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Questions tagged [x86]

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0
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2answers
136 views

Does anyone have an x86 EGA draw pixel routine?

So far, I have gotten by with using the BIOS draw-pixel routine here: http://stanislavs.org/helppc/int_10-c.html This works of course, but I can't imagine that commercial games used this BIOS call as ...
10
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2answers
284 views

How to use the “darker” CGA palette using x86 Assembly?

For those of you retro developers out there, I am having a hard time figuring out how exactly to select the "darker" color palette in 320x200 CGA mode. Here's what I have so far: setup_cga_graphics: ...
3
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1answer
164 views

What was the first publication documenting AT&T syntax assembly language?

What was the first publication to document what is (now) known as AT&T syntax assembly language?
13
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1answer
320 views

SYSENTER/SYSEXIT broken on Pentium Pro and Pentium II?

I was just What is linux-gate.so.1?, and it says this Intel recognized this problem early on and introduced a more efficient system call interface in the form of sysenter and sysexit instructions. ...
6
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4answers
369 views

Reason behind “ASCII Adjust” instructions being ASCII and not BCD?

I'm just curious if there was ever other instructions that were more ASCII-centric than the CISC associated ones we're left with now? Specifically, all the Binary Coded Decimal (BCD) instructions ...
0
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1answer
274 views

How do you put a 286 in Protected Mode?

From the Art of Intel x86 Assembly, Page 149, The 80386 added four control registers: CR0-CR3. These registers extend the msw registers of the 80286 [...] The book says earlier that, The 80286 ...
8
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3answers
522 views

x86 as a Pascal Machine?

From this answer by gsg about the usage of certain x86 instructions: Note that the x86 was originally designed as a Pascal machine, which is why there are instructions to support nested functions (...
1
vote
2answers
195 views

Mysterious things happening to stack when running a debug session

When I run a debug session using Freedos and debug.exe, I get a session like the following. I've added a description of what I saw as annotation on the image. Each step, I've printed out the stack ...
15
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2answers
1k views

The start of x86: Intel 8080 vs Intel 8086?

Why is it said that all modern Intel processors of the x86 family are said to descent from the Intel 8086 and not the Intel 8080? From the Wikipedia article on the Intel 8086, The 8086 gave rise to ...