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ARM DDI 0363E Copyright © 2009 ARM Limited. All rights reserved. 9-28
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Table 9-33 Data format, instruction cache and data cache, with parity
Data bit Description
[63:50] Not used, read-as-zero
[49] Parity bit for data value [31:24] or [63:56]
[48] Parity bit for data value [23:16] or [55:48]
[47:32] Data value, [31:16] or [63:48]
[31:18] Not used, read-as-zero
[17] Parity bit for data value [15:8] or [47:40]
[16] Parity bit for data value [7:0] or [39:32]
[15:0] Data value, [15:0] or [47:32]
Table 9-34 Data format, instruction cache, with ECC
Data bit Description
[63:52] Not used, read-as-zero
[51:48]
Upper or lower half of the ECC 64 code
a
[47:32] Data value, [31:16] or [63:48]
[31:20] Not used, read-as-zero
[19:16]
Upper or lower half of the ECC 64 code
b
[15:0] Data value, [15:0] or [47:32]
a. If accessing bits [31:16] of the data, bits [51:48] hold the lower half of the ECC code.
If accessing bits [63:48] of the data, bits [51:48] hold the upper half of the ECC code.
b. If accessing bits [15:0] of the data, bits [19:16] hold the lower half of the ECC code.
If accessing bits [47:32] of the data, bits [19:16] hold the upper half of the ECC code.
Table 9-35 Data format, data cache, with ECC
Data bit Description
[63:55] Not used, read-as-zero
[54:48]
ECC 32 code
a
[47:32] Data value, [31:16] or [63:48]
[31:23] Not used, read-as-zero
[22:16] ECC 32 code
[15:0] Data value [15:0] or [47:32]
a. For a 64 bit access, the ECC bits are
duplicated in bits [22:16] and bits
[54:48], and the two copies are identical.
For a 32 bit access, the ECC bits refer to
the whole 32 bit data value, even though
only 16 bits of data are accessed.