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105 lines
2.0 KiB
ArmAsm
105 lines
2.0 KiB
ArmAsm
17 years ago
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.extern pxCurrentTCB
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.extern vTaskSwitchContext
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.global vStartFirstTask
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.global vPortYield
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.set portCONTEXT_SIZE, 156
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.set portR0_OFFSET, 152
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.set portGPR_OFFSET, 32
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.set portCR_OFFSET, 28
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.set portXER_OFFSET, 24
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.set portLR_OFFSET, 20
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.set portCTR_OFFSET, 16
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.set portUSPRG0_OFFSET, 12
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.set portSRR0_OFFSET, 8
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.set portSRR1_OFFSET, 4
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.macro portRESTORE_CONTEXT
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# Get the address of the TCB.
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xor R0, R0, R0
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addis SP, R0, pxCurrentTCB@ha
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lwz SP, pxCurrentTCB@l( SP )
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# Get the task stack pointer from the TCB.
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lwz SP, 0( SP )
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# Pop the special purpose registers
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lwz R0, portSRR1_OFFSET( SP )
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mtspr SRR1, R0
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lwz R0, portSRR0_OFFSET( SP )
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mtspr SRR0, R0
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lwz R0, portUSPRG0_OFFSET( SP )
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mtspr 256, R0 #USPRG0
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lwz R0, portCTR_OFFSET( SP )
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mtspr CTR, R0
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lwz R0, portLR_OFFSET( SP )
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mtspr LR, R0
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lwz R0, portXER_OFFSET( SP )
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mtspr XER, R0
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lwz R0, portCR_OFFSET( SP )
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mtcr R0
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# Pop GPRs
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lmw R2, portGPR_OFFSET( SP )
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# Finally pop R0 and correct the stack pointer
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lwz R0, portR0_OFFSET( SP )
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addi R1, R1, portCONTEXT_SIZE
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# Start the task running
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rfi
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.endm
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.macro portSAVE_CONTEXT
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# Make room on the stack.
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subi R1, R1, portCONTEXT_SIZE
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# Push R0, then the GPRs
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stw R0, portR0_OFFSET( SP )
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stm R2, portGPR_OFFSET( SP )
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# Push the SFRs
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mfcr R0
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stw R0, portCR_OFFSET( SP )
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mfspr R0, XER
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stw R0, portXER_OFFSET( SP )
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mfspr R0, LR
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stw R0, portLR_OFFSET( SP )
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mfspr R0, CTR
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stw R0, portCTR_OFFSET( SP )
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mfspr R0, 256 #USPRG0
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stw R0, portUSPRG0_OFFSET( SP )
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mfspr R0, SRR0
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stw R0, portSRR0_OFFSET( SP )
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mfspr R0, SRR1
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stw R0, portSRR1_OFFSET( SP )
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# Get the address of the TCB.
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xor R0, R0, R0
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addis R2, R0, pxCurrentTCB@ha
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lwz R2, pxCurrentTCB@l( R2 )
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# Store the stack pointer into the TCB
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stw SP, 0( R2 )
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.endm
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vStartFirstTask:
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portRESTORE_CONTEXT
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rfi
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vPortYield:
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portSAVE_CONTEXT
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bl vTaskSwitchContext
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portRESTORE_CONTEXT
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NOP
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NOP
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