When ESC is pressed, change the color of the character.

;The code is to display the 26 characters in the;center of the screen.When ESC is pressed,the character;change color.;INT 9 is replaced by my program.;by: double; date:2009-09-26; ver:0.1assume cs:codesg,ds:datasg,ss:stacksgdatasg segment dw 0,0datasg endsstacksg segment db 128 dup (0)stacksg endscodesg segmentstart: mov ax,datasg mov ds,ax mov ax,stacksg mov ss,ax mov sp,128 mov ax,0 mov es,ax push es:[4 * 9] pop ds:[0] push es:[4 * 9 + 2] pop ds:[2] cli mov word ptr es:[4 * 9],offset int9 mov es:[4 * 9 + 2],cs sti ; here display the character a~z. call display ; here restore the orignal int 9. ; so, when the program terminates,keyboard input ; can work as before. mov ax,0 mov es,ax push ds:[0] pop es:[4 * 9] push ds:[2] pop es:[4 * 9 + 2] mov ax,4c00h int 21hdisplay: push ax push es mov ax,0b800h mov es,ax mov ah,'a's1: mov es:[160 * 12 + 2 * 40],ah call delay inc ah cmp ah,'z' jna s1 pop es pop ax retdelay:;The delay function is used just to make it;change slower, so people can see the ;changement. push ax push dx mov ax,0 mov dx,1000hs2: sub ax,1 sbb dx,0 cmp ax,0 jne s2 cmp dx,0 jne s2 pop dx pop ax retint9:;This segment is used to simulate the BIOS INT 9.;The INT progress is:;1. Get INT number.(In this example,the number is 9.);2. Pushf;3. IF = TF = 0;4. push cs;5. push ip;6. (ip) = (4 * N(9)),(cs) = (4 * N(9) + 2); what i should do in this simulation is just pushf; The other work is done by original INT 9 program. push ax push bx push es in al,60h ;get key`s scan code, and store it in al. pushf call dword ptr ds:[0] cmp al,1 ;ESC`s scan code is '1' jne ok mov ax,0b800h mov es,ax ;when ESC is pressed, the color option of the character ;increass by 1. inc byte ptr es:[160 * 12 + 2 * 40 + 1] ok: pop es pop bx pop ax iretcodesg endsend start