Xchg rax,rax

What Hacker News says

1. omnicognateDec 2025
   It happens to be the first instruction of the first snippet in the wonderful xchg rax,rax.

   https://www.xorpd.net/pages/xchg_rax/snip_00.html

   thread
2. cenazoicNov 2021
   Ruby Under the Microscope: http://patshaughnessy.net/ruby-under-a-microscope

   The CS Detective: https://nostarch.com/csdetective

   Mazes for Programmers: http://www.mazesforprogrammers.com/

   A Curious Moon: https://bigmachine.io/products/a-curious-moon/

   xchg rax,rax: https://www.xorpd.net/pages/xchg_rax/snip_00.html

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3. dahartAug 2024
   This reminded me of the puzzle book “xchg rax,rax”. Maybe that has some hidden insights… :P

   https://www.xorpd.net/pages/xchg_rax/snip_00.html

   thread
4. SonOfLilitDec 2014
   I was lucky enough to review a draft of this amazing book.

   Two of my favorite poems:

     ; 0x1
     .loop:
         xadd     rax,rdx
         loop     .loop
   
     ; 0x13
         mov      rcx,0x40
     .loop:
         mov      rdx,rax
         xor      rax,rbx
         and      rbx,rdx
         shl      rbx,0x1
         loop     .loop
   
   

   From the book's description on https://www.createspace.com/5067642:

     xchg rax, rax
     Authored by xorpd
   
     About the author: "Performs a bitwise logical exclusive-OR
     of the two packed double-precision floating-point values
     from the source operand (second operand) and the
     destination operand (first operand), and stores the result
     in the destination operand. The source operand can be an
     XMM register or a 128-bit memory location. The destination
     operand is an XMM register." 
     (Intel(r) 64 and IA-32 Architectures Software Developer's Manual)
   
     ; 0x40 assembly riddles
     "xchg rax,rax" is a collection of assembly gems and
     riddles I found over many years of reversing and writing
     assembly code. The book contains 0x40 short assembly
     snippets, each built to teach you one concept about
     assembly, math or life in general.
   
     Be warned - This book is not for beginners. It doesn't
     contain anything besides assembly code, and therefore some
     x86_64 assembly knowledge is required.

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