ZHCUAO0C November 2022 – November 2023 TMS320F280033 , TMS320F280034 , TMS320F280034-Q1 , TMS320F280036-Q1 , TMS320F280036C-Q1 , TMS320F280037 , TMS320F280037-Q1 , TMS320F280037C , TMS320F280037C-Q1 , TMS320F280038-Q1 , TMS320F280038C-Q1 , TMS320F280039 , TMS320F280039-Q1 , TMS320F280039C , TMS320F280039C-Q1
下面的函数可用于计算给定的 64 位对齐地址(无需左移地址)和相应的 64 位数据的 ECC。
//
//Calculate the ECC for an address/data pair
//
uint16 CalcEcc(uint32 address, uint64 data)
{
const uint32 addrSyndrome[8] = {0x554ea, 0x0bad1, 0x2a9b5, 0x6a78d,
0x19f83, 0x07f80, 0x7ff80, 0x0007f};
const uint64 dataSyndrome[8] = {0xb4d1b4d14b2e4b2e, 0x1557155715571557,
0xa699a699a699a699, 0x38e338e338e338e3,
0xc0fcc0fcc0fcc0fc, 0xff00ff00ff00ff00,
0xff0000ffff0000ff, 0x00ffff00ff0000ff};
const uint16 parity = 0xfc;
uint64 xorData;
uint32 xorAddr;
uint16 bit, eccBit, eccVal;
//
//Extract bits "20:2" of the address
//
address = (address >> 2) & 0x7ffff;
//
//Compute the ECC one bit at a time.
//
eccVal = 0;
for (bit = 0; bit < 8; bit++)
{
//
//Apply the encoding masks to the address and data
//
xorAddr = address & addrSyndrome[bit];
xorData = data & dataSyndrome[bit];
//
//Fold the masked address into a single bit for parity calculation.
//The result will be in the LSB.
//
xorAddr = xorAddr ^ (xorAddr >> 16);
xorAddr = xorAddr ^ (xorAddr >> 8);
xorAddr = xorAddr ^ (xorAddr >> 4);
xorAddr = xorAddr ^ (xorAddr >> 2);
xorAddr = xorAddr ^ (xorAddr >> 1);
//
//Fold the masked data into a single bit for parity calculation.
//The result will be in the LSB.
//
xorData = xorData ^ (xorData >> 32);
xorData = xorData ^ (xorData >> 16);
xorData = xorData ^ (xorData >> 8);
xorData = xorData ^ (xorData >> 4);
xorData = xorData ^ (xorData >> 2);
xorData = xorData ^ (xorData >> 1);
//
//Merge the address and data, extract the ECC bit, and add it in
//
eccBit = ((uint16)xorData ^ (uint16)xorAddr) & 0x0001;
eccVal |= eccBit << bit;
}
//
//Handle the bit parity.For odd parity, XOR the bit with 1
//
eccVal ^= parity;
return eccVal;
}