Sun Microelectronics
312
UltraSPARC User’s Manual
Undefined
: The value of these bits are undefined on reads and must be masked
off by software.
IC_pdec
: The two 4-bit pre-decode fields. The encodings are:
•
Bits<3:2> = 00
CALL, BPA, FBA, FBPA or BA
•
Bits<3:2> = 01
Not a CALL, JMPL, BPA, FBA, FBPA or BA
•
Bits<3:2> = 10
Normal JMPL (do not use return stack)
•
Bits<3:2> = 11
Return JMPL (use return stack)
•
Bit<1>
If clear, indicates a PC-relative CTI.
•
Bit<0>
If set, indicates a STORE.
Note:
The predecode bits are not updated when instructions are loaded into the
cache with ASI_ICACHE_INSTR. They are only accurate for instructions loaded
by instruction cache miss processing.
A.7.4 I-Cache LRU/BRPD/SP/NFA Fields
ASI 6F
16
, VA<63:14>=0, VA<13>=IC_set, VA<12:3>=IC_addr, VA<2:0>=0
Name: ASI_ICACHE_PRE_NEXT_FIELD
Figure A-13
I-Cache LRU/BRPD/SP/NFA Field Access Address Format (ASI 6F
16
)
Note:
Stores to ASI_ICACHE_PRE_NEXT_FIELD are undefined unless the
instruction cache is disabled via the IC bit of the LSU control register (see
“LSU_Control_Register” on page 306).
IC_set
: This 1-bit field selects a set (2-way associative).
IC_addr
: this 8-bit index (addr <12:5>) selects an IC_Line.
IC_line
: This 1-bit field selects two BRPD and one NFA fields for four 128-bit
aligned instructions.
Figure A-14
I-Cache LRU/BRPD/SP/NFA Field LDDA Access Data Format (ASI 6F
16
)
63
3
4
0
—
—
IC_set
IC_addr
12
13
14
5
IC_line
63
9
10
0
Undefined
IC_nfa
22
IC_sp
IC_lru
25
7
8
und.
12
23
24
IC_brpd 0 IC_brpd 1
11
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