This project consists of two separate x86 Assembly language programs for a DOS environment. Each program demonstrates fundamental concepts in low-level programming: one for iterative pattern generation (a numerical pyramid) and another for basic graphical output (colored squares) using BIOS and DOS interrupts.
This program draws a right-aligned pyramid of numbers on the console. It uses nested loops controlled by the CX register. The outer loop manages the rows, a second loop prints an increasing number of spaces for indentation, and a third loop prints a decreasing sequence of incrementing digits (e.g., ‘0123…’, ‘012…’, ‘01…’). PUSH CX and POP CX are used to save and restore the outer loop’s counter to prevent interference from the nested loops. Character output is handled by loading the character into the DL register and calling DOS interrupt int 21h with AH=2.
This program demonstrates basic graphics in text mode by manipulating the screen buffer via BIOS video services (int 10H). First, it clears the entire screen by setting the function to scroll/clear (MOV AH, 6), targeting the whole window (MOV AL, 0), and setting the video attribute in the BH register to blue (00010001b). Then, it draws two solid red squares by setting the video attribute to red (01000001b) and calling int 10H again for specific screen coordinate ranges defined by the CH/CL (top-left) and DH/DL (bottom-right) registers.