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79 lines
1.7 KiB
C
79 lines
1.7 KiB
C
EXTERN pxCurrentTCB
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EXTERN ulCriticalNesting
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; Context save and restore macro definitions
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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portSAVE_CONTEXT MACRO
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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 point to the task stack pointer.
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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 return address onto the 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-LR}^
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NOP
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SUB LR, LR, #60
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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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LDR R0, =ulCriticalNesting
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LDR R0, [R0]
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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 R1, =pxCurrentTCB
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LDR R0, [R1]
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STR LR, [R0]
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ENDM
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portRESTORE_CONTEXT MACRO
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; Set the LR to the task stack.
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LDR R1, =pxCurrentTCB
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LDR R0, [R1]
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LDR LR, [R0]
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; The critical nesting depth is the first item on the stack.
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; Load it into the ulCriticalNesting variable.
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LDR R0, =ulCriticalNesting
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LDMFD LR!, {R1}
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STR R1, [R0]
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; Get the SPSR from the stack.
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LDMFD LR!, {R0}
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MSR SPSR_cxsf, R0
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; Restore all system mode registers for the task.
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LDMFD LR, {R0-R14}^
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NOP
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; Restore the return address.
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LDR LR, [LR, #+60]
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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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ENDM
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