
3-30
Programmer’s Model
Copyright 2000–2001 by LSI Logic Corporation. All rights reserved.
Figure 3.16 Test State Register
UNP
Unpredictable
When read, these bits return unpredictable data. Writing
to these bits can cause unpredictable behavior or
changes to device configuration.
[31:13]
DDS
Disable Data Cache Streaming
When this bit is 1, it prevent the data cache from
streaming data to the ARM9E-S during a cache line fill.
When the bit is 0, data cache streaming is permitted.
12
DIS
Disable Instruction Cache Streaming
When this bit is 1, it prevents the instruction cache from
streaming data to the ARM9E-S during a cache line fill.
When the bit is 0, instruction cache streaming is
permitted.
11
DDL
Disable Data Cache Line Fill
When this bit is 1, it prevents the data cache from doing
a line fill on a cache miss. When the bit is 0, line fills are
permitted.
10
DIL
Disable Instruction Cache Line Fill
When this bit is 1, it prevents the data cache from doing
a line fill on a cache miss. When the bit is 0, line fills are
permitted.
9
R
Reserved
These bits are reserved.
[8:0]
Reading the Test State register returns bits [12:0] in the least significant
bits. The 19 most significant bits are unpredictable. Writing the Test State
register updates only bits [12:9].
In debug mode, you must be able to execute code without causing line
fills to update the caches, primarily to load new code into memory. This
means that STRs, if they hit the cache, must update the memory and the
cache, and that for LDRs or instruction prefetches that miss, a line fill is
not performed. When set, bits [10:9] prevent the respective cache from
performing a line fill on a cache miss. The memory mapping, as seen by
31
13 12
11
10
9
8
0
UNP
DDS DIS DDL DIL
R