Instruction - Revision history

Jnc: 'instruction set' is better equivalent for 'order code' than 'object code' (see EDSAC document)

2025-11-06T08:52:30Z

'instruction set' is better equivalent for 'order code' than 'object code' (see EDSAC document)

← Older revision		Revision as of 08:52, 6 November 2025
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	In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. add the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a [[word]], but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)		In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. add the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a [[word]], but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)

	Some early computers used the alternative term '''order''' for ~~instructions,~~ and '''order code''' for [[~~Object code\|machine code~~]]. This was more common in the UK; especially at Cambridge (on the [[EDSAC]], and descendants such as the [[LEO]]). In the US, uses included several [[Lincoln Laboratory]] computers, and the [[PDP-1]].		Some early computers used the alternative term '''order''' for instruction (and '''order code''' for [[instruction set]]). This was more common in the UK; especially at Cambridge (on the [[EDSAC]], and descendants such as the [[LEO]]). In the US, uses included several [[Lincoln Laboratory]] computers, and the [[PDP-1]].

	{{semi-stub}}		{{semi-stub}}

	~~==See also==~~

	* [[Instruction set]]

	==External links==		==External links==
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	* [https://www.cl.cam.ac.uk/relics/orders.notes.html The EDSAC Order Code]		* [https://www.cl.cam.ac.uk/relics/orders.notes.html The EDSAC Order Code]

	[[Category: ~~CPU~~ Basics]]		[[Category: Computer Basics]]

Jnc: 'order'/'order code' in the UK

2025-11-05T19:06:46Z

'order'/'order code' in the UK

← Older revision		Revision as of 19:06, 5 November 2025
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	In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. add the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a [[word]], but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)		In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. add the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a [[word]], but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)

	Some early computers used the alternative term '''order''' for instructions, and '''order code''' for [[Object code\|machine code]]. ~~Notable examples include~~ the [[Lincoln Laboratory]] computers, and the [[PDP-1]].		Some early computers used the alternative term '''order''' for instructions, and '''order code''' for [[Object code\|machine code]]. This was more common in the UK; especially at Cambridge (on the [[EDSAC]], and descendants such as the [[LEO]]). In the US, uses included several [[Lincoln Laboratory]] computers, and the [[PDP-1]].

	{{semi-stub}}		{{semi-stub}}
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	* [[Instruction set]]		* [[Instruction set]]

			==External links==

			* [https://www.cl.cam.ac.uk/relics/orders.notes.html The EDSAC Order Code]

	[[Category: CPU Basics]]		[[Category: CPU Basics]]

Larsbrinkhoff: Add order code. Maybe also ILLIAC and UNIVAC.

2025-11-04T06:19:26Z

Add order code. Maybe also ILLIAC and UNIVAC.

← Older revision		Revision as of 06:19, 4 November 2025
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	In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. add the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a [[word]], but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)		In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. add the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a [[word]], but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)

	Some early computers used the alternative term '''order''' for instructions.		Some early computers used the alternative term '''order''' for instructions, and '''order code''' for [[Object code\|machine code]]. Notable examples include the [[Lincoln Laboratory]] computers, and the [[PDP-1]].

	{{semi-stub}}		{{semi-stub}}

Jnc: /* See also */ +Instruction set

2023-06-03T17:50:34Z

Jnc: Especially early ones

2023-06-03T11:04:06Z

Especially early ones

← Older revision		Revision as of 11:04, 3 June 2023
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	An '''instruction''' is, at the highest level of abstraction, the smallest unit of computation which a [[programmer]] can direct the [[Central Processing Unit\|CPU]] to perform.		An '''instruction''' is, at the highest level of abstraction, the smallest unit of computation which a [[programmer]] can direct the [[Central Processing Unit\|CPU]] to perform.

	In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. a the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a [[word]], but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)		In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. add the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a [[word]], but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)

	Some computers ~~use~~ the alternative ~~word~~ '''order''' for instructions.		Some early computers used the alternative term '''order''' for instructions.

	{{semi-stub}}		{{semi-stub}}

	[[Category: CPU Basics]]		[[Category: CPU Basics]]

Larsbrinkhoff: Also "order".

2023-06-03T08:59:22Z

Also "order".

← Older revision		Revision as of 08:59, 3 June 2023
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	In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. a the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a [[word]], but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)		In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. a the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a [[word]], but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)

			Some computers use the alternative word '''order''' for instructions.

	{{semi-stub}}		{{semi-stub}}

	[[Category: CPU Basics]]		[[Category: CPU Basics]]

Jnc: better cat

2018-12-15T14:11:29Z

better cat

← Older revision		Revision as of 14:11, 15 December 2018
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	{{semi-stub}}		{{semi-stub}}

	[[Category: ~~Hardware~~ Basics]]		[[Category: CPU Basics]]

Jnc: +cat

2018-12-13T02:57:32Z

+cat

← Older revision		Revision as of 02:57, 13 December 2018
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	An '''instruction''' is, at the highest level of abstraction, the smallest unit of computation which a programmer can direct the [[Central Processing Unit\|CPU]] to perform.		An '''instruction''' is, at the highest level of abstraction, the smallest unit of computation which a [[programmer]] can direct the [[Central Processing Unit\|CPU]] to perform.

	In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. a the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a word, but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)		In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. a the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a [[word]], but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)

	{{semi-stub}}		{{semi-stub}}

			[[Category: Hardware Basics]]

Jnc: Correct cat

2018-10-19T12:21:11Z

Correct cat

← Older revision		Revision as of 12:21, 19 October 2018
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	In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. a the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a word, but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)		In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. a the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a word, but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)

	{{stub}}		{{semi-stub}}

Jnc: UNify tense

2017-10-02T14:54:58Z

UNify tense

← Older revision		Revision as of 14:54, 2 October 2017
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	An '''instruction''' is, at the highest level of abstraction, the smallest unit of computation which a programmer can direct the [[Central Processing Unit\|CPU]] to perform.		An '''instruction''' is, at the highest level of abstraction, the smallest unit of computation which a programmer can direct the [[Central Processing Unit\|CPU]] to perform.

	In more practical terms, the CPU operates by fetching items from [[main memory]]; each item ~~contained~~ a single directive for the CPU (e.g. a the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a word, but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)		In more practical terms, the CPU operates by fetching items from [[main memory]]; each item contains a single directive for the CPU (e.g. a the contents of one [[register]] to another, or move a unit of data from a register, to main memory) - those items are instructions. (An instruction is usually a word, but on some CPUs, multiple instructions could be packed in each word, while on others, some instructions took multiple words.)

	{{stub}}		{{stub}}

← Older revision		Revision as of 17:50, 3 June 2023
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	{{semi-stub}}		{{semi-stub}}

			==See also==

			* [[Instruction set]]

	[[Category: CPU Basics]]		[[Category: CPU Basics]]