2497: Logic Gates

2021-08-03T06:48:51Z

Bx19tri: /* Explanation */ explained short forms like XOR

{{comic
| number = 2497
| date = August 2, 2021
| title = Logic Gates
| image = logic_gates.png
| titletext = In C, the multiocular O represents the bitwise norxondor gorgonax.
}}

==Explanation==
{{incomplete|Created by a NORXONDOR GORGONAX. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

The comic lists logic gates. The first six are real, but the last six are made up and get increasingly absurd. The names for these last six are made up of the same letters and syllables as the first six so as to be consistent with their naming conventions.

The only real-life logic gate that was omitted is the XNOR gate (short for “eXclusive Not OR”; it compares the inputs, and if and only if they are equal, it outputs true). Note that the "NORG XORT" gate is logically equivalent to it, since it is an XNOR gate with NOT on both inputs, a modification that has no effect on the logic behavior.

An AND gate outputs true if and only if both inputs are true.

An OR gate outputs true if one or the other or both of the inputs are true.

A NOT outputs true if and only if the input is false.

A NOR (short for “Not OR”) gate outputs true if and only if both inputs are false.

A XOR (short for “eXclusive OR”) gate outputs true if one, or the other, but not both of the inputs are true.

A NAND (short for “Not AND”) gate outputs true if one or the other or both of the inputs is false.

Much like [[2360: Common Star Types]], as the list progresses, the names start to sound more like mythical creatures, closing with the "Norxondor gorgonax". Randall claims in the title-text that the {{w|multiocular O}} (ꙮ) character is used to represent the bitwise version of this operator (presumably ꙮꙮ represents the non-bitwise version), fitting as the multiocular O is used to refer to "many-eyed seraphim" (i.e. angels) in some religious literature. {{w|Gorgon}}s (beige or otherwise) have heads covered with snakes instead of hair, and so possess multiple eyes.

C is a low level programming language, and as such, it has many operations that correspond to logical (i. e. bitwise) operations. These contrast with operations that work in a non-bitwise way. For example, "&&" is the non-bitwise "AND" operator, while "&" is the bitwise "AND". In non-bitwise operations, 0 always represents "FALSE", while any non-zero value means "TRUE" for inputs, and 1 is used to represent TRUE for outputs. Thus, "14 && 3" gives the result 1: TRUE AND TRUE -> TRUE. Bitwise operations work on the corresponding bits of the inputs, in binary mode. Using the same values, where the decimal value 14 has the binary value 1110 and the decimal value 3 has the binary value 0011, we get

<code>
  1110 = 14<br />
& <u>0011</u> = 3<br />
  0010 = 2</code>

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

The comic shows a chart labelled 'COMMON LOGIC GATE SYMBOLS' showing twelve electronic logic gates arranged in three rows of four. Each gate is depicted as a schematic symbol, with the name of the gate shown underneath in capital script.

Top row:

AND GATE - (A standard gate symbol used in real life. Two inputs on the left lead to the vertical left edge of a solid D-shaped symbol. From the right side of the D there is one output.)

OR GATE - (A standard gate symbol used in real life. Two inputs on the left lead to a convex-crescent left edge of a crescent-shaped symbol. The right side of the crescent symbol's shape forms a point at its output. From the right side of the crescent there is one output.)

NOT GATE - (A standard gate symbol used in real life. One input leads to a triangular symbol pointing to the right. There is a small bubble symbol connected to the triangle on the output, which leads right.)

NOR GATE - (A standard gate symbol used in real life. This is identical to the OR GATE, except the output has a bubble attached, like the NOT GATE's output.)

Middle row:

XOR GATE - (A standard gate symbol used in real life. This is identical to the OR GATE, except the left-hand arc at the input has a double-stroked line.)

NAND GATE - (A standard gate symbol used in real life. This is identical to the AND GATE, except the output has a bubble attached, like the NOT GATE's output.)

NORX GATE - (An unusual symbol. This symbol has one input on the left leading to a convex-crescent left edge, like the OR GATE. The output side as a smooth crescent like the AND GATE but has two outputs.)

GAND ATE - (An unusual symbol. This symbol has two inputs on the left leading to a vertical left edge input, like the AND GATE. The output side has a convex-crescent double-stroked output like the mirror image of the XOR GATE's input. There are two outputs.)

Bottom row:

XAND GORT - (An unusual symbol. This resembles the NOT GATE except there are two inputs instead of one leading into the left side.)

NORG XORT - (An unusual symbol. This has a double-stroked convex-crescent input like the XOR GATE, but the two inputs have bubbles attached. The single output has a smooth crescent shape with a bubble, like a NAND GATE.)

ANDORX GANT - (An unusual symbol. Two inputs lead to a convex-crescent edge, and the two lines of this symbol now enter a double-stroked convex-crescent input like the XOR GATE. The two lines of -this- symbol have bubbles placed half way across their horizontal length, and are presumably the outputs.)

NORXONDOR GORGONAX - (An unusual symbol. The symbol is identical to the NOR GATE, except the upper and lower horizontal parts of the symbols hull have a NOT GATE placed on them - one pointing to the left on the upper line, and to the right on the lower line. There is one output to the symbol, with a bubble attached.)

{{comic discussion}}

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2497: Logic Gates