craigthomas/chip8c

A Super Chip 8 emulator written in C

chip8c's Issues

Question on Endian-ness for Union

It's a little unclear to me what the right way is in terms of the endian-ness logic. Code from the article (http://craigthomas.ca/blog/2014/06/21/writing-a-chip-8-emulator-part-1/) for this code shows the following:

struct {
      #ifdef WORDS_LITTLE_ENDIAN
         byte high, low;
      #else
         byte low, high;
      #endif
} BYTE;

Note the WORDS_LITTLE_ENDIAN. The code here in the repo shows:

struct {
      #ifdef WORDS_BIGENDIAN
         byte high, low;
      #else
         byte low, high;
      #endif
} BYTE;

Note the WORDS_BIGENDIAN. But the statements themselves -- within the directives -- are not reversed. A statement from the article is:

"Notice also that the definition of big- and little-endian appear to be backwards - this is because I’m developing on an x86-based system, which is little-endian."

So ... which is the backwards one? Is the implementation here in the repo correct?

Allow command argument override for `CFLAGS`

The Makefile does not allow an override for CFLAGS to be issued during compilation. For example, the following compilation will fail:

make CFLAGS=-DWORDS_BIGENDIAN

The Makefile needs to be updated to append an override to the CFLAGS definition.