How to add NEON assembly and intrinsic code on DM8148

SEUNGSIK KWAK

Hi all.

I'm planing to use neon assembly and intrinsic code to do extra work such as memory copy and color space conversion to YUV420 planar on DM8148 EZSDK 5.03.01.15. For the testing, I copied memcpy_neon.S(memcpy-neon.tar.gz) into OMX decoder(~/ti-ezsdk_dm814x-evm_5_03_01_15/component-sources/omx_05_02_00_30/examples/ti/omx/demos/decode) and made some change on makefile such adding source code and flag(-mcpu=cortex-a8 -mfpu=neon -mfloat-abi=softfp ) but I got a complain from compiler like below.

If I use mempcy_neon.S, I got a something like below.

~/ti-ezsdk_dm814x-evm_5_03_01_15/component-sources/omx_05_02_00_30/makerules/rules_a8.mk:76: target `src/memcpy_neon.S' doesn't match the target pattern

So, If I changed it to memcpy_neon.c, the result looks like below.

./src/memcpy_neon.c:25: error: expected identifier or '(' before '.' token
./src/memcpy_neon.c:34: error: stray '#' in program
./src/memcpy_neon.c:35:7: error: invalid suffix "f" on integer constant
./src/memcpy_neon.c:39: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'r2'
./src/memcpy_neon.c:39: error: stray '#' in program
./src/memcpy_neon.c:40:7: error: invalid suffix "f" on integer constant
./src/memcpy_neon.c:41: error: stray '#' in program
./src/memcpy_neon.c:42: error: stray '#' in program
./src/memcpy_neon.c:43: error: stray '#' in program
./src/memcpy_neon.c:44: error: stray '#' in program
./src/memcpy_neon.c:45: error: stray '#' in program
./src/memcpy_neon.c:46:7: error: invalid suffix "b" on integer constant
./src/memcpy_neon.c:47: error: stray '#' in program

...

Also, I found a one interesting thing is that the "rules_a8.mk" has a armv5t flag such as "CFLAGS_INTERNAL = -fPIC -fno-strict-aliasing -MD -MF $(DEPFILE).P -march=armv5t -Dfar= -D_DEBUG_=1 -DMULTICHANNEL_OPT=1".

I think that it is supposed to be something like "march=armv7-a" but I'm not sure. If anyone has an idea or information regarding how to get it working, please let me know.

Regards,

SK

over 13 years ago

0 Anand Balagopalakrishnan over 13 years ago

TI__Expert 5130 points

To build with Neon assembly code, you should use the following compiler flags:

-march=armv7-a -mtune=cortex-a8 -mfpu=neon -mfloat-abi=softfp

For best results, you should handcode Neon assembly routines.

0 SEUNGSIK KWAK over 13 years ago in reply to Anand Balagopalakrishnan

Intellectual 590 points

Hi Anand,

Thank you for the response. I think that my question was not clear. Basically, I got neon module being compiled and working. What I have replaced is memcpy to neon memcpy which has been written in assembly code. Long story short, the assembly code is compiled on command line like arm-none-linux-gnueabi-gcc -I. -O2 -mcpu=cortex-a8 -mfpu=neon -mfloat-abi=softfp -c ./src/memcpy_neon.S then add the obejct file into Makefile like below. I'm using OMX decode demo application.

EXTLIBS_a8host = $(omx_LIBPATH)/../lib/omxcore.av5T \
                 $(omx_LIBPATH)/../lib/memcfg.av5T                     \
                 $(omx_LIBPATH)/../lib/domx.av5T           \
                 $(omx_LIBPATH)/../lib/domx_delegates_shmem.av5T       \
                 $(omx_LIBPATH)/../lib/timmosal.av5T \
                 $(omx_LIBPATH)/../lib/omxcfg.av5T         \
                 $(osal_PATH)/packages/linuxdist/build/lib/osal.a \
                 $(osal_PATH)/packages/linuxdist/cstubs/lib/cstubs.a \
                 $(fc_PATH)/packages/ti/sdo/rcm/lib/debug/rcm_syslink.av5T \
                 $(fc_PATH)/packages/ti/sdo/fc/memutils/lib/release/memutils.av5T \
                 $(osal_PATH)/packages/ti/sdo/xdcruntime/linux/lib/debug/osal_linux_470.av5T \
                 $(fc_PATH)/packages/ti/sdo/fc/global/lib/debug/fcsettings.av5T \
                 $(syslink_PATH)/packages/ti/syslink/lib/syslink.a_debug \
                 $(linuxutils_PATH)/packages/ti/sdo/linuxutils/cmem/lib/cmem.a470MV \
                 $(uia_PATH)/packages/ti/uia/linux/lib/servicemgr.a \
				./memcpy_neon.o

If I added the compile flag( -mcpu=cortex-a8 -mfpu=neon -mfloat-abi=softfp) to makefile, it doesn't work.

Best Regards,

SK.

0 Daniel70334 over 13 years ago in reply to Anand Balagopalakrishnan

Expert 1745 points

Anand,

Can I clarify something? http://processors.wiki.ti.com/index.php/Cortex-A8 says that Neon auto vectorization compiler directives are:

-march=armv7-a -mtune=cortex-a8 -mfpu=neon -ftree-vectorize -ffast-math -mfloat-abi=softfp

But in your post, you do not specify "-mfpu=neon -ftree-vectorize". Are these necessary?

Also, is it important to specify -O3 for gcc toolchains? In previous projects, we have tended to set things to -Os ...

Thanks,

Dan -

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How to add NEON assembly and intrinsic code on DM8148