5 ms·

Why not just write out ProgramCounter, StackPointer, Accumulator, InputFileDescriptor etc? It doesn't take significantly longer to type. It's faster to read bec

Why not just write out ProgramCounter, StackPointer, Accumulator, InputFileDescriptor etc? It doesn't take significantly longer to type. It's faster to read because you can recognize the shape of those words and don't have to mentally substitute the actual works. Code is for reading, not for writing.

cestith 7y ago
Most of these abbreviations are well established. 'pc', 'sp', and 'a' are the names of those registers in many assembly languages.
- cr0sh 7y ago
  To clarify, you don't usually see just "a" for an accumulator, as there are usually more than one accumulator-style registers in a CPU, and in many cases they are split along byte (possibly word) boundaries. So you end up with accumulators called "A" and "B", but are composed of registers "AX" and "AY", and "BX" and "BY", with each being one byte (or word) wide; X and Y being high and low bytes/words of the register (and dependent on "endian-ess" too). Sometimes you even get where multiple registers can be referenced by a singular name - "D" is a popular choice, and may be made up of "A" and "B" (being low/high "registers" of the larger word). IIRC, the 6809 was like this (?) - A and B were 16 bit registers, but could be referenced as a 32-bit word "D" (or maybe I am thing of the 68k or some other architecture - it's been a long while). The only other time I have ever seen singular letters used for registers in assembly was for very old pre-microcomputer systems (beasts like the Univac and System/360 - though I think the PDP-8 had similar style). Also some of the very early "microcontrollers" (which were more like glorified sequencers with some extra memory and rudimentary branching, if any) had similar "registers" (Radio Shack once sold, as a part of their "Science Fair" electronic kits, a "Microcomputer Trainer" that was something like a very small 4-bit microcontroller with 128 bytes of memory or something like that - to teach assembler and a bit of hardware interfacing - it had "small" registers like that referred to in single letters).
  - gmfawcett 7y ago
    The 6502 is still in production, and has single-character register names (A, X, Y, P, S).
  - cestith 7y ago
    The 8080 had A, B, C, D, E, H and L. These mostly carried over to the 8085. Newer chips have ax/al/ah, eax, rax type names the grew out of the original names. The Zilog Z80 and Sharp LR35902 were mostly 8080 compatible. The MOS 6502 has, as gmfawcett said, single-letter names. These in turn carried over to Western Design Center (WDC)'s 65C816. There are actually separate instructions for loading and storing in A, X, Y and Z at least on the '816. LDX, STX, and so on. This means the Ricoh 2A03, Ricoh 5A22, Hitachi 6309, MOS 8501, MOS 8502, and the later MOS 65xx series and the CSG chips. A fun fact is that the 6502 had especially fast access to its zero page memory and special instructions for some functions on that page, the first 256 bytes of RAM. Language implementers sometimes made up for the dearth of registers by treating certain addresses in the zero page as additional registers. The Motorola 6800 had two accumulators, A and B. The stack pointer was merely S. X is the index register. It also treats the zero page specially. The 68000 series broke with this, having eight address registers a0-a7 and eight data registers d0-d7. All of the above used A as an accumulator at least by convention in the materials. SP is the literal name of the stack pointer on x86 in 16-bit mode. It's also used as an alias for R13 in at least some Arm (AArch32 on v7 and earlier for example). SP and PC are the stack pointer and program counter on the PDP-11. It's aliased to r1 on the Intel 80960 (i960) since that is the stack pointer on that platform. The PDP-8 used similar zero-page tricks to the MOS 6502, only given that it had one (1 !!!) register, that was necessary. All of these processors where CPUs for commercially successful systems. They might "only" be microcontrollers today. The MOS 6502 / 6510 and its variant the WDC 65C816 was in the Commodore 64, Commodore PET, the Vic-20, the Apple II, the Atari 2600, the Atari 400/800/600XL/800XL/1200XL/800XE/65XE/130XE, Nintendo Famicom, SuperFamicom, the NES, the SuperNES, BBC Micro, Ohio Scientific Challenger 4, Atari Lynx, Apple III, Apple IIgs, Acorn Atom, Acorn Electron, Franklin Ace, and loads of clones. The Z80 was in most Amstrad models, in the original TRS-80, the MSX standard, VTech Laser, Intercompex Hobbit, Mattel Aquarius, the Microbee, the NEC PC-6000 & PC-8800 series, Sinclair ZX line & Timex Sinclair, Coleco Adam, and again a bunch of clones. The Motorola 6809 was in the Tandy Color Computer, while the smaller CoCo MC-10 used the 6803. A few other companies built around this chip family, too. The Commodore 128 featured both a 6500 series processor and a Z80. Several of these processors still have versions produced in 2020, although they're not for your main desktop or your phone. Several of them are targets for emulation or new hobbyist software due to the popularity of their platforms. And yes, some of them are used as microcontrollers. Microcontrollers need code written for them, too.
earenndil 7y ago
You don't have to 'mentally substitute' the actual words. PC, SP, A, etc. are the words themselves. StackPointer is a pointless formalism.
- psychoslave 7y ago
  Could you also provide the meaning for the other (pointless) abbreviations? :)
pvitz 7y ago
Because e.g. pc and sp are exactly the abbreviations used in assembler for some decades?
- gmfawcett 7y ago
  We should probably mention that "e.g." is an abbreviation for the Latin "exempli gratia", and means "for example." ;-)
GuB-42 7y ago
Because it make the lines longer and long lines are bad. If it results in a horizontal scrollbar, it is terrible, but even without it, there is a reason papers are often printed in column format and most coding rules specify a maximum line length (often 80, though 120 is becoming popular these days, with big wide screen and all that). So long lines need to be split. Which is difficult to do properly and results in more lines, and more lines mean less of the code is visible at once and that makes it harder to see the big picture. But to each his own I guess. Anyway, you can try it out yourself. Just take the code, do the replacements and see for yourself.
- Minor49er 7y ago
  There are often ways of reformatting a line to break it if it's too long that also does not require renaming things. For example, a long list of conditions in an if statement can be broken into one condition per line. Results of comparisons can be put into their own variables. Logic flow can be adjusted and produce the same result. And so on.
- psychoslave 7y ago
  Started here: https://github.com/psychoslave/c4 https://github.com/psychoslave/c4 But help would be welcome to retrieve the intended meaning for many of variable names that were turned to nonsense, be it a comment here, an issue on the repository, a pull request or anything else.
- Hnrobert42 7y ago
  Are you reading this on an Apple Watch? I still generally use 80 characters out of habit, but given how monitors have grown, 120 or even 140 should be the new norm.
  - clarry 7y ago
    Adding an extra column for code|docs|other context is so much more useful than allowing longer lines for obese identifiers that rarely serve to make a point more clear. I'll take my four or five columns of 80 chars over two columns of 120-140 chars any day.
32gbsd 7y ago
It takes longer to type and read. All the little seconds fiddling with the mouse, popup menus, hand eye coordination wastes your time and prevents muscle memory. Its hard to reach max throughput with long variable names.
- deleted 7y ago
  [deleted]
- psychoslave 7y ago
  Humans don't read words letter by letter, you recognize the whole word pattern. Abbreviations are actually slowing you down on this point, at least the first times you encounter each new one. Having a longest but more usual term will take you least time of reading treatment. Autocompletion will rarely ask you to type more than four keystrokes for selecting any arbitrary long term. Meaningful terms in context often happen to be far more easier to grep. Except for sounding far more impenetrable to the lay man, there is not much left to these H4x0r turns. Of course jargon curse is not a prerogative of CS, this is a common spontaneous social behaviour.
- DagAgren 7y ago
  Typing speed is absolutely not the limiting factor for programming productivity. If you are actually limited by typing speed, you are doing something very, very wrong.
  - pavas 7y ago
    Besides, this issue has been solved for many years now. Auto-completion in modern IDEs has gotten really good.
userbinator 7y ago
Is it faster to read? Maybe in terms of bytes/s, but not in lexemes/s nor in terms of getting an overall idea of how everything works. Compare with this, which is probably more in the style you're thinking of: https://github.com/dotnet/roslyn/blob/master/src/Compilers/CSharp/Portable/Parser/LanguageParser.cs https://github.com/dotnet/roslyn/blob/master/src/Compilers/C... There's so much "noise" that it's hard to see the "big picture", and the repetition of VeryLongIdentifiers causes https://en.wikipedia.org/wiki/Semantic_satiation https://en.wikipedia.org/wiki/Semantic_satiation to occur quickly.
- pavas 7y ago
  If you're talking about a small, quickly-written, one-off piece of code, then I think truncated variable names are OK. If the code is anything that anyone else (including future you) will have to read, or a part of a larger system, then descriptive variable names are best. I can't count the number of times I've dropped into some source code with variable names that didn't mean anything and with no comments describing what they mean.
  - JustSomeNobody 7y ago
    If one understands anything at all about a cpu, then pc, sp, a mean something instantly.
    - Aachen 7y ago
      Agree on those, but t and tk can mean anything. We can symbolize everything and, as someone else argued, once you know tk is token you can just read it, but replacing variable names with the shortest possible names is still called obfuscation for a reason. I personally also hate the Java (and to a lesser extent, C#) custom to write MemoryLocationRepresentation when you can say pointer, but there is certainly a middle ground. Token is 5 characters, not 30.
- Hnrobert42 7y ago
  Consider non-native English speakers. For them, the abbreviation makes it much harder to read.

cestith 7y ago

Most of these abbreviations are well established. 'pc', 'sp', and 'a' are the names of those registers in many assembly languages.

cr0sh 7y ago
To clarify, you don't usually see just "a" for an accumulator, as there are usually more than one accumulator-style registers in a CPU, and in many cases they are split along byte (possibly word) boundaries. So you end up with accumulators called "A" and "B", but are composed of registers "AX" and "AY", and "BX" and "BY", with each being one byte (or word) wide; X and Y being high and low bytes/words of the register (and dependent on "endian-ess" too). Sometimes you even get where multiple registers can be referenced by a singular name - "D" is a popular choice, and may be made up of "A" and "B" (being low/high "registers" of the larger word). IIRC, the 6809 was like this (?) - A and B were 16 bit registers, but could be referenced as a 32-bit word "D" (or maybe I am thing of the 68k or some other architecture - it's been a long while). The only other time I have ever seen singular letters used for registers in assembly was for very old pre-microcomputer systems (beasts like the Univac and System/360 - though I think the PDP-8 had similar style). Also some of the very early "microcontrollers" (which were more like glorified sequencers with some extra memory and rudimentary branching, if any) had similar "registers" (Radio Shack once sold, as a part of their "Science Fair" electronic kits, a "Microcomputer Trainer" that was something like a very small 4-bit microcontroller with 128 bytes of memory or something like that - to teach assembler and a bit of hardware interfacing - it had "small" registers like that referred to in single letters).
- gmfawcett 7y ago
  The 6502 is still in production, and has single-character register names (A, X, Y, P, S).
- cestith 7y ago
  The 8080 had A, B, C, D, E, H and L. These mostly carried over to the 8085. Newer chips have ax/al/ah, eax, rax type names the grew out of the original names. The Zilog Z80 and Sharp LR35902 were mostly 8080 compatible. The MOS 6502 has, as gmfawcett said, single-letter names. These in turn carried over to Western Design Center (WDC)'s 65C816. There are actually separate instructions for loading and storing in A, X, Y and Z at least on the '816. LDX, STX, and so on. This means the Ricoh 2A03, Ricoh 5A22, Hitachi 6309, MOS 8501, MOS 8502, and the later MOS 65xx series and the CSG chips. A fun fact is that the 6502 had especially fast access to its zero page memory and special instructions for some functions on that page, the first 256 bytes of RAM. Language implementers sometimes made up for the dearth of registers by treating certain addresses in the zero page as additional registers. The Motorola 6800 had two accumulators, A and B. The stack pointer was merely S. X is the index register. It also treats the zero page specially. The 68000 series broke with this, having eight address registers a0-a7 and eight data registers d0-d7. All of the above used A as an accumulator at least by convention in the materials. SP is the literal name of the stack pointer on x86 in 16-bit mode. It's also used as an alias for R13 in at least some Arm (AArch32 on v7 and earlier for example). SP and PC are the stack pointer and program counter on the PDP-11. It's aliased to r1 on the Intel 80960 (i960) since that is the stack pointer on that platform. The PDP-8 used similar zero-page tricks to the MOS 6502, only given that it had one (1 !!!) register, that was necessary. All of these processors where CPUs for commercially successful systems. They might "only" be microcontrollers today. The MOS 6502 / 6510 and its variant the WDC 65C816 was in the Commodore 64, Commodore PET, the Vic-20, the Apple II, the Atari 2600, the Atari 400/800/600XL/800XL/1200XL/800XE/65XE/130XE, Nintendo Famicom, SuperFamicom, the NES, the SuperNES, BBC Micro, Ohio Scientific Challenger 4, Atari Lynx, Apple III, Apple IIgs, Acorn Atom, Acorn Electron, Franklin Ace, and loads of clones. The Z80 was in most Amstrad models, in the original TRS-80, the MSX standard, VTech Laser, Intercompex Hobbit, Mattel Aquarius, the Microbee, the NEC PC-6000 & PC-8800 series, Sinclair ZX line & Timex Sinclair, Coleco Adam, and again a bunch of clones. The Motorola 6809 was in the Tandy Color Computer, while the smaller CoCo MC-10 used the 6803. A few other companies built around this chip family, too. The Commodore 128 featured both a 6500 series processor and a Z80. Several of these processors still have versions produced in 2020, although they're not for your main desktop or your phone. Several of them are targets for emulation or new hobbyist software due to the popularity of their platforms. And yes, some of them are used as microcontrollers. Microcontrollers need code written for them, too.

earenndil 7y ago

You don't have to 'mentally substitute' the actual words. PC, SP, A, etc. are the words themselves. StackPointer is a pointless formalism.

psychoslave 7y ago
Could you also provide the meaning for the other (pointless) abbreviations? :)

pvitz 7y ago

Because e.g. pc and sp are exactly the abbreviations used in assembler for some decades?

gmfawcett 7y ago
We should probably mention that "e.g." is an abbreviation for the Latin "exempli gratia", and means "for example." ;-)

GuB-42 7y ago

Because it make the lines longer and long lines are bad. If it results in a horizontal scrollbar, it is terrible, but even without it, there is a reason papers are often printed in column format and most coding rules specify a maximum line length (often 80, though 120 is becoming popular these days, with big wide screen and all that). So long lines need to be split. Which is difficult to do properly and results in more lines, and more lines mean less of the code is visible at once and that makes it harder to see the big picture. But to each his own I guess. Anyway, you can try it out yourself. Just take the code, do the replacements and see for yourself.

Minor49er 7y ago
There are often ways of reformatting a line to break it if it's too long that also does not require renaming things. For example, a long list of conditions in an if statement can be broken into one condition per line. Results of comparisons can be put into their own variables. Logic flow can be adjusted and produce the same result. And so on.
psychoslave 7y ago
Started here: https://github.com/psychoslave/c4 https://github.com/psychoslave/c4 But help would be welcome to retrieve the intended meaning for many of variable names that were turned to nonsense, be it a comment here, an issue on the repository, a pull request or anything else.
Hnrobert42 7y ago
Are you reading this on an Apple Watch? I still generally use 80 characters out of habit, but given how monitors have grown, 120 or even 140 should be the new norm.
- clarry 7y ago
  Adding an extra column for code|docs|other context is so much more useful than allowing longer lines for obese identifiers that rarely serve to make a point more clear. I'll take my four or five columns of 80 chars over two columns of 120-140 chars any day.

32gbsd 7y ago

It takes longer to type and read. All the little seconds fiddling with the mouse, popup menus, hand eye coordination wastes your time and prevents muscle memory. Its hard to reach max throughput with long variable names.

deleted 7y ago
[deleted]
psychoslave 7y ago
Humans don't read words letter by letter, you recognize the whole word pattern. Abbreviations are actually slowing you down on this point, at least the first times you encounter each new one. Having a longest but more usual term will take you least time of reading treatment. Autocompletion will rarely ask you to type more than four keystrokes for selecting any arbitrary long term. Meaningful terms in context often happen to be far more easier to grep. Except for sounding far more impenetrable to the lay man, there is not much left to these H4x0r turns. Of course jargon curse is not a prerogative of CS, this is a common spontaneous social behaviour.
DagAgren 7y ago
Typing speed is absolutely not the limiting factor for programming productivity. If you are actually limited by typing speed, you are doing something very, very wrong.
- pavas 7y ago
  Besides, this issue has been solved for many years now. Auto-completion in modern IDEs has gotten really good.

userbinator 7y ago

Is it faster to read? Maybe in terms of bytes/s, but not in lexemes/s nor in terms of getting an overall idea of how everything works. Compare with this, which is probably more in the style you're thinking of: https://github.com/dotnet/roslyn/blob/master/src/Compilers/CSharp/Portable/Parser/LanguageParser.cs https://github.com/dotnet/roslyn/blob/master/src/Compilers/C... There's so much "noise" that it's hard to see the "big picture", and the repetition of VeryLongIdentifiers causes https://en.wikipedia.org/wiki/Semantic_satiation https://en.wikipedia.org/wiki/Semantic_satiation to occur quickly.

pavas 7y ago
If you're talking about a small, quickly-written, one-off piece of code, then I think truncated variable names are OK. If the code is anything that anyone else (including future you) will have to read, or a part of a larger system, then descriptive variable names are best. I can't count the number of times I've dropped into some source code with variable names that didn't mean anything and with no comments describing what they mean.
- JustSomeNobody 7y ago
  If one understands anything at all about a cpu, then pc, sp, a mean something instantly.
  - Aachen 7y ago
    Agree on those, but t and tk can mean anything. We can symbolize everything and, as someone else argued, once you know tk is token you can just read it, but replacing variable names with the shortest possible names is still called obfuscation for a reason. I personally also hate the Java (and to a lesser extent, C#) custom to write MemoryLocationRepresentation when you can say pointer, but there is certainly a middle ground. Token is 5 characters, not 30.
Hnrobert42 7y ago
Consider non-native English speakers. For them, the abbreviation makes it much harder to read.