Re: Arm semihosting v2 implementation isn't complete

[Tamar Christina <Tamar dot Christina at arm dot com>]

Hi Alexander,

 #ifdef THUMB_VXM
   #define AngelSWIInsn			"bkpt"
   #define AngelSWIAsm			bkpt
+#elif defined (SEMIHOST_V2) && (__ARM_ARCH == 8)

You'll want to use the same condition as the reason number setting code above,

#if defined (SEMIHOST_V2) && defined (SEMIHOST_V2_MIXED_MODE)

As we only want to use hlt in the mixed mode and not always.
The Armv8 check isn't needed due to the note in the specification
"Note: This requirement includes supporting the HLT encodings on ARMv7 and earlier processors, even though HLT
is only defined as an instruction in ARMv8."

So we just generate all the multilibs and leave it up to the implementations to support it or not.

Thanks,
Tamar

+  #define AngelSWIInsn			"hlt"
+  #define AngelSWIAsm			hlt
 #else
   #define AngelSWIInsn			"swi"
   #define AngelSWIAsm			swi
-- 


The 12/18/2018 15:09, Alexander Fedotov wrote:
> I suggest following patch:
> 
> On Tue, Dec 18, 2018 at 5:12 PM Alexander Fedotov <alfedotov@gmail.com> wrote:
> >
> > Hi Tamar
> >
> > I see HLT only in comments, not in defines:
> >
> > #ifdef THUMB_VXM
> >   #define AngelSWIInsn            "bkpt"
> >   #define AngelSWIAsm            bkpt
> > #else
> >   #define AngelSWIInsn            "swi"
> >   #define AngelSWIAsm            swi
> > #endif
> >
> >
> > On Tue, Dec 18, 2018 at 4:50 PM Tamar Christina <Tamar.Christina@arm.com> wrote:
> > >
> > > 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
> >
> >
> >
> > --
> > Best regards,
> > AF
> 
> 
> 
> -- 
> Best regards,
> AF



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