From b590f4ed4db110bb61da35fec288a467d32c9a62 Mon Sep 17 00:00:00 2001
From: johannst <johannst@users.noreply.github.com>
Date: Sun, 5 Feb 2023 17:28:38 +0000
Subject: deploy: 728d263753b998b8944a66eec1be0e743961fa1c

---
 binary/objdump.html | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

(limited to 'binary')

diff --git a/binary/objdump.html b/binary/objdump.html
index e61f55a..e97b853 100644
--- a/binary/objdump.html
+++ b/binary/objdump.html
@@ -157,6 +157,39 @@
 <h2 id="disassemble-section"><a class="header" href="#disassemble-section">Disassemble section</a></h2>
 <p>For example <code>.plt</code> section:</p>
 <pre><code class="language-markdown">  objdump -j .plt -d &lt;elf&gt;
+</code></pre>
+<h2 id="example-disassemble-raw-binary"><a class="header" href="#example-disassemble-raw-binary">Example: disassemble raw binary</a></h2>
+<p>This can be helpful for example as a cheap analysis tool when toying with JIT
+generating code. We could just write thee binary code buffer to a file and
+disassemble with <code>objdump</code>.</p>
+<p>To re-create that case, we just assemble and link some ELF file and then create
+a raw binary of the text section with <code>objcopy</code>.</p>
+<pre><code class="language-x86asm"># file: test.s
+.section .text, &quot;ax&quot;
+
+.global _start
+_start:
+    xor %rax, %rax
+    mov $0x8, %rax
+1:
+    cmp $0, %rax
+    je 2f
+    dec %rax
+    jmp 1b
+2:
+    # x86-64 exit(2) syscall
+    mov $0, %rdi
+    mov $60, %rax
+    syscall
+</code></pre>
+<pre><code class="language-bash"># Assemble &amp; link.
+as -o test.o test.s
+ld -o test test.o testc.o
+# ELF -&gt; binary (only take .text section).
+objcopy -O binary --only-section .text test test-bin
+
+# Disassemble raw binary.
+objdump -D -b binary -m i386:x86-64 test-bin
 </code></pre>
 
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