[Bug other/58133] New: GCC should emit arm assembly following the unified syntax

[Bug other/58133] New: GCC should emit arm assembly following the unified syntax

[sven.koehler at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58133

            Bug ID: 58133
           Summary: GCC should emit arm assembly following the unified
                    syntax
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sven.koehler at gmail dot com

I'm not aware of any command line switch to make gcc generate unified syntax.
The asm code that gcc generated in thumb mode follows the old devided syntax.
All documentation by Atmel these days is about the unified syntax. Also,
binutils has decided to disassemble to unified syntax by default.

A code example and how to reproduce the issue is given below.

Command:
arm-softfloat-eabi-gcc -mcpu=arm7tdmi -O2 -mthumb -S -o - foo.c

Contents of foo.c:
int main() { return 0; }

Generated Assembly (devided syntax):
main:
    mov    r0, #0
    bx    lr

Disassembly (unified syntax):
00000000 <main>:
   0:    2000          movs    r0, #0
   2:    4770          bx    lr

According to the documentation, mov r0,#0 is not a valid 16bit command.
The documentation however assumes the unified syntax.
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0489i/Cihcdbca.html


It might be argued that the transition from classic to unified syntax is to
error-prone or too much work. For me, it causes some trouble. I will have to
switch between unified syntax and devided syntax in inline assembly since gcc
uses devided and clang uses unified syntax.

[Bug other/58133] GCC should emit arm assembly following the unified syntax

[sven.koehler at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58133

--- Comment #1 from Sven <sven.koehler at gmail dot com> ---
It seems, that for targets like -mcpu=cortex-m4 the gcc does generate unified
syntax. So is the unified syntax only used for newer targets that use the
thumb2 instruction set whereas the divided syntax is used for older thumb1
targets?

[Bug other/58133] GCC should emit arm assembly following the unified syntax

[rearnsha at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58133

Richard Earnshaw <rearnsha at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |arm
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-08-19
     Ever confirmed|0                           |1

--- Comment #2 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
Unified syntax is currently only supported for ARM and Thumb2 stated (for the
latter it's mandatory).  Thumb1, for historical reasons, still uses the old
syntax.

This is a known issue.

[Bug other/58133] GCC should emit arm assembly following the unified syntax

[sven.koehler at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58133

--- Comment #3 from Sven <sven.koehler at gmail dot com> ---
(In reply to Richard Earnshaw from comment #2)
> This is a known issue.

So what needs to be done? Where do I find the source/configuration/whatever of
the code generator for thumb mode?

[Bug other/58133] GCC should emit arm assembly following the unified syntax

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58133

--- Comment #5 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
Oh and Kyrylo fixed up vfp.md last year too. So it's only ARM state that
remains. I have a few patches in flight that I'm testing.