用浮点运算很浪费时间, 于是就想了一个办法...
屏幕坐标都是整数, 我们不需要尾数, 把一个0.0000000 ~ 1.0000000 的数表示成0x00~0x80,最高位和低7位的中间是小数点, 由于二进制小数表示十进制小数会有误差,只能取近似值, 比如0.7880108,取0.7890625也就是0x65, 要把一个二进制整数调整成0.7890625倍, 只需要用0x65乘上那个整数再右移7位, OK , 按这个思路弄进程序里面运行...

运行效果:
XXXXXXXXXXXXXXXXXXXX/programs/view/TNCI_Cbmb-E/
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KC-LS1u机原理图 : XXXXXXXXXXXXXXXXXXXXXXXX/t/71330
KC-LS1u的C程序代码(乱七八糟的写来测试一下,暂时没进行特别优化, 即兴编写):
#include<io.h>

int sin[91] =  //格式 : 低8位的最高位为整数,尾数为小数
{
0x00, //sin(0) = 0 无误差
0x02, //sin(1) = 0.0174524,这里取值0.015625
0x04, //sin(2) = 0.0348995,这里取值0.03125
0x07, //sin(3) = 0.052336,这里取值0.0546875
0x09, //sin(4) = 0.0697565,这里取值0.0703125
0x0b, //sin(5) = 0.0871557,这里取值0.0859375
0x0d, //sin(6) = 0.1045285,这里取值0.1015625
0x10, //sin(7) = 0.1218693,这里取值0.125
0x12, //sin(8) = 0.1391731,这里取值0.140625
0x14, //sin(9) = 0.1564344,这里取值0.15625
0x16, //sin(10) = 0.1736482,这里取值0.171875
0x18, //sin(11) = 0.190809,这里取值0.1875
0x1b, //sin(12) = 0.2079117,这里取值0.2109375
0x1d, //sin(13) = 0.2249511,这里取值0.2265625
0x1f, //sin(14) = 0.2419219,这里取值0.2421875
0x21, //sin(15) = 0.258819,这里取值0.2578125
0x23, //sin(16) = 0.2756374,这里取值0.2734375
0x25, //sin(17) = 0.2923717,这里取值0.2890625
0x28, //sin(18) = 0.309017,这里取值0.3125
0x2a, //sin(19) = 0.3255682,这里取值0.328125
0x2c, //sin(20) = 0.3420201,这里取值0.34375
0x2e, //sin(21) = 0.3583679,这里取值0.359375
0x30, //sin(22) = 0.3746066,这里取值0.375
0x32, //sin(23) = 0.3907311,这里取值0.390625
0x34, //sin(24) = 0.4067366,这里取值0.40625
0x36, //sin(25) = 0.4226183,这里取值0.421875
0x38, //sin(26) = 0.4383711,这里取值0.4375
0x3a, //sin(27) = 0.4539905,这里取值0.453125
0x3c, //sin(28) = 0.4694716,这里取值0.46875
0x3e, //sin(29) = 0.4848096,这里取值0.484375
0x40, //sin(30) = 0.5, 无误差
0x42, //sin(31) = 0.5150381,这里取值0.515625
0x44, //sin(32) = 0.5299193,这里取值0.53125
0x46, //sin(33) = 0.544639,这里取值0.546875
0x48, //sin(34) = 0.5591929,这里取值0.5625
0x49, //sin(35) = 0.5735764,这里取值0.5703125
0x4b, //sin(36) = 0.5877852,这里取值0.5859375
0x4d, //sin(37) = 0.601815,这里取值0.6015625
0x4f, //sin(38) = 0.6156615,这里取值0.6171875
0x51, //sin(39) = 0.6293204,这里取值0.6328125
0x52, //sin(40) = 0.6427876,这里取值0.640625
0x54, //sin(41) = 0.656059,这里取值0.65625
0x56, //sin(42) = 0.6691306,这里取值0.671875
0x57, //sin(43) = 0.6819984,这里取值0.6796875
0x59, //sin(44) = 0.6946584,这里取值0.6953125
0x5a, //sin(45) = 0.7071068,这里取值0.7109375
0x5c, //sin(46) = 0.7193398,这里取值0.71875
0x5e, //sin(47) = 0.7313537,这里取值0.734375
0x5f, //sin(48) = 0.7431448,这里取值0.7421875
0x61, //sin(49) = 0.7547096,这里取值0.7578125
0x62, //sin(50) = 0.7660444,这里取值0.765625
0x63, //sin(51) = 0.777146,这里取值0.7734375
0x65, //sin(52) = 0.7880108,这里取值0.7890625
0x66, //sin(53) = 0.7986355,这里取值0.796875
0x68, //sin(54) = 0.809017,这里取值0.8125
0x69, //sin(55) = 0.819152,这里取值0.8203125
0x6a, //sin(56) = 0.8290376,这里取值0.828125
0x6b, //sin(57) = 0.838671,这里取值0.8359375
0x6d, //sin(58) = 0.8480481,这里取值0.8515625
0x6e, //sin(59) = 0.8571673,这里取值0.859375
0x6f, //sin(60) = 0.8660254,这里取值0.8671875
0x70, //sin(61) = 0.8746197,这里取值0.875
0x71, //sin(62) = 0.8829476,这里取值0.8828125
0x72, //sin(63) = 0.8910065,这里取值0.890625
0x73, //sin(64) = 0.8987941,这里取值0.8984375
0x74, //sin(65) = 0.9063078,这里取值0.90625
0x75, //sin(66) = 0.9135455,这里取值0.9140625
0x76, //sin(67) = 0.9205049,这里取值0.921875
0x77, //sin(68) = 0.9271839,这里取值0.9296875
0x78, //sin(69) = 0.9335804,这里取值0.9375
0x78, //sin(70) = 0.9396926,这里取值0.9375
0x79, //sin(71) = 0.9455186,这里取值0.9453125
0x7a, //sin(72) = 0.9510565,这里取值0.953125
0x7a, //sin(73) = 0.9563048,这里取值0.953125
0x7b, //sin(74) = 0.9612617,这里取值0.9609375
0x7c, //sin(75) = 0.9659258,这里取值0.96875
0x7c, //sin(76) = 0.9702957,这里取值0.96875
0x7d, //sin(77) = 0.9743701,这里取值0.9765625
0x7d, //sin(78) = 0.9781476,这里取值0.9765625
0x7e, //sin(79) = 0.9816272,这里取值0.984375
0x7e, //sin(80) = 0.9848078,这里取值0.984375
0x7e, //sin(81) = 0.9876883,这里取值0.984375
0x7f, //sin(82) = 0.9902681,这里取值0.9921875
0x7f, //sin(83) = 0.9925462,这里取值0.9921875
0x7f, //sin(84) = 0.9945219,这里取值0.9921875
0x7f, //sin(85) = 0.9961947,这里取值0.9921875
0x80, //sin(86) = 0.9975641,这里取值1
0x80, //sin(87) = 0.9984295,这里取值1
0x80, //sin(88) = 0.9993908,这里取值1
0x80, //sin(89) = 0.9998477,这里取值1
0x80  //sin(90) = 1,这里取值1
};


int sin_360[361];
int cos_360[361];


void sin_cos_csh()
{
unsigned int D = 0;
while(D != 361)
{
   if(D < 91) //角度为0到90度 取出sin值和cos值
   {
      sin_360[D] = sin[D];
      cos_360[D] = sin[90 - D];
   }
   else if(D > 90 && D < 181) //角度为91到180度 取出sin值和cos值
   {
      sin_360[D] = sin[180 - D];
      cos_360[D] = -sin[D - 90];
   }
   else if(D > 180 && D < 271) //角度为181到270度 取出sin值和cos值
   {
      sin_360[D] = -sin[D - 180];
      cos_360[D] = -sin[270 - D];
   }
   else //角度为271到360度 取出sin值和cos值
   {
      sin_360[D] = -sin[360 - D];
      cos_360[D] = sin[D - 270];
   }
   ++D;
}
}

void yuan(VRAMY,VRAMX,XD,YD,ZD,r,VRAM_DATA)
{
   int dd = 0,Y,X,Z,y,x,_sin,_cos;
   int _Y,_X,_Z;
   do
   {
      _sin = sin_360[dd];
      _cos = cos_360[dd];
      X = _cos*r >> 7;
      _Y = _sin*r >> 7;
      _sin = sin_360[XD];
      _cos = cos_360[XD];
      Y = _cos*_Y >> 7;
      _Z = _sin*_Y >> 7;
      _sin = sin_360[YD];
      _cos = cos_360[YD];
//     Z = _cos*_Z - _sin*X >> 7;
      _X = _sin*_Z + _cos*X >> 7;
      _sin = sin_360[ZD];
      _cos = cos_360[ZD];
      X = _cos*_X - _sin*Y >> 7;
      Y = _sin*_X + _cos*Y >> 7;

      y = VRAMY - Y; //转换为实际坐标
      x = VRAMX + X;
      VRAM[(y << 8) | (x & 0x00ff)] = VRAM_DATA; //写入显存
      dd += 10;
   }while(dd < 360);
}

void VRAM_qingping(unsigned char Y,unsigned char _Y,unsigned char DATA)
{
while(Y != _Y)
{
   _B = DATA;
   _A = 0;
   do
   {
     _A1 = Y;
     _A2 = 0x80;
     _A0 = _A;
     _NOP;
     _RAM = _B;
     _A = _A + 1;
     _A0 = _A;
     _NOP;
     _RAM = _B;
     _A = _A + 1;
     _A0 = _A;
     _NOP;
     _RAM = _B;
     _A = _A + 1;
     _A0 = _A;
     _NOP;
     _RAM = _B;
     _A = _A + 1;
     _A0 = _A;
     _NOP;
     _RAM = _B;
     _A = _A + 1;
     _A0 = _A;
     _NOP;
     _RAM = _B;
     _A = _A + 1;
     _A0 = _A;
     _NOP;
     _RAM = _B;
     _A = _A + 1;
     _A0 = _A;
     _NOP;
     _RAM = _B;
     _A = _A + 1;
   }while(_SUB_A_1 != -1);
   ++Y;
}

}

void zhongxinzhou(VRAMY,VRAMX,XD,YD,ZD,VRAM_DATA)
{

   int zz = -32,Y,X,Z,y,x,_sin,_cos;
   int _Y,_X,_Z;
   do
   {
      _sin = sin_360[XD];
      _cos = cos_360[XD];
      Y = - _sin*zz >> 7;
      _Z =  _cos*zz >> 7;
      _sin = sin_360[YD];
      _cos = cos_360[YD];
//     Z = _cos*_Z >> 7;
      _X = _sin*_Z >> 7;
      _sin = sin_360[ZD];
      _cos = cos_360[ZD];
      X = _cos*_X - _sin*Y >> 7;
      Y = _sin*_X + _cos*Y >> 7;

      y = VRAMY - Y; //转换为实际坐标
      x = VRAMX + X;
      VRAM[(y << 8) | (x & 0x00ff)] = VRAM_DATA; //写入显存
      zz += 4;
   }while(zz < 32);


}

main()
{
   int i,YD = 0,XD = 0,ZD = 0;
   VRAM_qingping(0,240,0x00);
   sin_cos_csh();
   while(1)
   {
      CTVGA_C &= ~0x01; //请求访问VRAM
      while((CTVGA_C & 0x80) == 0x80); //可以访问的时候跳出
      VRAM_qingping(120 - 100,120 + 100,0x00);

    //  ++YD;
   //   ++YD;
   //   if(YD == 360) YD = 0;
      ++XD;
      ++XD;
      ++XD;
      if(XD == 360) XD = 0;
      ++ZD;
      if(ZD == 360) ZD = 0;

      zhongxinzhou(120,128,XD,YD,ZD,0x1f);
      yuan(120,128,XD,YD,ZD,32,0x03);
      yuan(120,128,XD,YD,ZD,64,0xe0);
      yuan(120,128,XD,YD,ZD,80,0x13);
      yuan(120,128,XD,YD,ZD,96,0xe5);

      CTVGA_C |= 0x01; //请求VRAM显示
      for(i = 0;i != 7000;++i);
   }

}