A2osX/.Docs/Forth Words.md

A2osX Forth Words (0.94)

Description

This document lists all of the Forth Words supported in the A2osX implementation of FORTH-79. Note that not all Words are implemented at this time, please check the Status and Comment Columns. Currently only an interpreter is available (../bin/forth) | | | though a compiler is planned |

Word Notation

The following will help you understand the Forth Words defined in the tables below.

Stack Notation

The first line of each entry describes the execution of the definition:
i.e., before -- after
In this notation, the top of the stack is to the right. Words may also be shown in context when appropriate.

Attributes

The I/C Column symbols indicate attributes of the defined words:

 C    The  word may only be used during compilation of a  colon definition.
 I    Indicates  that  the word is IMMEDIATE and  will  execute during compilation, unless special action is taken.
 U    A user variable.

Stack Parameters

Unless otherwise stated, all reference to numbers apply to 16-bit signed integers. The implied range of values is shown as {from..to}. The content of an address is shown by double curly brackets, particularly for the contents of variables, i.e., BASE {{2..70}}.

addr {0..65,535}

A value representing the address of a byte, within the FORTH standard memory space. This addressed byte may represent the first byte of a larger data field in memory.

byte {0..255}

A value representing an 8 bit byte. When in a larger field, the higher bits are zero.

char {0..127}

A value representing a 7 bit ASCII character code. When in a larger field, the higher bits are zero.

n {-32,768..32,767}

16 bit signed integer number. Any other symbol refers to an arbitrary signed 16-bit integer in the range {-32,768..32,767}, unless otherwise noted.

u {0..65,535}

16 bit unsigned integer number.

d {-2,147,483,648..2,147,483,647}

32 bit signed 'double' number. The most significant 16-bits, with sign, is most accessible on the stack.

flag

A numerical value with two logical states; 0 = false, non-zero = true.

Input Text

name An arbitrary FORTH word accepted from the input stream. This notation refers to text from the input stream, not to values on the data stack. If the input stream is exhausted before encountering , an error condition exists.

Order

The definitions are listed in ASCII alphabetical order in several groups consisting of:

Nucleus Words

! * */ /MOD + +! +loop - / /MOD 0< 0= 0> 1+ 1- 2+ 2- < = > >R ?DUP @ ABS AND begin C! C@ colon CMOVE constant create D+ D< DEPTH DNEGATE do does> DROP DUP else EXECUTE EXIT FILL I if J LEAVE literal loop MAX MIN MOD MOVE NEGATE NOT OR OVER PICK R> R@ repeat ROLL ROT semicolon SWAP then U U/ until variable while XOR

(note that lower case entries refer to just the run-time code corresponding to a compiling word.)

Interpreter Words

#> #S ' ( -TRAILING . 79-STANDARD <# >IN ? ABORT BASE BLK CONTEXT CONVERT COUNT CR CURRENT DECIMAL EMIT EXPECT FIND FORTH HERE HOLD KEY PAD QUERY QUIT SIGN SPACE SPACES TYPE U. WORD

Compiler Words

+LOOP , ." : ; ALLOT BEGIN COMPILE CONSTANT CREATE DEFINITIONS DO DOES> ELSE FORGET IF IMMEDIATE LITERAL LOOP REPEAT STATE THEN UNTIL VARIABLE VOCABULARY WHILE [ [COMPILE] ]

Device Words

BLOCK BUFFER EMPTY-BUFFERS LIST LOAD SAVE-BUFFERS SCR UPDATE

STACK MANIPULATION

Word	Syntax	I/C	Status	Description	Comment
DUP	n -- n n	I,C	Working	Duplicate top of stack
?DUP	n -- n n	I,C	Working	duplicate n if non-zero
DROP	n --	I,C	Working	Drop top number from the stack
SWAP	n1 n2 -- n2 n1	I,C	Working	Reverse top two stack items
OVER	n1 n2 -- n1 n2 n1	I,C	Working	Leave a copy of the second number on the stack.
ROT	n1 n2 n3 -- n2 n3 n1	I,C	Working	Rotate the top three values, bringing the deepest to the top.
DEPTH	-- n			Leave number of the quantity of 16-bit values contained in the data stack, before n added
>R	n --	C		Move n to return stack
R>	-- n	C		Transfer n from the return stack to the data stack.
R@	-- n	C		Copy the number on top of the return stack to the data stack.

COMPARISON

Word	Syntax	I/C	Status	Description	Comment
<	n1 n2 -- flag	I,C	Working	True if n1 less than n2
=	n1 n2 -- flag	I,C	Working	True if n1 equal to n2
>	n1 n2 -- flag	I,C	Working	True if n1 greater than n2
0<	n -- flag	I,C	Working	True if n less than zero
0=	n -- flag	I,C	Working	True if n zero
0>	n -- flag	I,C	Working	True if n greater than zero

ARITHMETIC AND LOGICAL

Word	Syntax	I/C	Status	Description	Comment
+	n1 n2 -- n3	I,C	Working	Arithmetic result of n1 plus n2
+!	n addr --		Working	Add second 16-bit number to contents of address
-	n1 n2 -- n3	I,C	Working	Subtract n2 from n1 leaveing result in n3
*	n1 n2 -- n3	I,C	Working	Arithmetic product of n1 times n2
*/	n1 n2 n3 -- n4			Multiply n1 by n2, divide result by n3 and leave quotient in n4
*/MOD	n1 n2 n3 -- n4 n5			Multiply n1 by n2, divide result by n3 and leave remainder in n4 and quotient in n5
/	n1 n2 -- n3	I,C	Working	Divide n1 divide by n2, leave quotient in n3
/MOD	n1 n2 -- n3 n4	I,C	Working	Divide n1 divide by n2, leave remainder in n3 and quotient in n4
1+	n -- n+1			Increment n by one
1-	n -- n-1			Decrement n by one
2+	n -- n+2			Increment n by two
2-	n -- n-2			Decrement n by two
MOD	n1 n2 -- n3	I,C	Working	Divide n1 by n2, leaving the remainder n3, with the same sign as n1.
U*	un1 un2 -- ud3			Perform an unsigned multiplication of un1 by un2, leaving the double number product ud3. All values are unsigned.
U.	un --	I,C	Working	Display un converted according to BASE as an unsigned number, in a free-field format, with one trailing blank.
U/MOD	ud1 un2 -- un3 un4			Perform the unsigned division of double number ud1 by un2, leaving the remainder un3, and the quotient un4. All values are unsigned.
U<	un1 un2 -- flag			Leave the flag representing the magnitude comparison of un1 < un2 where un1 and un2 are treated as 16-bit unsigned integers.
ABS	n1 -- n1	I,C	Working	Absolute value of n1
MAX	n1 n2 -- n3	I,C	Working	Leave the greater of two numbers.
MIN	n1 n2 -- n3	I,C	Working	Leave the lesser of two numbers.
NEGATE	n -- -n			Leave the two's complement of a number, i.e., the difference of zero less n.
DNEGATE	d -- -d	I,C	Working	Leave the two's complement of a double number.
AND	n1 n2 -- n3	I,C	Working	Leave Logical bitwise AND of n1 and n2
OR	n1 n2 -- n3	I,C	Working	Leave the bitwise inclusive-or of two numbers.
XOR	n1 n2 -- n3	I,C	Working	Leave the bitwise exclusive-or of two numbers.

MEMORY

Word	Syntax	I/C	Status	Description	Comment
@	addr -- n	I,C	Working	Put on stack number at addr
!	n addr --	I,C	Working	Store second word at address on top
C@	addr -- byte		Working	Leave on stack addr, with high bits set to 0 for 16-bit field
C!	n addr --		Working	Store least significant of n in addr

CONTROL STRUCTURES

Word	Syntax	I/C	Status	Description	Comment
IFTRUE	flag --	I		Begin an IFTRUE ... OTHERWISE ... IFEND conditional sequence. These conditional words operate like IF ... ELSE ... THEN except that they cannot be nested, and are to be used only during interpretation. In conjunction with the words [ and ] they may be used within a colon-definition to control compilation, although they are not to be compiled.
OTHERWISE		I		An interpreter-level conditional word. See IFTRUE.
IFEND		I		Terminate a conditional interpretation sequence begun by IFTRUE.
DO	n1 n2 --	C	Working	Used in a colon-definition: DO ... LOOP or DO ... +LOOP Begin a loop which will terminate based on control parameters. The loop index begins at n2, and terminates based on the limit n1. At LOOP or +LOOP, the index is modified by a positive or negative value. The range of a DO-LOOP is determined by the terminating word. DO-LOOP may be nested. Capacity for three levels of nesting is specified as a minimum for standard systems.
LOOP	--	C	Working	Increment the DO-LOOP index by one, terminating the loop if the new index is equal to or greater than the limit. The limit and index are signed numbers in the range {-32,768..32,767}.
+LOOP	n --	C	Working	Increment index by n. Terminate loop if outside limit
LEAVE	--	C	Working	Force termination of a DO-LOOP at the next LOOP or +LOOP by setting the loop limit equal to the current value of the index. The index itself remains unchanged, and execution proceeds normally until the loop terminating word is encountered.
I	-- n	C	Working	Copy loop index on stack. May only be used in the form: DO ... I ... LOOP or DO ... I ... +LOOP
J	-- n	C		Return the index of the next outer loop. May only be used within a nested DO-LOOP in the form: DO ... DO ... J ... LOOP ... LOOP
IF	flag --	C	Working	Used in a colon-definition in the form: flag IF ... ELSE ... THEN or flag IF ... THEN If flag is true, the words following IF are executed and the words following ELSE are skipped. The ELSE part is optional. If flag is false, words between IF and ELSE, or between IF and THEN (when no ELSE is used), are skipped. IF-ELSE-THEN conditionals may be nested.
ELSE	--	C	Working	Used in a colon-definition in the form: IF ... ELSE ... THEN ELSE executes after the true part following IF. ELSE forces execution to skip till just after THEN. It has no effect on the stack. (see IF)
THEN	--	C	Working	Used in a colon-definition in the form: IF ... ELSE ... THEN or IF ... THEN THEN is the point where execution resumes after ELSE or IF (when no ELSE is present).
BEGIN	--	C	Working	Used in a colon-definition in the form: BEGIN ... flag UNTIL or BEGIN ... flag WHILE ... REPEAT BEGIN marks the start of a word sequence for repetitive execution. A BEGIN-UNTIL loop will be repeated until flag is true. A BEGIN-WHILE-REPEAT loop will be repeated until flag is false. The words after UNTIL or REPEAT will be executed when either loop is finished. flag is always dropped after being tested.
WHILE	flag --	C	Working	Used in the form: BEGIN ... flag WHILE ... REPEAT Select conditional execution based on flag. On a true flag, continue execution through to REPEAT, which then returns back to just after BEGIN. On a false flag, skip execution to just after REPEAT, exiting the structure.
REPEAT	--	C	Working	Used in a colon-definition in the form: BEGIN ... WHILE ... REPEAT At run-time, REPEAT returns to just after the corresponding BEGIN.
UNTIL	flag --	C	Working	LWithin a colon-definition, mark the end of a BEGIN-UNTIL loop, which will terminate based on flag. If flag is true, the loop is terminated. If flag is false, execution returns to the first word after BEGIN. BEGIN-UNTIL structures may be nested.

TERMINAL INPUT-OUTPUT

Word	Syntax	I/C	Status	Description	Comment
CR	--	I,C	Working	Do a carriage-return
EMIT	char --	I,C	Working	Transmit character to current output device
SPACE	--	I,C	Working	Transmit an ASCII blank to the current output device.
SPACES	n --	I,C	Working	Transmit n spaces to the current output device. Take no action for n of zero or less.
TYPE	addr n --	I,C	Working	Transmit n characters beginning at address to the current output device. No action takes place for n less than or equal to zero.
COUNT	addr -- addr+1 n	I,C	Working	Leave the address addr+1 and the character count of text beginning at addr. The first byte at addr must contain the character count n. Range of n is {0..255}.
KEY	-- char	I,C	Working	Read key, put ASCII value on stack
EXPECT	addr n --	I,C	Working	Transfer characters from the terminal beginning at addr, upward, until a "return" or the count of n has been received. Take no action for n less than or equal to zero. One or two nulls are added at the end of text.
QUERY				Accept input of up to 80 characters (or until a 'return') from the operator's terminal, into the terminal input buffer. WORD may be used to accept text from this buffer as the input stream, by setting >IN and BLK to zero.
WORD	char -- addr			Receive characters from the input stream until the non-zero delimiting character is encountered or the input stream is exhausted, ignoring leading delimiters. The characters are stored as a packed string with the character count in the first character position. The actual delimiter encountered (char or null) is stored at the end of the text but not included in the count. If the input stream was exhausted as WORD is called, then a zero length will result. The address of the beginning of this packed string is left on the stack.
-TRAILING	addr n1 -- addr n2			Adjust char count n1 of a text string at addr to exclude trailing blank, resulting in string at addr new length on n2

NUMERIC CONVERSION

Word	Syntax	I/C	Status	Description	Comment
<#	--			Initialize pictured number output
#>	d -- addr n			Terminate output string for TYPE
BASE	-- addr	U		Leave address of variable containing current input-output number conversion base. {{2..70}
OCTAL	--			Set the number base to 8.
DECIMAL	--			Set input-output numeric conversation base to ten
HEX	--			Set the numeric input-output conversion base to sixteen.
CONVERT	d1 addr1 -- d2 addr2			Convert to the equivalent stack number the text beginning at addr1+1 with regard to BASE. The new value is accumulated into double number d1, being left as d2. addr2 is the address of the first non-convertible character.

MASS STORAGE INPUT-OUTPUT

Word	Syntax	I/C	Status	Description	Comment
LIST	n --			List the ASCII symbolic contents of screen n on the current output device, setting SCR to contain n. n is unsigned.
LOAD	n --			Begin interpretation of screen n by making it the input stream; preserve the locators of the present input stream (from >IN and BLK). If interpretation is not terminated explicitly it will be terminated when the input stream is exhausted. Control then returns to the input stream containing LOAD, determined by the input stream locators >IN and BLK.
BLOCK	n -- addr			Return address of first byte of memory for block n. If block n is not in memory, retrieve it first
UPDATE				Mark the most recently referenced block as modified. The block will subsequently be automatically transferred to mass storage should its memory buffer be needed for storage of a different block, or upon execution of SAVE-BUFFERS.
SAVE-BUFFERS				Write all blocks to mass-storage that have been flagged as UPDATEd. An error condition results if mass-storage writing is not completed.
EMPTY-BUFFERS				Mark all block buffers as empty, without necessarily affecting their actual contents. UPDATEd blocks are not written to mass storage.

DEFINING WORDS

Word	Syntax	I/C	Status	Description	Comment
:	--	I	Working	Begin a colon definition
;	--	C	Working	End of a colon definition
CONSTANT	n --	I,C	Working	A defining word used in the form: n CONSTANT name to create a dictionary entry for name, leaving n in its parameter field. When name is later executed, n will be left on the stack.
VARIABLE	n --	I,C	Working	A defining word executed in the form: VARIABLE name to create a dictionary entry for name and allot two bytes for storage in the parameter field. The application must initialize the stored value. When name is later executed, it will place the storage address on the stack.

Words

Word	Syntax	I/C	Status	Description	Comment
#	ud1 -- ud2			Convert one digit of double number and add character to output string
#S	ud -- 0 0			Convert all significant digits of double number to output string
'	-- addr	I		Find address of next string in dictionary
(	--	I,C		Begin comment, terminated by )
,	n --			Allot two bytes in dictionary, storing n there
.	n --	I,C	Working	Print number
."	--	I,C	Working	Print message terminated by "
79-STANDARD				Returns Error if FORTH-79 Standard is not available
>IN	-- addr	U		Leave addr of variable of char offset input stream {0,,1023}
?	addr --	I,C	Working	Print contents of address
ABORT --				Clear data and return stacks
ALLOT	n --	I,C	Working	Add n bytes to parameter field of most recently defined word
BLK	-- addr	U		Leave the address of a variable containing the number of the mass storage block being interpreted as the input stream. If the content is zero, the input stream is taken from the terminal.
BUFFER	n -- addr			Obtain next block buffer, assign to n
CMOVE	addr1 addr2 n --			Move n bytes at addr1 to addr2
COMPILE		C		When a word containing COMPILE executes, the 16-bit value following the compilation address of COMPILE is copied (compiled) into the dictionary. i.e., COMPILE DUP will copy the compilation address of DUP. COMPILE [ 0 , ] will copy zero.
CONTEXT	-- addr	U		Leave the address of a variable specifying the vocabulary in which dictionary searches are to be made, during interpretation of the input stream.
CREATE				A defining word used in the form: CREATE name to create a dictionary entry for , without allocating any parameter field memory. When name is subsequently executed, the address of the first byte of name's parameter field is left on the stack.
CURRENT	-- addr	U		Leave the address of a variable specifying the vocabulary into which new word definitions are to be entered.
DEFINITIONS	--			Set current vocabulary to context vocabulary
DOES		I,C		Define the run-time action of a word created by a high-level defining word. Used in the form: : name ... CREATE ... DOES> ... ; and then namex name Marks the termination of the defining part of the defining word name and begins the defining of the run-time action for words that will later be defined by name. On execution of namex the sequence of words between DOES> and ; are executed, with the address of namex's parameter field on the stack.
EXECUTE	addr --			Execute the dictionary entry whose compilation address is on the stack.
EXIT		C		When compiled within a colon-definition, terminate execution of that definition, at that point. May not be used within a DO...LOOP.
FILL	addr n byte --	I,C	Working	Fill memory starting at addr with n copies of byte
FIND	-- addr			Leave the compilation address of the next word name, which is accepted from the input stream. If that word cannot be found in the dictionary after a search of CONTEXT and FORTH leave zero.
FORGET	--			Execute in the form: FORGET name Delete from the dictionary name (which is in the CURRENT vocabulary) and all words added to the dictionary after name, regardless of their vocabulary. Failure to find name in CURRENT or FORTH is an error condition.
FORTH	--	I		The name of the primary vocabulary. Execution makes FORTH the CONTEXT vocabulary. New definitions become a part of the FORTH until a differing CURRENT vocabulary is established. User vocabularies conclude by 'chaining' to FORTH, so it should be considered that FORTH is 'contained' within each user's vocabulary.y
HERE	-- addr		Working	Return address of next available dictionary location.
HOLD	char --			Insert ASCII character into pictured output string. May only be used between <# and #>.
IMMEDIATE				Marks the most recently made dictionary entry as a word which will be executed when encountered during compilation rather than compiled.
LITERAL	n --	I		f compiling, then compile the stack value n as a 16-bit literal, which when later executed, will leave n on the stack.
MOVE	addr1 addr2 n --			Move the specified quantity n of 16-bit memory cells beginning at addr1 into memory at addr2. The contents of addr1 is moved first. If n is negative or zero, nothing is moved.
NOT	flag1 -- flag2			Reverse the boolean value of flag1. This is identical to 0=.
PAD	-- addr	I,C	Working	The address of a scratch area used to hold character strings for intermediate processing. The minimum capacity of PAD is 64 characters (addr through addr+63).
PICK	n1 -- n2			Return the contents of the n1-th stack value, not counting n1 itself. An error condition results for n less than one. 2 PICK is equivalent to OVER. {1..n}
QUIT				Clear the return stack, setting execution mode, and return control to the terminal. No message is given.
ROLL	n --			Extract the n-th stack value to the top of the stack, not counting n itself, moving the remaining values into the vacated position. An error condition results for n less than one. {1..n} 3 ROLL = ROT 1 ROLL = null operation
SCR	-- addr	U		Leave the address of a variable containing the number of the screen most recently listed.
SIGN	n --	C		Insert the ASCII "-" (minus sign) into the pictured numeric output string, if n is negative.
STATE	-- addr	U		Leave the address of the variable containing the compilation state. A non-zero content indicates compilation is occurring, but the value itself may be installation dependent.
VOCABULARY	--			A defining word executed in the form: VOCABULARY name to create (in the CURRENT vocabulary) a dictionary entry for name, which specifies a new ordered list of word definitions. Subsequent execution of name will make it the CONTEXT vocabulary. When name becomes the CURRENT vocabulary (see DEFINITIONS), new definitions will be created in that list. In lieu of any further specification, new vocabularies 'chain' to FORTH. That is, when a dictionary search through a vocabulary is exhausted, FORTH will be searched.
[		I		End the compilation mode. The text from the input stream is subsequently executed. See ]
[COMPILE]		I,C		Used in a colon-definition in the form: [COMPILE] name Forces compilation of the following word. This allows compilation of an IMMEDIATE word when it would otherwise be executed.
]				Sets the compilation mode. The text from the input stream is subsequently compiled. See [

Extension Word Sets

DOUBLE NUMBER WORD SET

Word	Syntax	I/C	Status	Description	Comment
2!	d addr --			Store d in 4 consecutive bytes beginning at addr, as for a double number.
2@	addr -- d			Leave on the stack the contents of the four consecutive bytes beginning at addr, as for a double number.
2CONSTANT	d --			A defining word used in the form: d 2CONSTANT name to create a dictionary entry for name, leaving d in its parameter field. When name is later executed, d will be left on the stack.
2DROP	d --			Drop the top double number on the stack.
2DUP	d -- d d			Duplicate the top double number on the stack.
2OVER	d1 d2 -- d1 d2 d1			Leave a copy of the second double number on the stack.
2ROT	d1 d2 d3 -- d2 d3 d1			Rotate the third double number to the top of the stack.
2SWAP	d1 d2 -- d2 d1			Exchange the top two double numbers on the stack.
2VARIABLE				A defining word used in the form: 2VARIABLE name to create a dictionary entry of name and assign four bytes for storage in the parameter field. When name is later executed, it will leave the address of the first byte of its parameter field is placed on the stack.
D+	d1 d2 -- d3	I,C	Working	Leave the arithmetic sum of d1 and d2.
D-	d1 d2 -- d3	I,C	Working	Subtract d2 from d1 and leave the difference d3.
D.	d --	I,C	Working	Display d converted according to BASE in a free field format, with one trailing blank. Display the sign only if negative.
D.R	d n --			Display d converted according to BASE, right aligned in an n character field. Display the sign only if negative.
D0=	d -- flag			Leave true if d is zero.
D<	d1 d2 -- flag			True if d1 is less than d2.
D=	d1 d2 -- flag			True if d1 equals d2.
DABS	d1 -- d2	I,C	Working	Leave as a positive double number d2, the absolute value of a double number, d1. {0..2,147,483,647}
DMAX	d1 d2 -- d3			Leave the larger of two double numbers.
DMIN	d1 d2 -- d3			Leave the smaller of two double numbers.
DU<	ud1 ud2 -- flag			rue if ud1 is less than ud2. Both numbers are unsigned.

Assembler Word Set

Word	Syntax	I/C	Status	Description	Comment
;CODE	--	C,I		Used in the form: : name ... ;CODE Stop compilation and terminate a defining word name. ASSEMBLER becomes the CONTEXT vocabulary. When name is executed in the form: name namex to define the new namex, the execution address of namex will contain the address of the code sequence following the ;CODE in name. Execution of any namex will cause this machine code sequence to be executed.
ASSEMBLER	--	I		Select assembler as the CONTEXT vocabulary.
CODE	--			A defining word used in the form: CODE name ... END-CODE to create a dictionary entry for name to be defined by a following sequence of assembly language words. ASSEMBLER becomes the context vocabulary.
END-CODE				Terminate a code definition, resetting the CONTEXT vocabulary to the CURRENT vocabulary. If no errors have occurred, the code definition is made available for use.

##Reference Word Set

The Reference Word Set contain both Standard Word Definitions and uncontrolled word definitions.

Word	Syntax	I/C	Status	Description	Comment
!BITS	n1 addr n2 --			Store the value of n1 masked by n2 into the equivalent masked part of the contents of addr, without affecting bits outside the mask.
**	n1 n2 -- n3			Leave the value of n1 to the power n2.
+BLOCK	n1 -- n2			Leave the sum of n1 plus the number of the block being interpreted, n1 and n2 are unsigned.
-'	-- ( addr ) flag			Used in the form: -' name Leave the parameter field of name beneath zero (false) if the name can be found in the CONTEXT vocabulary; leave only true if not found.
-->		I		ontinue interpretation on the next sequential block. May be used within a colon definition that crosses a block boundary.
-MATCH	addr1 n1 addr2 n2 -- addr3 flag			Attempt to find the n2-character string beginning at addr2 somewhere in the n1-character string beginning at addr1. Return the last+1 character address addr3 of the match point and a flag which is zero if a match exists.
-TEXT	addr1 n1 addr2 -- n2			Compare two strings over the length n1 beginning at addr1 and addr2. Return zero if the strings are equal. If unequal, return n2, the difference between the last characters compared: addr1(i) - addr2(i)
.R	n1 n2 --			Print n1 right aligned in a field of n2 characters, according to BASE. If n2 is less than 1, no leading blanks are supplied.
/LOOP	n --			A DO-LOOP terminating word. The loop index is incremented by the unsigned magnitude of n. Until the resultant index exceeds the limit, execution returns to just after the corresponding DO: otherwise, the index and limit are discarded. Magnitude logic is used.
1+!	addr --			Add one to the 16-bit contents at addr.
1-!	addr --			Subtract 1 from the 16-bit contents at addr.
2*	n1 -- n2			Leave 2*(n1).
2/	n1 -- n2			Leave (n1)/2.
;:		C		Used to specify a new defining word: : name ... ;: ... ; name namex When name is executed, it creates an entry for the new word namex. Later execution of namex will execute the sequence of words between ;: and ; , with the address of the first (if any) parameters associated with namex on the stack.
;S				Stop interpretation of a block. For execution only.
<>	n1 n2 -- flag			Leave true if n1 is not equal to n2.
<BUILDS		C		Used in conjunction with DOES> in defining words, in the form: : name . . . <BUILDS . . . DOES> ... ; and then name namex When executes, <BUILDS creates a dictionary entry for the new namex. The sequence of words between established a parameter field for namex. When namex is later executed, the sequence of words following DOES> will be executed, with the parameter field address of namex on the data stack.
<CMOVE	addr1 addr2 n --			Copy n bytes beginning at addr1 to addr2. The move proceeds within the bytes from high memory toward low memory.
><	n1 -- n2			Swap the high and low bytes within n1.
>MOVE<	addr1 addr2 n --			Move n bytes beginning at addr1 to the memory beginning at addr2. During this move, the order of each byte pair is reversed.
@BITS	addr n1 -- n2			Return the 16-bits at addr masked by n1.
ABORT"	flag --	I,C		Used in a colon-definition in the form: ABORT" stack empty" If the flag is true, print the following text, till ". Then execute ABORT.
AGAIN		I,C		Effect an unconditional jump back to the start of a BEGIN-AGAIN loop.
ASCII	-- char (executing) - (compiling)	I,C		Leave the ASCII character value of the next non-blank character in the input stream. If compiling, compile it as a literal, which will be later left when executed.
ASHIFT	n1 n2 -- n3			Shift the value n1 arithmetically n2 bits left if n2 is positive, shifting zeros into the least-significant bit positions. If n2 is negative, n1 is shifted right. Sign extension is to be consistent with the processor's arithmetic shift.
B/BUF	-- 1024			A constant leaving 1024, the number of bytes per block buffer.
BELL				Activate a terminal bell or noise-maker as appropriate to the device in use.
BL	-- n			Leave the ASCII character value for space (decimal 32).
BLANKS	addr n --		Working	Fill an area of memory over n bytes with the value for ASCII blank, starting at addr. If n is less than or equal to zero, take no action.
C,	n --			Store the low-order 8 bits of n at the next byte in the dictionary, advancing the dictionary pointer.
CHAIN				Used in the form: CHAIN name Connect the CURRENT vocabulary to all definitions that might be entered into the vocabulary name in the future. The CURRENT vocabulary may not be FORTH or ASSEMBLER. Any given vocabulary may only be chained once, but may be the object of any number of chainings. For example, every user-defined vocabulary may include the sequence: CHAIN FORTH
COM	n1 -- n2			Leave the one's complement of n1.
CONTINUED	n --			Continue interpretation at block n.
CUR	-- addr			A variable pointing to the physical record number before which the tape is currently positioned. REWIND sets CUR=1.
DBLOCK	d -- addr			Identical to BLOCK but with a 32-bit block unsigned number.
DPL	-- addr			A variable containing the number of places after the fractional point for output conversion. If DPL contains zero, the last character output will be a decimal point. No point is output if DPL contains a negative value. DPL may be set explicitly, or by certain output words, but is unaffected by number input.
DUMP	addr n --			List the contents of n addresses at addr. Each line of values may be preceded by the address of the first value.
EDITOR		I		The name of the editor vocabulary. When this name is executed, EDITOR is established as the CONTEXT vocabulary.
END		I,C		A synonym for UNTIL.
ERASE	addr n --		Working	Fill an area of memory over n bytes with zeros, starting at addr. If n is zero or less, take no action.
FLD	-- addr			A variable pointing to the field length reserved for a number during output conversion.
H.	n --			Output n as a hexadecimal integer with one trailing blank. The current base is unchanged.
I'	-- n	C		Used within a colon-definition executed only from within a DO-LOOP to return the corresponding loop index.
INDEX	n1 n2 --			Print the first line of each screen over the range {n1..n2}. This displays the first line of each screen of source text, which conventionally contains a title.
INTERPRET				Begin interpretation at the character indexed by the contents of >IN relative to the block number contained in BLK, continuing until the input stream is exhausted. If BLK contains zero, interpret characters from the terminal input buffer.
K	-- n	C		Within a nested DO-LOOP, return the index of the second outer loop.
LAST	-- addr			A variable containing the address of the beginning of the last dictionary entry made, which may not yet be a complete or valid entry.
LINE	n -- addr			Leave the address of the beginning of line n for the screen whose number is contained in SCR. The range of n is {0..15}.
LINELOAD	n1 n2 --			Begin interpretation at line n1 of screen n2.
LOADS	n --			A defining word used in the form: n LOADS name When name is subsequently executed, block n will be loaded.
MAP0	-- addr			A variable pointing to the first location in the tape map.
MASK	n1 -- n2			Leave a mask of n1 most significant bits if n1 is positive, or n least significant bits if n1 is negative.
MS	n --			Delay for approximately n milliseconds.
NAND	n1 n2 -- n3			The one's complement of the logical and of n1 and n2.
NOR	n1 n2 -- n3			The one's complement of the logical or of n1 and n2.
NUMBER	addr -- n			Convert the count and character string at addr, to a signed 32-bit integer, using the current base. If numeric conversion is not possible, an error condition exists. The string may contain a preceding negative sign.
O.	n --			Print n in octal format with one trailing blank. The value in base is unaffected.
OFFSET	-- addr			A variable that contains the offset added to the block number on the stack by BLOCK to determine the actual physical block number. The user must add any desired offset when utilizing BUFFER.
PAGE				Clear the terminal screen or perform an action suitable to the output device currently active.
READ-MAP				Read to the next file mark on tape constructing a correspondence table in memory (the map) relating physical block position to logical block number. The tape should normally be rewound to its load point before executing READ-MAP.
REMEMBER				A defining word used in the form: REMEMBER name Defines a word which, when executed, will cause name and all subsequently defined words to be deleted from the dictionary. name may be compiled into and executed from a colon definition. The sequence DISCARD REMEMBER DISCARD provides a standardized preface to any group of transient word definitions.
REWIND				Rewind the tape to its load point, setting CUR=1.
ROTATE	n1 n2 -- n3			Rotate the value n1 left n2 bits if n2 is positive, right n2 bits if n2 is negative. Bits shifted out of one end of the cell are shifted back in at the opposite end.
S0	-- addr			Returns the address of the bottom of the stack, when empty.
SET	n addr --			A defining word used in the form: n addr SET name Defines a word name which, when executed, will cause the value n to be stored at address.
SHIFT	n1 n2 -- n3			Logical shift n1 left n2 bits if n2 in positive, right if n2 is negative. Zeros are shifted into vacated bit positions.
SP@	-- addr		Working	Return the address of the top of the stack, just before SP@ was executed
TEXT	c --			Accept characters from the input stream, as for WORD, into PAD, blank-filling the remainder of PAD to 64 characters.
THRU	n1 n2 --			Load consecutively the blocks from n1 through n2.
U,R	un1 n2 --			Output un1 as an unsigned number right justified in a field n2 characters wide. If n2 is smaller than the characters required for n1, no leading spaces are given.
USER	n --			A defining word used in the form: n USER name which creates a user variable name. n is the cell offset within the user area where the value for name is stored. Execution of name leaves its absolute user area storage address.
VLIST				List the word names of the CONTEXT vocabulary starting with the most recent definition.
WHERE				Output information about the status of FORTH, (e.g., after an error abort). Indicate at least the last word compiled and the last block accessed.
\LOOP	n --	I, C		A DO-LOOP terminating word. The loop index is decremented by n and the loop terminated when the resultant index becomes equal to or less than the limit. Magnitude logic is used, and n must be positive.

Words from original implementation that should be removed (or perhaps are really renamed)

Word	Syntax	I/C	Status	Description	Comment
?TERMINAL	-- f			True if terminal break request present
SIGN	( n d -- d			Insert sign of n to output string

License

A2osX is licensed under the GNU General Pulic License |

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) | | | any later version |

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details |

The full A2osX license can be found Here |

Copyright

Copyright 2015 -- 2019, Remy Gibert and the A2osX contributors |