8 ms·

x86 was designed in 78, basically for the purpose of running a primitive laser printer (or other similar workloads). The big problem with this is that the encod

x86 was designed in 78, basically for the purpose of running a primitive laser printer (or other similar workloads). The big problem with this is that the encoding space for instructions was "efficiently utilized". When new instructions, or worse, additional registers were later added, you had to fit the new instruction variants in somehow, and you did this by tacking on prefixes.

mschuster91 3y ago
Nah, x86 goes even earlier in its heritage - it was, effectively, a bolt-on on Intel's way older designs, as a huge part of the 8086 was being ASM source-compatible with the older 8xxx chips, even as the instruction set itself changed [1]. What utterly amazes me is that the original 8086 was mostly designed by hand by a team of not even two dozen people - and today, we got hundreds if not thousands of people working on designing ASICs... [1] https://en.wikipedia.org/wiki/Intel_8086#The_first_x86_design https://en.wikipedia.org/wiki/Intel_8086#The_first_x86_desig...
- hulitu 3y ago
  It is because testing plays a bigger part today than back then. The complexity has also increased (people do not design at transistor level anymore).
- irdc 3y ago
  Acckkghtually, if you go back far enough you end up at the Datapoint 2200. If you want to understand where some of the crazier parts of the 8086 originate from, Ken Shirriff has a nice read: http://www.righto.com/2023/08/datapoint-to-8086.html http://www.righto.com/2023/08/datapoint-to-8086.html
thaumasiotes 3y ago
> x86 was designed in 78, basically for the purpose of running a primitive laser printer It's interesting that ASCII is transparently just a bunch of control codes for a physical printer/typewriter, combining things like "advance the paper one line", "advance the paper one inch", "reset the carriage position", and "strike an F at the carriage position", all of which are different mechanical actions that you might want a typewriter to do. But now we have Unicode, which is dedicated to the purpose of assigning ID numbers to visual glyphs, and ASCII has been interpreted as a bunch of glyph references instead of a bunch of machine instructions, and there are the control codes with no visual representation, sitting in Unicode, being inappropriate in every possible way. It's kind of like if Unicode were to incorporate "start microwave" as part of a set with "1", "2", "3", etc.
- rswail 3y ago
  ASCII was used by teletypes, not typewriters. They were "cylinder" heads, as compared to IBM's golfball typewriters. The endless CR/LF/CRLF line ending problem would have been solved if the RS (Record Separator) ASCII code was used instead of the physical CR = carriage return, ie move print head back to start of line, and LF = line feed, ie rotate paper up one line. But Unix decided on LF, Apple used CR, Windows used CRLF, and even today, I had to get a guy to stop setting his system to "Windows" because he was screwing up a git repo with extraneous CRs.
  - deleted 3y ago
    [deleted]

mschuster91 3y ago

Nah, x86 goes even earlier in its heritage - it was, effectively, a bolt-on on Intel's way older designs, as a huge part of the 8086 was being ASM source-compatible with the older 8xxx chips, even as the instruction set itself changed [1]. What utterly amazes me is that the original 8086 was mostly designed by hand by a team of not even two dozen people - and today, we got hundreds if not thousands of people working on designing ASICs... [1] https://en.wikipedia.org/wiki/Intel_8086#The_first_x86_design https://en.wikipedia.org/wiki/Intel_8086#The_first_x86_desig...

hulitu 3y ago
It is because testing plays a bigger part today than back then. The complexity has also increased (people do not design at transistor level anymore).
irdc 3y ago
Acckkghtually, if you go back far enough you end up at the Datapoint 2200. If you want to understand where some of the crazier parts of the 8086 originate from, Ken Shirriff has a nice read: http://www.righto.com/2023/08/datapoint-to-8086.html http://www.righto.com/2023/08/datapoint-to-8086.html

thaumasiotes 3y ago

> x86 was designed in 78, basically for the purpose of running a primitive laser printer It's interesting that ASCII is transparently just a bunch of control codes for a physical printer/typewriter, combining things like "advance the paper one line", "advance the paper one inch", "reset the carriage position", and "strike an F at the carriage position", all of which are different mechanical actions that you might want a typewriter to do. But now we have Unicode, which is dedicated to the purpose of assigning ID numbers to visual glyphs, and ASCII has been interpreted as a bunch of glyph references instead of a bunch of machine instructions, and there are the control codes with no visual representation, sitting in Unicode, being inappropriate in every possible way. It's kind of like if Unicode were to incorporate "start microwave" as part of a set with "1", "2", "3", etc.

rswail 3y ago
ASCII was used by teletypes, not typewriters. They were "cylinder" heads, as compared to IBM's golfball typewriters. The endless CR/LF/CRLF line ending problem would have been solved if the RS (Record Separator) ASCII code was used instead of the physical CR = carriage return, ie move print head back to start of line, and LF = line feed, ie rotate paper up one line. But Unix decided on LF, Apple used CR, Windows used CRLF, and even today, I had to get a guy to stop setting his system to "Windows" because he was screwing up a git repo with extraneous CRs.
- deleted 3y ago
  [deleted]