汇编语言基础：执行LINE4后程序流向疑问（LINE5还是LINE3）

Let's start by formatting your code snippet to make the structure clearer:

MOV AX, SOMETHING
LINE1
LINE2
JZ LABEL1
LINE3
LABEL1:
LINE4
LABEL2:
LINE5

First, let's clarify how assembly labels work: labels like LABEL1 and LABEL2 are just markers for positions in the code—they don't change the flow of execution on their own. Execution follows a top-to-bottom sequence unless a jump instruction explicitly tells it to go somewhere else.

Now, let's walk through the flow relevant to your question:

• When the JZ LABEL1 instruction runs, it checks the Zero Flag (ZF). If ZF is set (meaning the prior operation resulted in 0), the program jumps directly to LABEL1 and executes LINE4.
• Once LINE4 finishes executing, there's no jump instruction here to send the program back to LINE3. So the CPU will just continue executing the next instruction in sequence, which is LINE5 (since LABEL2: is just a marker sitting right above LINE5).

To put it simply: after LINE4, program control moves straight to LINE5—it won't jump back to LINE3 unless you add an explicit jump instruction (like JMP LINE3) at the end of LINE4.

内容的提问来源于stack exchange，提问作者vijaydidmca