[OpenWrt-Devel] [RFC PATCH] ARM Cortex-A9: build the userspace with Thumb-2 instructions

Rui Salvaterra rsalvaterra at gmail.com
Fri Jun 19 05:45:25 EDT 2020

Thumb-2 code is denser than pure ARM, reducing RAM usage and improving
performance due to better instruction cache footprint.

There's no reason for not enabling this feature on other ARMv7 targets
(cortex-a7 and cortex-a8), but I don't have the hardware to test it.

Signed-off-by: Rui Salvaterra <rsalvaterra at gmail.com>
 include/target.mk | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/target.mk b/include/target.mk
index a2ceb7f783..dfc6f4e480 100644
--- a/include/target.mk
+++ b/include/target.mk
@@ -196,6 +196,9 @@ ifeq ($(DUMP),1)
     CPU_TYPE = sparc
     CPU_CFLAGS_ultrasparc = -mcpu=ultrasparc
+  ifeq ($(ARCH),arm)
+    CPU_CFLAGS_cortex-a9 = -mthumb
+  endif
   ifeq ($(ARCH),aarch64)
     CPU_TYPE ?= generic
     CPU_CFLAGS_generic = -mcpu=generic

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