FreeRTOS-Kernel/portable/IAR/ARM_CA9/portASM.h

; /*
   * ; * FreeRTOS Kernel V10.3.1
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   * ; * 1 tab == 4 spaces!
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EXTERN vTaskSwitchContext
EXTERN ulCriticalNesting
EXTERN pxCurrentTCB
EXTERN ulPortTaskHasFPUContext
EXTERN ulAsmAPIPriorityMask

portSAVE_CONTEXT macro

;
Save the LR and SPSR onto the system mode stack before switching to
;
system mode to save the remaining system mode registers
SRSDB sp !, # SYS_MODE
      CPS     # SYS_MODE
      PUSH    { R0 - R12, R14 }

;
Push the critical nesting count
LDR R2, = ulCriticalNesting
          LDR R1, [ R2 ]
PUSH    { R1 }

;
Does the task have a floating point context that needs saving ? If
;
ulPortTaskHasFPUContext is 0 then no.
   LDR R2, = ulPortTaskHasFPUContext
             LDR R3, [ R2 ]
CMP R3, # 0

;
Save the floating point context, if any
FMRXNE R1, FPSCR
                        VPUSHNE { D0 - D15 }
VPUSHNE { D16 - D31 }
PUSHNE  { R1 }

;
Save ulPortTaskHasFPUContext itself
    PUSH    { R3 }

;
Save the stack pointer in the TCB
LDR R0, = pxCurrentTCB
          LDR R1, [ R0 ]
STR SP, [ R1 ]

endm

; /**********************************************************************/

portRESTORE_CONTEXT macro

;
Set the SP to point to the stack of the task being restored.
   LDR R0, = pxCurrentTCB
             LDR R1, [ R0 ]
LDR SP, [ R1 ]

;
Is there a floating point context to restore ? If the restored
;
ulPortTaskHasFPUContext is zero then no.
   LDR R0, = ulPortTaskHasFPUContext
             POP     { R1 }
STR R1, [ R0 ]
CMP R1, # 0

;
Restore the floating point context, if any
                           POPNE   { R0 }
VPOPNE  { D16 - D31 }
VPOPNE  { D0 - D15 }
VMSRNE FPSCR, R0

;
Restore the critical section nesting depth
LDR R0, = ulCriticalNesting
          POP     { R1 }
STR R1, [ R0 ]

;
Ensure the priority mask is correct for the critical nesting depth
LDR R2, = portICCPMR_PRIORITY_MASK_REGISTER_ADDRESS
          CMP R1, # 0
MOVEQ R4, # 255
LDRNE R4, = ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT )
            STR R4, [ r2 ]

;
Restore all system mode registers other than the SP( which is already
                                                     ;
                                                     being used )
POP
{
    R0 - R12, R14
}

Return to the task code, loading CPSR on the way.
   RFEIA sp !

endm