Arithmetic overflow - Revision history

Sahaib: Modifying redirect categories using Capricorn ♑

2025-06-02T21:14:23Z

Modifying redirect categories using Capricorn ♑

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	#~~redirect~~ [[Integer overflow]]		#REDIRECT [[Integer overflow]]

			{{Redirect category shell\|
	{{R from merge}}		{{R from merge}}
			{{R from alternative name}}
			}}

	[[Category:Computer arithmetic]]		[[Category:Computer arithmetic]]

Christian75 at 12:58, 3 September 2017

2017-09-03T12:58:35Z

← Previous revision		Revision as of 12:58, 3 September 2017
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	#redirect [[Integer overflow]]		#redirect [[Integer overflow]]

			{{R from merge}}

			[[Category:Computer arithmetic]]

128.68.49.67: merge to integer overflow

2017-02-23T10:18:03Z

merge to integer overflow

← Previous revision		Revision as of 10:18, 23 February 2017
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		⚫	#redirect [[Integer overflow]]
	{{refimprove\|date=December 2013}}
	{{merge\|Integer overflow\|discuss=Talk:integer_overflow#Merger proposal\|date=September 2015}}

	<!-- Keep this note! Technical term, necessary for wikipedia articles; don't assign for wiktionary -->
	The term '''arithmetic overflow''' or simply '''overflow''' has the following meanings.

	# In a [[computer]], the condition that occurs when a calculation produces a result that is greater in magnitude than that which a given [[processor register\|register]] or [[Computer storage\|storage]] location can store or represent.
	# In a computer, the amount by which a calculated value is greater in magnitude than that which a given register or storage location can store or represent. Note that the overflow may be placed at another location.

	Most computers distinguish between two kinds of overflow conditions. A [[carry (arithmetic)\|carry]] occurs when the result of an addition or subtraction, considering the operands and result as unsigned numbers, does not fit in the result. Therefore, it is useful to check the [[carry flag]] after adding or subtracting numbers that are interpreted as unsigned values. An ''overflow'' proper occurs when the result does not have the sign that one would predict from the signs of the operands (e.g. a negative result when adding two positive numbers). Therefore, it is useful to check the [[overflow flag]] after adding or subtracting numbers that are represented in [[two's complement]] form (i.e. they are considered signed numbers).

	There are several methods of handling overflow:
	# Avoidance: by carefully ordering operations, checking operands in advance and selecting the correct data type, it is possible to ensure that the result will never be larger than can be stored.
	# Handling: If it is anticipated that overflow may occur and when it happens detected and other processing done. Example: it is possible to add two numbers each two bytes wide using just a byte addition in steps: first add the low bytes then add the high bytes, but if it is necessary to carry out of the low bytes this is arithmetic overflow of the byte addition and it necessary to detect and increment the sum of the high bytes. [[Central processing unit\|CPUs]] generally have a way of detecting this to support addition of numbers larger than their register size, typically using a status bit.
	# Propagation: if a value is too large to be stored it can be assigned a special value indicating that overflow has occurred and then have all successive operation return this flag value. This is useful so that the problem can be checked for once at the end of a long calculation rather than after each step. This is often supported in Floating Point Hardware called [[floating point unit\|FPU]]s.
	# An overflow condition may be ignored, particularly if the possibility has not been anticipated, but this gives incorrect results and can compromise a program's reliability and [[software security\|security]].

	[[Division by zero]] is ''not'' a form of arithmetic overflow. Mathematically, division by zero within [[Real numbers\|reals]] is explicitly [[Defined and undefined\|undefined]].

	==Overflow bugs==

	Unanticipated arithmetic overflow is a fairly common cause of [[software bug\|program errors]]. Such overflow bugs may be hard to discover and diagnose because they may manifest themselves only for very large input data sets, which are less likely to be used in validation tests.<ref>Joshua Bloch, [http://googleresearch.blogspot.com/2006/06/extra-extra-read-all-about-it-nearly.html "Extra, Extra - Read All About It: Nearly All Binary Searches and Mergesorts are Broken"]. Official Google Research Blog, June 2, 2006.</ref>

	For example, an unhandled arithmetic overflow in the engine steering software was the primary cause of the crash of the 1996 maiden flight of the [[Ariane 5 Flight 501\|Ariane 5]] rocket.<ref>{{cite web\|last=Gleick\|first=James\|title=A Bug and A Crash\|url=http://www.around.com/ariane.html\|work=New York Times Magazine\|accessdate=9 December 2013\|date=1 December 1996}}</ref> The software had been considered bug-free since it had been used in many previous flights, but those used smaller rockets which generated lower acceleration than Ariane 5.

	==See also==
	*[[IEEE 754]]
⚫	*[[Integer overflow]]
	*[[Arithmetic underflow]]

	==References==
	{{reflist}}

	{{DEFAULTSORT:Arithmetic Overflow}}
	[[Category:Computer arithmetic]]

141.166.41.125 at 21:08, 6 September 2015

2015-09-06T21:08:32Z

← Previous revision		Revision as of 21:08, 6 September 2015
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	{{refimprove\|date=December 2013}}		{{refimprove\|date=December 2013}}
	{{~~mergeto~~\|Integer overflow\|discuss=Talk:integer_overflow#Merger proposal\|date=September 2015}}		{{merge\|Integer overflow\|discuss=Talk:integer_overflow#Merger proposal\|date=September 2015}}

	<!-- Keep this note! Technical term, necessary for wikipedia articles; don't assign for wiktionary -->		<!-- Keep this note! Technical term, necessary for wikipedia articles; don't assign for wiktionary -->

141.166.41.125: Merge-to

2015-09-06T21:02:31Z

Merge-to

← Previous revision		Revision as of 21:02, 6 September 2015
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	{{refimprove\|date=December 2013}}		{{refimprove\|date=December 2013}}
			{{mergeto\|Integer overflow\|discuss=Talk:integer_overflow#Merger proposal\|date=September 2015}}

	<!-- Keep this note! Technical term, necessary for wikipedia articles; don't assign for wiktionary -->		<!-- Keep this note! Technical term, necessary for wikipedia articles; don't assign for wiktionary -->

Julietdeltalima: Fixed typo

2015-03-30T07:27:45Z

Fixed typo

← Previous revision		Revision as of 07:27, 30 March 2015
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	Unanticipated arithmetic overflow is a fairly common cause of [[software bug\|program errors]]. Such overflow bugs may be hard to discover and diagnose because they may manifest themselves only for very large input data sets, which are less likely to be used in validation tests.<ref>Joshua Bloch, [http://googleresearch.blogspot.com/2006/06/extra-extra-read-all-about-it-nearly.html "Extra, Extra - Read All About It: Nearly All Binary Searches and Mergesorts are Broken"]. Official Google Research Blog, June 2, 2006.</ref>		Unanticipated arithmetic overflow is a fairly common cause of [[software bug\|program errors]]. Such overflow bugs may be hard to discover and diagnose because they may manifest themselves only for very large input data sets, which are less likely to be used in validation tests.<ref>Joshua Bloch, [http://googleresearch.blogspot.com/2006/06/extra-extra-read-all-about-it-nearly.html "Extra, Extra - Read All About It: Nearly All Binary Searches and Mergesorts are Broken"]. Official Google Research Blog, June 2, 2006.</ref>

	For example, an unhandled arithmetic overflow in the engine steering software was the primary cause of the crash of the 1996 maiden flight of the [[Ariane 5 Flight 501\|Ariane 5]] rocket.<ref>{{cite web\|last=Gleick\|first=James\|title=A Bug and A Crash\|url=http://www.around.com/ariane.html\|work=New York Times Magazine\|accessdate=9 December 2013\|date=1 December 1996}}</ref> The software had been considered bug-free since it had been used in many previous flights; but those used smaller rockets which generated lower acceleration than Ariane 5.		For example, an unhandled arithmetic overflow in the engine steering software was the primary cause of the crash of the 1996 maiden flight of the [[Ariane 5 Flight 501\|Ariane 5]] rocket.<ref>{{cite web\|last=Gleick\|first=James\|title=A Bug and A Crash\|url=http://www.around.com/ariane.html\|work=New York Times Magazine\|accessdate=9 December 2013\|date=1 December 1996}}</ref> The software had been considered bug-free since it had been used in many previous flights, but those used smaller rockets which generated lower acceleration than Ariane 5.

	==See also==		==See also==

Pol098: ignoring is not handling. reworded opinion

2014-11-17T19:10:07Z

ignoring is not handling. reworded opinion

← Previous revision		Revision as of 19:10, 17 November 2014
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	# Handling: If it is anticipated that overflow may occur and when it happens detected and other processing done. Example: it is possible to add two numbers each two bytes wide using just a byte addition in steps: first add the low bytes then add the high bytes, but if it is necessary to carry out of the low bytes this is arithmetic overflow of the byte addition and it necessary to detect and increment the sum of the high bytes. [[Central processing unit\|CPUs]] generally have a way of detecting this to support addition of numbers larger than their register size, typically using a status bit.		# Handling: If it is anticipated that overflow may occur and when it happens detected and other processing done. Example: it is possible to add two numbers each two bytes wide using just a byte addition in steps: first add the low bytes then add the high bytes, but if it is necessary to carry out of the low bytes this is arithmetic overflow of the byte addition and it necessary to detect and increment the sum of the high bytes. [[Central processing unit\|CPUs]] generally have a way of detecting this to support addition of numbers larger than their register size, typically using a status bit.
	# Propagation: if a value is too large to be stored it can be assigned a special value indicating that overflow has occurred and then have all successive operation return this flag value. This is useful so that the problem can be checked for once at the end of a long calculation rather than after each step. This is often supported in Floating Point Hardware called [[floating point unit\|FPU]]s.		# Propagation: if a value is too large to be stored it can be assigned a special value indicating that overflow has occurred and then have all successive operation return this flag value. This is useful so that the problem can be checked for once at the end of a long calculation rather than after each step. This is often supported in Floating Point Hardware called [[floating point unit\|FPU]]s.
	# ~~Ignoring:~~ ~~This~~ is the ~~most~~ ~~common~~ ~~approach~~, but it gives incorrect results and can compromise a program's [[software security\|security]].		# An overflow condition may be ignored, particularly if the possibility has not been anticipated, but this gives incorrect results and can compromise a program's reliability and [[software security\|security]].

	[[Division by zero]] is ''not'' a form of arithmetic overflow. Mathematically, division by zero within [[Real numbers\|reals]] is explicitly [[Defined and undefined\|undefined]].		[[Division by zero]] is ''not'' a form of arithmetic overflow. Mathematically, division by zero within [[Real numbers\|reals]] is explicitly [[Defined and undefined\|undefined]].
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	==Overflow bugs==		==Overflow bugs==

	~~Arithmetic~~ overflow is a fairly common cause of [[software bug\|~~software~~ ~~failure~~]]s. Such overflow bugs may be hard to discover and diagnose because they may manifest themselves only for very large input data sets, which are less likely to be used in validation tests.<ref>Joshua Bloch, [http://googleresearch.blogspot.com/2006/06/extra-extra-read-all-about-it-nearly.html "Extra, Extra - Read All About It: Nearly All Binary Searches and Mergesorts are Broken"]. Official Google Research Blog, June 2, 2006.</ref>		Unanticipated arithmetic overflow is a fairly common cause of [[software bug\|program errors]]. Such overflow bugs may be hard to discover and diagnose because they may manifest themselves only for very large input data sets, which are less likely to be used in validation tests.<ref>Joshua Bloch, [http://googleresearch.blogspot.com/2006/06/extra-extra-read-all-about-it-nearly.html "Extra, Extra - Read All About It: Nearly All Binary Searches and Mergesorts are Broken"]. Official Google Research Blog, June 2, 2006.</ref>

	For example, an unhandled arithmetic overflow in the engine steering software was the primary cause of the crash of the maiden flight of the [[Ariane 5 Flight 501\|Ariane 5]] rocket.<ref>{{cite web\|last=Gleick\|first=James\|title=A Bug and A Crash\|url=http://www.around.com/ariane.html\|work=New York Times Magazine\|accessdate=9 December 2013\|date=1 December 1996}}</ref> The software had been considered bug-free since it had been used in many previous flights; but those used smaller rockets which generated ~~smaller~~ ~~accelerations~~ than Ariane 5's.		For example, an unhandled arithmetic overflow in the engine steering software was the primary cause of the crash of the 1996 maiden flight of the [[Ariane 5 Flight 501\|Ariane 5]] rocket.<ref>{{cite web\|last=Gleick\|first=James\|title=A Bug and A Crash\|url=http://www.around.com/ariane.html\|work=New York Times Magazine\|accessdate=9 December 2013\|date=1 December 1996}}</ref> The software had been considered bug-free since it had been used in many previous flights; but those used smaller rockets which generated lower acceleration than Ariane 5.

	==See also==		==See also==

Ixfd64: Reverted 1 edit by 208.117.204.3 (talk): Unexplained removal of content. (TW)

2014-09-12T19:00:50Z

Reverted 1 edit by 208.117.204.3 (talk): Unexplained removal of content. (TW)

← Previous revision		Revision as of 19:00, 12 September 2014
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	The term '''arithmetic overflow''' or simply '''overflow''' has the following meanings.		The term '''arithmetic overflow''' or simply '''overflow''' has the following meanings.

			# In a [[computer]], the condition that occurs when a calculation produces a result that is greater in magnitude than that which a given [[processor register\|register]] or [[Computer storage\|storage]] location can store or represent.
	]
			# In a computer, the amount by which a calculated value is greater in magnitude than that which a given register or storage location can store or represent. Note that the overflow may be placed at another location.

	Most computers distinguish between two kinds of overflow conditions. A [[carry (arithmetic)\|carry]] occurs when the result of an addition or subtraction, considering the operands and result as unsigned numbers, does not fit in the result. Therefore, it is useful to check the [[carry flag]] after adding or subtracting numbers that are interpreted as unsigned values. An ''overflow'' proper occurs when the result does not have the sign that one would predict from the signs of the operands (e.g. a negative result when adding two positive numbers). Therefore, it is useful to check the [[overflow flag]] after adding or subtracting numbers that are represented in [[two's complement]] form (i.e. they are considered signed numbers).		Most computers distinguish between two kinds of overflow conditions. A [[carry (arithmetic)\|carry]] occurs when the result of an addition or subtraction, considering the operands and result as unsigned numbers, does not fit in the result. Therefore, it is useful to check the [[carry flag]] after adding or subtracting numbers that are interpreted as unsigned values. An ''overflow'' proper occurs when the result does not have the sign that one would predict from the signs of the operands (e.g. a negative result when adding two positive numbers). Therefore, it is useful to check the [[overflow flag]] after adding or subtracting numbers that are represented in [[two's complement]] form (i.e. they are considered signed numbers).

208.117.204.3 at 19:00, 12 September 2014

2014-09-12T19:00:32Z

← Previous revision		Revision as of 19:00, 12 September 2014
Line 4:		Line 4:
	The term '''arithmetic overflow''' or simply '''overflow''' has the following meanings.		The term '''arithmetic overflow''' or simply '''overflow''' has the following meanings.

			]
	# In a [[computer]], the condition that occurs when a calculation produces a result that is greater in magnitude than that which a given [[processor register\|register]] or [[Computer storage\|storage]] location can store or represent.
	# In a computer, the amount by which a calculated value is greater in magnitude than that which a given register or storage location can store or represent. Note that the overflow may be placed at another location.

	Most computers distinguish between two kinds of overflow conditions. A [[carry (arithmetic)\|carry]] occurs when the result of an addition or subtraction, considering the operands and result as unsigned numbers, does not fit in the result. Therefore, it is useful to check the [[carry flag]] after adding or subtracting numbers that are interpreted as unsigned values. An ''overflow'' proper occurs when the result does not have the sign that one would predict from the signs of the operands (e.g. a negative result when adding two positive numbers). Therefore, it is useful to check the [[overflow flag]] after adding or subtracting numbers that are represented in [[two's complement]] form (i.e. they are considered signed numbers).		Most computers distinguish between two kinds of overflow conditions. A [[carry (arithmetic)\|carry]] occurs when the result of an addition or subtraction, considering the operands and result as unsigned numbers, does not fit in the result. Therefore, it is useful to check the [[carry flag]] after adding or subtracting numbers that are interpreted as unsigned values. An ''overflow'' proper occurs when the result does not have the sign that one would predict from the signs of the operands (e.g. a negative result when adding two positive numbers). Therefore, it is useful to check the [[overflow flag]] after adding or subtracting numbers that are represented in [[two's complement]] form (i.e. they are considered signed numbers).

Ixfd64: Reverted 1 edit by 208.117.204.3 (talk): Unexplained removal of content. (TW)

2014-09-12T19:00:28Z

Reverted 1 edit by 208.117.204.3 (talk): Unexplained removal of content. (TW)

← Previous revision		Revision as of 19:00, 12 September 2014
Line 19:		Line 19:
	==Overflow bugs==		==Overflow bugs==

			Arithmetic overflow is a fairly common cause of [[software bug\|software failure]]s. Such overflow bugs may be hard to discover and diagnose because they may manifest themselves only for very large input data sets, which are less likely to be used in validation tests.<ref>Joshua Bloch, [http://googleresearch.blogspot.com/2006/06/extra-extra-read-all-about-it-nearly.html "Extra, Extra - Read All About It: Nearly All Binary Searches and Mergesorts are Broken"]. Official Google Research Blog, June 2, 2006.</ref>

			For example, an unhandled arithmetic overflow in the engine steering software was the primary cause of the crash of the maiden flight of the [[Ariane 5 Flight 501\|Ariane 5]] rocket.<ref>{{cite web\|last=Gleick\|first=James\|title=A Bug and A Crash\|url=http://www.around.com/ariane.html\|work=New York Times Magazine\|accessdate=9 December 2013\|date=1 December 1996}}</ref> The software had been considered bug-free since it had been used in many previous flights; but those used smaller rockets which generated smaller accelerations than Ariane 5's.

	==See also==		==See also==

← Previous revision		Revision as of 19:10, 17 November 2014
Line 13:		Line 13:
	# Handling: If it is anticipated that overflow may occur and when it happens detected and other processing done. Example: it is possible to add two numbers each two bytes wide using just a byte addition in steps: first add the low bytes then add the high bytes, but if it is necessary to carry out of the low bytes this is arithmetic overflow of the byte addition and it necessary to detect and increment the sum of the high bytes. [[Central processing unit\|CPUs]] generally have a way of detecting this to support addition of numbers larger than their register size, typically using a status bit.		# Handling: If it is anticipated that overflow may occur and when it happens detected and other processing done. Example: it is possible to add two numbers each two bytes wide using just a byte addition in steps: first add the low bytes then add the high bytes, but if it is necessary to carry out of the low bytes this is arithmetic overflow of the byte addition and it necessary to detect and increment the sum of the high bytes. [[Central processing unit\|CPUs]] generally have a way of detecting this to support addition of numbers larger than their register size, typically using a status bit.
	# Propagation: if a value is too large to be stored it can be assigned a special value indicating that overflow has occurred and then have all successive operation return this flag value. This is useful so that the problem can be checked for once at the end of a long calculation rather than after each step. This is often supported in Floating Point Hardware called [[floating point unit\|FPU]]s.		# Propagation: if a value is too large to be stored it can be assigned a special value indicating that overflow has occurred and then have all successive operation return this flag value. This is useful so that the problem can be checked for once at the end of a long calculation rather than after each step. This is often supported in Floating Point Hardware called [[floating point unit\|FPU]]s.
	# ~~Ignoring:~~ ~~This~~ is the ~~most~~ ~~common~~ ~~approach~~, but it gives incorrect results and can compromise a program's [[software security\|security]].		# An overflow condition may be ignored, particularly if the possibility has not been anticipated, but this gives incorrect results and can compromise a program's reliability and [[software security\|security]].

	[[Division by zero]] is ''not'' a form of arithmetic overflow. Mathematically, division by zero within [[Real numbers\|reals]] is explicitly [[Defined and undefined\|undefined]].		[[Division by zero]] is ''not'' a form of arithmetic overflow. Mathematically, division by zero within [[Real numbers\|reals]] is explicitly [[Defined and undefined\|undefined]].
Line 19:		Line 19:
	==Overflow bugs==		==Overflow bugs==

	~~Arithmetic~~ overflow is a fairly common cause of [[software bug\|~~software~~ ~~failure~~]]s. Such overflow bugs may be hard to discover and diagnose because they may manifest themselves only for very large input data sets, which are less likely to be used in validation tests.<ref>Joshua Bloch, [http://googleresearch.blogspot.com/2006/06/extra-extra-read-all-about-it-nearly.html "Extra, Extra - Read All About It: Nearly All Binary Searches and Mergesorts are Broken"]. Official Google Research Blog, June 2, 2006.</ref>		Unanticipated arithmetic overflow is a fairly common cause of [[software bug\|program errors]]. Such overflow bugs may be hard to discover and diagnose because they may manifest themselves only for very large input data sets, which are less likely to be used in validation tests.<ref>Joshua Bloch, [http://googleresearch.blogspot.com/2006/06/extra-extra-read-all-about-it-nearly.html "Extra, Extra - Read All About It: Nearly All Binary Searches and Mergesorts are Broken"]. Official Google Research Blog, June 2, 2006.</ref>

	For example, an unhandled arithmetic overflow in the engine steering software was the primary cause of the crash of the maiden flight of the [[Ariane 5 Flight 501\|Ariane 5]] rocket.<ref>{{cite web\|last=Gleick\|first=James\|title=A Bug and A Crash\|url=http://www.around.com/ariane.html\|work=New York Times Magazine\|accessdate=9 December 2013\|date=1 December 1996}}</ref> The software had been considered bug-free since it had been used in many previous flights; but those used smaller rockets which generated ~~smaller~~ ~~accelerations~~ than Ariane 5's.		For example, an unhandled arithmetic overflow in the engine steering software was the primary cause of the crash of the 1996 maiden flight of the [[Ariane 5 Flight 501\|Ariane 5]] rocket.<ref>{{cite web\|last=Gleick\|first=James\|title=A Bug and A Crash\|url=http://www.around.com/ariane.html\|work=New York Times Magazine\|accessdate=9 December 2013\|date=1 December 1996}}</ref> The software had been considered bug-free since it had been used in many previous flights; but those used smaller rockets which generated lower acceleration than Ariane 5.

	==See also==		==See also==