Previously asked on edx code (edx Google Group) How to expand a field for course, such as adding a category field to a course.The reply says to add the field you want directly to the couesefields. Position common/lib/xmodule/course_module.py after. The field is automatically displayed in the Advanced settings. In this way I find that the field is indeed a property of course (experiment in the shell). Howeve
basically no design pattern, which cannot reflect the great superiority of the C ++ language in object-oriented design. Let's take a look at how this virtual works?
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76: employee P;
0040128d Lea ECx, [ebp-10h]
00401290 call @ ILT + 45 (employee: Employee) (00401032)
00401295 mov dword ptr [ebp-4], 0
77: manager m;
0040129c Lea ECx, [ebp-14h]
0040129f call @ ILT + 65 (Manager: Manager) (00401046)
004012a4 mov byte PTR [ebp-4], 1
78: employee * E =
of system_call. In system. h:
//// Set the system call function. // Parameter: n-interrupt number; addr-interrupt program offset address. // Idt [n] corresponds to the offset value of the interrupt number in the Interrupt Descriptor Table. The Interrupt Descriptor type is 15 and the privileged level is 3. # Define set_system_gate (n, addr) _ set_gate ( idt [n], 15,3, addr) /// set the macro function of the gate descriptor. // Parameter: gate_addr-Descriptor address; type-Descriptor field value
converted to the address of the method to be called and the list of its parameters (stored inTvarrec array), how to pass parameters when calling it. Some preparations are required:
1. First, let's take a look at the passed parameter table: Params. Its type is called Variable-enable by Delphi.Put an array (variant open array), equivalent to array of tvarrec, that is, Params isArray of tvarrec members. In other words, all types of parameters areDelphi is automatically converted to tvarrec (see
state transition.
on each platform, there is a specific directive that converts the execution of a process from user state to a core state, which is called the Operating system trap (operating system traps). After the process has been executed into the command, it can run the system call code in the kernel mentality.
In Linux it is through soft interrupts to achieve this, on the x86 platform, this instruction is int 0x80. That is, in Linux, the interface of the system call is a special case o
EAX, the parameter is EBX, ECX, edx, EDI, ESI to pass. Writing Shellcode To write Shellcode under Linux, you can use GCC to assemble directly. s file to compile the link, generate the standard executable Elf file, but also can be directly tested, but it is not convenient to extract machine code is very inconvenient.In order to facilitate the extraction of machine code, using the NASM compiler to generate the bin file, no other format data, convenient
project investments, while enterprise-class features such as monitoring, management, embedding, and extensibility are still in the process of being developed (Qlik has released Qlik sense, and each version of Tableau complements some enterprise-class features).There is a view that tableau and Qlik have been focused on optimizing the ease of use of the product to access more users, but less attention is pai
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Author: uuk[Software name]: Total Commander[Software Version]: 7.56a[Shelling method]: new version without shelling[Programming language]: Borland Delphi 2.0 [Overlay][Tools]: OD PEID IDA[Operating platform]: Windows XP[Software introduction]: A pretty good dual-column File Management Software[Author's statement]: it is only for research purposes. Please purchase a genuine version for use.We know that Total Commander has self-verification. by tracking the CreateFile and ReadFile functions, it is
8. Offset is the number of immediately. For example, [EBP + EDX * 8 + 200] is a valid address expression. Of course, in most cases, it is not necessary to have such a complex relationship as inter-address, proportional factor, or offset.
The basic unit of memory is byte ). Each byte has eight binary bits. Therefore, the maximum number of characters that each word can save is 11111111, that is, 255 in decimal format. In general, it is more convenient
# reset the IDT and gdt tables at the new location.16 call setup_idt # Set IDT. First, fill in the descriptor of the default processing process for all the 256 interrupt doors.17 Call setup_gdt # Set gdt.18 movl $0x10, % eax # Reload all segment registers after gdt is changed.19mov % ax, % DS20mov % ax, % es21mov % ax, % FS22mov % ax, % GS23lss init_stack, % ESP24 # Set the 8253 timing chip. Set counter channel 0 to send an interrupt request signal to the interrupt controller every 10 ms.25 mov
The following two hash functions (FNV bkdr) are optimized to hash short strings ending with 0 and get a 32-bit hash value.
----------------- By G-spider
FNV hash
Fnv32_t__stdcall fnv_32a_str_c(char *str){ unsigned char *s = (unsigned char *)str;/* unsigned string */ Fnv32_t hval= 2166136261; /* * FNV-1a hash each octet in the buffer */ do {/* xor the bottom with the current octet */hval ^= (Fnv32_t)*s;/* multiply by the 32 bit FNV magic prime mod 2^32 */hval *= 0x01000193;
function is located in x86/boot/pmjump. s, good, this is another piece of assembly code, and later, the kernel will directly jump back and forth between the assembly code and the C code. The Code is as follows:
26 Global (protected_mode_jump)27 movl % edX, % ESI # pointer to boot_params table2829 xorl % EBX, % EBX30 movw % CS, % BX31 shll $4, % EBX32 addl % EBX, 2f33 JMP 1f # Short jump to serialize on 386/48634 1:3536 movw $ __boot_ds, % CX37 movw $
can express all ASCII codes. That is to say, a memory unit can store an English character or number, while a Chinese character must be represented by a unicode code. That is to say, two memory units can hold a Chinese character. It is not hard to understand that the sixteen bits are two bytes. Of course, if there are sixteen bits, there must be thirty-two bits, sixty-fourteen bits, and so on. The thirty-two bits are called dual characters, and the sixty-fourteen bits are called four characters.
command is executed, the configured values are specified through the edX and eax registers, the high 32 bits of the specified value of edX, and the low 32 bits of the value specified by eax, when the preceding registers are set, edX is 0. MSR registers are filled with the specified MSR registers through the ECX registers. The registers of sysenter_cs_msr, sysent
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