FANCO-16 VERSION 3 PROGRAMS
           ===========================

These programs and libraries are kept on the
program server. Open any of them by ID on the
developer page; the source comes with it.

All of them are original work, released
under the MIT license (see /LICENSE.txt).
The font glyphs were drawn for this
project.


THE LIST
========

Games

  Blockfall         0x90871282   3,109 bytes
      Falling blocks. Uses font, text, box.
  Lantern Run       0x5203863b   5,246 bytes
      Maze chase. Uses font, text.
  Fridge Snake      0x110288de   3,985 bytes
      Climb the fridge door, eat the magnets,
      then bite the handle (LEFT+RIGHT) to
      open the fridge. Uses font, text.

Demonstrations

  Lines demo        0x1ec659bb     237 bytes
      A bouncing line with a trail. Uses line.
  SID arpeggiator   0x9cff75a1   1,296 bytes
      Three-voice music with a piano roll.

Benchmarks

  bench-fill        0xb6e79ce5     249 bytes
      Box fills and screen copies, about
      98,000 pixels per frame. Measures the
      blitter.
  bench-lines       0xeca00f79     247 bytes
      128 random lines per frame.
  bench-pixels      0xcec88aca     177 bytes
      Writes all 65,536 pixels with out.
      Measures the processor.

The benchmarks do not wait between frames.
They run as fast as virtual time allows, so the
pace shown on the developer page measures how
fast your browser is.

Relocatable libraries

  font              0x16a2db29     766 bytes
  text              0xdabf60f3      98 bytes
  line              0x5bf20a98     153 bytes
  box               0xbecb00d8     119 bytes

Sizes are of the uploaded image. A program's
download is its own size plus that of its
libraries.


LOADING A LIBRARY
=================

All four libraries are relocatable, so you
choose where they go. This loads the line
library at 3000:

        mov a, 0x0A98    ; ID, low word
        mov b, 0x5BF2    ; ID, high word
        mov p, 0x3000    ; where to load it
        sys load
        cmp a, 0
        bnz failed

If a library fails to load, the programs in
this list fill the screen with red and halt.


CALLING THE LIBRARIES
=====================

In each description, "keeps" lists registers
that are unchanged afterwards. All other
registers and the flags may change.

font
----

Data only, no code. The glyph for character c,
from 32 to 126, is the 8 bytes at

    base + (c - 32) * 8

Each byte is one row, top row first. Bit 7 is
the leftmost pixel.

text
----

    call base

  p     Address of the text, ending in a zero
        byte.
  x, y  Top left corner.
  a.lo  Color.
  r     Address of a font.

Keeps x, y and r. Afterwards p points just
past the zero byte. Each character is 8 pixels
wide. Text is not clipped and has no line
breaks, so keep it inside the screen.

line
----

    call [base]       ; draw a line

  x, y  Start point.
  a, b  End point. All coordinates 0-255.
  p.lo  Color.

    call [base+2]     ; plot one pixel

  x, y  The pixel.
  p.lo  Color.

Both keep x, y, p and r.

box
---

    call [base]       ; filled box
    call [base+2]     ; outline only

  x, y  Top left corner.
  a, b  Width and height, 1-256.
  p.lo  Color.

Both keep every register, but change the
blitter registers 62 to 6D. The box is clipped
at the screen edge.

text and font contain no addresses that need
correcting, so they work at any address
without relocation. Text and line keep their
working values on the stack and use no other
memory.