From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aneesh V Date: Mon, 6 Feb 2012 17:07:25 +0530 Subject: [U-Boot] [RFC PATCH 1/4] ARM: enable Thumb build In-Reply-To: <1328528248-20872-1-git-send-email-aneesh@ti.com> References: <1328528248-20872-1-git-send-email-aneesh@ti.com> Message-ID: <1328528248-20872-2-git-send-email-aneesh@ti.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Enable Thumb build and ARM-Thumb interworking based on the new config flag CONFIG_SYS_THUMB_BUILD Signed-off-by: Aneesh V --- README | 9 +++++++++ arch/arm/config.mk | 29 +++++++++++++++++------------ 2 files changed, 26 insertions(+), 12 deletions(-) diff --git a/README b/README index 9d713e8..dfe7fb3 100644 --- a/README +++ b/README @@ -420,6 +420,15 @@ The following options need to be configured: XWAY SoCs for booting from NOR flash. The U-Boot image needs to be swapped if a flash programmer is used. +- ARM Options: + CONFIG_SYS_THUMB_BUILD + + Use this flag to build U-Boot using the Thumb instruction + set for ARM architectures. Thumb instruction set provides + better code density. For ARM architectures that support + Thumb2 this flag will result in Thumb2 code generated by + GCC. + - Linux Kernel Interface: CONFIG_CLOCKS_IN_MHZ diff --git a/arch/arm/config.mk b/arch/arm/config.mk index 45f9dca..9a450d7 100644 --- a/arch/arm/config.mk +++ b/arch/arm/config.mk @@ -33,26 +33,31 @@ endif PLATFORM_CPPFLAGS += -DCONFIG_ARM -D__ARM__ -# Explicitly specifiy 32-bit ARM ISA since toolchain default can be -mthumb: -PF_CPPFLAGS_ARM := $(call cc-option,-marm,) +# Choose between ARM/Thumb instruction sets +ifeq ($(CONFIG_SYS_THUMB_BUILD),y) +PF_CPPFLAGS_ARM += $(call cc-option, -mthumb -mthumb-interwork, \ + -marm -mno-thumb-interwork) +else +PF_CPPFLAGS_ARM += $(call cc-option, -marm -mno-thumb-interwork) +endif # Try if EABI is supported, else fall back to old API, # i. e. for example: # - with ELDK 4.2 (EABI supported), use: -# -mabi=aapcs-linux -mno-thumb-interwork +# -mabi=aapcs-linux # - with ELDK 4.1 (gcc 4.x, no EABI), use: -# -mabi=apcs-gnu -mno-thumb-interwork +# -mabi=apcs-gnu # - with ELDK 3.1 (gcc 3.x), use: -# -mapcs-32 -mno-thumb-interwork -PF_CPPFLAGS_ABI := $(call cc-option,\ - -mabi=aapcs-linux -mno-thumb-interwork,\ - $(call cc-option,\ - -mapcs-32,\ +# -mapcs-32 +PLATFORM_CPPFLAGS += $(call cc-option,\ + -mabi=aapcs-linux,\ $(call cc-option,\ - -mabi=apcs-gnu,\ + -mapcs-32,\ + $(call cc-option,\ + -mabi=apcs-gnu,\ + )\ )\ - ) $(call cc-option,-mno-thumb-interwork,)\ - ) + ) PLATFORM_CPPFLAGS += $(PF_CPPFLAGS_ARM) $(PF_CPPFLAGS_ABI) # For EABI, make sure to provide raise() -- 1.7.1