From 2cad8341019659a65fc6e94992165b3d7b7a37db Mon Sep 17 00:00:00 2001 From: johannst Date: Sun, 23 Mar 2025 23:51:01 +0000 Subject: deploy: 916b73bee95494c205ba67e4a50e6a525afc3a3c --- development/gas.html | 258 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 258 insertions(+) create mode 100644 development/gas.html (limited to 'development/gas.html') diff --git a/development/gas.html b/development/gas.html new file mode 100644 index 0000000..3c87981 --- /dev/null +++ b/development/gas.html @@ -0,0 +1,258 @@ + + + + + + gas - Notes + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
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+

gas

+

Frequently used directives

+
    +
  • +

    .byte, .2byte, .4byte, .8byte to define a N byte value

    +
    .byte 0xaa
+.2byte 0xaabb
+.2byte 0xaa, 0xbb
+.4byte 0xaabbccdd
+.8byte 0xaabbccdd11223344
+
    +
    • +
  • +

    .ascii to define an ascii string

    +
    .ascii "foo"   ; allocates 3 bytes
+
    +
    • +
  • +

    .asciz to define an ascii string with '\0' terminator

    +
    .asciz "foo"   ; allocates 4 bytes (str + \0)
+
    +
    • +
  • +

    .macro to define assembler macros. Arguments are accessed with the +\arg syntax.

    +
    .macro defstr name str
+\name:
+    .ascii "\str"
+\name\()_len:
+    .8byte . - \name
+.endm
+
+; use as
+defstr foo, "foobar"
+
    +
    +

    Use \() to concatenate macro argument and literal.

    +
    +
    • +
  • +

    GNU Assembler

    +
    • +
  • +

    GNU Assembler Directives

    +
    • +
  • +

    GNU Assembler x86_64 dependent features

    +
    • +
+ +
+ + +
+
+ + + +
+ + + + + + + + + + + + + + + + + + +
+ + -- cgit v1.2.3