I am trying to validate successful compilation of a sample hello world using gcc for what I understand to be armv7 target. It is Snapdragon msm8974. I get the following errors:
hello_world.s: Assembler messages:
hello_world.s:1: Error: unknown pseudo-op: `.syntax'
hello_world.s:3: Error: junk at end of line, first unrecognized character is `@'
hello_world.s:6: Error: junk at end of line, first unrecognized character is `@'
hello_world.s:7: Error: junk at end of line, first unrecognized character is `@'
hello_world.s:8: Error: invalid char '{' beginning operand 1 `{ip'
hello_world.s:10: Error: junk at end of line, first unrecognized character is `@'
hello_world.s:11: Error: no such instruction: `ldr r0,=message'
hello_world.s:12: Error: no such instruction: `bl printf'
hello_world.s:14: Error: junk at end of line, first unrecognized character is `@'
hello_world.s:15: Error: expecting operand after ','; got nothing
hello_world.s:17: Error: junk at end of line, first unrecognized character is `@'
hello_world.s:18: Error: junk at end of line, first unrecognized character is `@'
hello_world.s:19: Error: invalid char '{' beginning operand 1 `{ip'
hello_world.s:21: Error: junk at end of line, first unrecognized character is `@'
hello_world.s:22: Error: junk at end of line, first unrecognized character is `@'
hello_world.s:23: Error: junk at end of line, first unrecognized character is `@'
Here is the code:
.syntax unified
@ --------------------------------
.global main
main:
@ Stack the return address (lr) in addition to a dummy register (ip) to
@ keep the stack 8-byte aligned.
push {ip, lr}
@ Load the argument and perform the call. This is like 'printf("...")' in C.
ldr r0, =message
bl printf
@ Exit from 'main'. This is like 'return 0' in C.
mov r0, #0 @ Return 0.
@ Pop the dummy ip to reverse our alignment fix, and pop the original lr
@ value directly into pc — the Program Counter — to return.
pop {ip, pc}
@ --------------------------------
@ Data for the printf calls. The GNU assembler's ".asciz" directive
@ automatically adds a NULL character termination.
message:
.asciz "Hello, world.\n"
What am I doing wrong? Here is my gcc version:
gcc (Ubuntu 4.9.2-10ubuntu13) 4.9.2
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
@Michael - Here is more detail.. Here is gcc -v from my working folder, which is composed of Samsung Source and AOSP:
sansari@ubuntu:~/WORKING_DIRECTORY$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.9/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.9.2-10ubuntu13' --with-bugurl=file:///usr/share/doc/gcc-4.9/README.Bugs --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.9 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.9 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-vtable-verify --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.9-amd64 --with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.9.2 (Ubuntu 4.9.2-10ubuntu13)
I am using a cross compiler; here is the line from my Makefile in my working folder:
CROSS_COMPILE ?= /arm-eabi-4.7/bin/arm-eabi-
I basically put the assembly code in the /external directory. I created another folder and put just the assembly code and created a Makefile as follows:
sansari@ubuntu:~/WORKING_DIRECTORY/external/shahin$ ls
hello_world.s Makefile template.s
sansari@ubuntu:~/WORKING_DIRECTORY/external/shahin$ more Makefile
hello_world: hello_world.s
gcc hello_world.s -o hello_world
When I run make from this same directory, not the working directory which is it's parent, but .../external/shahin, I get the errors you see.
@leppie - Thanks. Let me try that. I also suspect I need to specify other flags? Here is a line from Kconfig:
0628Samsung:KBUILD_AFLAGS = -D__ASSEMBLY__ -mabi=aapcs-linux -mno-thumb-interwork -funwind-tables -D__LINUX_ARM_ARCH__=7 -mcpu=cortex-a15 -include asm/unified.h -msoft-float -gdwarf-2
Can I just do:
make -D__ASSEMBLY__ -mabi=aapcs-linux -mno-thumb-interwork -funwind-tables -D__LINUX_ARM_ARCH__=7 -mcpu=cortex-a15 -include asm/unified.h -msoft-float -gdwarf-2
Or do I need to add these to my makefile in /external/shahin directory? I think both works. I just want you to verify it for errors please.
@Notlikethat - Thanks I am the proud owner of a a.out:-)
sansari@ubuntu:~/WORKING_DIRECTORY/external/shahin$ ls
a.out hello_world.S Makefile temp template.s
Ok. I put the a.out on the sdcard, and changed its permissions to 777 but I could not run it. I then moved it to /system/lib folder and could not run it. I thought this should run given that I used the same cross compiler that built the running image on my phone. What I mean is I successfully flashed the phone with the code that I am trying to add to here. And I used the same cross compiler. Can anyone suggest anything else? What am I doing wrong here? I am going to build another image entirely and flash the phone just to see if I can run this sample program. Is there anything else with less effort I need to look into first?
@dwelch - Just to be clear, did you write your last comment before I got the a.out? I think I am now using the right toolchain. Thanks.
