+int arch_invsqrt_lookup(int index)
+{
+ index &= 0x7f;
+ const uint8_t roundrom[128] = {
+ 0x069, 0x066, 0x063, 0x061, 0x05e, 0x05b, 0x059, 0x057,
+ 0x054, 0x052, 0x050, 0x04d, 0x04b, 0x049, 0x047, 0x045,
+ 0x043, 0x041, 0x03f, 0x03d, 0x03b, 0x039, 0x037, 0x036,
+ 0x034, 0x032, 0x030, 0x02f, 0x02d, 0x02c, 0x02a, 0x028,
+ 0x027, 0x025, 0x024, 0x022, 0x021, 0x01f, 0x01e, 0x01d,
+ 0x01b, 0x01a, 0x019, 0x017, 0x016, 0x015, 0x014, 0x012,
+ 0x011, 0x010, 0x00f, 0x00d, 0x00c, 0x00b, 0x00a, 0x009,
+ 0x008, 0x007, 0x006, 0x005, 0x004, 0x003, 0x002, 0x001,
+ 0x0fe, 0x0fa, 0x0f6, 0x0f3, 0x0ef, 0x0eb, 0x0e8, 0x0e4,
+ 0x0e1, 0x0de, 0x0db, 0x0d7, 0x0d4, 0x0d1, 0x0ce, 0x0cb,
+ 0x0c9, 0x0c6, 0x0c3, 0x0c0, 0x0be, 0x0bb, 0x0b8, 0x0b6,
+ 0x0b3, 0x0b1, 0x0af, 0x0ac, 0x0aa, 0x0a8, 0x0a5, 0x0a3,
+ 0x0a1, 0x09f, 0x09d, 0x09b, 0x099, 0x097, 0x095, 0x093,
+ 0x091, 0x08f, 0x08d, 0x08b, 0x089, 0x087, 0x086, 0x084,
+ 0x082, 0x080, 0x07f, 0x07d, 0x07b, 0x07a, 0x078, 0x077,
+ 0x075, 0x074, 0x072, 0x071, 0x06f, 0x06e, 0x06c, 0x06b,
+ };
+ return roundrom[index];
+};