Microcomputer Principle Jump Instruction 20, Microcomputer Principle Jump Instruction

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When studying various resonant circuits, the quality factor of the circuit is often involved in the question of the Q value, so what is the Q value? Let's take a closer look.

Figure 1 is a series resonant circuit consisting of capacitor c, inductor l, and the leakage resistance of the capacitor and the line resistance r of the inductor. The complex impedance z of this circuit is the sum of the complex impedances of the three elements.

z=r+jωl+(-j/ωc)=r+j(ωl-1/ωc) ⑴

The above resistor r is the real part of the complex number, and the difference between the inductive reactance and the capacitive reactance is the imaginary part of the complex number, and the imaginary part is called the reactance and is represented by x, which is the angular frequency of the applied signal.

When x=0, the circuit is in a resonant state, and the inductive and capacitive reactances cancel each other out, that is, the imaginary part in the equation is zero, so the impedance in the circuit is the smallest. Therefore, the current is maximum, and the circuit is a purely resistive load circuit at this time, and the voltage in the circuit is in phase with the current. The capacitive reactance of the circuit is equal to the inductive reactance at the time of resonance, so the RMS voltage at both ends of the capacitor and the inductor must be equal, and the RMS voltage on the capacitor uc=i*1 c=u cr=qu The quality factor q=1 cr, where i is the total current of the circuit.

The RMS voltage on the inductor ul= li= l*u r=qu and the quality factor q= l r

Because: uc=ul so q=1 cr= l r

The ratio of the voltage on the capacitor to the applied signal voltage u uc u= (i*1 c) ri=1 cr=q

The ratio of the voltage on the inductor to the applied signal voltage u ul u= li ri= l r=q

From the above analysis, it can be seen that the higher the quality factor of the circuit, the higher the voltage on the inductor or capacitor than the applied voltage.

Selectivity of the circuit: Figure 1 The total current of the circuit i=u z=u [r2+( l-1 c)2]1 2=u [r2+( l 0 0- 0 c 0)2]1 2 0 is the angular frequency when the circuit resonates. When the circuit resonates, there is:

0l=1/ω0c

So i=u 1 2= u 1 2= u r[1+q2( 0- 0 )2]1 2

Because the total current of the circuit i0=u r when the circuit is resonant, i=i0 [1+q2( 0- 0 )2]1 2 has: i i0=1 [1+q2( 0- 0 )2]1 2 as a function curve of this equation. Let (0-0)2=y

The curve is shown in Figure 2. There are three curves corresponding to three different q values, Q1> Q2> Q3. It can be seen from the figure that when the applied signal frequency deviates from the resonant frequency of the circuit 0, the higher the value of i i0, the faster the current drops under a certain frequency deviation, and the sharper the resonance curve.

In other words, the selectivity of the circuit is determined by the quality factor q of the circuit, and the higher the q value, the better the selectivity.

Judgment of the jump command.

When cf=0 is a jump.

jc: Carry to jump.

jle: If the sign is less than or equal to it, it will be redirected.

je: equals to jump.

jnc: If you don't carry, you will jump.

There are three types of jump commands:

1. Unconditional Jump to JMP.

2. Jump according to the value of CX and ECX registers: jcxz (cx is 0, it jumps), jecxz (ECX is 0, it jumps).

3. Jump according to the flag bit of the eflags register.

jc: if the carry bit is set then jump, that is, when the carry flag cf 1, the jump jne: if it is not equal (<> then jump, that is, when the zero flag zf=0, turn the jump je:

If it is equal (=), then jump, that is, when the zero flag zf=1, the jump inc: adds 1 to the target operand, similar to the ++ operation in c c++.

JMP unconditionally jumps, no returns, no stacks (to protect data). The call is redirected through the ingress address, and the return address is pressed into the stack.

JMG has no return, and if you want to come back, you need JMP.

A call is a procedure or function that is called back to the call location or the next sentence with ret, retf, etc.

Assembly language.

Since, jmp is the unconditional bai transfer instruction, and call is the subroutine calling the du instruction zhi.

The difference between JMP and Call is that the JMP command controls the DAO program to jump directly to the destination address to execute the program, and the program is always executed sequentially, and the instruction itself has no stack operation process. The call command jumps to the specified destination address to execute the subroutine, and after the subroutine is executed, it will return to the next instruction of the call command to execute the program, and there is a stack operation process for executing the call command.

Here are some examples: JMP near next; Jump to the next executor.

next: ;The destination address, from where the program will be executed downwards.

call next;Call the subroutine starting with the address next.

nop ;Return here when the subroutine is finished, and continue down the program.

next: ;The target address of the subroutine, from where the program will be executed downwards.

ret ;The subroutine returns the instruction, and the execution of the subroutine ends there, returning to the next instruction of the call instruction.

（1）jmp l1

l1: indicates l1- (current pointer +1).

2）call l2

l2 ；It is represented by l1- (current pointer +1).

Push the program into memory.

Res files are referred to as resource files in Windows programming and are used to store strings, program icons, and other references. Each of delphi's main programs contains an indicator that indicates that the home lies in the program's resource file of the same name. Clever use of resource files can be an unexpected role in programming.

It's reset. The meaning of the reset instruction.

Principles of Microcomputer is a professional basic course, which mainly includes microcomputer architecture, 8086 microprocessor and instruction system, assembly language design, and introduction to various components of microcomputer. Candidates are required to have a deep understanding of the basic concepts in the principles of microcomputers, be able to systematically master the structure of microcomputers, 8086 microprocessors and instruction systems, assembly language programming methods, interface circuit design and programming methods of microcomputer systems, etc., and have the ability to comprehensively use the knowledge learned to analyze and solve problems.

Microcomputer principle instruction je: if equal (=) then jump, that is, when the zero flag zf=1, turn jump. Part of the instruction set of the microcomputer principle:

1.Generic data transfer command mov(move) push(push onto the stack) pop(pop from the stack) out of the stack xchg(exchange) exchange 2Accumulator-specific transmission instruction in(in....

10x？

13x what does this x mean.

The ** itself is simple.

ax=aax*=2bx

axax*=4ax

bx

and logical operators (done in the operand part of a statement, done at assembly time) or a mnemonic for logical manipulation instructions.

In the opcode part of the statement, its operation is completed when the instruction is executed) - bitwise AND.

Only if the two digits of the "and" are all 1, the result is 1.

A certain number of itself and itself are "and", the operand does not change, and the carry flag cf is clear 0.

The purpose of the in instruction is to fetch the data of the port into the register ax(al).

Usage: in register, port number.