Create bootmgr.asm

Adding a happy window

bootmgr.asm

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+ORG 100h                ; Origin for .COM file
+
+; Set Video Mode 03h (Text Mode 80x25, 16 colors)
+MOV AH, 0               ; Function to set video mode
+MOV AL, 3               ; Mode 03h (80x25 text mode)
+INT 10h                 ; Call BIOS interrupt
+
+; Move the cursor to position (10, 10) (row 10, column 10)
+MOV AH, 02h             ; Function to move cursor
+MOV BH, 0               ; Page number (0 for active page)
+MOV DH, 10              ; Row (line 10)
+MOV DL, 10              ; Column (column 10)
+INT 10h                 ; Call BIOS interrupt
+
+; Display "Hello"
+MOV AH, 09h             ; Function to display string
+LEA DX, HelloMessage    ; Load address of "Hello" message
+INT 21h                 ; DOS interrupt for printing string
+
+; Exit program
+MOV AH, 4Ch             ; DOS function to terminate program
+INT 21h                 ; Call DOS interrupt
+
+HelloMessage DB 'Hello$' ; Message to be printed