3 based on Anton Blanchard microwatt dcache.vhdl
7 from enum
import Enum
, unique
9 from nmigen
import Module
, Signal
, Elaboratable
, Cat
, Repl
, Array
, Const
11 from nmigen
.hdl
.ast
import Display
16 from nmigen
.cli
import main
17 from nmutil
.iocontrol
import RecordObject
18 from nmutil
.util
import wrap
19 from nmigen
.utils
import log2_int
20 from soc
.experiment
.mem_types
import (LoadStore1ToDCacheType
,
21 DCacheToLoadStore1Type
,
25 from soc
.experiment
.wb_types
import (WB_ADDR_BITS
, WB_DATA_BITS
, WB_SEL_BITS
,
26 WBAddrType
, WBDataType
, WBSelType
,
27 WBMasterOut
, WBSlaveOut
,
28 WBMasterOutVector
, WBSlaveOutVector
,
29 WBIOMasterOut
, WBIOSlaveOut
)
31 from soc
.experiment
.cache_ram
import CacheRam
32 from soc
.experiment
.plru
import PLRU
35 from nmigen_soc
.wishbone
.sram
import SRAM
36 from nmigen
import Memory
37 from nmigen
.cli
import rtlil
39 from nmigen
.back
.pysim
import Simulator
, Delay
, Settle
41 from nmigen
.sim
.cxxsim
import Simulator
, Delay
, Settle
44 # TODO: make these parameters of DCache at some point
45 LINE_SIZE
= 64 # Line size in bytes
46 NUM_LINES
= 16 # Number of lines in a set
47 NUM_WAYS
= 4 # Number of ways
48 TLB_SET_SIZE
= 64 # L1 DTLB entries per set
49 TLB_NUM_WAYS
= 2 # L1 DTLB number of sets
50 TLB_LG_PGSZ
= 12 # L1 DTLB log_2(page_size)
51 LOG_LENGTH
= 0 # Non-zero to enable log data collection
53 # BRAM organisation: We never access more than
54 # -- WB_DATA_BITS at a time so to save
55 # -- resources we make the array only that wide, and
56 # -- use consecutive indices for to make a cache "line"
58 # -- ROW_SIZE is the width in bytes of the BRAM
59 # -- (based on WB, so 64-bits)
60 ROW_SIZE
= WB_DATA_BITS
// 8;
62 # ROW_PER_LINE is the number of row (wishbone
63 # transactions) in a line
64 ROW_PER_LINE
= LINE_SIZE
// ROW_SIZE
66 # BRAM_ROWS is the number of rows in BRAM needed
67 # to represent the full dcache
68 BRAM_ROWS
= NUM_LINES
* ROW_PER_LINE
71 # Bit fields counts in the address
73 # REAL_ADDR_BITS is the number of real address
77 # ROW_BITS is the number of bits to select a row
78 ROW_BITS
= log2_int(BRAM_ROWS
)
80 # ROW_LINE_BITS is the number of bits to select
82 ROW_LINE_BITS
= log2_int(ROW_PER_LINE
)
84 # LINE_OFF_BITS is the number of bits for
85 # the offset in a cache line
86 LINE_OFF_BITS
= log2_int(LINE_SIZE
)
88 # ROW_OFF_BITS is the number of bits for
90 ROW_OFF_BITS
= log2_int(ROW_SIZE
)
92 # INDEX_BITS is the number if bits to
94 INDEX_BITS
= log2_int(NUM_LINES
)
96 # SET_SIZE_BITS is the log base 2 of the set size
97 SET_SIZE_BITS
= LINE_OFF_BITS
+ INDEX_BITS
99 # TAG_BITS is the number of bits of
100 # the tag part of the address
101 TAG_BITS
= REAL_ADDR_BITS
- SET_SIZE_BITS
103 # TAG_WIDTH is the width in bits of each way of the tag RAM
104 TAG_WIDTH
= TAG_BITS
+ 7 - ((TAG_BITS
+ 7) % 8)
106 # WAY_BITS is the number of bits to select a way
107 WAY_BITS
= log2_int(NUM_WAYS
)
109 # Example of layout for 32 lines of 64 bytes:
111 # .. tag |index| line |
113 # .. | |---| | ROW_LINE_BITS (3)
114 # .. | |--- - --| LINE_OFF_BITS (6)
115 # .. | |- --| ROW_OFF_BITS (3)
116 # .. |----- ---| | ROW_BITS (8)
117 # .. |-----| | INDEX_BITS (5)
118 # .. --------| | TAG_BITS (45)
120 TAG_RAM_WIDTH
= TAG_WIDTH
* NUM_WAYS
123 return Array(Signal(TAG_RAM_WIDTH
, name
="cachetag_%d" % x
) \
124 for x
in range(NUM_LINES
))
126 def CacheValidBitsArray():
127 return Array(Signal(INDEX_BITS
, name
="cachevalid_%d" % x
) \
128 for x
in range(NUM_LINES
))
130 def RowPerLineValidArray():
131 return Array(Signal(name
="rows_valid%d" % x
) \
132 for x
in range(ROW_PER_LINE
))
135 TLB_SET_BITS
= log2_int(TLB_SET_SIZE
)
136 TLB_WAY_BITS
= log2_int(TLB_NUM_WAYS
)
137 TLB_EA_TAG_BITS
= 64 - (TLB_LG_PGSZ
+ TLB_SET_BITS
)
138 TLB_TAG_WAY_BITS
= TLB_NUM_WAYS
* TLB_EA_TAG_BITS
140 TLB_PTE_WAY_BITS
= TLB_NUM_WAYS
* TLB_PTE_BITS
;
142 assert (LINE_SIZE
% ROW_SIZE
) == 0, "LINE_SIZE not multiple of ROW_SIZE"
143 assert (LINE_SIZE
% 2) == 0, "LINE_SIZE not power of 2"
144 assert (NUM_LINES
% 2) == 0, "NUM_LINES not power of 2"
145 assert (ROW_PER_LINE
% 2) == 0, "ROW_PER_LINE not power of 2"
146 assert ROW_BITS
== (INDEX_BITS
+ ROW_LINE_BITS
), "geometry bits don't add up"
147 assert (LINE_OFF_BITS
== ROW_OFF_BITS
+ ROW_LINE_BITS
), \
148 "geometry bits don't add up"
149 assert REAL_ADDR_BITS
== (TAG_BITS
+ INDEX_BITS
+ LINE_OFF_BITS
), \
150 "geometry bits don't add up"
151 assert REAL_ADDR_BITS
== (TAG_BITS
+ ROW_BITS
+ ROW_OFF_BITS
), \
152 "geometry bits don't add up"
153 assert 64 == WB_DATA_BITS
, "Can't yet handle wb width that isn't 64-bits"
154 assert SET_SIZE_BITS
<= TLB_LG_PGSZ
, "Set indexed by virtual address"
157 def TLBValidBitsArray():
158 return Array(Signal(TLB_NUM_WAYS
) for x
in range(TLB_SET_SIZE
))
161 return Array(Signal(TLB_EA_TAG_BITS
) for x
in range (TLB_NUM_WAYS
))
164 return Array(Signal(TLB_TAG_WAY_BITS
) for x
in range (TLB_SET_SIZE
))
167 return Array(Signal(TLB_PTE_WAY_BITS
) for x
in range(TLB_SET_SIZE
))
170 return Array(Signal(WAY_BITS
, name
="hitway_%d" % x
) \
171 for x
in range(TLB_NUM_WAYS
))
173 # Cache RAM interface
175 return Array(Signal(WB_DATA_BITS
, name
="cache_out%d" % x
) \
176 for x
in range(NUM_WAYS
))
178 # PLRU output interface
180 return Array(Signal(WAY_BITS
) for x
in range(NUM_LINES
))
182 # TLB PLRU output interface
184 return Array(Signal(TLB_WAY_BITS
) for x
in range(TLB_SET_SIZE
))
186 # Helper functions to decode incoming requests
188 # Return the cache line index (tag index) for an address
190 return addr
[LINE_OFF_BITS
:SET_SIZE_BITS
]
192 # Return the cache row index (data memory) for an address
194 return addr
[ROW_OFF_BITS
:SET_SIZE_BITS
]
196 # Return the index of a row within a line
197 def get_row_of_line(row
):
198 return row
[:ROW_LINE_BITS
]
200 # Returns whether this is the last row of a line
201 def is_last_row_addr(addr
, last
):
202 return addr
[ROW_OFF_BITS
:LINE_OFF_BITS
] == last
204 # Returns whether this is the last row of a line
205 def is_last_row(row
, last
):
206 return get_row_of_line(row
) == last
208 # Return the next row in the current cache line. We use a
209 # dedicated function in order to limit the size of the
210 # generated adder to be only the bits within a cache line
211 # (3 bits with default settings)
213 row_v
= row
[0:ROW_LINE_BITS
] + 1
214 return Cat(row_v
[:ROW_LINE_BITS
], row
[ROW_LINE_BITS
:])
216 # Get the tag value from the address
218 return addr
[SET_SIZE_BITS
:REAL_ADDR_BITS
]
220 # Read a tag from a tag memory row
221 def read_tag(way
, tagset
):
222 return tagset
.word_select(way
, TAG_WIDTH
)[:TAG_BITS
]
224 # Read a TLB tag from a TLB tag memory row
225 def read_tlb_tag(way
, tags
):
226 return tags
.word_select(way
, TLB_EA_TAG_BITS
)
228 # Write a TLB tag to a TLB tag memory row
229 def write_tlb_tag(way
, tags
, tag
):
230 return read_tlb_tag(way
, tags
).eq(tag
)
232 # Read a PTE from a TLB PTE memory row
233 def read_tlb_pte(way
, ptes
):
234 return ptes
.word_select(way
, TLB_PTE_BITS
)
236 def write_tlb_pte(way
, ptes
, newpte
):
237 return read_tlb_pte(way
, ptes
).eq(newpte
)
240 # Record for storing permission, attribute, etc. bits from a PTE
241 class PermAttr(RecordObject
):
242 def __init__(self
, name
=None):
243 super().__init
__(name
=name
)
244 self
.reference
= Signal()
245 self
.changed
= Signal()
246 self
.nocache
= Signal()
248 self
.rd_perm
= Signal()
249 self
.wr_perm
= Signal()
252 def extract_perm_attr(pte
):
254 pa
.reference
= pte
[8]
263 # Type of operation on a "valid" input
267 OP_BAD
= 1 # NC cache hit, TLB miss, prot/RC failure
268 OP_STCX_FAIL
= 2 # conditional store w/o reservation
269 OP_LOAD_HIT
= 3 # Cache hit on load
270 OP_LOAD_MISS
= 4 # Load missing cache
271 OP_LOAD_NC
= 5 # Non-cachable load
272 OP_STORE_HIT
= 6 # Store hitting cache
273 OP_STORE_MISS
= 7 # Store missing cache
276 # Cache state machine
279 IDLE
= 0 # Normal load hit processing
280 RELOAD_WAIT_ACK
= 1 # Cache reload wait ack
281 STORE_WAIT_ACK
= 2 # Store wait ack
282 NC_LOAD_WAIT_ACK
= 3 # Non-cachable load wait ack
287 # In order to make timing, we use the BRAMs with
288 # an output buffer, which means that the BRAM
289 # output is delayed by an extra cycle.
291 # Thus, the dcache has a 2-stage internal pipeline
292 # for cache hits with no stalls.
294 # All other operations are handled via stalling
295 # in the first stage.
297 # The second stage can thus complete a hit at the same
298 # time as the first stage emits a stall for a complex op.
300 # Stage 0 register, basically contains just the latched request
302 class RegStage0(RecordObject
):
303 def __init__(self
, name
=None):
304 super().__init
__(name
=name
)
305 self
.req
= LoadStore1ToDCacheType(name
="lsmem")
306 self
.tlbie
= Signal()
307 self
.doall
= Signal()
308 self
.tlbld
= Signal()
309 self
.mmu_req
= Signal() # indicates source of request
312 class MemAccessRequest(RecordObject
):
313 def __init__(self
, name
=None):
314 super().__init
__(name
=name
)
316 self
.valid
= Signal()
318 self
.real_addr
= Signal(REAL_ADDR_BITS
)
319 self
.data
= Signal(64)
320 self
.byte_sel
= Signal(8)
321 self
.hit_way
= Signal(WAY_BITS
)
322 self
.same_tag
= Signal()
323 self
.mmu_req
= Signal()
326 # First stage register, contains state for stage 1 of load hits
327 # and for the state machine used by all other operations
328 class RegStage1(RecordObject
):
329 def __init__(self
, name
=None):
330 super().__init
__(name
=name
)
331 # Info about the request
332 self
.full
= Signal() # have uncompleted request
333 self
.mmu_req
= Signal() # request is from MMU
334 self
.req
= MemAccessRequest(name
="reqmem")
337 self
.hit_way
= Signal(WAY_BITS
)
338 self
.hit_load_valid
= Signal()
339 self
.hit_index
= Signal(INDEX_BITS
)
340 self
.cache_hit
= Signal()
343 self
.tlb_hit
= Signal()
344 self
.tlb_hit_way
= Signal(TLB_NUM_WAYS
)
345 self
.tlb_hit_index
= Signal(TLB_WAY_BITS
)
347 # 2-stage data buffer for data forwarded from writes to reads
348 self
.forward_data1
= Signal(64)
349 self
.forward_data2
= Signal(64)
350 self
.forward_sel1
= Signal(8)
351 self
.forward_valid1
= Signal()
352 self
.forward_way1
= Signal(WAY_BITS
)
353 self
.forward_row1
= Signal(ROW_BITS
)
354 self
.use_forward1
= Signal()
355 self
.forward_sel
= Signal(8)
357 # Cache miss state (reload state machine)
358 self
.state
= Signal(State
)
360 self
.write_bram
= Signal()
361 self
.write_tag
= Signal()
362 self
.slow_valid
= Signal()
363 self
.wb
= WBMasterOut()
364 self
.reload_tag
= Signal(TAG_BITS
)
365 self
.store_way
= Signal(WAY_BITS
)
366 self
.store_row
= Signal(ROW_BITS
)
367 self
.store_index
= Signal(INDEX_BITS
)
368 self
.end_row_ix
= Signal(ROW_LINE_BITS
)
369 self
.rows_valid
= RowPerLineValidArray()
370 self
.acks_pending
= Signal(3)
371 self
.inc_acks
= Signal()
372 self
.dec_acks
= Signal()
374 # Signals to complete (possibly with error)
375 self
.ls_valid
= Signal()
376 self
.ls_error
= Signal()
377 self
.mmu_done
= Signal()
378 self
.mmu_error
= Signal()
379 self
.cache_paradox
= Signal()
381 # Signal to complete a failed stcx.
382 self
.stcx_fail
= Signal()
385 # Reservation information
386 class Reservation(RecordObject
):
389 self
.valid
= Signal()
390 self
.addr
= Signal(64-LINE_OFF_BITS
)
393 class DTLBUpdate(Elaboratable
):
395 self
.tlbie
= Signal()
396 self
.tlbwe
= Signal()
397 self
.doall
= Signal()
398 self
.updated
= Signal()
399 self
.v_updated
= Signal()
400 self
.tlb_hit
= Signal()
401 self
.tlb_req_index
= Signal(TLB_SET_BITS
)
403 self
.tlb_hit_way
= Signal(TLB_WAY_BITS
)
404 self
.tlb_tag_way
= Signal(TLB_TAG_WAY_BITS
)
405 self
.tlb_pte_way
= Signal(TLB_PTE_WAY_BITS
)
406 self
.repl_way
= Signal(TLB_WAY_BITS
)
407 self
.eatag
= Signal(TLB_EA_TAG_BITS
)
408 self
.pte_data
= Signal(TLB_PTE_BITS
)
410 self
.dv
= Signal(TLB_PTE_WAY_BITS
)
412 self
.tb_out
= Signal(TLB_TAG_WAY_BITS
)
413 self
.pb_out
= Signal(TLB_NUM_WAYS
)
414 self
.db_out
= Signal(TLB_PTE_WAY_BITS
)
416 def elaborate(self
, platform
):
421 tagset
= Signal(TLB_TAG_WAY_BITS
)
422 pteset
= Signal(TLB_PTE_WAY_BITS
)
424 tb_out
, pb_out
, db_out
= self
.tb_out
, self
.pb_out
, self
.db_out
426 with m
.If(self
.tlbie
& self
.doall
):
427 pass # clear all back in parent
428 with m
.Elif(self
.tlbie
):
429 with m
.If(self
.tlb_hit
):
430 comb
+= db_out
.eq(self
.dv
)
431 comb
+= db_out
.bit_select(self
.tlb_hit_way
, 1).eq(1)
432 comb
+= self
.v_updated
.eq(1)
434 with m
.Elif(self
.tlbwe
):
436 comb
+= tagset
.eq(self
.tlb_tag_way
)
437 comb
+= write_tlb_tag(self
.repl_way
, tagset
, self
.eatag
)
438 comb
+= tb_out
.eq(tagset
)
440 comb
+= pteset
.eq(self
.tlb_pte_way
)
441 comb
+= write_tlb_pte(self
.repl_way
, pteset
, self
.pte_data
)
442 comb
+= pb_out
.eq(pteset
)
444 comb
+= db_out
.bit_select(self
.repl_way
, 1).eq(1)
446 comb
+= self
.updated
.eq(1)
447 comb
+= self
.v_updated
.eq(1)
451 def dcache_request(self
, m
, r0
, ra
, req_index
, req_row
, req_tag
,
452 r0_valid
, r1
, cache_valid_bits
, replace_way
,
453 use_forward1_next
, use_forward2_next
,
454 req_hit_way
, plru_victim
, rc_ok
, perm_attr
,
455 valid_ra
, perm_ok
, access_ok
, req_op
, req_go
,
457 tlb_hit
, tlb_hit_way
, tlb_valid_way
, cache_tag_set
,
458 cancel_store
, req_same_tag
, r0_stall
, early_req_row
):
459 """Cache request parsing and hit detection
462 class DCachePendingHit(Elaboratable
):
464 def __init__(self
, tlb_pte_way
, tlb_valid_way
, tlb_hit_way
,
465 cache_valid_idx
, cache_tag_set
,
470 self
.virt_mode
= Signal()
471 self
.is_hit
= Signal()
472 self
.tlb_hit
= Signal()
473 self
.hit_way
= Signal(WAY_BITS
)
474 self
.rel_match
= Signal()
475 self
.req_index
= Signal(INDEX_BITS
)
476 self
.reload_tag
= Signal(TAG_BITS
)
478 self
.tlb_hit_way
= tlb_hit_way
479 self
.tlb_pte_way
= tlb_pte_way
480 self
.tlb_valid_way
= tlb_valid_way
481 self
.cache_valid_idx
= cache_valid_idx
482 self
.cache_tag_set
= cache_tag_set
483 self
.req_addr
= req_addr
484 self
.hit_set
= hit_set
486 def elaborate(self
, platform
):
492 virt_mode
= self
.virt_mode
494 tlb_pte_way
= self
.tlb_pte_way
495 tlb_valid_way
= self
.tlb_valid_way
496 cache_valid_idx
= self
.cache_valid_idx
497 cache_tag_set
= self
.cache_tag_set
498 req_addr
= self
.req_addr
499 tlb_hit_way
= self
.tlb_hit_way
500 tlb_hit
= self
.tlb_hit
501 hit_set
= self
.hit_set
502 hit_way
= self
.hit_way
503 rel_match
= self
.rel_match
504 req_index
= self
.req_index
505 reload_tag
= self
.reload_tag
507 rel_matches
= Array(Signal(name
="rel_matches_%d" % i
) \
508 for i
in range(TLB_NUM_WAYS
))
509 hit_way_set
= HitWaySet()
511 # Test if pending request is a hit on any way
512 # In order to make timing in virtual mode,
513 # when we are using the TLB, we compare each
514 # way with each of the real addresses from each way of
515 # the TLB, and then decide later which match to use.
517 with m
.If(virt_mode
):
518 for j
in range(TLB_NUM_WAYS
):
519 s_tag
= Signal(TAG_BITS
, name
="s_tag%d" % j
)
521 s_pte
= Signal(TLB_PTE_BITS
)
522 s_ra
= Signal(REAL_ADDR_BITS
)
523 comb
+= s_pte
.eq(read_tlb_pte(j
, tlb_pte_way
))
524 comb
+= s_ra
.eq(Cat(req_addr
[0:TLB_LG_PGSZ
],
525 s_pte
[TLB_LG_PGSZ
:REAL_ADDR_BITS
]))
526 comb
+= s_tag
.eq(get_tag(s_ra
))
528 for i
in range(NUM_WAYS
):
529 is_tag_hit
= Signal(name
="is_tag_hit_%d_%d" % (j
, i
))
530 comb
+= is_tag_hit
.eq(go
& cache_valid_idx
[i
] &
531 (read_tag(i
, cache_tag_set
) == s_tag
)
533 with m
.If(is_tag_hit
):
534 comb
+= hit_way_set
[j
].eq(i
)
536 comb
+= hit_set
[j
].eq(s_hit
)
537 with m
.If(s_tag
== reload_tag
):
538 comb
+= rel_matches
[j
].eq(1)
540 comb
+= is_hit
.eq(hit_set
[tlb_hit_way
])
541 comb
+= hit_way
.eq(hit_way_set
[tlb_hit_way
])
542 comb
+= rel_match
.eq(rel_matches
[tlb_hit_way
])
544 s_tag
= Signal(TAG_BITS
)
545 comb
+= s_tag
.eq(get_tag(req_addr
))
546 for i
in range(NUM_WAYS
):
547 is_tag_hit
= Signal(name
="is_tag_hit_%d" % i
)
548 comb
+= is_tag_hit
.eq(go
& cache_valid_idx
[i
] &
549 (read_tag(i
, cache_tag_set
) == s_tag
))
550 with m
.If(is_tag_hit
):
551 comb
+= hit_way
.eq(i
)
553 with m
.If(s_tag
== reload_tag
):
554 comb
+= rel_match
.eq(1)
559 class DCache(Elaboratable
):
560 """Set associative dcache write-through
561 TODO (in no specific order):
562 * See list in icache.vhdl
563 * Complete load misses on the cycle when WB data comes instead of
564 at the end of line (this requires dealing with requests coming in
568 self
.d_in
= LoadStore1ToDCacheType("d_in")
569 self
.d_out
= DCacheToLoadStore1Type("d_out")
571 self
.m_in
= MMUToDCacheType("m_in")
572 self
.m_out
= DCacheToMMUType("m_out")
574 self
.stall_out
= Signal()
576 self
.wb_out
= WBMasterOut()
577 self
.wb_in
= WBSlaveOut()
579 self
.log_out
= Signal(20)
581 def stage_0(self
, m
, r0
, r1
, r0_full
):
582 """Latch the request in r0.req as long as we're not stalling
586 d_in
, d_out
, m_in
= self
.d_in
, self
.d_out
, self
.m_in
588 r
= RegStage0("stage0")
590 # TODO, this goes in unit tests and formal proofs
591 with m
.If(~
(d_in
.valid
& m_in
.valid
)):
592 #sync += Display("request collision loadstore vs MMU")
595 with m
.If(m_in
.valid
):
596 sync
+= r
.req
.valid
.eq(1)
597 sync
+= r
.req
.load
.eq(~
(m_in
.tlbie | m_in
.tlbld
))
598 sync
+= r
.req
.dcbz
.eq(0)
599 sync
+= r
.req
.nc
.eq(0)
600 sync
+= r
.req
.reserve
.eq(0)
601 sync
+= r
.req
.virt_mode
.eq(1)
602 sync
+= r
.req
.priv_mode
.eq(1)
603 sync
+= r
.req
.addr
.eq(m_in
.addr
)
604 sync
+= r
.req
.data
.eq(m_in
.pte
)
605 sync
+= r
.req
.byte_sel
.eq(~
0) # Const -1 sets all to 0b111....
606 sync
+= r
.tlbie
.eq(m_in
.tlbie
)
607 sync
+= r
.doall
.eq(m_in
.doall
)
608 sync
+= r
.tlbld
.eq(m_in
.tlbld
)
609 sync
+= r
.mmu_req
.eq(1)
611 sync
+= r
.req
.eq(d_in
)
612 sync
+= r
.tlbie
.eq(0)
613 sync
+= r
.doall
.eq(0)
614 sync
+= r
.tlbld
.eq(0)
615 sync
+= r
.mmu_req
.eq(0)
616 with m
.If(~
(r1
.full
& r0_full
)):
618 sync
+= r0_full
.eq(r
.req
.valid
)
620 def tlb_read(self
, m
, r0_stall
, tlb_valid_way
,
621 tlb_tag_way
, tlb_pte_way
, dtlb_valid_bits
,
622 dtlb_tags
, dtlb_ptes
):
624 Operates in the second cycle on the request latched in r0.req.
625 TLB updates write the entry at the end of the second cycle.
629 m_in
, d_in
= self
.m_in
, self
.d_in
631 index
= Signal(TLB_SET_BITS
)
632 addrbits
= Signal(TLB_SET_BITS
)
635 amax
= TLB_LG_PGSZ
+ TLB_SET_BITS
637 with m
.If(m_in
.valid
):
638 comb
+= addrbits
.eq(m_in
.addr
[amin
: amax
])
640 comb
+= addrbits
.eq(d_in
.addr
[amin
: amax
])
641 comb
+= index
.eq(addrbits
)
643 # If we have any op and the previous op isn't finished,
644 # then keep the same output for next cycle.
645 with m
.If(~r0_stall
):
646 sync
+= tlb_valid_way
.eq(dtlb_valid_bits
[index
])
647 sync
+= tlb_tag_way
.eq(dtlb_tags
[index
])
648 sync
+= tlb_pte_way
.eq(dtlb_ptes
[index
])
650 def maybe_tlb_plrus(self
, m
, r1
, tlb_plru_victim
):
651 """Generate TLB PLRUs
656 if TLB_NUM_WAYS
== 0:
658 for i
in range(TLB_SET_SIZE
):
660 tlb_plru
= PLRU(WAY_BITS
)
661 setattr(m
.submodules
, "maybe_plru_%d" % i
, tlb_plru
)
662 tlb_plru_acc_en
= Signal()
664 comb
+= tlb_plru_acc_en
.eq(r1
.tlb_hit
& (r1
.tlb_hit_index
== i
))
665 comb
+= tlb_plru
.acc_en
.eq(tlb_plru_acc_en
)
666 comb
+= tlb_plru
.acc
.eq(r1
.tlb_hit_way
)
667 comb
+= tlb_plru_victim
[i
].eq(tlb_plru
.lru_o
)
669 def tlb_search(self
, m
, tlb_req_index
, r0
, r0_valid
,
670 tlb_valid_way
, tlb_tag_way
, tlb_hit_way
,
671 tlb_pte_way
, pte
, tlb_hit
, valid_ra
, perm_attr
, ra
):
676 hitway
= Signal(TLB_WAY_BITS
)
678 eatag
= Signal(TLB_EA_TAG_BITS
)
680 TLB_LG_END
= TLB_LG_PGSZ
+ TLB_SET_BITS
681 comb
+= tlb_req_index
.eq(r0
.req
.addr
[TLB_LG_PGSZ
: TLB_LG_END
])
682 comb
+= eatag
.eq(r0
.req
.addr
[TLB_LG_END
: 64 ])
684 for i
in range(TLB_NUM_WAYS
):
685 is_tag_hit
= Signal()
686 comb
+= is_tag_hit
.eq(tlb_valid_way
[i
]
687 & read_tlb_tag(i
, tlb_tag_way
) == eatag
)
688 with m
.If(is_tag_hit
):
692 comb
+= tlb_hit
.eq(hit
& r0_valid
)
693 comb
+= tlb_hit_way
.eq(hitway
)
696 comb
+= pte
.eq(read_tlb_pte(hitway
, tlb_pte_way
))
699 comb
+= valid_ra
.eq(tlb_hit | ~r0
.req
.virt_mode
)
700 with m
.If(r0
.req
.virt_mode
):
701 comb
+= ra
.eq(Cat(Const(0, ROW_OFF_BITS
),
702 r0
.req
.addr
[ROW_OFF_BITS
:TLB_LG_PGSZ
],
703 pte
[TLB_LG_PGSZ
:REAL_ADDR_BITS
]))
704 comb
+= perm_attr
.eq(extract_perm_attr(pte
))
706 comb
+= ra
.eq(Cat(Const(0, ROW_OFF_BITS
),
707 r0
.req
.addr
[ROW_OFF_BITS
:REAL_ADDR_BITS
]))
709 comb
+= perm_attr
.reference
.eq(1)
710 comb
+= perm_attr
.changed
.eq(1)
711 comb
+= perm_attr
.nocache
.eq(0)
712 comb
+= perm_attr
.priv
.eq(1)
713 comb
+= perm_attr
.rd_perm
.eq(1)
714 comb
+= perm_attr
.wr_perm
.eq(1)
716 def tlb_update(self
, m
, r0_valid
, r0
, dtlb_valid_bits
, tlb_req_index
,
717 tlb_hit_way
, tlb_hit
, tlb_plru_victim
, tlb_tag_way
,
718 dtlb_tags
, tlb_pte_way
, dtlb_ptes
):
726 comb
+= tlbie
.eq(r0_valid
& r0
.tlbie
)
727 comb
+= tlbwe
.eq(r0_valid
& r0
.tlbld
)
729 m
.submodules
.tlb_update
= d
= DTLBUpdate()
730 with m
.If(tlbie
& r0
.doall
):
731 # clear all valid bits at once
732 for i
in range(TLB_SET_SIZE
):
733 sync
+= dtlb_valid_bits
[i
].eq(0)
734 with m
.If(d
.updated
):
735 sync
+= dtlb_tags
[tlb_req_index
].eq(d
.tb_out
)
736 sync
+= dtlb_ptes
[tlb_req_index
].eq(d
.pb_out
)
737 with m
.If(d
.v_updated
):
738 sync
+= dtlb_valid_bits
[tlb_req_index
].eq(d
.db_out
)
740 comb
+= d
.dv
.eq(dtlb_valid_bits
[tlb_req_index
])
742 comb
+= d
.tlbie
.eq(tlbie
)
743 comb
+= d
.tlbwe
.eq(tlbwe
)
744 comb
+= d
.doall
.eq(r0
.doall
)
745 comb
+= d
.tlb_hit
.eq(tlb_hit
)
746 comb
+= d
.tlb_hit_way
.eq(tlb_hit_way
)
747 comb
+= d
.tlb_tag_way
.eq(tlb_tag_way
)
748 comb
+= d
.tlb_pte_way
.eq(tlb_pte_way
)
749 comb
+= d
.tlb_req_index
.eq(tlb_req_index
)
752 comb
+= d
.repl_way
.eq(tlb_hit_way
)
754 comb
+= d
.repl_way
.eq(tlb_plru_victim
[tlb_req_index
])
755 comb
+= d
.eatag
.eq(r0
.req
.addr
[TLB_LG_PGSZ
+ TLB_SET_BITS
:64])
756 comb
+= d
.pte_data
.eq(r0
.req
.data
)
758 def maybe_plrus(self
, m
, r1
, plru_victim
):
764 if TLB_NUM_WAYS
== 0:
767 for i
in range(NUM_LINES
):
769 plru
= PLRU(WAY_BITS
)
770 setattr(m
.submodules
, "plru%d" % i
, plru
)
771 plru_acc_en
= Signal()
773 comb
+= plru_acc_en
.eq(r1
.cache_hit
& (r1
.hit_index
== i
))
774 comb
+= plru
.acc_en
.eq(plru_acc_en
)
775 comb
+= plru
.acc
.eq(r1
.hit_way
)
776 comb
+= plru_victim
[i
].eq(plru
.lru_o
)
778 def cache_tag_read(self
, m
, r0_stall
, req_index
, cache_tag_set
, cache_tags
):
779 """Cache tag RAM read port
783 m_in
, d_in
= self
.m_in
, self
.d_in
785 index
= Signal(INDEX_BITS
)
788 comb
+= index
.eq(req_index
)
789 with m
.Elif(m_in
.valid
):
790 comb
+= index
.eq(get_index(m_in
.addr
))
792 comb
+= index
.eq(get_index(d_in
.addr
))
793 sync
+= cache_tag_set
.eq(cache_tags
[index
])
795 def dcache_request(self
, m
, r0
, ra
, req_index
, req_row
, req_tag
,
796 r0_valid
, r1
, cache_valid_bits
, replace_way
,
797 use_forward1_next
, use_forward2_next
,
798 req_hit_way
, plru_victim
, rc_ok
, perm_attr
,
799 valid_ra
, perm_ok
, access_ok
, req_op
, req_go
,
801 tlb_hit
, tlb_hit_way
, tlb_valid_way
, cache_tag_set
,
802 cancel_store
, req_same_tag
, r0_stall
, early_req_row
):
803 """Cache request parsing and hit detection
808 m_in
, d_in
= self
.m_in
, self
.d_in
811 hit_way
= Signal(WAY_BITS
)
816 hit_set
= Array(Signal(name
="hit_set_%d" % i
) \
817 for i
in range(TLB_NUM_WAYS
))
818 cache_valid_idx
= Signal(INDEX_BITS
)
820 # Extract line, row and tag from request
821 comb
+= req_index
.eq(get_index(r0
.req
.addr
))
822 comb
+= req_row
.eq(get_row(r0
.req
.addr
))
823 comb
+= req_tag
.eq(get_tag(ra
))
825 comb
+= go
.eq(r0_valid
& ~
(r0
.tlbie | r0
.tlbld
) & ~r1
.ls_error
)
826 comb
+= cache_valid_idx
.eq(cache_valid_bits
[req_index
])
828 m
.submodules
.dcache_pend
= dc
= DCachePendingHit(tlb_pte_way
,
829 tlb_valid_way
, tlb_hit_way
,
830 cache_valid_idx
, cache_tag_set
,
834 comb
+= dc
.tlb_hit
.eq(tlb_hit
)
835 comb
+= dc
.reload_tag
.eq(r1
.reload_tag
)
836 comb
+= dc
.virt_mode
.eq(r0
.req
.virt_mode
)
838 comb
+= dc
.req_index
.eq(req_index
)
839 comb
+= is_hit
.eq(dc
.is_hit
)
840 comb
+= hit_way
.eq(dc
.hit_way
)
841 comb
+= req_same_tag
.eq(dc
.rel_match
)
843 # See if the request matches the line currently being reloaded
844 with m
.If((r1
.state
== State
.RELOAD_WAIT_ACK
) &
845 (req_index
== r1
.store_index
) & req_same_tag
):
846 # For a store, consider this a hit even if the row isn't
847 # valid since it will be by the time we perform the store.
848 # For a load, check the appropriate row valid bit.
849 valid
= r1
.rows_valid
[req_row
% ROW_PER_LINE
]
850 comb
+= is_hit
.eq(~r0
.req
.load | valid
)
851 comb
+= hit_way
.eq(replace_way
)
853 # Whether to use forwarded data for a load or not
854 comb
+= use_forward1_next
.eq(0)
855 with m
.If((get_row(r1
.req
.real_addr
) == req_row
) &
856 (r1
.req
.hit_way
== hit_way
)):
857 # Only need to consider r1.write_bram here, since if we
858 # are writing refill data here, then we don't have a
859 # cache hit this cycle on the line being refilled.
860 # (There is the possibility that the load following the
861 # load miss that started the refill could be to the old
862 # contents of the victim line, since it is a couple of
863 # cycles after the refill starts before we see the updated
864 # cache tag. In that case we don't use the bypass.)
865 comb
+= use_forward1_next
.eq(r1
.write_bram
)
866 comb
+= use_forward2_next
.eq(0)
867 with m
.If((r1
.forward_row1
== req_row
) & (r1
.forward_way1
== hit_way
)):
868 comb
+= use_forward2_next
.eq(r1
.forward_valid1
)
870 # The way that matched on a hit
871 comb
+= req_hit_way
.eq(hit_way
)
873 # The way to replace on a miss
874 with m
.If(r1
.write_tag
):
875 comb
+= replace_way
.eq(plru_victim
[r1
.store_index
])
877 comb
+= replace_way
.eq(r1
.store_way
)
879 # work out whether we have permission for this access
880 # NB we don't yet implement AMR, thus no KUAP
881 comb
+= rc_ok
.eq(perm_attr
.reference
882 & (r0
.req
.load | perm_attr
.changed
)
884 comb
+= perm_ok
.eq((r0
.req
.priv_mode | ~perm_attr
.priv
) &
886 (r0
.req
.load
& perm_attr
.rd_perm
)))
887 comb
+= access_ok
.eq(valid_ra
& perm_ok
& rc_ok
)
888 # Combine the request and cache hit status to decide what
889 # operation needs to be done
890 comb
+= nc
.eq(r0
.req
.nc | perm_attr
.nocache
)
891 comb
+= op
.eq(Op
.OP_NONE
)
893 with m
.If(~access_ok
):
894 comb
+= op
.eq(Op
.OP_BAD
)
895 with m
.Elif(cancel_store
):
896 comb
+= op
.eq(Op
.OP_STCX_FAIL
)
898 comb
+= opsel
.eq(Cat(is_hit
, nc
, r0
.req
.load
))
899 with m
.Switch(opsel
):
901 comb
+= op
.eq(Op
.OP_LOAD_HIT
)
903 comb
+= op
.eq(Op
.OP_LOAD_MISS
)
905 comb
+= op
.eq(Op
.OP_LOAD_NC
)
907 comb
+= op
.eq(Op
.OP_STORE_HIT
)
909 comb
+= op
.eq(Op
.OP_STORE_MISS
)
911 comb
+= op
.eq(Op
.OP_STORE_MISS
)
913 comb
+= op
.eq(Op
.OP_BAD
)
915 comb
+= op
.eq(Op
.OP_BAD
)
917 comb
+= op
.eq(Op
.OP_NONE
)
918 comb
+= req_op
.eq(op
)
919 comb
+= req_go
.eq(go
)
921 # Version of the row number that is valid one cycle earlier
922 # in the cases where we need to read the cache data BRAM.
923 # If we're stalling then we need to keep reading the last
925 with m
.If(~r0_stall
):
926 with m
.If(m_in
.valid
):
927 comb
+= early_req_row
.eq(get_row(m_in
.addr
))
929 comb
+= early_req_row
.eq(get_row(d_in
.addr
))
931 comb
+= early_req_row
.eq(req_row
)
933 def reservation_comb(self
, m
, cancel_store
, set_rsrv
, clear_rsrv
,
934 r0_valid
, r0
, reservation
):
935 """Handle load-with-reservation and store-conditional instructions
940 with m
.If(r0_valid
& r0
.req
.reserve
):
942 # XXX generate alignment interrupt if address
943 # is not aligned XXX or if r0.req.nc = '1'
944 with m
.If(r0
.req
.load
):
945 comb
+= set_rsrv
.eq(1) # load with reservation
947 comb
+= clear_rsrv
.eq(1) # store conditional
948 with m
.If(~reservation
.valid | r0
.req
.addr
[LINE_OFF_BITS
:64]):
949 comb
+= cancel_store
.eq(1)
951 def reservation_reg(self
, m
, r0_valid
, access_ok
, set_rsrv
, clear_rsrv
,
957 with m
.If(r0_valid
& access_ok
):
958 with m
.If(clear_rsrv
):
959 sync
+= reservation
.valid
.eq(0)
960 with m
.Elif(set_rsrv
):
961 sync
+= reservation
.valid
.eq(1)
962 sync
+= reservation
.addr
.eq(r0
.req
.addr
[LINE_OFF_BITS
:64])
964 def writeback_control(self
, m
, r1
, cache_out
):
965 """Return data for loads & completion control logic
969 d_out
, m_out
= self
.d_out
, self
.m_out
971 data_out
= Signal(64)
972 data_fwd
= Signal(64)
974 # Use the bypass if are reading the row that was
975 # written 1 or 2 cycles ago, including for the
976 # slow_valid = 1 case (i.e. completing a load
977 # miss or a non-cacheable load).
978 with m
.If(r1
.use_forward1
):
979 comb
+= data_fwd
.eq(r1
.forward_data1
)
981 comb
+= data_fwd
.eq(r1
.forward_data2
)
983 comb
+= data_out
.eq(cache_out
[r1
.hit_way
])
986 with m
.If(r1
.forward_sel
[i
]):
987 dsel
= data_fwd
.word_select(i
, 8)
988 comb
+= data_out
.word_select(i
, 8).eq(dsel
)
990 comb
+= d_out
.valid
.eq(r1
.ls_valid
)
991 comb
+= d_out
.data
.eq(data_out
)
992 comb
+= d_out
.store_done
.eq(~r1
.stcx_fail
)
993 comb
+= d_out
.error
.eq(r1
.ls_error
)
994 comb
+= d_out
.cache_paradox
.eq(r1
.cache_paradox
)
997 comb
+= m_out
.done
.eq(r1
.mmu_done
)
998 comb
+= m_out
.err
.eq(r1
.mmu_error
)
999 comb
+= m_out
.data
.eq(data_out
)
1001 # We have a valid load or store hit or we just completed
1002 # a slow op such as a load miss, a NC load or a store
1004 # Note: the load hit is delayed by one cycle. However it
1005 # can still not collide with r.slow_valid (well unless I
1006 # miscalculated) because slow_valid can only be set on a
1007 # subsequent request and not on its first cycle (the state
1008 # machine must have advanced), which makes slow_valid
1009 # at least 2 cycles from the previous hit_load_valid.
1011 # Sanity: Only one of these must be set in any given cycle
1013 if False: # TODO: need Display to get this to work
1014 assert (r1
.slow_valid
& r1
.stcx_fail
) != 1, \
1015 "unexpected slow_valid collision with stcx_fail"
1017 assert ((r1
.slow_valid | r1
.stcx_fail
) | r1
.hit_load_valid
) != 1, \
1018 "unexpected hit_load_delayed collision with slow_valid"
1020 with m
.If(~r1
.mmu_req
):
1021 # Request came from loadstore1...
1022 # Load hit case is the standard path
1023 with m
.If(r1
.hit_load_valid
):
1024 sync
+= Display("completing load hit data=%x", data_out
)
1026 # error cases complete without stalling
1027 with m
.If(r1
.ls_error
):
1028 sync
+= Display("completing ld/st with error")
1030 # Slow ops (load miss, NC, stores)
1031 with m
.If(r1
.slow_valid
):
1032 sync
+= Display("completing store or load miss data=%x",
1036 # Request came from MMU
1037 with m
.If(r1
.hit_load_valid
):
1038 sync
+= Display("completing load hit to MMU, data=%x",
1040 # error cases complete without stalling
1041 with m
.If(r1
.mmu_error
):
1042 sync
+= Display("combpleting MMU ld with error")
1044 # Slow ops (i.e. load miss)
1045 with m
.If(r1
.slow_valid
):
1046 sync
+= Display("completing MMU load miss, data=%x",
1049 def rams(self
, m
, r1
, early_req_row
, cache_out
, replace_way
):
1051 Generate a cache RAM for each way. This handles the normal
1052 reads, writes from reloads and the special store-hit update
1055 Note: the BRAMs have an extra read buffer, meaning the output
1056 is pipelined an extra cycle. This differs from the
1057 icache. The writeback logic needs to take that into
1058 account by using 1-cycle delayed signals for load hits.
1063 for i
in range(NUM_WAYS
):
1064 do_read
= Signal(name
="do_rd%d" % i
)
1065 rd_addr
= Signal(ROW_BITS
)
1066 do_write
= Signal(name
="do_wr%d" % i
)
1067 wr_addr
= Signal(ROW_BITS
)
1068 wr_data
= Signal(WB_DATA_BITS
)
1069 wr_sel
= Signal(ROW_SIZE
)
1070 wr_sel_m
= Signal(ROW_SIZE
)
1071 _d_out
= Signal(WB_DATA_BITS
, name
="dout_%d" % i
)
1073 way
= CacheRam(ROW_BITS
, WB_DATA_BITS
, True)
1074 setattr(m
.submodules
, "cacheram_%d" % i
, way
)
1076 comb
+= way
.rd_en
.eq(do_read
)
1077 comb
+= way
.rd_addr
.eq(rd_addr
)
1078 comb
+= _d_out
.eq(way
.rd_data_o
)
1079 comb
+= way
.wr_sel
.eq(wr_sel_m
)
1080 comb
+= way
.wr_addr
.eq(wr_addr
)
1081 comb
+= way
.wr_data
.eq(wr_data
)
1084 comb
+= do_read
.eq(1)
1085 comb
+= rd_addr
.eq(early_req_row
[:ROW_BITS
])
1086 comb
+= cache_out
[i
].eq(_d_out
)
1090 # Defaults to wishbone read responses (cache refill)
1092 # For timing, the mux on wr_data/sel/addr is not
1093 # dependent on anything other than the current state.
1095 with m
.If(r1
.write_bram
):
1096 # Write store data to BRAM. This happens one
1097 # cycle after the store is in r0.
1098 comb
+= wr_data
.eq(r1
.req
.data
)
1099 comb
+= wr_sel
.eq(r1
.req
.byte_sel
)
1100 comb
+= wr_addr
.eq(get_row(r1
.req
.real_addr
))
1102 with m
.If(i
== r1
.req
.hit_way
):
1103 comb
+= do_write
.eq(1)
1105 # Otherwise, we might be doing a reload or a DCBZ
1107 comb
+= wr_data
.eq(0)
1109 comb
+= wr_data
.eq(wb_in
.dat
)
1110 comb
+= wr_addr
.eq(r1
.store_row
)
1111 comb
+= wr_sel
.eq(~
0) # all 1s
1113 with m
.If((r1
.state
== State
.RELOAD_WAIT_ACK
)
1114 & wb_in
.ack
& (replace_way
== i
)):
1115 comb
+= do_write
.eq(1)
1117 # Mask write selects with do_write since BRAM
1118 # doesn't have a global write-enable
1119 with m
.If(do_write
):
1120 comb
+= wr_sel_m
.eq(wr_sel
)
1122 # Cache hit synchronous machine for the easy case.
1123 # This handles load hits.
1124 # It also handles error cases (TLB miss, cache paradox)
1125 def dcache_fast_hit(self
, m
, req_op
, r0_valid
, r0
, r1
,
1126 req_hit_way
, req_index
, req_tag
, access_ok
,
1127 tlb_hit
, tlb_hit_way
, tlb_req_index
):
1132 with m
.If(req_op
!= Op
.OP_NONE
):
1133 sync
+= Display("op:%d addr:%x nc: %d idx: %x tag: %x way: %x",
1134 req_op
, r0
.req
.addr
, r0
.req
.nc
,
1135 req_index
, req_tag
, req_hit_way
)
1137 with m
.If(r0_valid
):
1138 sync
+= r1
.mmu_req
.eq(r0
.mmu_req
)
1140 # Fast path for load/store hits.
1141 # Set signals for the writeback controls.
1142 sync
+= r1
.hit_way
.eq(req_hit_way
)
1143 sync
+= r1
.hit_index
.eq(req_index
)
1145 with m
.If(req_op
== Op
.OP_LOAD_HIT
):
1146 sync
+= r1
.hit_load_valid
.eq(1)
1148 sync
+= r1
.hit_load_valid
.eq(0)
1150 with m
.If((req_op
== Op
.OP_LOAD_HIT
) |
(req_op
== Op
.OP_STORE_HIT
)):
1151 sync
+= r1
.cache_hit
.eq(1)
1153 sync
+= r1
.cache_hit
.eq(0)
1155 with m
.If(req_op
== Op
.OP_BAD
):
1156 # Display(f"Signalling ld/st error valid_ra={valid_ra}"
1157 # f"rc_ok={rc_ok} perm_ok={perm_ok}"
1158 sync
+= r1
.ls_error
.eq(~r0
.mmu_req
)
1159 sync
+= r1
.mmu_error
.eq(r0
.mmu_req
)
1160 sync
+= r1
.cache_paradox
.eq(access_ok
)
1163 sync
+= r1
.ls_error
.eq(0)
1164 sync
+= r1
.mmu_error
.eq(0)
1165 sync
+= r1
.cache_paradox
.eq(0)
1167 with m
.If(req_op
== Op
.OP_STCX_FAIL
):
1170 sync
+= r1
.stcx_fail
.eq(0)
1172 # Record TLB hit information for updating TLB PLRU
1173 sync
+= r1
.tlb_hit
.eq(tlb_hit
)
1174 sync
+= r1
.tlb_hit_way
.eq(tlb_hit_way
)
1175 sync
+= r1
.tlb_hit_index
.eq(tlb_req_index
)
1177 # Memory accesses are handled by this state machine:
1179 # * Cache load miss/reload (in conjunction with "rams")
1180 # * Load hits for non-cachable forms
1181 # * Stores (the collision case is handled in "rams")
1183 # All wishbone requests generation is done here.
1184 # This machine operates at stage 1.
1185 def dcache_slow(self
, m
, r1
, use_forward1_next
, use_forward2_next
,
1186 cache_valid_bits
, r0
, replace_way
,
1187 req_hit_way
, req_same_tag
,
1188 r0_valid
, req_op
, cache_tags
, req_go
, ra
):
1194 req
= MemAccessRequest("mreq_ds")
1196 adjust_acks
= Signal(3)
1198 sync
+= r1
.use_forward1
.eq(use_forward1_next
)
1199 sync
+= r1
.forward_sel
.eq(0)
1201 with m
.If(use_forward1_next
):
1202 sync
+= r1
.forward_sel
.eq(r1
.req
.byte_sel
)
1203 with m
.Elif(use_forward2_next
):
1204 sync
+= r1
.forward_sel
.eq(r1
.forward_sel1
)
1206 sync
+= r1
.forward_data2
.eq(r1
.forward_data1
)
1207 with m
.If(r1
.write_bram
):
1208 sync
+= r1
.forward_data1
.eq(r1
.req
.data
)
1209 sync
+= r1
.forward_sel1
.eq(r1
.req
.byte_sel
)
1210 sync
+= r1
.forward_way1
.eq(r1
.req
.hit_way
)
1211 sync
+= r1
.forward_row1
.eq(get_row(r1
.req
.real_addr
))
1212 sync
+= r1
.forward_valid1
.eq(1)
1215 sync
+= r1
.forward_data1
.eq(0)
1217 sync
+= r1
.forward_data1
.eq(wb_in
.dat
)
1218 sync
+= r1
.forward_sel1
.eq(~
0) # all 1s
1219 sync
+= r1
.forward_way1
.eq(replace_way
)
1220 sync
+= r1
.forward_row1
.eq(r1
.store_row
)
1221 sync
+= r1
.forward_valid1
.eq(0)
1223 # One cycle pulses reset
1224 sync
+= r1
.slow_valid
.eq(0)
1225 sync
+= r1
.write_bram
.eq(0)
1226 sync
+= r1
.inc_acks
.eq(0)
1227 sync
+= r1
.dec_acks
.eq(0)
1229 sync
+= r1
.ls_valid
.eq(0)
1230 # complete tlbies and TLB loads in the third cycle
1231 sync
+= r1
.mmu_done
.eq(r0_valid
& (r0
.tlbie | r0
.tlbld
))
1233 with m
.If((req_op
== Op
.OP_LOAD_HIT
)
1234 |
(req_op
== Op
.OP_STCX_FAIL
)):
1235 with m
.If(~r0
.mmu_req
):
1236 sync
+= r1
.ls_valid
.eq(1)
1238 sync
+= r1
.mmu_done
.eq(1)
1240 with m
.If(r1
.write_tag
):
1241 # Store new tag in selected way
1242 for i
in range(NUM_WAYS
):
1243 with m
.If(i
== replace_way
):
1244 ct
= Signal(TAG_RAM_WIDTH
)
1245 comb
+= ct
.eq(cache_tags
[r1
.store_index
])
1246 comb
+= ct
.word_select(i
, TAG_WIDTH
).eq(r1
.reload_tag
)
1247 sync
+= cache_tags
[r1
.store_index
].eq(ct
)
1248 sync
+= r1
.store_way
.eq(replace_way
)
1249 sync
+= r1
.write_tag
.eq(0)
1251 # Take request from r1.req if there is one there,
1252 # else from req_op, ra, etc.
1254 comb
+= req
.eq(r1
.req
)
1256 comb
+= req
.op
.eq(req_op
)
1257 comb
+= req
.valid
.eq(req_go
)
1258 comb
+= req
.mmu_req
.eq(r0
.mmu_req
)
1259 comb
+= req
.dcbz
.eq(r0
.req
.dcbz
)
1260 comb
+= req
.real_addr
.eq(ra
)
1262 with m
.If(~r0
.req
.dcbz
):
1263 comb
+= req
.data
.eq(r0
.req
.data
)
1265 comb
+= req
.data
.eq(0)
1267 # Select all bytes for dcbz
1268 # and for cacheable loads
1269 with m
.If(r0
.req
.dcbz |
(r0
.req
.load
& ~r0
.req
.nc
)):
1270 comb
+= req
.byte_sel
.eq(~
0) # all 1s
1272 comb
+= req
.byte_sel
.eq(r0
.req
.byte_sel
)
1273 comb
+= req
.hit_way
.eq(req_hit_way
)
1274 comb
+= req
.same_tag
.eq(req_same_tag
)
1276 # Store the incoming request from r0,
1277 # if it is a slow request
1278 # Note that r1.full = 1 implies req_op = OP_NONE
1279 with m
.If((req_op
== Op
.OP_LOAD_MISS
)
1280 |
(req_op
== Op
.OP_LOAD_NC
)
1281 |
(req_op
== Op
.OP_STORE_MISS
)
1282 |
(req_op
== Op
.OP_STORE_HIT
)):
1283 sync
+= r1
.req
.eq(req
)
1284 sync
+= r1
.full
.eq(1)
1286 # Main state machine
1287 with m
.Switch(r1
.state
):
1289 with m
.Case(State
.IDLE
):
1290 # XXX check 'left downto. probably means len(r1.wb.adr)
1291 # r1.wb.adr <= req.real_addr(
1292 # r1.wb.adr'left downto 0
1294 sync
+= r1
.wb
.adr
.eq(req
.real_addr
)
1295 sync
+= r1
.wb
.sel
.eq(req
.byte_sel
)
1296 sync
+= r1
.wb
.dat
.eq(req
.data
)
1297 sync
+= r1
.dcbz
.eq(req
.dcbz
)
1299 # Keep track of our index and way
1300 # for subsequent stores.
1301 sync
+= r1
.store_index
.eq(get_index(req
.real_addr
))
1302 sync
+= r1
.store_row
.eq(get_row(req
.real_addr
))
1303 sync
+= r1
.end_row_ix
.eq(
1304 get_row_of_line(get_row(req
.real_addr
))
1306 sync
+= r1
.reload_tag
.eq(get_tag(req
.real_addr
))
1307 sync
+= r1
.req
.same_tag
.eq(1)
1309 with m
.If(req
.op
== Op
.OP_STORE_HIT
):
1310 sync
+= r1
.store_way
.eq(req
.hit_way
)
1312 # Reset per-row valid bits,
1313 # ready for handling OP_LOAD_MISS
1314 for i
in range(ROW_PER_LINE
):
1315 sync
+= r1
.rows_valid
[i
].eq(0)
1317 with m
.If(req_op
!= Op
.OP_NONE
):
1318 sync
+= Display("cache op %d", req
.op
)
1320 with m
.Switch(req
.op
):
1321 with m
.Case(Op
.OP_LOAD_HIT
):
1322 # stay in IDLE state
1325 with m
.Case(Op
.OP_LOAD_MISS
):
1326 #Display(f"cache miss real addr:" \
1327 # f"{req_real_addr}" \
1328 # f" idx:{get_index(req_real_addr)}" \
1329 # f" tag:{get_tag(req.real_addr)}")
1332 # Start the wishbone cycle
1333 sync
+= r1
.wb
.we
.eq(0)
1334 sync
+= r1
.wb
.cyc
.eq(1)
1335 sync
+= r1
.wb
.stb
.eq(1)
1337 # Track that we had one request sent
1338 sync
+= r1
.state
.eq(State
.RELOAD_WAIT_ACK
)
1339 sync
+= r1
.write_tag
.eq(1)
1341 with m
.Case(Op
.OP_LOAD_NC
):
1342 sync
+= r1
.wb
.cyc
.eq(1)
1343 sync
+= r1
.wb
.stb
.eq(1)
1344 sync
+= r1
.wb
.we
.eq(0)
1345 sync
+= r1
.state
.eq(State
.NC_LOAD_WAIT_ACK
)
1347 with m
.Case(Op
.OP_STORE_HIT
, Op
.OP_STORE_MISS
):
1348 with m
.If(~req
.dcbz
):
1349 sync
+= r1
.state
.eq(State
.STORE_WAIT_ACK
)
1350 sync
+= r1
.acks_pending
.eq(1)
1351 sync
+= r1
.full
.eq(0)
1352 sync
+= r1
.slow_valid
.eq(1)
1354 with m
.If(~req
.mmu_req
):
1355 sync
+= r1
.ls_valid
.eq(1)
1357 sync
+= r1
.mmu_done
.eq(1)
1359 with m
.If(req
.op
== Op
.OP_STORE_HIT
):
1360 sync
+= r1
.write_bram
.eq(1)
1362 # dcbz is handled much like a load miss except
1363 # that we are writing to memory instead of reading
1364 sync
+= r1
.state
.eq(State
.RELOAD_WAIT_ACK
)
1366 with m
.If(req
.op
== Op
.OP_STORE_MISS
):
1367 sync
+= r1
.write_tag
.eq(1)
1369 sync
+= r1
.wb
.we
.eq(1)
1370 sync
+= r1
.wb
.cyc
.eq(1)
1371 sync
+= r1
.wb
.stb
.eq(1)
1373 # OP_NONE and OP_BAD do nothing
1374 # OP_BAD & OP_STCX_FAIL were
1375 # handled above already
1376 with m
.Case(Op
.OP_NONE
):
1378 with m
.Case(Op
.OP_BAD
):
1380 with m
.Case(Op
.OP_STCX_FAIL
):
1383 with m
.Case(State
.RELOAD_WAIT_ACK
):
1384 ld_stbs_done
= Signal()
1385 # Requests are all sent if stb is 0
1386 comb
+= ld_stbs_done
.eq(~r1
.wb
.stb
)
1388 with m
.If((~wb_in
.stall
) & r1
.wb
.stb
):
1389 # That was the last word?
1390 # We are done sending.
1391 # Clear stb and set ld_stbs_done
1392 # so we can handle an eventual
1393 # last ack on the same cycle.
1394 with m
.If(is_last_row_addr(r1
.wb
.adr
, r1
.end_row_ix
)):
1395 sync
+= r1
.wb
.stb
.eq(0)
1396 comb
+= ld_stbs_done
.eq(1)
1398 # Calculate the next row address in the current cache line
1399 rarange
= r1
.wb
.adr
[ROW_OFF_BITS
: LINE_OFF_BITS
]
1400 sync
+= rarange
.eq(rarange
+ 1)
1402 # Incoming acks processing
1403 sync
+= r1
.forward_valid1
.eq(wb_in
.ack
)
1404 with m
.If(wb_in
.ack
):
1405 sync
+= r1
.rows_valid
[r1
.store_row
% ROW_PER_LINE
].eq(1)
1407 # If this is the data we were looking for,
1408 # we can complete the request next cycle.
1409 # Compare the whole address in case the
1410 # request in r1.req is not the one that
1411 # started this refill.
1412 with m
.If(r1
.full
& r1
.req
.same_tag
&
1413 ((r1
.dcbz
& r1
.req
.dcbz
) |
1414 (~r1
.dcbz
& (r1
.req
.op
== Op
.OP_LOAD_MISS
))) &
1415 (r1
.store_row
== get_row(r1
.req
.real_addr
))):
1416 sync
+= r1
.full
.eq(0)
1417 sync
+= r1
.slow_valid
.eq(1)
1418 with m
.If(~r1
.mmu_req
):
1419 sync
+= r1
.ls_valid
.eq(1)
1421 sync
+= r1
.mmu_done
.eq(1)
1422 sync
+= r1
.forward_sel
.eq(~
0) # all 1s
1423 sync
+= r1
.use_forward1
.eq(1)
1425 # Check for completion
1426 with m
.If(ld_stbs_done
& is_last_row(r1
.store_row
,
1428 # Complete wishbone cycle
1429 sync
+= r1
.wb
.cyc
.eq(0)
1431 # Cache line is now valid
1432 cv
= Signal(INDEX_BITS
)
1433 sync
+= cv
.eq(cache_valid_bits
[r1
.store_index
])
1434 sync
+= cv
.bit_select(r1
.store_way
, 1).eq(1)
1435 sync
+= r1
.state
.eq(State
.IDLE
)
1437 # Increment store row counter
1438 sync
+= r1
.store_row
.eq(next_row(r1
.store_row
))
1440 with m
.Case(State
.STORE_WAIT_ACK
):
1441 st_stbs_done
= Signal()
1442 comb
+= st_stbs_done
.eq(~r1
.wb
.stb
)
1443 comb
+= acks
.eq(r1
.acks_pending
)
1445 with m
.If(r1
.inc_acks
!= r1
.dec_acks
):
1446 with m
.If(r1
.inc_acks
):
1447 comb
+= adjust_acks
.eq(acks
+ 1)
1449 comb
+= adjust_acks
.eq(acks
- 1)
1451 comb
+= adjust_acks
.eq(acks
)
1453 sync
+= r1
.acks_pending
.eq(adjust_acks
)
1455 # Clear stb when slave accepted request
1456 with m
.If(~wb_in
.stall
):
1457 # See if there is another store waiting
1458 # to be done which is in the same real page.
1459 with m
.If(req
.valid
):
1460 ra
= req
.real_addr
[0:SET_SIZE_BITS
]
1461 sync
+= r1
.wb
.adr
[0:SET_SIZE_BITS
].eq(ra
)
1462 sync
+= r1
.wb
.dat
.eq(req
.data
)
1463 sync
+= r1
.wb
.sel
.eq(req
.byte_sel
)
1465 with m
.Elif((adjust_acks
< 7) & req
.same_tag
&
1466 ((req
.op
== Op
.OP_STORE_MISS
)
1467 |
(req
.op
== Op
.OP_STORE_HIT
))):
1468 sync
+= r1
.wb
.stb
.eq(1)
1469 comb
+= st_stbs_done
.eq(0)
1471 with m
.If(req
.op
== Op
.OP_STORE_HIT
):
1472 sync
+= r1
.write_bram
.eq(1)
1473 sync
+= r1
.full
.eq(0)
1474 sync
+= r1
.slow_valid
.eq(1)
1476 # Store requests never come from the MMU
1477 sync
+= r1
.ls_valid
.eq(1)
1478 comb
+= st_stbs_done
.eq(0)
1479 sync
+= r1
.inc_acks
.eq(1)
1481 sync
+= r1
.wb
.stb
.eq(0)
1482 comb
+= st_stbs_done
.eq(1)
1484 # Got ack ? See if complete.
1485 with m
.If(wb_in
.ack
):
1486 with m
.If(st_stbs_done
& (adjust_acks
== 1)):
1487 sync
+= r1
.state
.eq(State
.IDLE
)
1488 sync
+= r1
.wb
.cyc
.eq(0)
1489 sync
+= r1
.wb
.stb
.eq(0)
1490 sync
+= r1
.dec_acks
.eq(1)
1492 with m
.Case(State
.NC_LOAD_WAIT_ACK
):
1493 # Clear stb when slave accepted request
1494 with m
.If(~wb_in
.stall
):
1495 sync
+= r1
.wb
.stb
.eq(0)
1497 # Got ack ? complete.
1498 with m
.If(wb_in
.ack
):
1499 sync
+= r1
.state
.eq(State
.IDLE
)
1500 sync
+= r1
.full
.eq(0)
1501 sync
+= r1
.slow_valid
.eq(1)
1503 with m
.If(~r1
.mmu_req
):
1504 sync
+= r1
.ls_valid
.eq(1)
1506 sync
+= r1
.mmu_done
.eq(1)
1508 sync
+= r1
.forward_sel
.eq(~
0) # all 1s
1509 sync
+= r1
.use_forward1
.eq(1)
1510 sync
+= r1
.wb
.cyc
.eq(0)
1511 sync
+= r1
.wb
.stb
.eq(0)
1513 def dcache_log(self
, m
, r1
, valid_ra
, tlb_hit_way
, stall_out
):
1516 d_out
, wb_in
, log_out
= self
.d_out
, self
.wb_in
, self
.log_out
1518 sync
+= log_out
.eq(Cat(r1
.state
[:3], valid_ra
, tlb_hit_way
[:3],
1519 stall_out
, req_op
[:3], d_out
.valid
, d_out
.error
,
1520 r1
.wb
.cyc
, r1
.wb
.stb
, wb_in
.ack
, wb_in
.stall
,
1523 def elaborate(self
, platform
):
1528 # Storage. Hopefully "cache_rows" is a BRAM, the rest is LUTs
1529 cache_tags
= CacheTagArray()
1530 cache_tag_set
= Signal(TAG_RAM_WIDTH
)
1531 cache_valid_bits
= CacheValidBitsArray()
1533 # TODO attribute ram_style : string;
1534 # TODO attribute ram_style of cache_tags : signal is "distributed";
1536 """note: these are passed to nmigen.hdl.Memory as "attributes".
1537 don't know how, just that they are.
1539 dtlb_valid_bits
= TLBValidBitsArray()
1540 dtlb_tags
= TLBTagsArray()
1541 dtlb_ptes
= TLBPtesArray()
1542 # TODO attribute ram_style of
1543 # dtlb_tags : signal is "distributed";
1544 # TODO attribute ram_style of
1545 # dtlb_ptes : signal is "distributed";
1547 r0
= RegStage0("r0")
1550 r1
= RegStage1("r1")
1552 reservation
= Reservation()
1554 # Async signals on incoming request
1555 req_index
= Signal(INDEX_BITS
)
1556 req_row
= Signal(ROW_BITS
)
1557 req_hit_way
= Signal(WAY_BITS
)
1558 req_tag
= Signal(TAG_BITS
)
1560 req_data
= Signal(64)
1561 req_same_tag
= Signal()
1564 early_req_row
= Signal(ROW_BITS
)
1566 cancel_store
= Signal()
1568 clear_rsrv
= Signal()
1573 use_forward1_next
= Signal()
1574 use_forward2_next
= Signal()
1576 cache_out
= CacheRamOut()
1578 plru_victim
= PLRUOut()
1579 replace_way
= Signal(WAY_BITS
)
1581 # Wishbone read/write/cache write formatting signals
1585 tlb_tag_way
= Signal(TLB_TAG_WAY_BITS
)
1586 tlb_pte_way
= Signal(TLB_PTE_WAY_BITS
)
1587 tlb_valid_way
= Signal(TLB_NUM_WAYS
)
1588 tlb_req_index
= Signal(TLB_SET_BITS
)
1590 tlb_hit_way
= Signal(TLB_WAY_BITS
)
1591 pte
= Signal(TLB_PTE_BITS
)
1592 ra
= Signal(REAL_ADDR_BITS
)
1594 perm_attr
= PermAttr("dc_perms")
1597 access_ok
= Signal()
1599 tlb_plru_victim
= TLBPLRUOut()
1601 # we don't yet handle collisions between loadstore1 requests
1603 comb
+= self
.m_out
.stall
.eq(0)
1605 # Hold off the request in r0 when r1 has an uncompleted request
1606 comb
+= r0_stall
.eq(r0_full
& r1
.full
)
1607 comb
+= r0_valid
.eq(r0_full
& ~r1
.full
)
1608 comb
+= self
.stall_out
.eq(r0_stall
)
1610 # Wire up wishbone request latch out of stage 1
1611 comb
+= self
.wb_out
.eq(r1
.wb
)
1613 # call sub-functions putting everything together, using shared
1614 # signals established above
1615 self
.stage_0(m
, r0
, r1
, r0_full
)
1616 self
.tlb_read(m
, r0_stall
, tlb_valid_way
,
1617 tlb_tag_way
, tlb_pte_way
, dtlb_valid_bits
,
1618 dtlb_tags
, dtlb_ptes
)
1619 self
.tlb_search(m
, tlb_req_index
, r0
, r0_valid
,
1620 tlb_valid_way
, tlb_tag_way
, tlb_hit_way
,
1621 tlb_pte_way
, pte
, tlb_hit
, valid_ra
, perm_attr
, ra
)
1622 self
.tlb_update(m
, r0_valid
, r0
, dtlb_valid_bits
, tlb_req_index
,
1623 tlb_hit_way
, tlb_hit
, tlb_plru_victim
, tlb_tag_way
,
1624 dtlb_tags
, tlb_pte_way
, dtlb_ptes
)
1625 self
.maybe_plrus(m
, r1
, plru_victim
)
1626 self
.maybe_tlb_plrus(m
, r1
, tlb_plru_victim
)
1627 self
.cache_tag_read(m
, r0_stall
, req_index
, cache_tag_set
, cache_tags
)
1628 self
.dcache_request(m
, r0
, ra
, req_index
, req_row
, req_tag
,
1629 r0_valid
, r1
, cache_valid_bits
, replace_way
,
1630 use_forward1_next
, use_forward2_next
,
1631 req_hit_way
, plru_victim
, rc_ok
, perm_attr
,
1632 valid_ra
, perm_ok
, access_ok
, req_op
, req_go
,
1634 tlb_hit
, tlb_hit_way
, tlb_valid_way
, cache_tag_set
,
1635 cancel_store
, req_same_tag
, r0_stall
, early_req_row
)
1636 self
.reservation_comb(m
, cancel_store
, set_rsrv
, clear_rsrv
,
1637 r0_valid
, r0
, reservation
)
1638 self
.reservation_reg(m
, r0_valid
, access_ok
, set_rsrv
, clear_rsrv
,
1640 self
.writeback_control(m
, r1
, cache_out
)
1641 self
.rams(m
, r1
, early_req_row
, cache_out
, replace_way
)
1642 self
.dcache_fast_hit(m
, req_op
, r0_valid
, r0
, r1
,
1643 req_hit_way
, req_index
, req_tag
, access_ok
,
1644 tlb_hit
, tlb_hit_way
, tlb_req_index
)
1645 self
.dcache_slow(m
, r1
, use_forward1_next
, use_forward2_next
,
1646 cache_valid_bits
, r0
, replace_way
,
1647 req_hit_way
, req_same_tag
,
1648 r0_valid
, req_op
, cache_tags
, req_go
, ra
)
1649 #self.dcache_log(m, r1, valid_ra, tlb_hit_way, stall_out)
1653 def dcache_load(dut
, addr
, nc
=0):
1654 yield dut
.d_in
.load
.eq(1)
1655 yield dut
.d_in
.nc
.eq(nc
)
1656 yield dut
.d_in
.addr
.eq(addr
)
1657 yield dut
.d_in
.valid
.eq(1)
1659 yield dut
.d_in
.valid
.eq(0)
1661 while not (yield dut
.d_out
.valid
):
1663 data
= yield dut
.d_out
.data
1667 def dcache_store(dut
, addr
, data
, nc
=0):
1668 yield dut
.d_in
.load
.eq(0)
1669 yield dut
.d_in
.nc
.eq(nc
)
1670 yield dut
.d_in
.data
.eq(data
)
1671 yield dut
.d_in
.byte_sel
.eq(~
0)
1672 yield dut
.d_in
.addr
.eq(addr
)
1673 yield dut
.d_in
.valid
.eq(1)
1675 yield dut
.d_in
.valid
.eq(0)
1676 yield dut
.d_in
.byte_sel
.eq(0)
1678 while not (yield dut
.d_out
.valid
):
1682 def dcache_sim(dut
):
1684 yield dut
.d_in
.valid
.eq(0)
1685 yield dut
.d_in
.load
.eq(0)
1686 yield dut
.d_in
.priv_mode
.eq(1)
1687 yield dut
.d_in
.nc
.eq(0)
1688 yield dut
.d_in
.addr
.eq(0)
1689 yield dut
.d_in
.data
.eq(0)
1690 yield dut
.m_in
.valid
.eq(0)
1691 yield dut
.m_in
.addr
.eq(0)
1692 yield dut
.m_in
.pte
.eq(0)
1693 # wait 4 * clk_period
1699 # Cacheable read of address 4
1700 data
= yield from dcache_load(dut
, 0x4)
1701 addr
= yield dut
.d_in
.addr
1702 assert data
== 0x0000000100000000, \
1703 f
"data @%x=%x expected 0x0000000100000000" % (addr
, data
)
1705 # Cacheable read of address 30
1706 data
= yield from dcache_load(dut
, 0x530)
1707 addr
= yield dut
.d_in
.addr
1708 assert data
== 0x0000004D0000004C, \
1709 f
"data @%x=%x expected 0000004D0000004C" % (addr
, data
)
1711 # 2nd Cacheable read of address 30
1712 data
= yield from dcache_load(dut
, 0x530)
1713 addr
= yield dut
.d_in
.addr
1714 assert data
== 0x0000004D0000004C, \
1715 f
"data @%x=%x expected 0000004D0000004C" % (addr
, data
)
1717 # Non-cacheable read of address 100
1718 data
= yield from dcache_load(dut
, 0x100, nc
=1)
1719 addr
= yield dut
.d_in
.addr
1720 assert data
== 0x0000004100000040, \
1721 f
"data @%x=%x expected 0000004100000040" % (addr
, data
)
1723 # Store at address 530
1724 yield from dcache_store(dut
, 0x530, 0x121)
1726 # Store at address 30
1727 yield from dcache_store(dut
, 0x530, 0x12345678)
1729 # 3nd Cacheable read of address 530
1730 data
= yield from dcache_load(dut
, 0x530)
1731 addr
= yield dut
.d_in
.addr
1732 assert data
== 0x12345678, \
1733 f
"data @%x=%x expected 0x12345678" % (addr
, data
)
1743 vl
= rtlil
.convert(dut
, ports
=[])
1744 with
open("test_dcache.il", "w") as f
:
1748 for i
in range(0,128):
1749 mem
.append((i
*2)|
((i
*2+1)<<32))
1750 memory
= Memory(width
=64, depth
=16*8, init
=mem
)
1751 sram
= SRAM(memory
=memory
, granularity
=8)
1754 m
.submodules
.dcache
= dut
1755 m
.submodules
.sram
= sram
1757 m
.d
.comb
+= sram
.bus
.cyc
.eq(dut
.wb_out
.cyc
)
1758 m
.d
.comb
+= sram
.bus
.stb
.eq(dut
.wb_out
.stb
)
1759 m
.d
.comb
+= sram
.bus
.we
.eq(dut
.wb_out
.we
)
1760 m
.d
.comb
+= sram
.bus
.sel
.eq(dut
.wb_out
.sel
)
1761 m
.d
.comb
+= sram
.bus
.adr
.eq(dut
.wb_out
.adr
[3:])
1762 m
.d
.comb
+= sram
.bus
.dat_w
.eq(dut
.wb_out
.dat
)
1764 m
.d
.comb
+= dut
.wb_in
.ack
.eq(sram
.bus
.ack
)
1765 m
.d
.comb
+= dut
.wb_in
.dat
.eq(sram
.bus
.dat_r
)
1771 sim
.add_sync_process(wrap(dcache_sim(dut
)))
1772 with sim
.write_vcd('test_dcache.vcd'):
1775 if __name__
== '__main__':