Enabling Semihosting In J-Link Rdi + Axd - Segger J-Link User Manual

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19.6 Enabling Semihosting in J-Link RDI + AXD

This semihosting mechanism can be disabled or changed by the following debugger
internal variables:
$semihosting_enabled
Set this variable to 0 to disable semihosting. If you are debugging an application run-
ning from ROM, this allows you to use an additional watchpoint unit.
Set this variable to 1 to enable semihosting. This is the default.
Set this variable to 2 to enable Debug Communications Channel (DCC) semihosting.
The S bit in $vector_catch has no effect unless semihosting is disabled.
$semihosting_vector
This variable controls the location of the breakpoint set by J-Link RDI to detect a
semihosted SWI. It is set to the SWI entry in the exception vector table () by default.
19.6.0.1 Using SWIs in your application
If your application requires semihosting as well as having its own SWI handler, set
$semihosting_vector to an address in your SWI handler. This address must point to
an instruction that is only executed if your SWI handler has identified a call to a
semihosting SWI. All registers must already have been restored to whatever values
they had on entry to your SWI handler.
J-Link / J-Trace (UM08001)
CHAPTER 19
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Semihosting