Branch instruction commands are as follows:
0xea00088e
The corresponding binary is:
11101010000000000000100010001110
The analysis is as follows:
1110 is unconditional.
101 is the flag of branch instruction
000000000000100010001110 is a total of 24 bits, that is, our 0x88e, which can represent the maximum number of 2 to the power of 24, that is, 64 MB, so branch instruction can jump to or from the front to the back to jump to 32 MB space.
Then let's see what happened to 0x88e:
0x88e
objectsize; declare a global numeric variable, initialized to 0
Objectsize Seta 0xff; assign the variable objectsize to 0xff
Space objectsize; reference this variable
Gbll statusb; declare a Global Logical variable statusb
Statusb SETl {true}; assign true to the logic variable statusb
Ltls, lcll, and lcls
Ltls declares a local numeric variable and initializes it to 0.
Lcll declares a local logical variable and initializes it to {false}
Lcls declares a local string variable and initializes it
First: Basic knowledge
(1) Register, use rules for parameter passing
A. In the subroutine, use the register R4 ~ R11 to save local variables.
B. Register R12 is used for Scratch registers between subprograms (used to save the SP and use this register to exit the register when the function returns) and is recorded as IP addresses.
C. Register R13 is used as the data stack pointer and recorded as sp. The SP value in the register must be the same as that in the exit subroutine.
D. Register R14 is c
Now many people are in {Function onclick (){Tagshow (Event)}} "> Learning arm {Function onclick (){Tagshow (Event)}} "> Embedded {Function onclick (){Tagshow (Event)}} "> Embedded system {Function onclick (){Tagshow (Event)}} "> Develop ARM core boards such as ARM9 {Function onclick (){Tagshow (Event)}} "> Knowledge, so learn about arm {Function onclick (){Tagshow (Event)}} "> Commands are inevitable. Next I will make a simple summary of the knowledge about the Captain in learning arm commands,
Detailed description of the CPSR register of ARM9.
Recently I have been studying embedded underlying system development. When writing startup code, I need to set the SP of each mode. I need to adjust the CPU working mode. Some code is as follows:
.equ DISABLE_IRQ, 0x80.equ DISABLE_FIQ, 0x40.equ SYS_MOD, 0x1f.equ IRQ_MOD, 0x12.equ FIQ_MOD, 0x11.equ SVC_MOD, 0x13.equ ABT_MOD, 0x17.equ UND_MOD, 0x1bmsr cpsr_c,#(DISABLE_IRQ|DISABLE_FIQ|SVC_MOD)ldr sp,=_SVC_STACKmsr cpsr_c,#(DISABLE_IRQ|DISABLE_FIQ|I
(' reduce () of empty sequence with no initial value ')Accum_value = initializerFor x in it:Accum_value = function (Accum_value, x)Return Accum_value
If we use the familiar for loop to do the above reduce, we can do this:
The code is as follows:
>>> LST = range (1,6)>>> LST[1, 2, 3, 4, 5]>>> r = 0>>> for I in range (len (LST)):... r + = Lst[i]...>>> R15
For universal, reduce is concise.
In order to exercise thinking, to see such a problem, there ar
gyroscope, battery voltage detection, 4 led;4 for commissioning, a set of 4 p dial switch, active buzzer, two 6P with AB Encoder motor interface.I share out is the hardware + software matching, no exaggeration to say, directly to me this PCB sent to proofing back welding, program burn write in, adjust the parameters should be simple upright.Link settings0:r0:0x001:r1:0x012:r2:0x023:r3:0x034:r4:0x045:r5:0x056:r6:0x067:r7:0x078:r8:0x089:r9:0x0910:r10:0x0a11:r11:0x0b12:r12:0x0c13:r13:0x0d14:r14:0x
Write down and share it. It is too easy to decompile androidapk. If your SDK is old enough, you can bypass it. If the SDK is new, okay. Obfuscation of APK. It does not mean that ndk should at least encrypt Java, if it is not an open-source project.
The progurad provided by the latest R15 is 4.4. Anyway, I have a problem. What is the RP problem ?, I can't export the APK and keep prompting for errors. Conversion to Dalvik format failed with error 1
will appear in r15 ),
This makes building faster.
However, it also has an impact on the source code of the library. The following forms of code will no longer be compiled:
Int id = view. getId (); switch (id) {case R. id. button1:
action1();
break;
case R.id.button2:
action2();
break;
case R.id.button3:
action3();
break;
}
This is because
switchThe statement requires all case labels, such
R.id.button1Is a constant during compilation
Stack Overflow Attack series: shellcode in linux x86 64-bit attacks get root permissions (1) how to execute functions, shellcoderoot
There are already many examples of stack overflow on the Internet, but it rarely involves 64-bit linux related to the operating system. Recently, I have been researching this, so I wrote a series of blog posts, one is to help you remember, and the other is to help more people explore each other.Register
The X86-64 has 16 64-bit registers: % rax, % rbx, % rcx, % rdx
is valid after the clock is valid. This means that the data signal is first established, and the clock signal is then established. Enter the register at the CP rising edge.
Difference between latches and triggers:When the latch level is triggered, the glitch at the input end is brought into the output, and the trigger can effectively suppress the interference at the input end due to the edge effect;
Register: A small storage area used to store data. It is used to temporarily store the data
the next cycle of data path and complete register decoding, it is then sent to the Execution Unit to complete the reading of registers, the ALU operation, and the write-back of the operation result. The instructions for accessing the memory are required to complete the access to the memory. Although a single instruction still needs three clock cycles on the pipeline, the processor throughput is about one instruction per cycle through parallel processing of multiple components, which improves th
12.1680-v6107-20.rev_a_debug_troubleshoot.pdf
When the function is called, The R0-R3 passes four parameters, the rest are saved through the stack, and the parameters are imported from the right to the left order into the stack.
R13 is the stack pointer Stack pointer (SP). It does not need to be used for other purposes and always points to the current position in the stack. When context switch is enabled, Rex uses SP to switch the execution of different tasks (points SP to the stack of different
found in the current version of the deleted project www.2cto.com, exists in the previous version-accurately copy svn cp-r19 $ URL/filename-check result svnstatus-submit svn ci-m "resurrected c.txt fromr19" svn mer Ge-r m: n path compares two version trees, apply the difference to local copy the final version tree of the initial version tree a copy of the work that receives the difference merge branch-find the version svn log-v -- stop-on-copy $ URL generated by the Branch to find the branch the
, because the code at the beginning of the runtime is in the on-chip SRAM, we have to jump in the SRAM to use the location-independent code, then B is the best choice, because it is a relative jump. Ldrpc, _undefined_instruction_undefined_instruction:. Word undefined_instructionThe feeling is really showing off, two instructions connected to the result is that the CPU will jump to the undefined_instruction link address to execute (SDRAM). Then in fact, an LDR pc,=undefined_instruction is enough,
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.