Gamevar operators - Revision history

Hendricks266 at 19:06, 15 December 2024

2024-12-15T19:06:06Z

← Older revision		Revision as of 12:06, 15 December 2024
Line 1:		Line 1:
			<span {{code}}> <'''operator'''> <gamevar> <constant\|gamevar></span>

	<span {{code}}> <'''operator'''> <gamevar> (<constant>~~\|<gamevar>)~~</span>		<span {{code}}> <'''operator'''>'''var''' <gamevar> <constant> </span> ''(deprecated)''

	<span {{code}}> <'''operator'''>'''~~var~~''' <gamevar> <~~constant~~> </span> ''(~~Deprecated~~)''		<span {{code}}> <'''operator'''>'''varvar''' <gamevar> <gamevar></span> ''(deprecated)''

	~~<span {{code}}> <'''operator'''>'''varvar''' <gamevar> <gamevar></span> ''(Deprecated)''~~		EDuke32 CON supports a range of binary operators that perform various arithmetic and bitwise logical operations on variables, here denoted as [[gamevar]]s.


	~~eduke32~~ CON supports a range of binary operators that perform various arithmetic and bitwise logical operations on variables, here denoted as [[gamevar]]s.

	The syntax is similar to Intel x86 assembly, where the first argument is the destination as well as the first operand (2-address code).		The syntax is similar to Intel x86 assembly, where the first argument is the destination as well as the first operand (2-address code).

	In older versions of ~~eduke32 (and in vanilla Duke Nukem 3D)~~, it was necessary to distinguish between '''var''', and '''varvar''' binary operations. The difference between them is that the singular '''var''' operations expect a gamevar for the first, and a constant value (or label) for the second argument, while the '''varvar''' operations expect gamevars for both arguments.		In older versions of EDuke32, it was necessary to distinguish between '''var''', and '''varvar''' binary operations. The difference between them is that the singular '''var''' operations expect a gamevar for the first, and a constant value (or label) for the second argument, while the '''varvar''' operations expect gamevars for both arguments.

	This distinction is no longer required, and one can now write the operator without any '''var''' appendix, and use either constant or variable as the second argument.		This distinction is no longer required, and one can now write the operator without any '''var''' appendix, and use either constant or variable as the second argument.

	==== Example ====		==== Example ====
Line 43:		Line 41:
	\|sub		\|sub
	\|<code><nowiki>-</nowiki></code>		\|<code><nowiki>-</nowiki></code>
	\|<nowiki>&~~ndash~~;</nowiki>		\|<nowiki>−</nowiki>
	\|subtraction		\|subtraction
	\|		\|
Line 61:		Line 59:
	\|mod		\|mod
	\|<code>%</code>		\|<code>%</code>
	\|		\|mod
	\|[[Wikipedia:Modulo operation\|modulo]], remainder		\|[[Wikipedia:Modulo operation\|modulo]], remainder
	\|Ensure that <value> does not equal 0 at any time; sign of the result is that of left hand side operand (dividend).		\|Ensure that <value> does not equal 0 at any time; sign of the result is that of left hand side operand (dividend).
Line 67:		Line 65:
	\|and		\|and
	\|<code>&</code>		\|<code>&</code>
	\|		\|∧
	\|[[Wikipedia:Bitwise operation\|bitwise]] AND		\|[[Wikipedia:Bitwise operation\|bitwise]] AND
	\|The bits in the result are set only if they were set in both of the values being operated on. Ex. (all numbers are [[Wikipedia:Binary numeral system\|base-2]]): 01001010 AND 11110100 is 01000000		\|The bits in the result are set only if they were set in both of the values being operated on. Ex. (all numbers are [[Wikipedia:Binary numeral system\|base-2]]): 01001010 AND 11110100 is 01000000
Line 73:		Line 71:
	\|or		\|or
	\|<code><nowiki>\|</nowiki></code>		\|<code><nowiki>\|</nowiki></code>
	\|		\|∨
	\|[[Wikipedia:Bitwise operation\|bitwise]] OR		\|[[Wikipedia:Bitwise operation\|bitwise]] OR
	\|The bits in the result are set only if they were set in either of the values being operated on. Ex.: 01001010 OR 11110100 is 11111110		\|The bits in the result are set only if they were set in either of the values being operated on. Ex.: 01001010 OR 11110100 is 11111110
Line 79:		Line 77:
	\|xor		\|xor
	\|<code>^</code>		\|<code>^</code>
	\|		\|⊕
	\|[[Wikipedia:Bitwise operation\|bitwise]] XOR		\|[[Wikipedia:Bitwise operation\|bitwise]] XOR
	\|The bits in the result are set if only one of the values being operated on has those bits set. Ex.: 01001010 XOR 11110100 is 10111110		\|The bits in the result are set if only one of the values being operated on has those bits set. Ex.: 01001010 XOR 11110100 is 10111110

Doom64hunter: Formatting and make it more apparent that the 'var' affix is no longer needed

2021-01-10T09:59:21Z

Formatting and make it more apparent that the 'var' affix is no longer needed

← Older revision		Revision as of 02:59, 10 January 2021
Line 1:		Line 1:
	~~<'''operator'''>'''var''' <gamevar> <value><br>~~
	~~<'''operator'''>'''varvar''' <gamevar> <value>~~

	~~Gamevar operators are commands that perform various mathematical and bitwise logical operations on [[~~gamevar~~]]s. The first argument must be a writable~~ gamevar ~~and is taken as the destination as well and the first operand (2-address code~~).		<span {{code}}> <'''operator'''> <gamevar> (<constant>\|<gamevar>)</span>

	~~For example:~~		<span {{code}}> <'''operator'''>'''var''' <gamevar> <constant> </span> ''(Deprecated)''

	~~setvar temp 1~~ /~~/ assigns~~ a ~~value~~ of 1 to the gamevar ''~~temp~~''.		<span {{code}}> <'''operator'''>'''varvar''' <gamevar> <gamevar></span> ''(Deprecated)''


			eduke32 CON supports a range of binary operators that perform various arithmetic and bitwise logical operations on variables, here denoted as [[gamevar]]s.

			The syntax is similar to Intel x86 assembly, where the first argument is the destination as well as the first operand (2-address code).

			In older versions of eduke32 (and in vanilla Duke Nukem 3D), it was necessary to distinguish between '''var''', and '''varvar''' binary operations. The difference between them is that the singular '''var''' operations expect a gamevar for the first, and a constant value (or label) for the second argument, while the '''varvar''' operations expect gamevars for both arguments.

			This distinction is no longer required, and one can now write the operator without any '''var''' appendix, and use either constant or variable as the second argument.

			==== Example ====

			var temp 0 0 // initialize a global variable with initial value 0

	~~addvar~~ temp 1 // ~~adds~~ 1 to ''temp''~~, causing its value to become 2~~.		set temp 1 // assigns a value of 1 to the gamevar ''temp''.

	~~mulvar~~ temp 2 // multiplies ''temp'' by 2, causing its value to become 4.		add temp 1 // adds 1 to ''temp'', causing its value to become 2.

			mul temp 2 // multiplies ''temp'' by 2, causing its value to become 4.

			== Operators ==

	{\| {{prettytable}}		{\| {{prettytable}}
Line 68:		Line 83:
	\|The bits in the result are set if only one of the values being operated on has those bits set. Ex.: 01001010 XOR 11110100 is 10111110		\|The bits in the result are set if only one of the values being operated on has those bits set. Ex.: 01001010 XOR 11110100 is 10111110
	\|}		\|}

	~~{{varsuffix}}~~

	[[Category:Gamevar manipulation]]		[[Category:Gamevar manipulation]]

Hendricks266 at 20:21, 8 March 2015

2015-03-08T20:21:46Z

← Older revision		Revision as of 13:21, 8 March 2015
Line 54:		Line 54:
	\|		\|
	\|[[Wikipedia:Bitwise operation\|bitwise]] AND		\|[[Wikipedia:Bitwise operation\|bitwise]] AND
	\|The bits in the result are set only if they were set in both of the values being operated on. Ex. (all numbers are [[Wikipedia:Binary numeral system\|base-2]]):~~<br/>~~		\|The bits in the result are set only if they were set in both of the values being operated on. Ex. (all numbers are [[Wikipedia:Binary numeral system\|base-2]]): 01001010 AND 11110100 is 01000000
	01001010 AND 11110100 is 01000000
	\|-		\|-
	\|or		\|or
Line 61:		Line 60:
	\|		\|
	\|[[Wikipedia:Bitwise operation\|bitwise]] OR		\|[[Wikipedia:Bitwise operation\|bitwise]] OR
	\|The bits in the result are set only if they were set in either of the values being operated on. Ex.:~~<br/>~~		\|The bits in the result are set only if they were set in either of the values being operated on. Ex.: 01001010 OR 11110100 is 11111110
	01001010 OR 11110100 is 11111110
	\|-		\|-
	\|xor		\|xor
Line 68:		Line 66:
	\|		\|
	\|[[Wikipedia:Bitwise operation\|bitwise]] XOR		\|[[Wikipedia:Bitwise operation\|bitwise]] XOR
	\|The bits in the result are set if only one of the values being operated on has those bits set. Ex.:~~<br/>~~		\|The bits in the result are set if only one of the values being operated on has those bits set. Ex.: 01001010 XOR 11110100 is 10111110
	01001010 XOR 11110100 is 10111110
	\|}		\|}

Hendricks266 at 20:20, 8 March 2015

2015-03-08T20:20:10Z

← Older revision		Revision as of 13:20, 8 March 2015
Line 55:		Line 55:
	\|[[Wikipedia:Bitwise operation\|bitwise]] AND		\|[[Wikipedia:Bitwise operation\|bitwise]] AND
	\|The bits in the result are set only if they were set in both of the values being operated on. Ex. (all numbers are [[Wikipedia:Binary numeral system\|base-2]]):<br/>		\|The bits in the result are set only if they were set in both of the values being operated on. Ex. (all numbers are [[Wikipedia:Binary numeral system\|base-2]]):<br/>
	01001010 AND~~<br/>~~		01001010 AND 11110100 is 01000000
	11110100 is~~<br/>~~
	01000000
	\|-		\|-
	\|or		\|or
Line 64:		Line 62:
	\|[[Wikipedia:Bitwise operation\|bitwise]] OR		\|[[Wikipedia:Bitwise operation\|bitwise]] OR
	\|The bits in the result are set only if they were set in either of the values being operated on. Ex.:<br/>		\|The bits in the result are set only if they were set in either of the values being operated on. Ex.:<br/>
	01001010 OR~~<br/>~~		01001010 OR 11110100 is 11111110
	11110100 is~~<br/>~~
	11111110
	\|-		\|-
	\|xor		\|xor
Line 73:		Line 69:
	\|[[Wikipedia:Bitwise operation\|bitwise]] XOR		\|[[Wikipedia:Bitwise operation\|bitwise]] XOR
	\|The bits in the result are set if only one of the values being operated on has those bits set. Ex.:<br/>		\|The bits in the result are set if only one of the values being operated on has those bits set. Ex.:<br/>
	01001010 XOR~~<br/>~~		01001010 XOR 11110100 is 10111110
	11110100 is~~<br/>~~
	10111110
	\|}		\|}

Helixhorned: specify mod behavior with negative arguments, see further discussion on the discussion page.

2012-04-22T16:26:03Z

specify mod behavior with negative arguments, see further discussion on the discussion page.

← Older revision		Revision as of 09:26, 22 April 2012
Line 48:		Line 48:
	\|		\|
	\|[[Wikipedia:Modulo operation\|modulo]], remainder		\|[[Wikipedia:Modulo operation\|modulo]], remainder
	\|Ensure that <value> does not equal 0 at any time; ~~'''It is undefined whether the sign of the result follows the divisor or the dividend''' (for now). <strike>~~sign of the result is that of left hand side operand~~</strike>~~		\|Ensure that <value> does not equal 0 at any time; sign of the result is that of left hand side operand (dividend).
	\|-		\|-
	\|and		\|and

Helixhorned: slight re-wording; in bitwise ops examples, state that numbers are base-0.

2012-04-19T16:29:33Z

slight re-wording; in bitwise ops examples, state that numbers are base-0.

← Older revision		Revision as of 09:29, 19 April 2012
Line 42:		Line 42:
	\|÷		\|÷
	\|division with rounding toward 0 for nonnegative dividends		\|division with rounding toward 0 for nonnegative dividends
	\|Ensure that <value> does not equal 0 at any time. '''The rounding ~~mode of~~ negative dividends ~~is undefined~~.'''		\|Ensure that <value> does not equal 0 at any time. '''The rounding behavior is undefined for negative dividends.'''
	\|-		\|-
	\|mod		\|mod
Line 54:		Line 54:
	\|		\|
	\|[[Wikipedia:Bitwise operation\|bitwise]] AND		\|[[Wikipedia:Bitwise operation\|bitwise]] AND
	\|The bits in the result are set only if they were set in both of the values being operated on. Ex.:<br/>		\|The bits in the result are set only if they were set in both of the values being operated on. Ex. (all numbers are [[Wikipedia:Binary numeral system\|base-2]]):<br/>
	01001010 AND<br/>		01001010 AND<br/>
	11110100 is<br/>		11110100 is<br/>

Helixhorned: warn dividing negative numbers, since EDuke32 CON currently implements an incorrect optimization (right shifting negative numbers by X isn't the same as dividing them by 2^X)

2012-04-19T16:25:47Z

warn dividing negative numbers, since EDuke32 CON currently implements an incorrect optimization (right shifting negative numbers by X isn't the same as dividing them by 2^X)

← Older revision		Revision as of 09:25, 19 April 2012
Line 41:		Line 41:
	\|<code>/</code>		\|<code>/</code>
	\|÷		\|÷
	\|division with rounding toward 0		\|division with rounding toward 0 for nonnegative dividends
	\|Ensure that <value> does not equal 0 at any time.		\|Ensure that <value> does not equal 0 at any time. '''The rounding mode of negative dividends is undefined.'''
	\|-		\|-
	\|mod		\|mod

TX at 22:43, 18 April 2012

2012-04-18T22:43:21Z

← Older revision		Revision as of 15:43, 18 April 2012
Line 6:		Line 6:
	For example:		For example:

	setvar temp 3 // assigns a value of 1 to the gamevar ''temp''.		setvar temp 1 // assigns a value of 1 to the gamevar ''temp''.

	addvar temp 1 // adds 1 to ''temp'', causing its value to become 2.		addvar temp 1 // adds 1 to ''temp'', causing its value to become 2.

TX: Reverted edits by Rasmusthorup (talk) to last revision by Helixhorned

2012-04-18T22:42:28Z

Reverted edits by Rasmusthorup (talk) to last revision by Helixhorned

← Older revision		Revision as of 15:42, 18 April 2012
Line 6:		Line 6:
	For example:		For example:

	setvar temp 3 // assigns a value of 1 to the gamevar ''temp''~~. Am i reading this wrong? Rasmusthorup~~.		setvar temp 3 // assigns a value of 1 to the gamevar ''temp''.

	addvar temp 1 // adds 1 to ''temp'', causing its value to become 2.		addvar temp 1 // adds 1 to ''temp'', causing its value to become 2.

Rasmusthorup at 20:22, 18 April 2012

2012-04-18T20:22:19Z

← Older revision		Revision as of 13:22, 18 April 2012
Line 6:		Line 6:
	For example:		For example:

	setvar temp 3 // assigns a value of 1 to the gamevar ''temp''.		setvar temp 3 // assigns a value of 1 to the gamevar ''temp''. Am i reading this wrong? Rasmusthorup.

	addvar temp 1 // adds 1 to ''temp'', causing its value to become 2.		addvar temp 1 // adds 1 to ''temp'', causing its value to become 2.