Hacking PowerPC Assembly Compiler?

[BullyWiiPlaza]

What are my best options for a PowerPC assembly to bytecode compiler? I want to write assembly code and assemble it to be used on the Wii U. The Wii has a tool called ASMWiiRd however, it seems to deadlock for me when I run it after extraction. If I run it from the archive, it compiles assembly just fine. I'm on Windows 10. Another old Wii tool is PyiiASMH but installing all dependent libraries is painful and non-user friendly. Python is literally terrible with all those different versions and incompatibility galore.

If I implemented the whole thing manually in Java, would it be a good idea? Any hints, tips I could use to cut down on the tedious work of parsing every instruction/definition manually? I also didn't find any other PowerPC assembly compilers out there so I might be missing something obvious. Is the Wii U assembly even identical to the Wii's? It seems to be for the most part at least. Are there even differences?

 

[Neesh]

Well, i don't think it's a real good idea to implement the whole thing to java(Java's awesome and everything but.... come on! it's a pain in the but!) So i would just stick with it originally.

 

[street]

i think they would be differences as one is far more powerful ive trolled the net and also only found the one for the wii or unity for wii u

 

[BullyWiiPlaza]

Well, i don't think it's a real good idea to implement the whole thing to java(Java's awesome and everything but.... come on! it's a pain in the but!) So i would just stick with it originally.

If I stick to "important" instructions only it could be kinda cool and useful

 

[Onion_Knight]

What are my best options for a PowerPC assembly to bytecode compiler? I want to write assembly code and assemble it to be used on the Wii U. The Wii has a tool called ASMWiiRd however, it seems to deadlock for me when I run it after extraction. If I run it from the archive, it compiles assembly just fine. I'm on Windows 10. Another old Wii tool is PyiiASMH but installing all dependent libraries is painful and non-user friendly. Python is literally terrible with all those different versions and incompatibility galore.

If I implemented the whole thing manually in Java, would it be a good idea? Any hints, tips I could use to cut down on the tedious work of parsing every instruction/definition manually? I also didn't find any other PowerPC assembly compilers out there so I might be missing something obvious. Is the Wii U assembly even identical to the Wii's? It seems to be for the most part at least. Are there even differences?

Marcan talked about the fact that the Wii U processor is an evolved Wii Processor. So its based on the 750 PPC architecture.

I don't know about windows support but qemu would fit the bill, you can use qemu-ppc to install a minimal (no gui) ppc vm with the 750 architecture that should allow you to compile PPC assembly that should run natively on the wii u.

 

[NWPlayer123]

What are my best options for a PowerPC assembly to bytecode compiler? I want to write assembly code and assemble it to be used on the Wii U. The Wii has a tool called ASMWiiRd however, it seems to deadlock for me when I run it after extraction. If I run it from the archive, it compiles assembly just fine. I'm on Windows 10. Another old Wii tool is PyiiASMH but installing all dependent libraries is painful and non-user friendly. Python is literally terrible with all those different versions and incompatibility galore.

If I implemented the whole thing manually in Java, would it be a good idea? Any hints, tips I could use to cut down on the tedious work of parsing every instruction/definition manually? I also didn't find any other PowerPC assembly compilers out there so I might be missing something obvious. Is the Wii U assembly even identical to the Wii's? It seems to be for the most part at least. Are there even differences?

Just make a project to compile a .S file and use DevKitPPC like we do in libwiiu ???

 

[vgmoose]

Just make a project to compile a .S file and use DevKitPPC like we do in libwiiu ???

Yes, gcc has a pretty weird feature where you can just compile .S files like you would .C files. You can also generate .S files with the -S flag.

Attached is an example of a hello world assembly project. The main difference is all references to *.c in the Makefile are replaced with *.s. I think this should always work... but I haven't really played around

 

[BullyWiiPlaza]

Just make a project to compile a .S file and use DevKitPPC like we do in libwiiu ???

Thanks! This was quite obvious after all. I also looked at Hawkeye's source code and it is doing something similar.

I tried to compile some random assembly in a file named ASM.S with the contents

li r0, 5
nop

but the result was this:

>powerpc-eabi-gcc ASM.S -o ASM.o
ASM.S: Assembler messages:
ASM.S:1: Error: unsupported relocation against r0

A small s as file extension doesn't change anything. Well, I just want to compile the assembly, how can I do it?

 

[vgmoose]

I tried to compile some random assembly in a file named ASM.S with the contents

li r0, 5
nop

but the result was this:

>powerpc-eabi-gcc ASM.S -o ASM.o
ASM.S: Assembler messages:
ASM.S:1: Error: unsupported relocation against r0

A small s as file extension doesn't change anything. Well, I just want to compile the assembly, how can I do it?

It looks like gcc expects the registers without the r in front, like this:

li 0, 5
nop

I've seen it both ways online: this site has the r's in its examples, and this one does not. I'm not sure why, but when the r is left out it does compile for me. Does it still do what you expect it to?

 

[BullyWiiPlaza]

I'm not sure why, but when the r is left out it does compile for me. Does it still do what you expect it to?

Well, no. I can't get it to compile something at all:

>powerpc-eabi-gcc ASM.s -o ASM.o
c:/devkitpro/devkitppc/bin/../lib/gcc/powerpc-eabi/4.8.2/../../../../powerpc-eabi/lib/crt0.o: In function `_start':
/home/davem/projects/devkitpro/buildscripts/.devkitPPC-i686-w64-mingw32/powerpc-eabi/newlib/powerpc-eabi/libgloss/rs6000/crt0.S:122: undefined reference to `main'
collect2.exe: error: ld returned 1 exit status

Without a new line at the end:

>powerpc-eabi-gcc ASM.s -o ASM.o
ASM.s: Assembler messages:
ASM.s: Warning: end of file not at end of a line; newline inserted
c:/devkitpro/devkitppc/bin/../lib/gcc/powerpc-eabi/4.8.2/../../../../powerpc-eabi/lib/crt0.o: In function `_start':
/home/davem/projects/devkitpro/buildscripts/.devkitPPC-i686-w64-mingw32/powerpc-eabi/newlib/powerpc-eabi/libgloss/rs6000/crt0.S:122: undefined reference to `main'
collect2.exe: error: ld returned 1 exit status

Trying to compile just nop for example also doesn't work.

 

[wj44]

Well, no. I can't get it to compile something at all:

>powerpc-eabi-gcc ASM.s -o ASM.o
c:/devkitpro/devkitppc/bin/../lib/gcc/powerpc-eabi/4.8.2/../../../../powerpc-eabi/lib/crt0.o: In function `_start':
/home/davem/projects/devkitpro/buildscripts/.devkitPPC-i686-w64-mingw32/powerpc-eabi/newlib/powerpc-eabi/libgloss/rs6000/crt0.S:122: undefined reference to `main'
collect2.exe: error: ld returned 1 exit status

Without a new line at the end:

>powerpc-eabi-gcc ASM.s -o ASM.o
ASM.s: Assembler messages:
ASM.s: Warning: end of file not at end of a line; newline inserted
c:/devkitpro/devkitppc/bin/../lib/gcc/powerpc-eabi/4.8.2/../../../../powerpc-eabi/lib/crt0.o: In function `_start':
/home/davem/projects/devkitpro/buildscripts/.devkitPPC-i686-w64-mingw32/powerpc-eabi/newlib/powerpc-eabi/libgloss/rs6000/crt0.S:122: undefined reference to `main'
collect2.exe: error: ld returned 1 exit status

Trying to compile just nop for example also doesn't work.

powerpc-eabi-as -mregnames -mgekko asm.s -o asm.o
powerpc-eabi-ld -Ttext 0x80000000 asm.o
powerpc-eabi-objcopy -O binary asm.o asm.bin

 

[BullyWiiPlaza]

powerpc-eabi-as -mregnames -mgekko asm.s -o asm.o
powerpc-eabi-ld -Ttext 0x80000000 asm.o
powerpc-eabi-objcopy -O binary asm.o asm.bin

>powerpc-eabi-as -mregnames -mgekko asm.s -o asm.o
Assembler messages:
Error: invalid switch -mgekko
Error: unrecognized option -mgekko

Weird, apparently it works like that in ppctools.py.

 

[wj44]

>powerpc-eabi-as -mregnames -mgekko asm.s -o asm.o
Assembler messages:
Error: invalid switch -mgekko
Error: unrecognized option -mgekko

Weird, apparently it works like that in

ppctools.py

Use the files included in TCPGecko:
powerpc-gekko-as -mregnames -mgekko asm.s -o asm.o
powerpc-gekko-ld -Ttext 0x80000000 asm.o
powerpc-gekko-objcopy -O binary asm.o asm.bin

 

[BullyWiiPlaza]

Use the files included in TCPGecko:
powerpc-gekko-as -mregnames -mgekko asm.s -o asm.o
powerpc-gekko-ld -Ttext 0x80000000 asm.o
powerpc-gekko-objcopy -O binary asm.o asm.bin

It worked with the files from here, thanks mate

 

[vgmoose]

Leaving this here for anyone using powerpc-eabi-gcc:

$ cat asm.s
li 0, 4
nop
$ powerpc-eabi-gcc -nostdinc -fno-builtin -c  *.s
$ ls | grep *.o
asm.o
$ powerpc-eabi-ld -Ttext 1800000 --oformat binary *.o -o asm.bin
powerpc-eabi-ld: warning: cannot find entry symbol _start; defaulting to 01800000
$ ls | grep *.bin
asm.bin

And there's also the hello world example I attached above, which does produce a working hello world binary when you cd into it and run make.

It looks like gcc expects the registers without the r in front, like this:
I'm not sure why, but when the r is left out it does compile for me.

It seems that it's the use of -mregnames:

$ cat asm.s
li r0, 4
nop
$ powerpc-eabi-gcc -nostdinc -fno-builtin -mregnames -c  *.s
$ powerpc-eabi-ld -Ttext 1800000 --oformat binary *.o -o asm.bin
powerpc-eabi-ld: warning: cannot find entry symbol _start; defaulting to 01800000
$ ls | grep *.bin
asm.bin

 

[cory1492]

afaik without -mregnames it expects either %r0 or (possibly, on ppc you can use 0 for a zero-offset-instead-of-register-with-zero-in-it for some instructions) 0 for register names, where with it you can also use r0

If you want to generate position independent code (ie: you don't have to specify text offset), I use this on x360/xenon toolchain, skipping gcc for .s files:

xenon-as.exe -be -many -mregnames input.S -o output.elf
xenon-objcopy.exe output.elf -O binary output.bin

presumably your toolchain should have powerpc-eabi-as and powerpc-eabi-objcopy, though may not support the -be or -many flags, and for whatever reason I chose to name the objects as .elf instead of .o... oh well xD

 

[BullyWiiPlaza]

On Kali Linux 2016.2 release, I'm getting this strange error:

./powerpc-eabi-gcc -nostdinc -fno-builtin -mregnames -c assembly.s -o assembly.o
as: unrecognized option '-m750cl'

Documentation:

./powerpc-eabi-gcc --h
Usage: powerpc-eabi-gcc [options] file...
Options:
  -pass-exit-codes         Exit with highest error code from a phase
  --help                   Display this information
  --target-help            Display target specific command line options
  --help={common|optimizers|params|target|warnings|[^]{joined|separate|undocumented}}[,...]
                           Display specific types of command line options
  (Use '-v --help' to display command line options of sub-processes)
  --version                Display compiler version information
  -dumpspecs               Display all of the built in spec strings
  -dumpversion             Display the version of the compiler
  -dumpmachine             Display the compiler's target processor
  -print-search-dirs       Display the directories in the compiler's search path
  -print-libgcc-file-name  Display the name of the compiler's companion library
  -print-file-name=<lib>   Display the full path to library <lib>
  -print-prog-name=<prog>  Display the full path to compiler component <prog>
  -print-multiarch         Display the target's normalized GNU triplet, used as
                           a component in the library path
  -print-multi-directory   Display the root directory for versions of libgcc
  -print-multi-lib         Display the mapping between command line options and
                           multiple library search directories
  -print-multi-os-directory Display the relative path to OS libraries
  -print-sysroot           Display the target libraries directory
  -print-sysroot-headers-suffix Display the sysroot suffix used to find headers
  -Wa,<options>            Pass comma-separated <options> on to the assembler
  -Wp,<options>            Pass comma-separated <options> on to the preprocessor
  -Wl,<options>            Pass comma-separated <options> on to the linker
  -Xassembler <arg>        Pass <arg> on to the assembler
  -Xpreprocessor <arg>     Pass <arg> on to the preprocessor
  -Xlinker <arg>           Pass <arg> on to the linker
  -save-temps              Do not delete intermediate files
  -save-temps=<arg>        Do not delete intermediate files
  -no-canonical-prefixes   Do not canonicalize paths when building relative
                           prefixes to other gcc components
  -pipe                    Use pipes rather than intermediate files
  -time                    Time the execution of each subprocess
  -specs=<file>            Override built-in specs with the contents of <file>
  -std=<standard>          Assume that the input sources are for <standard>
  --sysroot=<directory>    Use <directory> as the root directory for headers
                           and libraries
  -B <directory>           Add <directory> to the compiler's search paths
  -v                       Display the programs invoked by the compiler
  -###                     Like -v but options quoted and commands not executed
  -E                       Preprocess only; do not compile, assemble or link
  -S                       Compile only; do not assemble or link
  -c                       Compile and assemble, but do not link
  -o <file>                Place the output into <file>
  -pie                     Create a position independent executable
  -shared                  Create a shared library
  -x <language>            Specify the language of the following input files
                           Permissible languages include: c c++ assembler none
                           'none' means revert to the default behavior of
                           guessing the language based on the file's extension

Options starting with -g, -f, -m, -O, -W, or --param are automatically
passed on to the various sub-processes invoked by powerpc-eabi-gcc.  In order to pass
other options on to these processes the -W<letter> options must be used.

For bug reporting instructions, please see:
<http://wiki.devkitpro.org/index.php/Bug_Reports>.

Linux binaries download: https://mega.nz/#!K5sz0BjJ!cKL8N8r52-pboMuejRp-JF7VUTlaqC_-s-GtntX9Vn4

On Windows, the same command is working:

powerpc-eabi-gcc -nostdinc -fno-builtin -mregnames -c assembly.s -o assembly.o
assembly.s: Assembler messages:
assembly.s: Warning: end of file not at end of a line; newline inserted

Also apparently the command line arguments are the same.

Windows binaries download: https://mega.nz/#!C5NhFbCB!PNClMrO1Ebk50rqDj2Ou5BWYkG91LrJEog6Lmrn5UNA

 

[QuarkTheAwesome]

Just a quick note; the whole "unsupported relocation against r0" thing is because of one of those weird little Assembly idiosyncrasies. There's three main styles of PowerPC - Intel (li r3, 5) AT&T (li %r3, 5) and what I like to call "raw" syntax (li 3, 5). There's a few other small things around variable declarations that seperate the three as well. Anyway, devKitPPC uses a rather old version of GCC that only supports AT&T and raw syntax. Not all is lost; @FIX94 has a legendary .h file that somehow #defines Intel syntax into working just fine.

As for your problem, looks like a borked devKitPPC. Can it compile something like HBL alright? The ./ also messes with me a bit. You've got this all on your PATH, right?

 

[BullyWiiPlaza]

So can you get it working on Linux somehow? I didn't do any further testing. Then I can take those files for my tools since some Linux folks are crying that there is no disassembly support right now

You've got this all on your PATH, right?

The file is locally in the same folder, not the PATH since I don't require people to have a "full" devkitPro installation just for two files. Check out the Java project here.

 

[BullyWiiPlaza]

Alright, the following bash script works for me on Kali Linux 64-bit 2016.2 release

root@kali:~/Desktop/PyiiASMH/lib/linux2_x86_64# cat asm.s
li r0, 0
nop
root@kali:~/Desktop/PyiiASMH/lib/linux2_x86_64# ./compile.sh
3800000060000000

compile.sh:

#!/bin/sh

# Compile the source to object code
./powerpc-eabi-as -mregnames -mgekko asm.s -o asm.o

# Build the binary from object code
./powerpc-eabi-objcopy -O "binary" asm.o asm

# Delete the object code file
rm asm.o

# Print out the hexadecimal binary file contents
xxd -p asm

# Remove the compiled binary
rm asm

The necessary powerpc binaries are here.