MCU assembler execution order 100

First of all, ajmp start is an unconditional jump, which is a direct jump to start, and the interrupt entry and pseudo instructions in the middle are not executed when the main program is run normally for the first time, but they are all assembled into instructions** exist in the rom, but they are skipped when executed, but they still exist when they are assembled.

The LJMP address space is 16 bits, and the jumpable range is 64K, which occupies 3 bytes.

AJMP and SJMP jumps to 11-bit addresses and 8-bit addresses, respectively, which are relative ranges centered on this instruction, which account for 2 bytes.

The main difference between them is that the one who jumps far takes up more ROM space, while in the case of a tight rom, the short one can be used.

JMP is generally used for variable address addressing, and needs to be used in conjunction with DPTR.

0000: ajmp start

0030: mov sp,#5fh

mov p1,#0ffh

mov p3,#0ffh

setb it0

setb ea

setb ex0

ljmp $ The main program is in this endless loop.

In the future, if there is an external interrupt 0, the following procedure is executed.

0003: ljmp int_0

int_0:cpl ;Counter.

reti ;Fall back to the main program and continue the endless loop.

The pseudo-directive org 30h just tells the compiler that the following instruction is stored in the 30h location of the ** area.

LJMP is a 3-byte long jump instruction with a range of up to 64 KAjmp is a 2-byte medium jump instruction with a range of 2K

SJMP is a 2-byte relative jump instruction, with a range of 128, you can generally write assembly jmp pseudo instructions, and the compiler can directly optimize and select the actual instructions to generate ljmp, ajmp, and sjmp according to the actual situation of compilation.

It must be executed sequentially, and there is no transfer instruction that is executed sequentially.

...Outside the world.

..No one will help you.

..There's too little money.

..It would take at least a day to finish that compilation.

If you don't study hard, now take 20 virtual ingots, who is so kind??

Enter: debug "File name" in the runtime.

The assembler is written in pseudo-** and must be compiled into machine code in order to run. However, if your assembler is not large, you can write and debug it in debug.

1. All assembly language programs, if on the PC, generate exe files, if on the microcontroller, convert into hex or bin files, burn into the microcontroller, but both start trial run, both use debug

The number of scores less than 60 is counted.

score db 56,89,76,60,35,16,100 data definitions.

count equ $-score count indicates the number of data.

rs dw ?The number of scores less than 60.

mov cx, count cx, set the number of cycles.

lea bx, score bx point to the initial address.

mov dx, 0 is set to 0 initially

lop1: mov al, [bx] takes the number.

CMP AL, 60 comparison.

If the JAE LOP2 is greater than or equal to, the comparison continues.

The number of inc dx is increased by 1

loop lop1 to continue the loop.

MOV RS, DX number send RS

Assemblers are executed sequentially, and if you want to jump to a different location, you must execute the jump command, otherwise it is executed sequentially. There is no return instruction for assembly.,The return instructions are all pseudo-instructions.,After compilation, they're all jump instructions.。。。 If you want a program to be executed out of order, you have to use the jump command in the assembly...

After each function in the C language is executed, the return is a call to the jump instruction...

In the assembly, the operation of the CPU is detailed to each step, such as the transfer of form parameters, you must put the form parameter command into the parameter table, and then call the jump instruction to complete the function call, the automatic variable in the operation must be completed by you personally test the instruction, and you must save the return address of the function call, and put the return value of the function return value to the return value position after execution, and then jump to this address to complete a function call...

Of course, the above process is the rule of the C language, if it is an assembler you are free, there is no need to follow the way of the C language...

It's very simple: one by one.