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GR716-DS-UM, May 2019, Version 1.29
131
www.cobham.com/gaisler
GR716
16.6.2 ASR17, LEON3 configuration register
The ancillary state register 17 (%asr17) provides information on current LEON3FT configuration.
This can be used to enhance the performance of software. There are also a few bits that are writable to
configure certain aspects of the processor.
Table 122.
LEON3 configuration register (%asr17)
31
28
27
26
25
24
23
22
21
20
18
17
16
INDEX
R
NOTAG
R
REXV
REXM
RESERVED
R
R
0
0
1
1
01b
00b
0
0
0
r
r
r
r
r
rw
r
r
r
15
14
13
12
11
10
9
8
7
5
4
0
R
DW
SV
LD
FPU
M
V8
NWP
NWIN
0
0
0
0
3
0
1
4
30
r
rw
rw
r
r
r
r
r
r
31:28
Processor index (INDEX) -Processor index is set to zero.
27
Reserved and not used
26
Tagged arithmetic (NOTAG) - Then the processor supports tagged arithmetic.and compare-and-
swap (CASA) instruction.
27
Reserved and not used
24:23
REX version (REXV) - REX version
22:21
REX mode (REXM) - set to ‘00’ for REX enabled, ‘01’ for REX illegal and ‘10’ for REX transpar-
ent mode. Writable with reset value ‘01’ when REX support has been enabled
20:18
Reserved for future implementations
17
Reserved for future implementations
16:15
Reserved for future implementations
14
Disable write error trap (DWT). When set, a write error trap (tt = 0x2b) will be ignored. Set to zero
after reset.
13
Single-vector trapping (SVT) enable. If set, will enable single-vector trapping. Set to zero after reset.
12
Load delay (LDDEL) - Indicates 1-cycle load delay is used.
11:10
FPU Option (FPU) - Indicates system has a GRFPU-Lite
9
MAC instruction (M) - Set to zero to indicate multiply-accumulate (MAC) instruction is NOT avail-
able
8
MUL/DIV instructions available (V8) - Indicates SPARC V8 multiply and divide instructions are
available
7:5
Hardward watchpoints (NWP) - Number of watchpoints available is 4
4:0
Register windows (NWIM) - Number of implemented registers windows corresponds to NWIN+1
i.e. 31 for GR716.