On Fri, 2010-07-09 at 16:59 +0530, Ajmal Ahammed wrote: > Sir, > > My name is Ajmal A. I was compiling a program with neon > intrinsics for arm cortex A-8. When I examined the output code, I > observed that, among the available 32 d-registers of neon, the program > uses only those from d16 (either if it's used as double word registers > or quad word registers). And another problem is with the vld > instructions. For vld instruction, it always uses the registers d16, > d17, .... Even if there are free registers like d26,d27, etc it pushes > the contents of the registers d16, d17,... to the stack. > > Without a testcase it is impossible to tell for sure what is happening. Please post an example. > I am using gcc 4.4.0, compiled using android-ndk-r4. > > For compiling I used the following command: > /home/master/ajmal/ndk/build/ > prebuilt/linux-x86/arm-eabi-4.4.0/bin/arm-eabi-gcc > -I/home/master/ajmal/ndk/build/platforms/android-3/arch-arm/usr/include > -fpic -mthumb-interwork -ffunction-sections -funwind-tables > -fstack-protector -fno-short-enums -D__ARM_ARCH_5__ -D__ARM_ARCH_5T__ > -D__ARM_ARCH_5E__ -D__ARM_ARCH_5TE__ -Wno-psabi -march=armv7-a > -mfloat-abi=softfp -mthumb -Os -fomit-frame-pointer > -fno-strict-aliasing -finline-limit=64 -mfpu=neon > -I/home/master/ajmal/ndk/sources/cpufeatures > -I/home/master/ajmal/ndk/samples/hello-neon/jni -DANDROID > -DHAVE_NEON=1 -Wa,--noexecstack -O3 -DNDEBUG -g -c -MMD -MP -MF > /home/master/ajmal/ndk/samples/hello-neon/bin/ndk/local/armeabi-v7a/objs/helloneon/$1.o.d > /home/master/ajmal/ndk/samples/hello-neon/jni/$1.c -o > /home/master/ajmal/ndk/samples/hello-neon/bin/ndk/local/armeabi-v7a/objs/helloneon/$1.o > > where $1 is the filename without the extension. > > I have tried the latest version of gcc (4.5.0) also, with no better results. > > Can you please tell me if there is a special reason for not using the > other d registers, or for the stack operations. I have gone through > the gcc manuals and some files gcc sources, but I couldn't clarify the > doubt. > > (My language proficiency is not so good, and this is the first time I > am writing an e-mail for such an authority. I am sorry for any > mistakes due to them). > > Thank you in advance. > Ajmal. A
