ST20-GP6 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST20-GP6

GPS PROCESSOR

STMicroelectronics 

ST20-GP6

4.6.5 Restrictions on trap handlers

There are various restrictions that must be placed on trap handlers to ensure that they work cor-

rectly.

1 Trap handlers must not deschedule or timeslice. Trap handlers alter the Enables masks,

therefore they must not allow other processes to execute until they have completed.

2 Trap handlers must have their Enable masks set to mask all traps in their trap group to

avoid the possibility of a trap handler trapping to itself.

3 Trap handlers must terminate via the tret (trap return) instruction. The only exception to this

is that a scheduler kernel may use restart to return to a previously shadowed process.

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