Memory ECC Syndromes

When Tsunami detects a correctable ECC error, the ECC syndrome for the quadword in error is latched on error into the SYN field in P0_ERROR or P1_ERROR depending on where the error is occurred. When the CPU detects a correctable ECC error, the ECC syndrome for the first quadword is latched into the C_SYNDROME0 field of the C_BOX; the ECC syndrome for the low quadword is saved in the C_SYNDROME1 field of the C_BOX.

See the tables below for decoding single bit errors in the data and check bits. A syndrome of zero implies no error in that quadword. If the syndrome is not in either of these tables, then the error involved more than one bit.

ECC Syndrome Table

Syndrome

Bit

Syndrome

Bit

Syndrome

Bit

Syndrome

Bit

CE

00

0E

16

4F

32

8F

48

CB

01

0B

17

4A

33

8A

49

D3

02

13

18

52

34

92

50

D5

03

15

19

54

35

94

51

D6

04

16

20

57

36

97

52

D9

05

19

21

58

37

98

53

DA

06

1A

22

5B

38

9B

54

DC

07

1C

23

5D

39

9D

55

23

08

E3

24

A2

40

62

56

25

09

E5

25

A4

41

64

57

26

10

E6

26

A7

42

67

58

29

11

E9

27

A8

43

68

59

2A

12

EA

28

AB

44

6B

60

2C

13

EC

29

AD

45

6D

61

31

14

F1

30

B0

46

70

62

34

15

F4

31

B5

47

75

63


ECC Syndromes for Single Check Bit Errors

Syndrome

Bit

Syndrome

Bit

Syndrome

Bit

Syndrome

Bit

01

0

04

2

10

4

40

6

02

1

08

3

20

5

80

7