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EMIT
This will take the number hold on the
top of the stack and display it on the terminal, as its original ASCII character.
e.g.
HEX 41 EMIT <CR>
will instruct the Forth to move into
hexadecimal mode, push 41H onto the stack and then take that number and display
it on the terminal. In this example the character displayed will be an
"A". The actual character displayed may be any of the recognizable
ASCII character, a graphic character, or a control code depending on the value
of the number on the stack
EMITC
As EMIT
but control character are also dealt with.
KEY
This will poll keyboard, wait for a key
to be pressed and push the ASCII code of this key onto the stack, without
displaying it on the terminal.
e.g.
KEY <CR>
Press "A" on keyboard will
instruct the computer to wait for a key to be pressed (press the "A")
and then push the ASCII value of this key, in this case 41H onto the top of the
stack. In order to display this character, try the following
KEY EMIT <CR>
Now hit any key and its ASCII value will
be printed followed by OK. So if you now type "A" it would print
"AOK".
CR
This will transmit a carriage return and
line feed to the display.
.
Convert the number hold on the stack
using the current BASE and print it on
the screen with a trailing space. e.g. suppose the stack contains 16H and base
is decimal (10), then will print 22 (this is 16 + 6), if base where hexadecimal
(16) then would print 16. In order to see this working we will alter the base
and push numbers onto the stack. Remember that just typing in a valid number
will result in it being pushed onto the stack. There are two words to alter BASE:
HEX
Use hexadecimal base.
DECIMAL
Use decimal base.
Try
1)
HEX 1F7 . <CR>
This will print
1F7
DECIMAL 2048 . <CR>
This
will print
2048
DECIMAL 2048 HEX . <CR>
Thiw
will print
800
since this is the HEX
equivalent of 2048. Remember that . will remove the number from the stack that
it is printing.
U.
Prints the number held on the topo of
the stack as an unsigned number.
e.g.
HEX C000 U. <CR>
will push C000H onto the stack and then
print it. If whe use just . we will get a negative result
HEX C000 . <CR>
will print
-4000
?
Print the value contained at the address
on top of the stack using the current BASE.
Suppose the top of the stack contains FF40H, location FF40/41H contains 0014H
and current BASE is 10 (DECIMAL),
then ? will print 20 which is the decimal equivalent of 14H.
TYPE
This uses the top two numbers held on
the stack and will print a selected number of characters starting at a specific
address onto the screen. The top number on the stack is the character count and
the second number is the address to start at.
e.g.
HEX 6100 20 TYPE
(note that 6100H is pushed onto the
stack and 20H is pushed on top of it: 20H top, 6100H second. This will print 32
(20H) ASCII characters correpsonding to the data starting at address 6100H).
DUMP
This take the top number on the stack an
prints out 80H bytes starting at this address.
."
This is used in the form ."
character string" and will display
the string contained within " "
on the screen
." THIS IS A CHARACTHER STRING" <CR>
will put
THIS IS A CHARACTER STRING
on the screen. Note that spaces between
the string and the quotes.
SPACE
This will display a single blank/space
on the screen.
SPACES
This will display n spaces on the
screen, where n is the number on the top of the stack
e.g.
DECIMAL 10 SPACES <CR>
will print 10 spaces on the screen.
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