[U-Boot] [PATCH v2 8/9] arm: use thumb interworking returns in libgcc

[Allen Martin]

On Wed, Aug 01, 2012 at 03:15:45PM -0700, V, Aneesh wrote:
> > 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.

Yes, in particular bx is available in armv4t but not armv4, and there
are architectures being compiled -march=armv4 in u-boot:

$ grep march arch/arm/cpu/*/config.mk
arch/arm/cpu/arm1136/config.mk:PLATFORM_CPPFLAGS += -march=armv5
arch/arm/cpu/arm1176/config.mk:PLATFORM_CPPFLAGS += -march=armv5t
arch/arm/cpu/arm720t/config.mk:PLATFORM_CPPFLAGS += -march=armv4
-mtune=arm7tdmi
arch/arm/cpu/arm920t/config.mk:PLATFORM_CPPFLAGS += -march=armv4
arch/arm/cpu/arm925t/config.mk:PLATFORM_CPPFLAGS += -march=armv4
arch/arm/cpu/arm926ejs/config.mk:PLATFORM_CPPFLAGS += -march=armv5te
arch/arm/cpu/arm946es/config.mk:PLATFORM_CPPFLAGS +=  -march=armv4
arch/arm/cpu/arm_intcm/config.mk:PLATFORM_CPPFLAGS +=  -march=armv4
arch/arm/cpu/armv7/config.mk:PF_CPPFLAGS_ARMV7 := $(call cc-option,
-march=armv7-a, -march=armv5)
arch/arm/cpu/ixp/config.mk:PLATFORM_CPPFLAGS += -mbig-endian
-march=armv5te -mtune=strongarm1100
arch/arm/cpu/lh7a40x/config.mk:PLATFORM_CPPFLAGS += -march=armv4
arch/arm/cpu/pxa/config.mk:PLATFORM_CPPFLAGS += -march=armv5te
-mtune=xscale
arch/arm/cpu/s3c44b0/config.mk:PLATFORM_CPPFLAGS += -march=armv4
-mtune=arm7tdmi -msoft-float
arch/arm/cpu/sa1100/config.mk:PLATFORM_CPPFLAGS += -march=armv4
-mtune=strongarm1100

Probably some of these are actually armv4t, but I don't want to touch
them :^)

-Allen
-- 
nvpublic