[U-Boot] [RFC PATCH 1/2] armv7: enable Thumb build for armv7
Aneesh V
aneesh at ti.com
Mon Mar 14 14:27:37 CET 2011
Signed-off-by: Aneesh V <aneesh at ti.com>
---
README | 9 +++++++++
arch/arm/cpu/armv7/config.mk | 5 +++++
2 files changed, 14 insertions(+), 0 deletions(-)
diff --git a/README b/README
index f1547a4..ff3a345 100644
--- a/README
+++ b/README
@@ -370,6 +370,15 @@ The following options need to be configured:
2. The core frequency as calculated above is multiplied
by this value.
+- 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/cpu/armv7/config.mk b/arch/arm/cpu/armv7/config.mk
index 49ac9c7..b7bebad 100644
--- a/arch/arm/cpu/armv7/config.mk
+++ b/arch/arm/cpu/armv7/config.mk
@@ -31,3 +31,8 @@ PLATFORM_CPPFLAGS += -march=armv5
# =========================================================================
PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,\
$(call cc-option,-malignment-traps,))
+
+ifeq ($(CONFIG_SYS_THUMB_BUILD),y)
+# Enable Thumb mode build if compiler supports it
+PLATFORM_CPPFLAGS += $(call cc-option,-mthumb -mthumb-interwork)
+endif
--
1.7.0.4
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