Overview of the JMP Instruction The JMP instruction is an unconditional transfer instruction that can modify the IP (Instruction Pointer) or simultaneously modify both the CS (Code Segment Register) and IP, thereby changing the execution flow of the program. The JMP instruction requires two key pieces of information: The destination address for the transfer The … Read more
“Assembly Language”, 3rd Edition by Wang Shuang Chapter 15: External Interrupts (Page 285) Experiment 15: Install a new INT 9 interrupt routine Install a new INT 9 interrupt routine that, under DOS, displays a full screen of “A” when the “A” key is pressed and held down; other keys are processed normally. Tip: The scan … Read more
1. Core Concepts: 16-bit Segments vs. 32-bit Segments In the x86 architecture, the length and characteristics of a “segment” depend on the operating mode of the processor. 16-bit Segment: Maximum Length:64KB (<span>0FFFFh</span>). Typical Modes:Real Mode and Virtual 8086 Mode. This is the only option for 8086/8088 and is a requirement for 80386+ in real mode. … Read more
01 Introduction In the field of embedded development, whether it is necessary to learn assembly language cannot be simply answered with “yes” or “no”; it depends onthe specific development scenario, hardware platform, and career positioning. The overall trend is that the “general demand” for assembly is declining, but its “irreplaceability” in specific scenarios still exists. … Read more
“Assembly Language”, 3rd Edition by Wang Shuang Chapter 13: int Instruction (Page 262) Experiment 13: Writing and Applying Interrupt Routines ———————————— Note: This is the answer and analysis for Experiment 13, Question 3. ———————————– (3) The following program displays four lines of English poetry on lines 2, 4, 6, and 8 of the screen. Complete … Read more
“Assembly Language”, 3rd Edition by Wang Shuang Chapter 13 int Instruction (Page 262) Experiment 13 Writing and Applying Interrupt Routines ———————————— Note: This is the code example and analysis for Experiment 13Question 1. ———————————– (1) Write and install the int 7cH interrupt routine, which displays a null-terminated string. The interrupt routine is installed at 0:200. … Read more
1. Instruction Overview Starting from the Intel 80386 processor, the instruction set introduced a powerful set of bit manipulation instructions. These instructions allow programmers to precisely manipulate individual binary bits within operands, including operations such as testing, setting, clearing, complementing, and searching. This greatly enhances the efficiency and convenience of performing bit-level operations (such as … Read more
Click the blue “Most Programmer” to follow me! Add a “star“, every day at 18:03 to learn technology together! This is a typical case of “knowing the phenomenon but not the reason behind it”, a common issue in our learning process.When teachers or textbooks mention that “accessing address 0 is an illegal access”, how many … Read more
1. Overview Processor control instructions are used to directly manage the core state and behavior of the CPU, rather than performing data calculations or transfers. Their functions include setting flags, executing no-operations, synchronizing with coprocessors, and implementing atomic operations in multiprocessor environments. These instructions are fundamental for writing robust and efficient low-level code, especially when … Read more
1. Instruction Overview Starting from the Intel 80386 processor, the instruction set introduced a very useful set of conditional byte set instructions (<span>SETcc</span>). The function of this set of instructions is not to perform program flow jumps, but to set a byte value to 1 or 0 based on the current state of the CPU … Read more