Hi Allen, On Wed, Aug 1, 2012 at 2:55 PM, Allen Martin <[email protected]> wrote:
> On Wed, Aug 01, 2012 at 02:11:48PM -0700, V, Aneesh wrote: > > Hi Allen, > > > > On Wed, Aug 1, 2012 at 1:32 PM, Allen Martin <[email protected]<mailto: > [email protected]>> wrote: > > If CONFIG_SYS_THUMB_BUILD is enabled, use thumb interworking return > > instructions from libgcc routines, otherwise use ARM returns. > > > > Signed-off-by: Allen Martin <[email protected]<mailto: > [email protected]>> > > --- > > arch/arm/include/asm/assembler.h | 10 ++++++++++ > > arch/arm/lib/_ashldi3.S | 3 ++- > > arch/arm/lib/_ashrdi3.S | 3 ++- > > arch/arm/lib/_divsi3.S | 15 +++++++++++---- > > arch/arm/lib/_lshrdi3.S | 3 ++- > > arch/arm/lib/_modsi3.S | 9 ++++++++- > > arch/arm/lib/_udivsi3.S | 8 +++++--- > > arch/arm/lib/_umodsi3.S | 18 +++++++++++++++++- > > arch/arm/lib/memcpy.S | 10 ++++++++++ > > arch/arm/lib/memset.S | 3 ++- > > 10 files changed, 69 insertions(+), 13 deletions(-) > > > > diff --git a/arch/arm/include/asm/assembler.h > b/arch/arm/include/asm/assembler.h > > index 5e4789b..25ece01 100644 > > --- a/arch/arm/include/asm/assembler.h > > +++ b/arch/arm/include/asm/assembler.h > > @@ -13,6 +13,7 @@ > > * Do not include any C declarations in this file - it is included by > > * assembler source. > > */ > > +#include <config.h> > > > > /* > > * Endian independent macros for shifting bytes within registers. > > @@ -58,3 +59,12 @@ > > * Cache alligned > > */ > > #define CALGN(code...) code > > + > > +/* > > + * return instruction > > + */ > > +#ifdef CONFIG_SYS_THUMB_BUILD > > +#define RET bx lr > > +#else > > +#define RET mov pc, lr > > > > Why not "bx lr" in all cases? In that case you can just replace all the > instances of > > "mov pc, lr" directly by "bx lr" instead of this macro. That looks > cleaner to me. > > I didn't want to break any older ARM architectures that don't support the > bx instruction but use this code. > > Which is earlier than armv4t, right? On quick look it didn't seem there is anything older than that in u-boot. But yes, it's perhaps better to be safe. > > > BTW, as far as I remember when I did this originally my compiler was > compiling > > all assembly functions in ARM and it was automatically converting "mov > pc, lr" to > > "bx lr" ,where necessary. Maybe that was just my compiler and I don't > remember > > the details now. Did you really face any issue with "mov pc, lr" making > wrong jumps? > > Yes, without this change if I disassemble the code I'm seeing it's > still a mov instruction and it hangs. > > Ok. br, Aneesh
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