.type rt_get_PSP, %function
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.global rt_get_PSP
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rt_get_PSP:
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.fnstart
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.cantunwind
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MOV R0,SP
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BX LR
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.fnend
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.size rt_get_PSP, .-rt_get_PSP
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/*--------------------------- _alloc_box ------------------------------------*/
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# void *_alloc_box (void *box_mem);
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/* Function wrapper for Unprivileged/Privileged mode. */
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.type _alloc_box, %function
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.global _alloc_box
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_alloc_box:
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.fnstart
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.cantunwind
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LDR R3,=rt_alloc_box
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MOV R12, R3
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MRS R3, CPSR
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AND R3, 0x1F
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CMP R3, 0x12 /* IRQ mode*/
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BNE PrivilegedA
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CMP R3, 0x1F /* System mode*/
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BNE PrivilegedA
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SVC 0
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BX LR
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PrivilegedA:
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BX R12
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.fnend
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.size _alloc_box, .-_alloc_box
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/*--------------------------- _free_box -------------------------------------*/
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# int _free_box (void *box_mem, void *box);
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/* Function wrapper for Unprivileged/Privileged mode. */
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.type _free_box, %function
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.global _free_box
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_free_box:
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.fnstart
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.cantunwind
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LDR R3,=rt_free_box
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MOV R12, R3
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MRS R3, CPSR
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AND R3, 0x1F
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CMP R3, 0x12 /* IRQ mode*/
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BNE PrivilegedA
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CMP R3, 0x1F /* System mode*/
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BNE PrivilegedA
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SVC 0
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BX LR
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PrivilegedF:
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BX R12
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.fnend
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.size _free_box, .-_free_box
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/*-------------------------- SVC_Handler ------------------------------------*/
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# void SVC_Handler (void);
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.type SVC_Handler, %function
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.global SVC_Handler
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SVC_Handler:
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.fnstart
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.cantunwind
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/* Within an IRQ ISR the link register has an offset from the true return
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address, but an SWI ISR does not. Add the offset manually so the same
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ISR return code can be used in both cases. */
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STMFD SP!, {R0,LR} /* Store registers. */
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ADD LR, LR, #4 /* Align LR with IRQ handler */
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SaveContext
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MOV R11, LR /* Save Task Stack Pointer */
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LDMFD SP!, {R0,LR} /* Restore registers and return. */
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STMFD SP!, {R11} /* Save Task Stack Pointer */
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LDR R5, [LR,#-4] /* Calculate address of SWI instruction and load it into r5. */
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BIC R5, R5,#0xff000000 /* Mask off top 8 bits of instruction to give SWI number. */
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CMP R5, #0
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BNE SVC_User /* User SVC Number > 0 */
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MOV LR, PC /* set LR to return address */
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BX R12 /* Call SVC Function */
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LDMFD SP!, {R11} /* Load Task Stack Pointer */
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STMIB R11!, {R0-R3} /* Store return values to Task stack */
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SVC_Exit:
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B RestoreContext /* return to the task */
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/*------------------- User SVC ------------------------------*/
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SVC_User:
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LDR R6,=SVC_Count
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LDR R6,[R6]
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CMP R5,R6
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LDMFDHI SP!, {R11}
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BHI SVC_Done /* Overflow */
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LDR R4,=SVC_Table - 4
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LSLS R5,R5,#2
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LDR R4,[R4,R5] /* Load SVC Function Address */
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/* R0-R3,R12 are unchanged */
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MOV LR, PC /* set LR to return address */
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BX R4 /* Call SVC Function */
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LDMFD SP!, {R11} /* Load Task Stack Pointer */
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BEQ SVC_Exit /* no need in return values */
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STMIB R11!, {R0-R3} /* Store return values to Task stack */
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SVC_Done:
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B RestoreContext /* return to the task */
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.fnend
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.size SVC_Handler, .-SVC_Handler
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/*-------------------------- IRQ_Handler ---------------------------------*/
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# void IRQ_Handler (void);
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.type IRQ_Handler, %function
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.global IRQ_Handler
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IRQ_Handler:
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.fnstart
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.cantunwind
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SaveContext
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MOV R0, #0xFFFFFF00
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LDR R0, [R0] /* Load address of raised IRQ handler*/
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MOV LR, PC
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BX R0
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MOV R0, #0xFFFFFF00
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STR R0, [R0] /* Clear interrupt */
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B RestoreContext
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.fnend
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.size IRQ_Handler, .-IRQ_Handler
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/*-------------------------- SysTick_Handler --------------------------------*/
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# void SysTick_Handler (void);
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.type SysTick_Handler, %function
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.global SysTick_Handler
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SysTick_Handler:
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.fnstart
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.cantunwind
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PUSH {LR}
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BL rt_systick
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POP {LR}
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BX LR /* return to IRQ handler */
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/*-------------------------- End --------------------------------*/
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.fnend
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.size SysTick_Handler, .-SysTick_Handler
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/*----------------------------------------------------------------------------
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* end of file
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*---------------------------------------------------------------------------*/
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.end
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