1 files changed, 25 insertions, 0 deletions

diff --git a/meta/conf/machine/include/arm/feature-arm-thumb.inc b/meta/conf/machine/include/arm/feature-arm-thumb.inc
new file mode 100644
index 0000000000..fa3a4e5c1f
--- /dev/null
+++ b/meta/conf/machine/include/arm/feature-arm-thumb.inc
@@ -0,0 +1,25 @@
+# The instruction set the compiler should use when generating application
+# code. The kernel is always compiled with arm code at present. arm code
+# is the original 32 bit ARM instruction set, thumb code is the 16 bit
+# encoded RISC sub-set. Thumb code is smaller (maybe 70% of the ARM size)
+# but requires more instructions (140% for 70% smaller code) so may be
+# slower.
+TUNEVALID[thumb] = "Use thumb instructions instead of ARM"
+ARM_THUMB_M_OPT = "${@['-marm', '-mthumb'][d.getVar('ARM_INSTRUCTION_SET', True) == 'thumb']}"
+TUNE_CCARGS .= "${@bb.utils.contains("TUNE_FEATURES", "thumb", " ${ARM_THUMB_M_OPT}", "", d)}"
+OVERRIDES .= "${@bb.utils.contains("TUNE_FEATURES", "thumb", ":thumb", "", d)}"
+
+ARMPKGSFX_THUMB .= "${@bb.utils.contains("TUNE_FEATURES", [ "armv4", "thumb" ], "t", "", d)}"
+ARMPKGSFX_THUMB .= "${@bb.utils.contains("TUNE_FEATURES", [ "armv5", "thumb" ], "t", "", d)}"
+ARMPKGSFX_THUMB .= "${@bb.utils.contains("TUNE_FEATURES", [ "armv6", "thumb" ], "t", "", d)}"
+ARMPKGSFX_THUMB .= "${@bb.utils.contains("TUNE_FEATURES", [ "armv7a", "thumb" ], "t2", "", d)}"
+
+# Whether to compile with code to allow interworking between the two
+# instruction sets. This allows thumb code to be executed on a primarily
+# arm system and vice versa. It is strongly recommended that DISTROs not
+# turn this off - the actual cost is very small.
+TUNEVALID[no-thumb-interwork] = "Disable mixing of thumb and ARM functions"
+TUNE_CCARGS .= "${@bb.utils.contains("TUNE_FEATURES", "no-thumb-interwork", " -mno-thumb-interwork", " -mthumb-interwork", d)}"
+OVERRIDES .= "${@bb.utils.contains("TUNE_FEATURES", "no-thumb-interwork", ":thumb-interwork", "", d)}"
+
+TARGET_CC_KERNEL_ARCH += "-mno-thumb-interwork -marm"