real-mode – Tarik Billa

Printing out a number in assembly language?

January 6, 2024 by Tarik

Have you tried int 21h service 2? DL is the character to print. mov dl,’A’ ; print ‘A’ mov ah,2 int 21h To print the integer value, you’ll have to write a loop to decompose the integer to individual characters. If you’re okay with printing the value in hex, this is pretty trivial. If you … Read more

Cannot write to screen memory in C

June 2, 2023 by Tarik

In real mode to address the first full 1MiB of memory a mechanism called 20-bit segment:offset addressing is used. 0xb8000 is a physical memory address. You need to use something called a far pointer that allows you to address memory with real mode segmentation. The different types of pointers are described in this Stackoverflow Answer … Read more

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