Assembly 绘制正方形的汇编代码
我需要一个汇编代码在屏幕中间画一个正方形Assembly 绘制正方形的汇编代码,assembly,Assembly,我需要一个汇编代码在屏幕中间画一个正方形 使用BIOS视频服务,屏幕分辨率应为320x200。维度的长度应为20像素。正方形的颜色应为黄色,背景为黑色,如下所示:BIOS服务具有极高的开销,不应用于绘制单个像素 对于“模式0x13”,您可以直接访问显示内存-它是每像素1字节,从0xA000:0x0000开始,其中每个水平线跟随前一个水平线(无间隙/填充)。例如: mov ax,0xA0000 mov es,ax xor di,di ;es:di = a
使用BIOS视频服务,屏幕分辨率应为320x200。维度的长度应为20像素。正方形的颜色应为黄色,背景为黑色,如下所示:BIOS服务具有极高的开销,不应用于绘制单个像素 对于“模式0x13”,您可以直接访问显示内存-它是每像素1字节,从0xA000:0x0000开始,其中每个水平线跟随前一个水平线(无间隙/填充)。例如:
mov ax,0xA0000
mov es,ax
xor di,di ;es:di = address of top left pixel
要填充屏幕的顶行,需要将320字节(像素)设置为零。因此:
mov ax,0xA0000
mov es,ax
xor di,di ;es:di = address of top left pixel
xor ax,ax ;al = ah = black
mov cx,320/2 ;cx = number of pairs of pixels to set
cld ;Set direction to make sure
rep stosw ;Set entire line to black
现在,您需要将顶部的许多行设置为黑色,因此:
mov ax,0xA0000
mov es,ax
xor di,di ;es:di = address of top left pixel
;Do top lines
mov bx,(200-BOX_Y)/2 ;bx = number of lines at top to make black
xor ax,ax ;al = ah = black
.topLoop:
mov cx,320/2 ;cx = number of pairs of pixels to set
cld ;Set direction to make sure
rep stosw ;Set entire line to black
sub bx,1 ;bx = number of lines left to do
jne .topLoop ;Do next line if there are more lines to do
下一部分是盒子本身。对于每一行,你希望在左边有一些黑色的像素,中间有黄色的像素,右边有更多的黑色像素:
;Do middle lines
mov bx,BOX_Y ;bx = number of lines in middle
.middleLoop:
mov cx,(320-BOX_X)/2 ;cx = number of pixels to set
rep stosb ;Set left black
mov cx,BOX_X
mov al,BOX_COLOUR ;al = box colour
rep stosb ;Set middle coloured part
mov cx,320-(320-BOX_X)/2 - BOX_X
xor al,al ;al = black
rep stosb ;Set right black part
sub bx,1 ;bx = number of lines left to do
jne .middleLoop ;Do next line if there are more lines to do
最后,您还需要将底线设置为黑色。这就像做最上面的一行。完整的代码如下所示:
mov ax,0xA0000
mov es,ax
xor di,di ;es:di = address of top left pixel
;Do top lines
mov bx,(200-BOX_Y)/2 ;bx = number of lines at top to make black
xor ax,ax ;al = ah = black
.topLoop:
mov cx,320/2 ;cx = number of pairs of pixels to set
cld ;Set direction to make sure
rep stosw ;Set entire line to black
sub bx,1 ;bx = number of lines left to do
jne .topLoop ;Do next line if there are more lines to do
;Do middle lines
mov bx,BOX_Y ;bx = number of lines in middle
.middleLoop:
mov cx,(320-BOX_X)/2 ;cx = number of pixels to set
rep stosb ;Set left black
mov cx,BOX_X
mov al,BOX_COLOUR ;al = box colour
rep stosb ;Set middle coloured part
mov cx,320-(320-BOX_X)/2 - BOX_X
xor al,al ;al = black
rep stosb ;Set right black part
sub bx,1 ;bx = number of lines left to do
jne .middleLoop ;Do next line if there are more lines to do
mov ax,0xA0000
mov es,ax
xor di,di ;es:di = address of top left pixel
;Do bottom lines
mov bx,200 - BOX_Y - (200-BOX_Y)/2
.bottomLoop:
mov cx,320/2 ;cx = number of pairs of pixels to set
rep stosw ;Set entire line to black
sub bx,1 ;bx = number of lines left to do
jne .bottomLoop ;Do next line if there are more lines to do
注:以上所有代码都是针对NASM的(不同的汇编器可以不同);所有这些都没有经过测试。我以为你是真的。您需要定义一些常量才能使其工作(
BOX\u X
、BOX\u Y
和BOX\u color
)。在各种情况下都可以更有效地完成。无论您使用什么调用约定,或者推送和弹出修改过的寄存器,或者执行ret
,我都不介意。我假设0x00是黑色的(并且懒得猜测黄色的值);这可能是错误的(值如何映射到颜色取决于您如何设置调色板,因此任何值都可以是任何颜色,0x00可能是亮粉色或其他任何颜色,而不是黑色)该死的,这让我回过神来!我还有一本1000多页的EGA和VGA编程指南,在某处尘封。谢谢你的帮助。。。。。。。。竖起大拇指