{"id":13656,"date":"2022-12-08T16:20:44","date_gmt":"2022-12-08T16:20:44","guid":{"rendered":"http:\/\/blog.bachi.net\/?p=13656"},"modified":"2022-12-08T20:19:59","modified_gmt":"2022-12-08T20:19:59","slug":"assembly-intel-vs-att-syntax","status":"publish","type":"post","link":"https:\/\/blog.bachi.net\/?p=13656","title":{"rendered":"Assembly Intel vs. AT&T Syntax \/ GAS vs. NASM"},"content":{"rendered":"

Differences in Intel (NASM) vs AT&T (GAS) Syntax.<\/a><\/p>\n

Linux assemblers: A comparison of GAS and NASM<\/a>, A side-by-side look at GNU Assembler (GAS) and Netwide Assembler (NASM)<\/p>\n

NASM Vs GAS (Practical differences)<\/a>
\nCan I use Intel syntax of x86 assembly with GCC?<\/a>
\nUsing “.intel_syntax noprefix” how can I get memory address of a label?<\/a>
\nWhich variable size to use (db, dw, dd) with x86 assembly?<\/a>
\nWhat’s the difference between equ and db in NASM?<\/a>
\n“no such instruction error” when assembling an array declaration<\/a>
\nDifference between .equ and .word in ARM Assembly?<\/a>
\nWhy are there empty address spaces between data sections in memory (x86 \/ nasm)?<\/a>
\nWhat does the dollar sign ($) mean in x86 assembly when calculating string lengths like “$ – label”? [duplicate]<\/a><\/p>\n

\r\nmov si, name              \r\nmov si, [name]\r\nmov si, word ptr [name]\r\nmov si, offset name\r\n<\/pre>\n
EQU defines a symbol to a given constant value: when EQU is used, the source line must contain a label. The action of EQU is to define the given label name to the value of its (only) operand. This definition is absolute, and cannot change later. So, for example,<\/p>\n
\r\nmessage         db      'hello, world' \r\nmsglen          equ     $-message\r\n<\/pre>\n
defines msglen to be the constant 12. msglen may not then be redefined later. This is not a preprocessor definition either: the value of msglen is evaluated once, using the value of $ (see section 3.5 for an explanation of $) at the point of definition, rather than being evaluated wherever it is referenced and using the value of $ at the point of reference.<\/p>\n\n\n\n\n\n\n\n\n\n\n
Operand <\/font><\/u><\/td>\n Format<\/font><\/u><\/td>\n 6811\/6812example<\/font><\/u><\/td>\n<\/tr>\n
no operand<\/font><\/td>\naccumulator and inherent<\/font><\/td>\nclra<\/font><\/td>\n<\/tr>\n
<expression><\/font><\/td>\ndirect, extended, or relative<\/font><\/td>\nldaa<\/font> 4<\/font><\/td>\n<\/tr>\n
#<expression><\/font><\/td>\nimmediate<\/font><\/td>\nldaa<\/font> #4<\/font><\/td>\n<\/tr>\n
<expression>,R<\/font><\/td>\nindexed with address register<\/font><\/td>\nldaa<\/font> 4,x<\/font><\/td>\n<\/tr>\n
<expr>,<expr><\/font><\/td>\nbit set or clear<\/font><\/td>\nbset<\/font> 4,#$01<\/font><\/td>\n<\/tr>\n
<expr>,<expr>,<expr><\/font><\/td>\nbit test and branch<\/font><\/td>\nbrset<\/font> 4,#$01,there<\/font><\/td>\n<\/tr>\n
<expr>,R,<expr>,<expr><\/font><\/td>\nbit test and branch<\/font><\/td>\nbrset<\/font> 4,x,#$01,there<\/font><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"
Differences in Intel (NASM) vs AT&T (GAS) Syntax. Linux assemblers: A comparison of GAS and NASM, A side-by-side look at GNU Assembler (GAS) and Netwide Assembler (NASM) NASM Vs GAS (Practical differences) Can I use Intel syntax of x86 assembly with GCC? Using “.intel_syntax noprefix” how can I get memory address of a label? Which […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-13656","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/blog.bachi.net\/index.php?rest_route=\/wp\/v2\/posts\/13656","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.bachi.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.bachi.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.bachi.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.bachi.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=13656"}],"version-history":[{"count":10,"href":"https:\/\/blog.bachi.net\/index.php?rest_route=\/wp\/v2\/posts\/13656\/revisions"}],"predecessor-version":[{"id":13666,"href":"https:\/\/blog.bachi.net\/index.php?rest_route=\/wp\/v2\/posts\/13656\/revisions\/13666"}],"wp:attachment":[{"href":"https:\/\/blog.bachi.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13656"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.bachi.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=13656"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.bachi.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=13656"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}