8086-ASSEMBLY-LANGUAGE-PROGRAMS/Source Code/Patterns/triangle_pattern.asm at main · Amey-Thakur/8086-ASSEMBLY-LANGUAGE-PROGRAMS · GitHub

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; =============================================================================
; TITLE: Right-Angled Triangle Pattern
; DESCRIPTION: Generate an increasing star pattern (*) using nested loops
;              to iterate through rows and columns.
; AUTHOR: Amey Thakur (https://github.com/Amey-Thakur)
; REPOSITORY: https://github.com/Amey-Thakur/8086-ASSEMBLY-LANGUAGE-PROGRAMS
; LICENSE: MIT License
; =============================================================================

.MODEL SMALL
.STACK 100H

; -----------------------------------------------------------------------------
; DATA SEGMENT
; -----------------------------------------------------------------------------
.DATA
    ROWS DB 5                           ; Total height of the triangle
    MSG  DB 'Right-Angled Star Triangle:', 0DH, 0AH, '$'

; -----------------------------------------------------------------------------
; CODE SEGMENT
; -----------------------------------------------------------------------------
.CODE
MAIN PROC
    ; Segment registers initialization
    MOV AX, @DATA
    MOV DS, AX

    ; Header text
    LEA DX, MSG
    MOV AH, 09H
    INT 21H

    MOV BL, 1                           ; Number of stars for first row
    MOV BH, ROWS                        ; Counter for total rows

    ; -------------------------------------------------------------------------
    ; OUTER ROW LOOP: Managed by BH
    ; -------------------------------------------------------------------------
ROW_START:
    PUSH BX                             ; Preserve state for inner processing

    ; -------------------------------------------------------------------------
    ; INNER COLUMN LOOP: Managed by CL
    ; -------------------------------------------------------------------------
    MOV CL, BL                          ; Load current star count
STAR_PRINT:
    MOV DL, '*'
    MOV AH, 02H
    INT 21H
    LOOP STAR_PRINT                     ; Automatically decrements CX and loops

    ; Print Newline (CR/LF sequence)
    MOV DL, 0DH
    MOV AH, 02H
    INT 21H
    MOV DL, 0AH
    INT 21H

    POP BX                              ; Restore counters
    INC BL                              ; Increase star count for next row
    DEC BH                              ; One less row to process
    JNZ ROW_START                       ; Continue until BH is 0

    ; Exit
    MOV AH, 4CH
    INT 21H
MAIN ENDP
END MAIN

; =============================================================================
; TECHNICAL NOTES
; =============================================================================
; 1. LOOP ARCHITECTURE:
;    - Standard nested loop architecture (O(N^2)).
;    - Uses CX register with the 'LOOP' opcode for efficient inner iteration.
;    - Expected Output:
;      *
;      **
;      ***
;      ****
;      *****
; = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =