35 lines
1002 B
ArmAsm
35 lines
1002 B
ArmAsm
;/*****************************************************************************/
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; OSasm.s: low-level OS commands, written in assembly */
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; Runs on LM4F120/TM4C123/MSP432
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; Lab 3 starter file
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; March 2, 2016
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AREA |.text|, CODE, READONLY, ALIGN=2
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THUMB
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REQUIRE8
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PRESERVE8
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EXTERN RunPt ; currently running thread
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EXPORT StartOS
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EXPORT SysTick_Handler
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IMPORT Scheduler
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SysTick_Handler ; 1) Saves R0-R3,R12,LR,PC,PSR
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CPSID I ; 2) Prevent interrupt during switch
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;YOU IMPLEMENT THIS (same as Lab 2)
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CPSIE I ; 9) tasks run with interrupts enabled
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BX LR ; 10) restore R0-R3,R12,LR,PC,PSR
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StartOS
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;YOU IMPLEMENT THIS (same as Lab 2)
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CPSIE I ; Enable interrupts at processor level
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BX LR ; start first thread
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ALIGN
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END
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