Hello (near) namesake, and welcome to Vogons. 🙂

Kind of weird to see someone use the dollar sign notation for hex values in 8086/8088 assembly.

Sorry I'm not much of help in actually answering your question. 😅

What assembler are you using? If you are targeting an 8088, in NASM at least, you'll want to include the CPU 8086 directive at the top of your code. You might think the assembler is just directly converting your assembly instructions to their bytecode, but frequently I see it trying to do clever optimizations here and there. So it could be including some unsupported operations inadvertently that way. Plus, without the CPU 8086 directive, you may accidentally find yourself using an instruction that is supported by the 8088, in a form it's not.

Have you stepped through the assembly on either configuration to see what it thinks it's doing?

Namrok wrote on 2023-07-23, 12:39:

What assembler are you using? If you are targeting an 8088, in NASM at least, you'll want to include the CPU 8086 directive at the top of your code. You might think the assembler is just directly converting your assembly instructions to their bytecode, but frequently I see it trying to do clever optimizations here and there. So it could be including some unsupported operations inadvertently that way. Plus, without the CPU 8086 directive, you may accidentally find yourself using an instruction that is supported by the 8088, in a form it's not.

Have you stepped through the assembly on either configuration to see what it thinks it's doing?

I'm using as86 with the -0 flag to make sure it produces 86/88 bytecode.

But indeed, stepping through it on real hardware was the solution: I did so on dosbox but apparently doesbox does not produce the trace interrupt. Real hardware does. And I did indeed accidently enabled the tracing bit earlier.
Thanks!