|
楼主 |
发表于 2008-6-3 13:33:29
|
显示全部楼层
补充一句
利用这个算法即可:输入x0—x7,输出Y0—Y7
c1 = 0x2C62, c3 = 0x25A0;
c5 = 0x1924, c7 = 0x08D4;
c0 = 0xB505, c2 = 0x29CF;
c6 = 0x1151;
g0 = x0 + x7; h2 = x0 - x7;
g1 = x1 + x6; h3 = x1 - x6;
h1 = x2 + x5; g3 = x2 - x5;
h0 = x3 + x4; g2 = x3 - x4;
p0 = g0 + h0; r0 = g0 - h0;
p1 = g1 + h1; r1 = g1 - h1;
q1 = g2; s1 = h2;
s0a= h3 + g3; q0a= h3 - g3;
s0 = (s0a * c0 + 0x7FFF) >> 16;
q0 = (q0a * c0 + 0x7FFF) >> 16;
P0 = p0 + p1; P1 = p0 - p1;
R1 = c6 * r1 + c2 * r0; R0 = c6 * r0 - c2 * r1;
Q1 = q1 + q0; Q0 = q1 - q0;
S1 = s1 + s0; S0 = s1 - s0;
Y0 = P0; Y4 = P1;
Y2 = R1>>13; Y6 = R0>>13;
Y1 = (c7 * Q1 + c1 * S1) >>13;
Y7 = (c7 * S1 - c1 * Q1) >>13;
Y5 = (c3 * Q0 + c5 * S0) >>13;
Y3 = (c3 * S0 - c5 * Q0) >>13;
我的邮箱:mqykyo@yahoo.cn
[ 本帖最后由 mqyucn 于 2008-6-3 13:45 编辑 ] |
|