[Bug c/43102] New: ARM V6 (Cortex-M1) Unable to jump from assembly to C code while debuging.

[Bug c/43102] New: ARM V6 (Cortex-M1) Unable to jump from assembly to C code while debuging.

[josiejoppen at gmail dot com]

The "bl <imm>" instruction from the assembly to a function written in 'C
language', generates an exception.

Unable to proceed..

tried all other options. 
guess this is with the compiler,


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           Summary: ARM V6 (Cortex-M1) Unable to jump from assembly to C
                    code while debuging.
           Product: gcc
           Version: 4.4.1
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: josiejoppen at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43102

[Bug target/43102] ARM V6 (Cortex-M1) Unable to jump from assembly to C code while debuging.

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2010-02-17 04:43 -------
Isn't the M1 a thumb2 only target or is it a combo thumb2/arm target?  If it is
the later, are you sure that you don't want blx instead?


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pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|major                       |normal
          Component|c                           |target


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43102

[Bug target/43102] ARM V6 (Cortex-M1) Unable to jump from assembly to C code while debuging.

[rearnsha at gcc dot gnu dot org]

------- Comment #2 from rearnsha at gcc dot gnu dot org  2010-02-17 10:09 -------
Pinskia: The M1 is best thought of as a thumb1 only processor, blx is for
jumping across instruction sets.

We need a testcase that demonstrates this problem, without one we can't help.


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rearnsha at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43102

[Bug target/43102] ARM V6 (Cortex-M1) Unable to jump from assembly to C code while debuging.

[josiejoppen at gmail dot com]

------- Comment #3 from josiejoppen at gmail dot com  2010-02-17 14:00 -------
the cortex m1 is a thumb2 only target. Also the command "BLX #imm" is not
supported under ARM V6 arch. Now as a case history, I can tell the following.
Initially i had trouble getting into interrupts. i found that the functions
were running in assembly, at that time when interrupt comes; they are not able
to jump to an ISR written in "C". so i wrote the ISRs in assembly. that came
out well. later the application became bigger, now it does not branch across
functions. 
this happens for a bigger piece of code only. if the code is kept small, i dont
find this. i checked the added codes seperately. as a small app..


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43102