Opcode syntax: Difference between revisions

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Revision as of 15:17, 28 August 2011 view source osdev>Lithium26 added inteltoatt script ← Older edit		Latest revision as of 05:38, 9 June 2024 view source Xtex (talk \| contribs) Interface administrators, Administrators 977 edits m Bot: Replace deprecated source tag with syntaxhighlight
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Line 13: '''Escapes:''' Special characters are written as C-style escapes (\n, \", \#, \\, ...). '''Comments:''' Either C-style ( /* ... / ) or shell style (# ...). '''Directive syntax:''' Directives begin with a period (".align 4" to align on a ~~doubleword~~32-bit boundary, ".word 0x1234" is the equivalent of "DW 1234h"). '''Strings:''' Defined using special directives, .ascii (or .asciz for a zero-terminated string). Example: msg: .ascii "Hello, World!\n" '''Current location address:''' Indicated by a period (".", equivalent to Intel syntax "$"). Line 35: The AT&T syntax format for macros: <syntaxhighlight lang="asm"> ~~<code>~~ .macro <name> <args> <operations> .endm </syntaxhighlight> ~~</code>~~ Example: <syntaxhighlight lang="asm"> ~~<pre>~~ .macro write string movw string, %si call printstr .endm </syntaxhighlight> ~~</pre>~~ This would be equivalent to the NASM macro: <syntaxhighlight lang="asm"> ~~<pre>~~ %macro write 1 mov si, %1 call printstr %endmacro </syntaxhighlight> ~~</pre>~~ Additionally, the cpp and m4[[M4]] macro preprocessors are often used for macro handling. == Converting small snippets of code from Intel syntax to AT&T == You can use the following script to convert short snippets of code (one liners) from Intel syntax to AT&T syntax: <~~source~~syntaxhighlight lang="bash">#!/bin/bash set -e Line 100: tail -n +$lineno "$objdump" </syntaxhighlight> ~~</source>~~ == Sources ==▼ ▲== ~~Sources~~See Also == === External Links === [http://www.delorie.com/djgpp/v2faq/faq17_1.html DJGPP AT&T Assembly Tutorial] [http://asm.sourceforge.net//howto/Assembly-HOWTO.html Linux Assembly HOWTO] [https://savannah.nongnu.org/projects/gas-user/ GAS/AS End User Help Project] [~~http~~https://savannah.nongnu.org/projects/pgubook/ Programming from the Ground Up]▼ [http://www.gnu.org/software/binutils/manual/gas-2.9.1/html_chapter/as_toc.html Using as] ▲[http://savannah.nongnu.org/projects/pgubook/ Programming from the Ground Up] [[Category:Assembly]]