From the Internet found a neon command optimization yuv420 to rgb24 code, in the cortex-A8 architecture, clock speed 1g CPU for a frame of qcif (176x144) data test, in addition, compared with the popular algorithm written in C on the Internet, it is found that the speed of the former is more than 700 times that of the latter: the former uses 1000 ms for 112 cycles, and the latter uses 88645 Ms. The related code is as follows:
Assembly Code
Area |. text |, code, readonly; name this block of code
How many registers does the ARM processor contain? What registers are available in each mode? What are the functions of these registers? Let's learn about arm registers with these questions! I believe you will gain some benefits after reading this article.The ARM processor has 37 registers.It contains 31 General registers and 6 State registers.
========================================================== ========================================================== ========USR System Supervisor abort
of dynamic debugging experiments, it is found that the Android Application will call the pthread_create function to create a thread for reverse debugging. Therefore, the method to crack a breakpoint under the Java_com_yaotong_crackme_MainActivity_securityCheck function cannot be achieved directly.
Therefore, the code of the App is modified to prevent anti-debugging of the App ., Locate the location of the ARM assembly command BLX R7 at A8CE 9C58 in
. After several rounds of dynamic debugging experiments, it is found that the Android Application will call the pthread_create function to create a thread for reverse debugging. Therefore, the method to crack a breakpoint under the Java_com_yaotong_crackme_MainActivity_securityCheck function cannot be achieved directly.
Therefore, the code of the App is modified to prevent anti-debugging of the App ., Locate the location of the ARM assembly command BLX R7
others from using their app for dynamic debugging. After several rounds of dynamic debugging experiments, it was found that the Android application would call the function pthread_create to create the thread to reverse debug. Therefore, directly in the function java_com_yaotong_crackme_mainactivity_securitycheck at the breakpoint implementation of the method can not be directly achieved. Therefore, in order to prevent the anti-debugging of the app, the code of the program is modified. , locate
address, R5 is the kernel file of the beginning of the address. Check to see if the address is conflicting.
The R5 equals R2 so that the decompress kernel address is after the 64K stack.
(9) the function Decompress_kernel () that calls the file misc.c, extracts the kernel at the end of the cache (R2 address). At this point the Register values change as follows:
R0 is the size of the kernel after decompression
R4 is the address when kernel is executed
R5 is the starting address for kernel after
dual 4G and full Netcom version, supporting dual SIM, running the Nubia UI 3.0 user interface based on Android 5.1 depth customization, the overall configuration belongs to the middle-end mainstream level.
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register (R15) while CPU is runningJlink Error:can not read register (XPSR) while CPU is runningJlink error:can Not read register 0 (R0) while CPU is runningJlink Error:can Not read Register 1 (R1) while CPU is runningJlink Error:can Not read Register 2 (R2) while CPU is runningJlink Error:can Not read Register 3 (R3) while CPU is runningJlink Error:can Not read Register 4 (R4) while CPU is runningJlink Error:can Not read Register 5 (R5) while CPU is runningJlink Error:can Not read register 6 (
word, the recovery scene, exception handling returns, ^ indicates that the user mode is not allowed
10.STM passes a value from the Register list to the storage space. Stmia R1!,{R3-R9}; Stores the R3-R9 data to the address that R1 points to, and the R1 value is updated. STMFD SP!,{R0-R7,LR}; Save in the field and R0~R7,LR into the stack
11.ASR (arithmetic right shift), ROR (loop right S
In single-chip microcomputer often used to 16 (2) into the BCD code, although the C language programming is more convenient, but the assembly is often needed
Here is a 24-bit binary to the BCD code for example, where the BCD code is stored in a compressed manner, that is, 4-bit storage of a
/* Ingress parameter R1,R2,R3 holds 24-bit binary number, r1-bit maximum 8-bit exit parameter R4,R5,R6,R7 */mov R4, #0 mov R5, #0 mov R6, #0 mov
Recently, an Acer8481 device was installed with Ubuntu10.10 and then turned on. The brightness was too bright and the system's brightness adjustment function did not seem to work. So google found this article: Ubuntu10.10brightnessprobleminAcerAspire4741 according to its practice: sudovi/etc/default/grub (used to use vi)
Recently, an Acer 8481 installed Ubuntu 10.10 and then started on the machine. The brightness was too bright and the system's brightness adjustment function did not seem to wor
. The display is surrounded by a black border and has an ASUS logo just below the screen.
The touchpad is located almost directly below the G and H keys. The position is slightly to the left because the keyboard is joined by the full number button. Of course, there's plenty of room to put your hands on when you type.
Asus Vivobook S500ca's fuselage is 15.1 x 10.2 x 0.8 inches, while Acer Aspire v5-571p-6499 has a fuselage siz
Remote]type = Imapremotehost = $dav _mail_serverremoteport = 1143remo Teuser = $your _account, no @remotepass = $your _pwdssl = Falsesslcacertfile =/etc/ssl/certs/ Ca-certificates.crtmaxconnections = 1realdelete = noAttention:1. The company mailbox in the custom directory preferably no Chinese name, or bad luck will be error2. To create a local directory ~/mail3. Maxcoinnections can only be set to 1, more than 1 I have encountered an error, can only slowly downloadOK, and then in the ~ director
guiding ideology of ROP is to hope that all malicious attacks are concatenated through the sequences of instructions in existing functions. This piece of instruction is a logical fragment that can be connected to each other by means of a jump instruction (x86 on the RET and jmp on ARM, which is the relevant instruction of the PC), called Gadget. The ultimate manifestation of ROP attacks is a string of gadgets.The power of ROP is that any logic can be realized by finding an overflow defect, and
Feroceon2. the CPU is responsible for all SATA transmissions, so there must be a service responsible for configuring SATA hardware to read data in the cache. If I find this service, I may run my code before it.
After reading a lot of code, setting a lot of breakpoints, and modifying it many times, I finally found a qualified service. I connected the service to run my code before execution. Here is the original code:
000167BE ; r0 - slot in sata_req000167BE sub_0_167BE:000167BE P
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