Mstop Stop Task - Texas Instruments TMS320F28004x Technical Reference Manual

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MSTOP
Stop Task
Operands
none
Opcode
LSW: 0000 0000 0000 0000
MSW: 0111 1111 1000 0000
The MSTOP instruction must be placed to indicate the end of each task. In addition,
Description
placing MSTOP in unused memory locations within the CLA program RAM can be useful
for debugging and preventing run away CLA code. When MSTOP enters the D2 phase
of the pipeline, the MIRUN flag for the task is cleared and the associated interrupt is
flagged in the PIE vector table.
There are three special cases that can occur when single-stepping a task such that the
MPC reaches the MSTOP instruction.
1. If you are single-stepping or halted in "task A" and "task B" comes in before the MPC
2. In this case you have single-stepped or halted in "task A" and the MPC has reached
3. Case 2 can be handled slightly differently if there is control over when "task B" comes
The MSTOP instruction cannot be placed 3 instructions before or after a MBCNDD,
Restrictions
MCCNDD
This instruction does not modify flags in the MSTF register.
Flags
Flag
Modified
This is a single-cycle instruction.
Pipeline
instruction. The MSTOP instruction cannot be placed with 3 instructions of a MBCNDD,
MCCNDD
SPRUI33 – November 4 2015 – Revised January 2017
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This instruction does not have any operands
reaches the MSTOP, then "task B" will start if you continue to step through the
MSTOP instruction. Basically if "task B" is pending before the MPC reaches MSTOP
in "task A" then there is no issue in "task B" starting and no special action is required.
the MSTOP with no tasks pending. If "task B" comes in at this point, it will be flagged
in the MIFR register but it may or may not start if you continue to single-step through
the MSTOP instruction of "task A". It depends on exactly when the new task comes
in. To reliably start "task B" perform a soft reset and reconfigure the MIER bits. Once
this is done, you can start single-stepping "task B".
in (for example using the IACK instruction to start the task). In this case you have
single-stepped or halted in "task A" and the MPC has reached the MSTOP with no
tasks pending. Before forcing "task B", run free to force the CLA out of the debug
state. Once this is done you can force "task B" and continue debugging.
or MRCNDD instruction.
TF ZF
No No
or MRCNDD instruction.
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NF LUF
No No
Table 4-22 shows the pipeline behavior of the MSTOP
Instruction Set
LVF
No
Control Law Accelerator (CLA)
689