Talk:X86 Assembly

List of all talk pages related to this book:

• X86 Assembly
• X86 Assembly/16, 32, and 64 Bits
• X86 Assembly/16 32 and 64 Bits
• X86 Assembly/Advanced Interrupts
• X86 Assembly/Arithmetic
• X86 Assembly/Bootloaders
• X86 Assembly/Comments
• X86 Assembly/Control Flow
• X86 Assembly/Data Transfer
• X86 Assembly/Debug Information
• X86 Assembly/FASM Syntax
• X86 Assembly/GAS Syntax
• X86 Assembly/GNU assembly syntax
• X86 Assembly/Global Descriptor Table
• X86 Assembly/Interfacing with Linux
• X86 Assembly/Intrinsic Data Types
• X86 Assembly/Introduction
• X86 Assembly/MMX
• X86 Assembly/Machine Language Conversion
• X86 Assembly/NASM Syntax
• X86 Assembly/Other Instructions
• X86 Assembly/Print Version
• X86 Assembly/Programmable Interval Timer
• X86 Assembly/Protected Mode
• X86 Assembly/SSE
• X86 Assembly/Shift and Rotate
• X86 Assembly/X86 Architecture
• X86 Assembly/X86 Family
• X86 Assembly/X86 Instructions/Other Instructions
• X86 Assembly/YASM Syntax
• X86 Assembly/x86 Assemblers

Templates

I have created a few templates for writing ASM instructions:

• Template:x86-inst
• Template:x86-inst-1
• Template:x86-inst-2
• Template:x86-inst-3

Which will display assembly instructions with 0, 1, 2 and 3 operands, respectfully.

• Template:x86_Assembly_Page

This template goes at the top of every page in the book, for uniformity.

• Template:x86 Assembly Stub

This template marks a page in this book as being a stub.

--Whiteknight (talk) (current) 19:08, 14 December 2005 (UTC)

Eatingrapunzel created the x86-inst-3 template, so I added it to the list Ziom 2.0 WB (discuss • contribs) 14:03, 30 June 2022 (UTC)

Overhaul

I've completely overhauled this page, and moved the information into neat subpages which are more manageable. I have also moved the page from "Programming:x86 Assembly" to simply x86 Assembly, and have instituted the "forward-slash" naming convention for subpages. --Whiteknight (talk) (current) 21:09, 8 December 2005 (UTC)

Ask for Help

Would someone please work on this page. It's a good quick start guide at most right now, but to a newcomer to assembly like myself, it gives little info. The the example for mov for instance is more advanced than what is previously talked about. There isn't any details about syntax before that point. I get the gist of it, but it would be better for someone to add a section before that some time which gives a very basic program and gives details of what each line does and if it's always needed or platform specific (say from Windows to Linux to 16 bit Dos even.)

--HarleyL 13:42, 12 Apr 2005 (UTC)

When I came to this book a month ago seeking to learn NASM, I didn't get much out of it. When I returned recently, I realized there is a fair bit of info here, but it's mostly in a reference book format. What do people think about turning section 2 into the big thrust -making lesson plans for each of the mentioned assemblers- and then moving the rest to the back as appendices? Gabriel Lein 15:05, 14 April 2006 (UTC)

In X86 Assembly/X86 Architecture#Addressing_modes, what is the difference between base displacement and direct offset addressing?

In section 2.2 x86 instruction set although the book mentions both styles of syntax it does not make clear which syntax the examples are using, although the comments sometimes make this clear it would be worthwhile to have a note at the start of the section or with each example stating which syntax is used.

Also in the examples the instructions are suffixed with the size of operand (l, b or w) which although improves readability it generates confusion for beginners because those features appear to be GNU (GAS) specific and may not work in their respective assembler a quick note about this would alleviate the confusion. --Petersmith131 (talk) 04:42, 20 September 2010 (UTC)

Reverse Engineering Wikibook

I have added some links from the book I've been working on, Reverse Engineering to point to this page. It would be nice if this book was beefed up a little bit, and maybe if it included at least some info on Intel syntax as well, because the RE book uses mostly Intel. If nobody else jumps on to this task, i might work on it some myself. --Whiteknight 01:27, 3 October 2005 (UTC)

Other resources

I'm not sure if anyone is interested, but there is a guide on the same topic at http://www.drpaulcarter.com/pcasm/. downloadable as PDF or POSTSCRIPT, 195 pages long.

203.51.107.3 05:29, 27 March 2006 (UTC) 

RiRi Weissenhower

Link Edit

added the link to the wikipedia article on processor registers --Jikanter 19:57, 6 August 2006 (UTC)

Order of second byte

I have done some study recently via ICY Hexplorer and an x86 ASM help file, and I noticed that for the second byte whoever wrote it had it somewhat reversed. It was originally Mod-Reg-R/M, whereas it's actually Mod-R/M-Reg, so I changed it to be so, as well as changed the hexadecimal representation of it. I hope nobody minds, as I just found an error and had to correct it.

Context switching?

Some information on context switching would be interesting 69.31.174.216 21:54, 27 July 2007 (UTC)

"Print this string" MBR / GNU AS?

I use GNU AS (+"objcopy -O binary" to get raw content) and because here sadly isn't any mbr examples for it here and this place feels so awkwardly quiet anyway that I just have to say something I'll bother you with this question I might solve myself too. So, I have the following:

.code16
Start:	xor %bh, %bh;
	mov $0xe, %ah;
	mov String, %si;

Print:	movb %cs:(%bp, %si), %al;
	cmp %al, '\0;
	je Infin;
	int $0x10;
	inc %si;
	jmp Print;

Infin:	jmp Infin;

String:	.ascii	"Insert string here\0"

The problem is that the label addresses aren't based on 0x7c00 and I don't know what to do to get them so. Also, is there some shorter way of doing this? --212.149.216.233 (talk) 15:30, 12 March 2008 (UTC)

You need one conditional branch to exit the loop.

You also need a branch at the end of the loop to return to the top of the loop.

Does that mean you need two branch instructions in the loop?

Often assembly language programmers put the conditional branch at the end of the loop -- then they only need one branch instruction in the loop, rather than two.

Smart assembly language programmers use subroutines that have already been written and tested.

Does the following example answer your questions? --DavidCary (talk) 05:54, 24 March 2009 (UTC)

; "Hello World" program from http://hem.passagen.se/danma/asmprog.htm
; This is a DOS program => it's loaded at address 0x100
; The address is needed by Nasm, so it can calculate the pointer values.
; To give Nasm the address, you use the command ORG:
[ORG 0x100]
        mov     ah, 9           ; Print String
        mov     dx, msg         ; (DX=Pointer to msg)
        int     0x21            ;

        mov     ax, 0x4C00      ; Terminate program
        int     0x21            ;

msg     db      'Hello World!$'   ; Insert the message.. A string ending in "$"

Copyright of intel - amd developers manuals.

Hi. I'm writing a x86 assembly manual for el.wikibooks. I use as reference the intel-amd developer manuals and i was wondering to what extent there could be a copyright problem in using material from those manuals.

--Chomwitt (talk) 22:14, 27 April 2009 (UTC)

It depends on how verbatim you are referencing the original material, you can copy a phrase here and there but you best formulate your own structure and wording , it should also be appreciated if you mentioned the original sources. --Panic (talk) 23:27, 27 April 2009 (UTC)

Main page diagram

There's a large diagram on the main page that appears to be showing the effects of various shift instructions on the content of the AL register, but there's no explanatory text or even a label, so I'm wondering if it should be removed. Jfmantis (discuss • contribs) 05:55, 17 February 2011 (UTC)

Ping

Hello Folks, I have been adding content for a couple of months now and I plan on adding/editing until I run out of ideas/stop finding things that need work. I am more focused on adding now but there are some sections that need some rework eventually. Is there anyone else out there? Syaghmour (discuss • contribs) 13:10, 25 October 2012 (UTC)

Interfacing with Linux

I'm new to wikibooks and I started a new talkpage to discuss the "Interfacing with Linux" page. Talk:X86_Assembly/Interfacing_with_Linux --Luckyxxl (discuss • contribs) 16:33, 17 September 2013 (UTC)

License of the code examples?

I don't see explicit licensing statements here in this wikibook, so looks like it is the CC BY-SA? Would it be a good idea to license them more permissively? For example, OsDev.org has relicensed everything to public domain, so their code can be used without any restrictions at all.

I would like to embed the GDT setup code (in X86 Assembly/Global Descriptor Table) into my programming project, but I don't want to license my project under CC BY-SA. Or is the code example on that page so small that it can't even be considered copyrightable? (btw I personally think intellectual property is nothing but unnecessary and harmful madness.)

--130.232.38.44 (discuss) 12:43, 2 June 2016 (UTC)