begriffs open source - cmsis-freertos/blob - Source/portable/RVDS/ARM7

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54

55 IMPORT ulCriticalNesting ;

56 IMPORT pxCurrentTCB ;

57

58

59 MACRO

60 portRESTORE_CONTEXT

61

62

63 LDR R0, =pxCurrentTCB ; Set the LR to the task stack. The location was...

64 LDR R0, [R0] ; ... stored in pxCurrentTCB

65 LDR LR, [R0]

66

67 LDR R0, =ulCriticalNesting ; The critical nesting depth is the first item on...

68 LDMFD LR!, {R1} ; ...the stack. Load it into the ulCriticalNesting var.

69 STR R1, [R0] ;

70

71 LDMFD LR!, {R0} ; Get the SPSR from the stack.

72 MSR SPSR_cxsf, R0 ;

73

74 LDMFD LR, {R0-R14}^ ; Restore all system mode registers for the task.

75 NOP ;

76

77 LDR LR, [LR, #+60] ; Restore the return address

78

79 ; And return - correcting the offset in the LR to obtain ...

80 SUBS PC, LR, #4 ; ...the correct address.

81

82 MEND

83

84 ; /**********************************************************************/

85

86 MACRO

87 portSAVE_CONTEXT

88

89

90 STMDB SP!, {R0} ; Store R0 first as we need to use it.

91

92 STMDB SP,{SP}^ ; Set R0 to point to the task stack pointer.

93 NOP ;

94 SUB SP, SP, #4 ;

95 LDMIA SP!,{R0} ;

96

97 STMDB R0!, {LR} ; Push the return address onto the stack.

98 MOV LR, R0 ; Now we have saved LR we can use it instead of R0.

99 LDMIA SP!, {R0} ; Pop R0 so we can save it onto the system mode stack.

100

101 STMDB LR,{R0-LR}^ ; Push all the system mode registers onto the task stack.

102 NOP ;

103 SUB LR, LR, #60 ;

104

105 MRS R0, SPSR ; Push the SPSR onto the task stack.

106 STMDB LR!, {R0} ;

107

108 LDR R0, =ulCriticalNesting ;

109 LDR R0, [R0] ;

110 STMDB LR!, {R0} ;

111

112 LDR R0, =pxCurrentTCB ; Store the new top of stack for the task.

113 LDR R1, [R0] ;

114 STR LR, [R1] ;

115

116 MEND

117

118 END