使用8086汇编语言绘制圆 [英] Drawing a circle using 8086 Assembly Language

问题描述

我试图使用8086汇编器绘制一个圆.我尝试使用中点圆算法，该算法由于某种原因而令人遗憾地导致绘制了一个倾斜的正方形(屏幕截图)以下).作为参考，我重写了python中的算法，并成功地画了一个圆.

I was trying to draw a circle using 8086 assembler. I tried utilizing the midpoint circle algorithm which sadly resulted in drawing a tilted square for some reason (screenshots below). For reference, I rewrote the algorithm in python and managed to draw a circle without a problem.

我感觉我的负数操作有问题，但我一生都无法解决，因为Turbo Debugger告诉我的是什么也没有.你能指导我正确的方向吗? 我附上以下代码:

I have a feeling that there is something wrong with my negative numbers manipulation but can't for the life of me figure it out because Turbo Debugger is telling me literally nothing. Could you guide me in the right direction? I enclose the code below:

; Program: graph.asm
.MODEL small
.STACK 256

.DATA

.CODE

jmp start
;=========================================
; Basic program to draw a circle
;=========================================
 mode db 18 ;640 x 480
 x_center dw 300
 y_center dw 200
 y_value dw 0
 x_value dw 100
 decision dw 1
 colour db 1 ;1=blue
;=========================================
start:
 mov ah,00 ;subfunction 0
 mov al,mode ;select mode 18 
 int 10h ;call graphics interrupt
;==========================
 mov bx, x_value
 sub decision, bx
 mov al,colour ;colour goes in al
 mov ah,0ch
 
drawcircle:
 mov al,colour ;colour goes in al
 mov ah,0ch
 
 mov cx, x_value ;Octonant 1
 add cx, x_center ;( x_value + x_center,  y_value + y_center)
 mov dx, y_value
 add dx, y_center
 int 10h
 
 mov cx, x_value ;Octonant 4
 neg cx
 add cx, x_center ;( -x_value + x_center,  y_value + y_center)
 int 10h
 
 mov cx, y_value ;Octonant 2
 add cx, x_center ;( y_value + x_center,  x_value + y_center)
 mov dx, x_value
 add dx, y_center
 int 10h
 
 mov cx, y_value ;Octonant 3
 neg cx
 add cx, x_center ;( -y_value + x_center,  x_value + y_center)
 int 10h
 
 mov cx, x_value ;Octonant 7
 add cx, x_center ;( x_value + x_center,  -y_value + y_center)
 mov dx, y_value
 neg dx
 add dx, y_center
 int 10h
 
 mov cx, x_value ;Octonant 5
 neg cx
 add cx, x_center ;( -x_value + x_center,  -y_value + y_center)
 int 10h

 mov cx, y_value ;Octonant 8
 add cx, x_center ;( y_value + x_center,  -x_value + y_center)
 mov dx, x_value
 neg dx
 add dx, y_center
 int 10h
 
 mov cx, y_value ;Octonant 6
 neg cx
 add cx, x_center ;( -y_value + x_center,  -x_value + y_center)
 int 10h
 
 inc y_value

condition1:
 cmp decision,0
 ja condition2
 mov cx, y_value
 mov ax, 2
 imul cx
 add cx, 1
 inc cx
 add decision, cx
 mov bx, y_value
 mov dx, x_value
 cmp bx, dx
 ja readkey
 jmp drawcircle

condition2:
 dec x_value
 mov cx, y_value
 sub cx, x_value
 mov ax, 2
 imul cx
 inc cx
 add decision, cx
 mov bx, y_value
 mov dx, x_value
 cmp bx, dx
 ja readkey
 jmp drawcircle


 
;==========================
readkey:
 mov ah,00
 int 16h ;wait for keypress
;==========================
endd:
 mov ah,00 ;again subfunc 0
 mov al,03 ;text mode 3
 int 10h ;call int
 mov ah,04ch
 mov al,00 ;end program normally
 int 21h 

END Start

尝试在汇编器中 尝试使用Python

Attempt in Assembler Attempt in Python

预先感谢您的帮助！

推荐答案

您的汇编代码绘制的正方形来自等式:

the square which is your assembly code drew comes from equation :

|x| + |y| = constant 

这意味着您的值不会平方

This means your values are not getting squared

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