Build requirements:
-------------------

- gcc or clang (for `mksums` and converting a checksummer to BASIC)
- ca65 / ld65 (for building the individual checksummers)
- petcat (for creating .PRG files from BASIC sources)

Build instructions:
-------------------

To build everything:

    make

make is expected to be GNU make, so e.g. on a BSD system, type `gmake` instead
of `make` everywhere.

To build only the `mksums` tool:

    make mksums

To clean up:

    make clean

To clean up AND remove the targets:

    make distclean

make variables:

    CC          command to execute the C compiler (default: cc)
    CFLAGS      flags for the C compiler (default: -g0 -O2)
    C64AS       command to execute ca65 (default: ca65)
    C64LD       command to execute ld65 (default: ld65)
    PETCAT      command to execute petcat (default: petcat)

Usage:
------

For creating checksums:

    mksums [-s] < input.prg > checksums.txt

creates checksums for the input.prg BASIC program in checksums.txt
-s:     allow shifted spaces in input.prg

For typing a BASIC program with checksumming:

  - Load the .prg for your target platform
  - Type `RUN` and `NEW`
  - Start typing your program, checksums appear in upper right corner
  - When finished, SAVE your program to disk (never use the datasette!!)
  - Reset or turn of computer to deactivate the checksummer
  - Load your typed program and enjoy.

 PERMSSN    UID  GID    PACKED    SIZE  RATIO METHOD CRC     STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                  317     623  50.9% -lh5- e17c Oct 21 02:41 f64summer/c64.prg
[generic]                  269     499  53.9% -lh5- e0ba Oct 21 02:29 f64summer/c64/Makefile
[generic]                   78      82  95.1% -lh5- e825 Oct 21 02:29 f64summer/c64/src/f64summer.cfg
[generic]                  441    1103  40.0% -lh5- 8167 Oct 21 02:29 f64summer/c64/src/main.s
[generic]                  452     962  47.0% -lh5- 6868 Oct 21 02:41 f64summer/c128.prg
[generic]                  269     499  53.9% -lh5- e0ba Oct 21 02:29 f64summer/c128/Makefile
[generic]                   79      83  95.2% -lh5- ac8a Oct 21 02:29 f64summer/c128/src/f64summer.cfg
[generic]                  621    1655  37.5% -lh5- b711 Oct 21 02:29 f64summer/c128/src/main.s
[generic]                  681    1295  52.6% -lh5- 4148 Oct 21 02:29 f64summer/LICENSE
[generic]                  365     701  52.1% -lh5- 2a1b Oct 21 02:32 f64summer/Makefile
[generic]                 4016    9116  44.1% -lh5- b5cf Oct 21 02:41 f64summer/mksums
[generic]                  341     675  50.5% -lh5- 49a6 Oct 21 02:41 f64summer/plus4.prg
[generic]                  269     499  53.9% -lh5- e0ba Oct 21 02:29 f64summer/plus4/Makefile
[generic]                   78      82  95.1% -lh5- e825 Oct 21 02:29 f64summer/plus4/src/f64summer.cfg
[generic]                  472    1201  39.3% -lh5- ef6d Oct 21 02:29 f64summer/plus4/src/main.s
[generic]                  656    1401  46.8% -lh5- 6f34 Oct 21 02:29 f64summer/README.txt
[generic]                 1463    3776  38.7% -lh5- b61b Oct 21 02:35 f64summer/tools/mksums.c
[generic]                  695    1908  36.4% -lh5- 7c75 Oct 21 02:29 f64summer/tools/mprg2bas.c
[generic]                  351     713  49.2% -lh5- 8366 Oct 21 02:41 f64summer/vic20.prg
[generic]                  269     499  53.9% -lh5- e0ba Oct 21 02:29 f64summer/vic20/Makefile
[generic]                   78      82  95.1% -lh5- e825 Oct 21 02:29 f64summer/vic20/src/f64summer.cfg
[generic]                  497    1249  39.8% -lh5- b9d7 Oct 21 02:29 f64summer/vic20/src/main.s
[generic]                 6362   11388  55.9% -lh5- 42df Oct 27 23:56 f64summer/mksums.68k
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total        23 files   19119   40091  47.7%            Oct 27 20:57