Hi Allen,
On Wed, Aug 1, 2012 at 2:55 PM, Allen Martin amartin@nvidia.com 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 <amartin@nvidia.com<mailto:
amartin@nvidia.com>> 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 <amartin@nvidia.com<mailto:
amartin@nvidia.com>>
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