First, copyright law in many countries makes it almost certain that the C64 font resulted in the creation of copyrights for someone at some point. This is the easy starting point.
The next question is who owns the resulting copyrights today, following the multiple liquidations of Commodore-related entities.
Another question is, given that no one has been prosecuting those copyrights for many years now, what impact does this have on their enforceability.
Yet more questions arise because it is has been noticed that the C64 and Atari 8-bit computer fonts have identical lower-case characters, with the ones on the Atari pre-dating the C64 ones considerably. I.e., it is probable that the lower-case characters of the C64 font were created by someone other than Commodore.
Then arises some more interesting questions.
Commodore had tried on occasion to update the C64 font, but gave up when they realised that in various subtle ways that software depended on the exact contents of the C64's character ROM to function correctly. Apparently they tried just moving the dot on the lower case I and found that it caused at least one program to fail.
Thus it may be argued that the C64 font is required, 100% verbatim, to create a computer that is compatible with the C64. This rather exotic legal argument is important for countries that have a copyright exemption for the purposes of interoperability. Australia is one of those.
The relevant Australian legislation is section 47D of the Copyright Act, 1968:
Reproducing computer programs to make interoperable products (1) Subject to this Division, the copyright in a literary work that is a computer program is not infringed by the making of a reproduction or adaptation of the work if:Given that the character ROM has been acknowledged by Commodore employees in the past as being vital to providing interoperability with the C64, does this section apply?
(a) the reproduction or adaptation is made by, or on behalf of, the owner or licensee of the copy of the program (theoriginal program ) used for making the reproduction or adaptation; and
(b) the reproduction or adaptation is made for the purpose of obtaining information necessary to enable the owner or licensee, or a person acting on behalf of the owner or licensee, to make independently another program (the new program ), or anarticle, to connect to and be used together with, or otherwise to interoperate with, the original program or any other program; and
(c) the reproduction or adaptation is made only to the extent reasonably necessary to obtain the information referred to in paragraph (b); and
(d) to the extent that the new program reproduces or adapts the original program, it does so only to the extent necessary to enable the new program to connect to and be used together with, or otherwise to interoperate with, the original program or the other program; and
(e) the information referred to in paragraph (b) is not readily available to the owner or licensee from another source when the reproduction or adaptation is made.
(2) Subsection (1) does not apply to the making of a reproduction or adaptation of a computer program from an infringingcopy of the computer program.
First, if you own a C64 character ROM, it is clear that you could rely on sub-section 1(a) to make a copy, and include that in your own FPGA bitstream. That would require you to run the synthesis process yourself. Not very convenient.
Since that test fails, we must now satisfy 1(a) through 1(e) for a developer of the C65GS to be able to distribute a bitstream that includes the C64 character ROM.
1(a) requires that the ROM be sourced from a legal copy. This can be done by reading the ROM from a real C64.
1(b) is satisfied if such a legally sourced copy is used to satisfy the needs of interoperability with any program. Since there exists programs that I would like to make the C65GS interoperable with, that are understood to rely on the exact contents of the C64 character ROM, this is satisfied.
1(c) is satisfied because we need the entire ROM to provide the interoperability. Having only part of the ROM would not suffice.
1(d) is satisfied because such programs require the ROM to be available just as it was on the original C64 -- i.e., mapped to a particular memory location, and visible by default to the video controller in particular ways -- in order for the C65GS to interoperate with them. Failing on any point of this would not suffice to provide interoperability with the C64's software portfolio.
1(e) requires that the information (the contents of the ROM) is not readily available from another source. This is where it gets a bit interesting again.
The C64 & C65 ROMs can be freely downloaded from the internet in many places. Thus, it can be argued that they are readily available. However, if they are readily available in this way, then it must be on the basis of those copies being legal copies. If they are not legal copies, then they are not candidates to contradict 1(e).
This is a bit interesting, because depending on the answer to this unanswerable question, indicates from where the ROM should be sourced -- and existing online source, or from a real C64 ROM chip (or other undeniably legal source).
To add to the complexity is JiffyDOS, which is an adaption of the C64 ROM set, and for C64C's the JiffyDOS ROM contains the character ROM. JiffyDOS is apparently still available for purchase. However, what is not clear is whether JiffyDOS includes the C64 character ROM on the basis of an interoperability exemption, or on the basis of a license from a past or present owner of the ROM.
The JiffyDOS situation has yet another facet: To provide interoperability with a JiffyDOS-enabled C64, it is just as necessary to have the complete C64 character ROM as for a non-JiffyDOS-enabled C64.
So what is the situation? Can I include the C64 character ROM or not, and if so, where should it be copied from?
I think the answer is clear as mud.
Then there is the question of whether any of the symbols defined in ASCII 1963, ASCII 1967 or Unicode which have only one or very few possible representations in an 8x8 grid are actually copyrightable at all. Similarly, the publishing of PETSCII as a de facto standard probably makes the ordering of the characters unenforceable in terms of copyrights.
It is rather frustrating that the situation is so horribly vexed.
The simpler solution to avoid all possible problems in this regard, is that I should include a freely-distributable 8x8 font, which gets replaced in memory by the correct font when the C65GS loads a ROM from the SD card, so that the bitstream contains material that could be subject to an external copyright claim.
Fortunately, there are some free 8x8 fonts out there, like this one or this one.
So the only down side is that the kickstart display will not be in the C64 font.
Of course, if I get the OS a little further, it could boot up with a proportional font for the boot display, and side-step this sticky problem altogether... So I have a couple of solutions open to me.