Arm semihosting v2 implementation isn't complete

[Tamar Christina]

Hi Alex

> -----Original Message-----
> From: newlib-owner@sourceware.org <newlib-owner@sourceware.org> On
> Behalf Of Alexander Fedotov
> Sent: Tuesday, December 18, 2018 13:08
> To: Newlib <newlib@sourceware.org>
> Subject: Arm semihosting v2 implementation isn't complete
> 
> Hi all
> 
> I see that number of commits were dedicated to changes for Arm
> Semihosting v2 specification that states:
> ARM encourages semihosting callers to implement support for trapping using
> HLT on A32 and T32 as a configurable option. ARM strongly discourages
> semihosting callers from mixing the HLT and SVC mechanisms within the
> same executable.
> 
> At the moment there is no HLT instruction used in libgloss/arm.

There is, see swi.h, we don't support mixing of HLT and SVC (as mentioned in the specification bit you quoted) so they are in different libraries.
HLT is used when you used the MIXED_MODE spec files. E.g. aprofile-validation-v2m.specs will use HLT and aprofile-validation.specs uses SVC.

Regards,
Tamar

> 
> So the question is: is there any reason to not have HLT right now ?
> 
> Alex