smg://从0到f的二进制
db 00111111b//0
db 00000110b//1
db 01011011b//2
db 01001111b//3
db 01100110b//4
db 01101101b//5
db 01111101b//6
db 00000111b//7
db 01111111b//8
db 01101111b//9
db 01110111b//a//+
db 01111100b//b//-
db 00111001b//c//*
db 01011110b//d//÷
db 01111001b//e//=
db 01110001b//f//清空
ret