Peter Cordes
  • Member for 5 years, 3 months
  • Last seen this week
  • Halifax, Canada
1 answers
15 votes
1k views
Was there a 'git' in the 1990s?
Accepted answer
25 votes

You are nuts, unfortunately. The thing that's now called Git didn't exist at all until Linus invented it after experience with BitKeeper, and thinking about distributed version control. Linux didn't ...

View answer
7 answers
15 votes
5k views
Are there any good, non-abandoned PC emulators?
6 votes

Is BOCHS any good for this sort of thing? Bochs can be compiled to emulate many different x86 CPUs, from early 386 to the most recent x86-64 Intel and AMD processors which may even not reached the ...

View answer
3 answers
12 votes
2k views
What 8086 instructions accept REP?
12 votes

You can't repeat arbitrary instructions with rep. In asm syntax, rep just means to include an F3 byte as a prefix for this instruction. There is no implication that it actually means repeat, it's ...

View answer
5 answers
29 votes
9k views
Are MS-DOS and Windows 9x vulnerable to Meltdown?
7 votes

mainly I'm trying to dispute the claim that computers have been vulnerable to Meltdown since 1995. The claim was never that all computers since 1995 were vulnerable, just some. Also not that all ...

View answer
2 answers
24 votes
6k views
The start of x86: Intel 8080 vs Intel 8086?
Accepted answer
52 votes

8086 was designed to make asm source porting from 8080 easy (not the other direction). It is not binary compatible with 8080, and not source-compatible either. 8080 is not an x86 CPU. 8080 is a ...

View answer
7 answers
48 votes
11k views
Did any compiler fully use Intel x87 80-bit floating point?
42 votes

TL:DR: Yes, most C/C++ compilers other than MSVC expose an 80-bit IEEE754 Extended Precision format (x87, 68881) as long double, and some implementations of other languages have it as REAL10 or ...

View answer
5 answers
21 votes
8k views
Will PC-DOS run faster on 4 or 8 core modern machines?
4 votes

DOS itself won't do anything to boot up the "extra" cores in a multicore system, running only on the boot CPU. A program that does that is normally called an operating system. You could certainly ...

View answer
20 answers
87 votes
19k views
Have programming languages driven hardware development?
12 votes

Some ARM CPUs used to have partial support for executing Java bytecode in hardware with https://en.wikipedia.org/wiki/Jazelle Direct Bytecode eXecution (DBX). With modern JITing JVMs, that became ...

View answer
5 answers
7 votes
1k views
Power of university computer in the '70s?
2 votes

In terms of a modern CPU: The 36 double-precision MFLOPs that @Raffzahn mentions for a CDC 7600 (1969) is about equivalent to a single-core 2.25 MHz Haswell or Skylake (not GHz). i.e. less than one ...

View answer
3 answers
38 votes
5k views
Why are first four x86 GPRs named in such unintuitive order?
10 votes

@davidbak suggests a possible physical implementation motivation for the design choice: In the time we're talking guys writing the instruction set would prioritize minimal number of gates and then ...

View answer
3 answers
47 votes
8k views
What's the relationship between early 90s Pentium microprocessor and today's Intel designs?
10 votes

Pentium 4 (NetBurst uarch-family) was Intel's dead-end misadventure between the original Pentium Pro / PII / PII (P6 uarch) and its current mainstream CPUs. Intel had hoped to clock P4 much higher, ...

View answer