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Perform the default action Ignore signal Capture signal: Perform signal processing function, switch to user state. Snapping: Signal functionsIgnore signal: sig_ignDefault action: SIG_DFL(3) Multi-signal processingProcessing method:1. Recursive, call the same handler function2. Ignoring a second signal3. Block the second signal until the first one is processedSixth section non-local jumpThe C language, the user-level exception control flow form, is provided through the setj

work correctly for any viable trajectory. 2. Elimination Method:Dynamically assigns a separate block to each integer ID, and passes to the thread routine a pointer to the blockFive, Deadlock:A set of threads is blocked, waiting for a condition that will never be true.How to resolve a deadlockA. Do not allow deadlocks to occur:B. Let the deadlock occur:Resources:1. Teaching Materials: 11th chapter "Network Programming"2. Teaching Materials: 12th chapter "Concurrent Programming"20135223 He Weizin

FeelingsJust beginning to touch Java, feel both confused and hard, because they have not been in a self-learning way to contact a new programming course, long time to find more difficult. I think, teacher and student relationship is eldest brother and brother! Why do you say that, because the teacher experienced the student age and more understanding of the situation of students, leading students to learn and impart some experience, so that students l

a logic gate based on the individual bits of the input word.In the HCL, we declare all word-level signals as int, without specifying the size of the wordIn the HCL, a multiplexed function is described using a condition expression. Each case I has a Boolean expression select and an integer expression, expr. The former indicates when to choose this case, the latter represents the resulting valueThe Arithmetic/logic unit (ALU) is a very important combination circuit. This circuit has 3 inputs: two

Division Instruction no definition for all condition code bits Bit operations Directives :and logic with or logical or not logic does not affect the flag bit XOR or test instruction except for the four kinds of, set CF, of 0,af undefined, SF,ZF, PF sets the shift instruction based on the result of the operation:SHL logical left SHIFT instruction SHR logical Right SHIFT instruction shift instruction based on result set SF,ZF,PF bit ROL loop left shift instruction ROR loop right Shift instructio

cause a set of states called deadlock zones. Deadlock is a rather difficult problem because it is unpredictable. Mutex lock Order rule : If for each pair of mutex (S,T) in the program, assign a whole order to all the locks, each thread requests the lock in this order, and is released according to reverse, the program is deadlock-free.How to resolve a deadlock do not let a deadlock occur: Static strategy: Design appropriate resource allocation algorithm, do not le

-feeling bad, read a lot of confusion, code execution is also less. This week's code package gives me a good chance to practice understanding! So I just took the code out of the video in handy. The feeling learned a lot of content. In particular, the function of fork such functions are in the execution of the code to feel its principle. It was really touching when I finished it!!!Because there is also a recent project of this course, the internet also searched a lot of communication between the

shared. 10.7 redirectsI/O redirection: Use the DUP2 function:#include int dup2(int OIDFD,int newfd); Returns: a non-negative descriptor if successful, or1 if an error occurs10.8 Standard I/OStandard I/O library (LIBC): Advanced input-Output functions#include extern FILE *stdin;/* standard input, file descriptor 0*/ extern FILE *stdout;/* Standard output, file descriptor 1*/ extern file *STDERR;/* standard error, file descriptor 2*/ The standard I/O library m

, stack pointer, program counter, and general purpose register value. Each thread shares other parts of the process context with other threads. This includes the entire user virtual address space, which consists of read-only text (code), read-write data, heaps, and all shared library code and data regions. Threads also share the same set of open files. Registers are never shared.mapping variables to storageIn threaded C programs, variables are mapped to virtual storage according to their storage

, double Int→float will not overflow but may be roundedInt/float→double results retain exact valuesDouble→float may overflow to ±∞ and may be rounded due to small accuracyThe float/double→int rounds to 0 and can overflow.Problems encountered:1. Error in compiling the 28-page code in the bookCheck the code seems to be nothing wrong, do not know why ... at last, I commented out the line . The source code is as follows2. Exercise 2.52 do not understand, I hope the teacher can explain in classI

-point numbers，权重是2 的E次幂。Case 1: Normalized value. When exp is not full modulus is 1 or 0. The Order field is interpreted as a biased representation of a signed integer.Case 2: Non-normalized value: When the Order field is full 0 o'clock, the number represented is a non-normalized form. In this case, the order value is E = 1-bias, and the value of the mantissa is M = f, which is the value of the small number field, which does not contain the implied beginning of 1Case 3: Special Value: The Order

frees the allocated blocks that the program no longer needs, called garbage , and the process of automatically reclaiming heap storage is called garbage collection . The garbage collector periodically identifies the garbage blocks and calls free accordingly, putting the blocks back into the idle listSecond, the garbage collector sees the memory as a forward-reaching graph, only when there is a path from any root node to reach p, it is said that node p is reachable, and the unreachable point is

that is a member of the size class.This method is fast and efficient for memory use.3. Partner Systems　　Each of these size classes is a power of 2Thus, given the size of the address and block, it is easy to calculate the address of its partner, that is to say: The address of a block and its partner's address only a different.Pros: Quick Search, quick merge.9.10 Garbage CollectionThe garbage collector is a dynamic storage allocator that automatically frees the allocated blocks that the program n

information is accessed relative to the frame pointer. Program register groups are the only resources that can be shared by all processes. 根据惯例寄存器%eax,%edx,%ecx被划分为调用者保存寄存器。 %ebx,%esi,%edi被划分为被调用者保存寄存器。 %ebp,%esp 惯例保持 %eax用来保存返回值 The call command has a target, which indicates the address of the instruction at the beginning of the called process, and the effect is to put the return address into the stack and jump to the beginning of the called procedure. The RET instruction pop

, such as read, are stopped in the Read function, and so on, the Read function is finished, in fact, the control is no longer in main, but through the read function to jump to the kernel. Also such as the signal, the process receives the signal, the trigger control jumps to the signal processing program.This is also true of the non-local jump that is now spoken. The control jumped away. The user-level exception control flow form, called a non-local jump, transfers control directly from one

program uses a program stack to support procedure calls. The machine uses stacks to pass process parameters, store return information, save registers, and local storage. 2. Translation control (1) Call command The target is the address of the instruction that indicates the start of the called process The effect is to put the return address into the stack and jump to the beginning of the called procedure. (2) RET instruction POPs the address from the stack and

entire wordSuppose we want to design a logic circuit to find the minimum value in a set of characters A,b,c, using the HCL to express is:int Min3 =[A b 1:C;];Two types of memory devices: Clock registers, random access memoryProcessing an instruction consists of a number of operations (six basic stages that can be organized into the calculations required to implement all Y86 directives):1. Take the finger2. Decoding3. Implementation4. Visit5. Write back6. Update your PCThe processor never needs

small-end method.Note: The destination address of the branch instruction and the calling instruction is an absolute address, rather than using a PC-relative addressing method as in IA32. The processor uses a PC-relative addressing method, and the branch instruction is encoded more succinctly, which also allows the code to be copied from one part of the memory to another without having to update all the branch destination addresses.For example:An important property of the ⑤ instruction set is th

misses/number of references Hit Ratio = 1-No hit Hit time No hit penalty: Because of the extra time required to miss the 2. Specific impact: Cache Size: Hit ratio +, hit Time + Block Size: Spatial locality +, hit ratio +, number of cache rows-, time locality-, no hit penalty + Degree of coupling: E value big, jitter-, Price +, hit Time +, no hit penalty +, control logic + "compromise for not hit penalty low, low degree of coupling, not hit penalty high, use hig

status code stat from the result of the instruction execution, based on Icode,imem_error,instr_valid,dmem_error. update pc stage generates a new value for the program counter, depending on the type of instruction and whether to select the branch, the new PC may be valc, Valm, or Valp. Please explain why there is only one if statement in the C language code, and the assembly code contains two conditional branches?A: The first conditional branch is part of th