INTRODUCTION
The
Apricot's
Internal
Boot ROM
contains
the
software
which
is
executed
first of all
when
the
machine
is
switched
on.
The
ROM
contains
a calculator,
and
a
number
of
software
and
hardware
tests.
When
a
disk
is
inserted
and
the
conditions for booting are satisfactory,
the
boot ROM will
load
in
the
operating
system
and
execute
it. Below is a
list
of
the
boot
ROM's
operation.
1.
Initialize Hardware.
2.
Print
logo
and
"Testing"
message
on
the
screen.
3. Perform Software
tests
on
hardware.
4.
Display
the
results
of
the
tests.
5.
Cycle
in
an
enless loop
testing
for
the
Calculator key
or
a
disk
being inserted.
6.
When
a disk is inserted,
check
for validity as a
system
disk
and
read
in
then
execute
the
Bios.
APPLICATIONS INTEREST
Very
little
use
can
be
made
of
the
boot ROM from
applications software.
One
of
the
features
it
has is an ability
to "cold-boot"
the
machine.
The
ROM
entry
point
(At
OFFFF
hex)
has
to
be
jumped
to.
Programming
Example:
Software
Reset
5000
rem
--
"GOTO
5000"
will
have
the
same
effect
as
pressing
reset.
5010
def
seg=&hffff:boot=O:call
boot
The
Logo
that
is loaded from
disk
can
also be displayed,
if
the
standard
Apricot logo
is
used,
it
will
be a copy of
the
one
in
the
Boot
ROM
Programming
example:
Logo
Display
Program
This
routine
will
display
the
Apricot Logo
in
the
centre of
the
screen
at
the
top:
10
def
seg=&HfOOO:o=-2:for
1=195
to
207
20
o=o+l:poke 1*2+160, 114+o:poke 1*2+161,67
30
poke 1*2,93+o:poke 1*2+1,67:next
40
poke 252,82:poke 253,67:poke 242,77:poke 243,67
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