The error message you're getting looks like you're trying to
0 instead of
r0, which isn't possible. Check your asm to make sure.
However, if your assembler .bat isn't working even on existing skills, it might be that it isn't compatible with how/where you've got your devkitPro set up. If this is the case, it won't load the right language specs and will throw errors on stuff that's perfectly legal to do.
This one works for me, just make sure that
startDir is set to the path to your devkitPro:
I can't upload .bats here so paste this into a text file and save it as Assemble_ARM.bat
@rem Assemble into an elf
%as% -g -mcpu=arm7tdmi -mthumb-interwork %1 -o "%~n1.elf"
@rem Print symbol table
%readelf% -s "%~n1.elf" > "%~n1.symbols.log"
@rem Extract raw assembly binary (text section) from elf
%objcopy% -S "%~n1.elf" -O binary "%~n1.dmp"
echo y | del "%~n1.elf"