This PR is mostly a complete rewrite of the emulator for 6502/65c02 opcodes.
It provides an easier to maintain implementation of the instructions, by using few macros rather than having hand-written code for each function.
All undocumented, previously missing opcodes for 6502 are also implemented.
The patch also includes a detailed documentation of those opcodes, for reference to developers.
This PR should fix one of the milestones listed here for the next version of CC65:
https://github.com/cc65/wiki/wiki/Before-the-next-release
load and run address now configured from header
fix error codes not to conflict with test
fix test/misc/endless.c which is supposed to fail if an endless loop does not occur
The targets allow to run cc65 programs in the sim65 exection
einvironment. As there are no "real" i/o facilities there's no
need for header files. Paravirtualized entry points are mapped
to $FFF0 ff. There's a large cc65 progam area from $0200-$FFEF.
The binary format includes a one-byte header indicating the required
execution environment: The value 0 means 6502 and the value 1
means 65C02. The load adress for the binary is fixed to $0200.
Note: Running sim65C02 programs currently doesn't work bcause
sim65 doesn't actually implement 65C02 opcodes.
