Assembly.md

x64 Cheat Sheet

• https://cs.brown.edu/courses/cs033/docs/guides/x64_cheatsheet.pdf

  • %rax: By convention, %rax is used to store a function’s return value, if it exists and is no more than 64 bits long. (Larger return types like structs are returned using the stack.)

    • %eax, %ax, %al

  • %rip: Understanding %rip register in intel assembly

  • %retq: What is the difference between retq and ret?

• DCL(DoubleCheckedLocking) 的例子

  • singletons[i].reference = new Singleton();

    # note that the Symantec JIT using a handle-based object allocation system
    0206106A   mov         eax,0F97E78h
    0206106F   call        01F6B210                  ; allocate space for
                                                     ; Singleton, return result in eax
    02061074   mov         dword ptr [ebp],eax       ; EBP is &singletons[i].reference 
                                                    ; store the unconstructed object here.
    02061077   mov         ecx,dword ptr [eax]       ; dereference the handle to
                                                     ; get the raw pointer
    02061079   mov         dword ptr [ecx],100h      ; Next 4 lines are
    0206107F   mov         dword ptr [ecx+4],200h    ; Singleton's inlined constructor
    02061086   mov         dword ptr [ecx+8],400h
    0206108D   mov         dword ptr [ecx+0Ch],0F84030h