Simplified _addrModeError as much as possible (still has to put the mode into a string only if an error occurred.
Simplified _addrModeError as much as possible (still has to put the mode into a string only if an error occurred.

git-svn-id: dd14d189f2554b0b3f4c2209a95c13d2029e3fe8@433 96dfbd92-d197-e211-9ca9-00110a534b34

RyuKojiro/v6502