1 """LOAD / STORE Computation Unit.
3 This module covers POWER9-compliant Load and Store operations,
4 with selection on each between immediate and indexed mode as
5 options for the calculation of the Effective Address (EA),
6 and also "update" mode which optionally stores that EA into
7 an additional register.
10 Note: it took 15 attempts over several weeks to redraw the diagram
11 needed to capture this FSM properly. To understand it fully, please
12 take the time to review the links, video, and diagram.
15 Stores are activated when Go_Store is enabled, and use a sync'd "ADD" to
16 compute the "Effective Address", and, when ready the operand (src3_i)
17 is stored in the computed address (passed through to the PortInterface)
19 Loads are activated when Go_Write[0] is enabled. The EA is computed,
20 and (as long as there was no exception) the data comes out (at any
21 time from the PortInterface), and is captured by the LDCompSTUnit.
23 TODO: dcbz, yes, that's going to be complicated, has to be done
24 with great care, to detect the case when dcbz is set
25 and *not* expect to read any data, just the address.
26 so, wait for RA but not RB.
28 Both LD and ST may request that the address be computed from summing
29 operand1 (src[0]) with operand2 (src[1]) *or* by summing operand1 with
30 the immediate (from the opcode).
32 Both LD and ST may also request "update" mode (op_is_update) which
33 activates the use of Go_Write[1] to control storage of the EA into
34 a *second* operand in the register file.
36 Thus this module has *TWO* write-requests to the register file and
37 *THREE* read-requests to the register file (not all at the same time!)
38 The regfile port usage is:
50 It's a multi-level Finite State Machine that (unfortunately) nmigen.FSM
51 is not suited to (nmigen.FSM is clock-driven, and some aspects of
52 the nested FSMs below are *combinatorial*).
54 * One FSM covers Operand collection and communication address-side
55 with the LD/ST PortInterface. its role ends when "RD_DONE" is asserted
57 * A second FSM activates to cover LD. it activates if op_is_ld is true
59 * A third FSM activates to cover ST. it activates if op_is_st is true
61 * TODO document DCBZ (not complete yet)
63 * The "overall" (fourth) FSM coordinates the progression and completion
64 of the three other FSMs, firing "WR_RESET" which switches off "busy"
68 https://libre-soc.org/3d_gpu/ld_st_comp_unit.jpg
70 Links including to walk-through videos:
72 * https://libre-soc.org/3d_gpu/architecture/6600scoreboard/
73 * http://libre-soc.org/openpower/isa/fixedload
74 * http://libre-soc.org/openpower/isa/fixedstore
78 * https://bugs.libre-soc.org/show_bug.cgi?id=302
79 * https://bugs.libre-soc.org/show_bug.cgi?id=216
83 * EA - Effective Address
88 from nmigen
.compat
.sim
import run_simulation
89 from nmigen
.cli
import verilog
, rtlil
90 from nmigen
import Module
, Signal
, Mux
, Cat
, Elaboratable
, Array
, Repl
91 from nmigen
.hdl
.rec
import Record
, Layout
93 from nmutil
.latch
import SRLatch
, latchregister
94 from nmutil
.byterev
import byte_reverse
95 from nmutil
.extend
import exts
97 from soc
.experiment
.compalu_multi
import go_record
, CompUnitRecord
98 from soc
.experiment
.l0_cache
import PortInterface
99 from soc
.experiment
.pimem
import LDSTException
100 from soc
.fu
.regspec
import RegSpecAPI
102 from openpower
.decoder
.power_enums
import MicrOp
, Function
, LDSTMode
103 from soc
.fu
.ldst
.ldst_input_record
import CompLDSTOpSubset
104 from openpower
.decoder
.power_decoder2
import Data
105 from openpower
.consts
import MSR
106 from soc
.config
.test
.test_loadstore
import TestMemPspec
109 from nmutil
.util
import Display
112 # TODO: LDSTInputData and LDSTOutputData really should be used
113 # here, to make things more like the other CompUnits. currently,
114 # also, RegSpecAPI is used explicitly here
117 class LDSTCompUnitRecord(CompUnitRecord
):
118 def __init__(self
, rwid
, opsubset
=CompLDSTOpSubset
, name
=None):
119 CompUnitRecord
.__init
__(self
, opsubset
, rwid
,
120 n_src
=3, n_dst
=2, name
=name
)
122 self
.ad
= go_record(1, name
="cu_ad") # address go in, req out
123 self
.st
= go_record(1, name
="cu_st") # store go in, req out
125 self
.exc_o
= LDSTException("exc_o")
127 self
.ld_o
= Signal(reset_less
=True) # operation is a LD
128 self
.st_o
= Signal(reset_less
=True) # operation is a ST
130 # hmm... are these necessary?
131 self
.load_mem_o
= Signal(reset_less
=True) # activate memory LOAD
132 self
.stwd_mem_o
= Signal(reset_less
=True) # activate memory STORE
135 class LDSTCompUnit(RegSpecAPI
, Elaboratable
):
136 """LOAD / STORE Computation Unit
141 * :pi: a PortInterface to the memory subsystem (read-write capable)
142 * :rwid: register width
143 * :awid: address width
147 * :src_i: Source Operands (RA/RB/RC) - managed by rd[0-3] go/req
151 * :o_data: Dest out (LD) - managed by wr[0] go/req
152 * :addr_o: Address out (LD or ST) - managed by wr[1] go/req
153 * :exc_o: Address/Data Exception occurred. LD/ST must terminate
155 TODO: make exc_o a data-type rather than a single-bit signal
161 * :oper_i: operation being carried out (POWER9 decode LD/ST subset)
162 * :issue_i: LD/ST is being "issued".
163 * :shadown_i: Inverted-shadow is being held (stops STORE *and* WRITE)
164 * :go_rd_i: read is being actioned (latches in src regs)
165 * :go_wr_i: write mode (exactly like ALU CompUnit)
166 * :go_ad_i: address is being actioned (triggers actual mem LD)
167 * :go_st_i: store is being actioned (triggers actual mem STORE)
168 * :go_die_i: resets the unit back to "wait for issue"
170 Control Signals (Out)
171 ---------------------
173 * :busy_o: function unit is busy
174 * :rd_rel_o: request src1/src2
175 * :adr_rel_o: request address (from mem)
176 * :sto_rel_o: request store (to mem)
177 * :req_rel_o: request write (result)
178 * :load_mem_o: activate memory LOAD
179 * :stwd_mem_o: activate memory STORE
181 Note: load_mem_o, stwd_mem_o and req_rel_o MUST all be acknowledged
182 in a single cycle and the CompUnit set back to doing another op.
183 This means deasserting go_st_i, go_ad_i or go_wr_i as appropriate
184 depending on whether the operation is a ST or LD.
186 Note: LDSTCompUnit takes care of LE/BE normalisation:
187 * LD data is normalised after receipt from the PortInterface
188 * ST data is normalised *prior* to sending onto the PortInterface
189 TODO: use one module for the byte-reverse as it's quite expensive in gates
192 def __init__(self
, pi
=None, rwid
=64, awid
=48, opsubset
=CompLDSTOpSubset
,
193 debugtest
=False, name
=None):
194 super().__init
__(rwid
)
197 self
.cu
= cu
= LDSTCompUnitRecord(rwid
, opsubset
, name
=name
)
198 self
.debugtest
= debugtest
# enable debug output for unit testing
200 # POWER-compliant LD/ST has index and update: *fixed* number of ports
201 self
.n_src
= n_src
= 3 # RA, RB, RT/RS
202 self
.n_dst
= n_dst
= 2 # RA, RT/RS
204 # set up array of src and dest signals
205 for i
in range(n_src
):
206 j
= i
+ 1 # name numbering to match src1/src2
208 setattr(self
, name
, getattr(cu
, name
))
211 for i
in range(n_dst
):
212 j
= i
+ 1 # name numbering to match dest1/2...
213 name
= "dest%d_o" % j
214 setattr(self
, name
, getattr(cu
, name
))
219 self
.rdmaskn
= cu
.rdmaskn
220 self
.wrmask
= cu
.wrmask
225 # HACK: get data width from dest[0]. this is used across the board
226 # (it really shouldn't be)
227 self
.data_wid
= self
.dest
[0].shape()
229 self
.go_rd_i
= self
.rd
.go_i
# temporary naming
230 self
.go_wr_i
= self
.wr
.go_i
# temporary naming
231 self
.go_ad_i
= self
.ad
.go_i
# temp naming: go address in
232 self
.go_st_i
= self
.st
.go_i
# temp naming: go store in
234 self
.rd_rel_o
= self
.rd
.rel_o
# temporary naming
235 self
.req_rel_o
= self
.wr
.rel_o
# temporary naming
236 self
.adr_rel_o
= self
.ad
.rel_o
# request address (from mem)
237 self
.sto_rel_o
= self
.st
.rel_o
# request store (to mem)
239 self
.issue_i
= cu
.issue_i
240 self
.shadown_i
= cu
.shadown_i
241 self
.go_die_i
= cu
.go_die_i
243 self
.oper_i
= cu
.oper_i
244 self
.src_i
= cu
._src
_i
246 self
.o_data
= Data(self
.data_wid
, name
="o") # Dest1 out: RT
247 self
.addr_o
= Data(self
.data_wid
, name
="ea") # Addr out: Update => RA
248 self
.exc_o
= cu
.exc_o
249 self
.done_o
= cu
.done_o
250 self
.busy_o
= cu
.busy_o
255 self
.load_mem_o
= cu
.load_mem_o
256 self
.stwd_mem_o
= cu
.stwd_mem_o
258 def elaborate(self
, platform
):
264 issue_i
= self
.issue_i
266 #####################
267 # latches for the FSM.
268 m
.submodules
.opc_l
= opc_l
= SRLatch(sync
=False, name
="opc")
269 m
.submodules
.src_l
= src_l
= SRLatch(False, self
.n_src
, name
="src")
270 m
.submodules
.alu_l
= alu_l
= SRLatch(sync
=False, name
="alu")
271 m
.submodules
.adr_l
= adr_l
= SRLatch(sync
=False, name
="adr")
272 m
.submodules
.lod_l
= lod_l
= SRLatch(sync
=False, name
="lod")
273 m
.submodules
.sto_l
= sto_l
= SRLatch(sync
=False, name
="sto")
274 m
.submodules
.wri_l
= wri_l
= SRLatch(sync
=False, name
="wri")
275 m
.submodules
.upd_l
= upd_l
= SRLatch(sync
=False, name
="upd")
276 m
.submodules
.rst_l
= rst_l
= SRLatch(sync
=False, name
="rst")
277 m
.submodules
.lsd_l
= lsd_l
= SRLatch(sync
=False, name
="lsd") # done
283 op_is_ld
= Signal(reset_less
=True)
284 op_is_st
= Signal(reset_less
=True)
285 op_is_dcbz
= Signal(reset_less
=True)
286 op_is_st_or_dcbz
= Signal(reset_less
=True)
288 # ALU/LD data output control
289 alu_valid
= Signal(reset_less
=True) # ALU operands are valid
290 alu_ok
= Signal(reset_less
=True) # ALU out ok (1 clock delay valid)
291 addr_ok
= Signal(reset_less
=True) # addr ok (from PortInterface)
292 ld_ok
= Signal(reset_less
=True) # LD out ok from PortInterface
293 wr_any
= Signal(reset_less
=True) # any write (incl. store)
294 rda_any
= Signal(reset_less
=True) # any read for address ops
295 rd_done
= Signal(reset_less
=True) # all *necessary* operands read
296 wr_reset
= Signal(reset_less
=True) # final reset condition
297 canceln
= Signal(reset_less
=True) # cancel (active low)
300 alu_o
= Signal(self
.data_wid
, reset_less
=True)
301 ldd_o
= Signal(self
.data_wid
, reset_less
=True)
303 ##############################
304 # reset conditions for latches
306 # temporaries (also convenient when debugging)
307 reset_o
= Signal(reset_less
=True) # reset opcode
308 reset_w
= Signal(reset_less
=True) # reset write
309 reset_u
= Signal(reset_less
=True) # reset update
310 reset_a
= Signal(reset_less
=True) # reset adr latch
311 reset_i
= Signal(reset_less
=True) # issue|die (use a lot)
312 reset_r
= Signal(self
.n_src
, reset_less
=True) # reset src
313 reset_s
= Signal(reset_less
=True) # reset store
315 # end execution when a terminating condition is detected:
316 # - go_die_i: a speculative operation was cancelled
317 # - exc_o.happened: an exception has occurred
319 comb
+= terminate
.eq(self
.go_die_i | self
.exc_o
.happened
)
321 comb
+= reset_i
.eq(issue_i | terminate
) # various
322 comb
+= reset_o
.eq(self
.done_o | terminate
) # opcode reset
323 comb
+= reset_w
.eq(self
.wr
.go_i
[0] | terminate
) # write reg 1
324 comb
+= reset_u
.eq(self
.wr
.go_i
[1] | terminate
) # update (reg 2)
325 comb
+= reset_s
.eq(self
.go_st_i | terminate
) # store reset
326 comb
+= reset_r
.eq(self
.rd
.go_i |
Repl(terminate
, self
.n_src
))
327 comb
+= reset_a
.eq(self
.go_ad_i | terminate
)
329 p_st_go
= Signal(reset_less
=True)
330 sync
+= p_st_go
.eq(self
.st
.go_i
)
332 # decode bits of operand (latched)
333 oper_r
= CompLDSTOpSubset(name
="oper_r") # Dest register
334 comb
+= op_is_st
.eq(oper_r
.insn_type
== MicrOp
.OP_STORE
) # ST
335 comb
+= op_is_ld
.eq(oper_r
.insn_type
== MicrOp
.OP_LOAD
) # LD
336 comb
+= op_is_dcbz
.eq(oper_r
.insn_type
== MicrOp
.OP_DCBZ
) # DCBZ
337 comb
+= op_is_st_or_dcbz
.eq(op_is_st | op_is_dcbz
)
338 # dcbz is special case of store
340 #comb += Display("compldst_multi: op_is_dcbz = %i",
341 # (oper_r.insn_type == MicrOp.OP_DCBZ))
342 op_is_update
= oper_r
.ldst_mode
== LDSTMode
.update
# UPDATE
343 op_is_cix
= oper_r
.ldst_mode
== LDSTMode
.cix
# cache-inhibit
344 comb
+= self
.load_mem_o
.eq(op_is_ld
& self
.go_ad_i
)
345 comb
+= self
.stwd_mem_o
.eq(op_is_st
& self
.go_st_i
)
346 comb
+= self
.ld_o
.eq(op_is_ld
)
347 comb
+= self
.st_o
.eq(op_is_st
)
349 ##########################
350 # FSM implemented through sequence of latches. approximately this:
352 # - src_l[0] : operands
354 # - alu_l : looks after add of src1/2/imm (EA)
355 # - adr_l : waits for add (EA)
356 # - upd_l : waits for adr and Regfile (port 2)
358 # - lod_l : waits for adr (EA) and for LD Data
359 # - wri_l : waits for LD Data and Regfile (port 1)
360 # - st_l : waits for alu and operand2
361 # - rst_l : waits for all FSM paths to converge.
362 # NOTE: use sync to stop combinatorial loops.
364 # opcode latch - inverted so that busy resets to 0
365 # note this MUST be sync so as to avoid a combinatorial loop
366 # between busy_o and issue_i on the reset latch (rst_l)
367 sync
+= opc_l
.s
.eq(issue_i
) # XXX NOTE: INVERTED FROM book!
368 sync
+= opc_l
.r
.eq(reset_o
) # XXX NOTE: INVERTED FROM book!
371 sync
+= src_l
.s
.eq(Repl(issue_i
, self
.n_src
) & ~self
.rdmaskn
)
372 sync
+= src_l
.r
.eq(reset_r
)
373 #### sync += Display("reset_r = %i",reset_r)
375 # alu latch. use sync-delay between alu_ok and valid to generate pulse
376 comb
+= alu_l
.s
.eq(reset_i
)
377 comb
+= alu_l
.r
.eq(alu_ok
& ~alu_valid
& ~rda_any
)
380 comb
+= adr_l
.s
.eq(reset_i
)
381 sync
+= adr_l
.r
.eq(reset_a
)
384 comb
+= lod_l
.s
.eq(reset_i
)
385 comb
+= lod_l
.r
.eq(ld_ok
)
388 comb
+= wri_l
.s
.eq(issue_i
)
389 sync
+= wri_l
.r
.eq(reset_w |
Repl(wr_reset |
390 (~self
.pi
.busy_o
& op_is_update
),
391 #(self.pi.busy_o & op_is_update),
392 #self.done_o | (self.pi.busy_o & op_is_update),
395 # update-mode operand latch (EA written to reg 2)
396 sync
+= upd_l
.s
.eq(reset_i
)
397 sync
+= upd_l
.r
.eq(reset_u
)
400 comb
+= sto_l
.s
.eq(addr_ok
& op_is_st_or_dcbz
)
401 sync
+= sto_l
.r
.eq(reset_s | p_st_go
)
403 # ld/st done. needed to stop LD/ST from activating repeatedly
404 comb
+= lsd_l
.s
.eq(issue_i
)
405 sync
+= lsd_l
.r
.eq(reset_s | p_st_go | ld_ok
)
408 comb
+= rst_l
.s
.eq(addr_ok
) # start when address is ready
409 comb
+= rst_l
.r
.eq(issue_i
)
411 # create a latch/register for the operand
412 with m
.If(self
.issue_i
):
413 sync
+= oper_r
.eq(self
.oper_i
)
414 with m
.If(self
.done_o | terminate
):
418 ldd_r
= Signal(self
.data_wid
, reset_less
=True) # Dest register
419 latchregister(m
, ldd_o
, ldd_r
, ld_ok
, name
="ldo_r")
421 # and for each input from the incoming src operands
423 for i
in range(self
.n_src
):
425 src_r
= Signal(self
.data_wid
, name
=name
, reset_less
=True)
426 with m
.If(self
.rd
.go_i
[i
]):
427 sync
+= src_r
.eq(self
.src_i
[i
])
428 with m
.If(self
.issue_i
):
432 # and one for the output from the ADD (for the EA)
433 addr_r
= Signal(self
.data_wid
, reset_less
=True) # Effective Address
434 latchregister(m
, alu_o
, addr_r
, alu_l
.q
, "ea_r")
436 # select either zero or src1 if opcode says so
437 op_is_z
= oper_r
.zero_a
438 src1_or_z
= Signal(self
.data_wid
, reset_less
=True)
439 m
.d
.comb
+= src1_or_z
.eq(Mux(op_is_z
, 0, srl
[0]))
441 # select either immediate or src2 if opcode says so
442 op_is_imm
= oper_r
.imm_data
.ok
443 src2_or_imm
= Signal(self
.data_wid
, reset_less
=True)
444 m
.d
.comb
+= src2_or_imm
.eq(Mux(op_is_imm
, oper_r
.imm_data
.data
, srl
[1]))
446 # now do the ALU addr add: one cycle, and say "ready" (next cycle, too)
447 comb
+= alu_o
.eq(src1_or_z
+ src2_or_imm
) # actual EA
448 m
.d
.sync
+= alu_ok
.eq(alu_valid
& canceln
) # keep ack in sync with EA
450 ############################
451 # Control Signal calculation
455 comb
+= self
.busy_o
.eq(opc_l
.q
) # | self.pi.busy_o) # busy out
457 # 1st operand read-request only when zero not active
458 # 2nd operand only needed when immediate is not active
459 slg
= Cat(op_is_z
, op_is_imm
) #is this correct ?
460 bro
= Repl(self
.busy_o
, self
.n_src
)
461 comb
+= self
.rd
.rel_o
.eq(src_l
.q
& bro
& ~slg
)
463 # note when the address-related read "go" signals are active
464 comb
+= rda_any
.eq(self
.rd
.go_i
[0] | self
.rd
.go_i
[1])
466 # alu input valid when 1st and 2nd ops done (or imm not active)
467 comb
+= alu_valid
.eq(busy_o
& ~
(self
.rd
.rel_o
[0] | self
.rd
.rel_o
[1]) &
470 # 3rd operand only needed when operation is a store
471 comb
+= self
.rd
.rel_o
[2].eq(src_l
.q
[2] & busy_o
& op_is_st
)
473 # all reads done when alu is valid and 3rd operand needed
474 comb
+= rd_done
.eq(alu_valid
& ~self
.rd
.rel_o
[2])
476 # address release only if addr ready, but Port must be idle
477 comb
+= self
.adr_rel_o
.eq(alu_valid
& adr_l
.q
& busy_o
)
479 # the write/store (etc) all must be cancelled if an exception occurs
480 # note: cancel is active low, like shadown_i,
481 # while exc_o.happpened is active high
482 comb
+= canceln
.eq(~self
.exc_o
.happened
& self
.shadown_i
)
484 # store release when st ready *and* all operands read (and no shadow)
485 # dcbz is special case of store -- TODO verify shadows
486 comb
+= self
.st
.rel_o
.eq(sto_l
.q
& busy_o
& rd_done
& op_is_st_or_dcbz
&
489 # request write of LD result. waits until shadow is dropped.
490 comb
+= self
.wr
.rel_o
[0].eq(rd_done
& wri_l
.q
& busy_o
& lod_l
.qn
&
493 # request write of EA result only in update mode
494 comb
+= self
.wr
.rel_o
[1].eq(upd_l
.q
& busy_o
& op_is_update
&
497 # provide "done" signal: select req_rel for non-LD/ST, adr_rel for LD/ST
498 comb
+= wr_any
.eq(self
.st
.go_i | p_st_go |
499 self
.wr
.go_i
[0] | self
.wr
.go_i
[1])
500 comb
+= wr_reset
.eq(rst_l
.q
& busy_o
& canceln
&
501 ~
(self
.st
.rel_o | self
.wr
.rel_o
[0] |
503 (lod_l
.qn | op_is_st_or_dcbz
)
505 comb
+= self
.done_o
.eq(wr_reset
& (~self
.pi
.busy_o | op_is_ld
))
507 ######################
508 # Data/Address outputs
510 # put the LD-output register directly onto the output bus on a go_write
511 comb
+= self
.o_data
.data
.eq(self
.dest
[0])
512 with m
.If(self
.wr
.go_i
[0]):
513 comb
+= self
.dest
[0].eq(ldd_r
)
515 # "update" mode, put address out on 2nd go-write
516 comb
+= self
.addr_o
.data
.eq(self
.dest
[1])
517 with m
.If(op_is_update
& self
.wr
.go_i
[1]):
518 comb
+= self
.dest
[1].eq(addr_r
)
520 # need to look like MultiCompUnit: put wrmask out.
521 # XXX may need to make this enable only when write active
522 comb
+= self
.wrmask
.eq(bro
& Cat(op_is_ld
, op_is_update
))
524 ###########################
525 # PortInterface connections
528 # connect to LD/ST PortInterface.
529 comb
+= pi
.is_ld_i
.eq(op_is_ld
& busy_o
) # decoded-LD
530 comb
+= pi
.is_st_i
.eq(op_is_st_or_dcbz
& busy_o
) # decoded-ST
531 comb
+= pi
.is_dcbz_i
.eq(op_is_dcbz
& busy_o
) # decoded-DCBZ
532 comb
+= pi
.data_len
.eq(oper_r
.data_len
) # data_len
533 # address: use sync to avoid long latency
534 sync
+= pi
.addr
.data
.eq(addr_r
) # EA from adder
535 with m
.If(op_is_dcbz
):
536 sync
+= Display("LDSTCompUnit.DCBZ: EA from adder %x", addr_r
)
538 sync
+= pi
.addr
.ok
.eq(alu_ok
& lsd_l
.q
) # "do address stuff" (once)
539 comb
+= self
.exc_o
.eq(pi
.exc_o
) # exception occurred
540 comb
+= addr_ok
.eq(self
.pi
.addr_ok_o
) # no exc, address fine
541 # connect MSR.PR for priv/virt operation
542 comb
+= pi
.msr_pr
.eq(oper_r
.msr
[MSR
.PR
])
543 comb
+= Display("LDSTCompUnit: oper_r.msr %x pi.msr_pr=%x",
544 oper_r
.msr
, oper_r
.msr
[MSR
.PR
])
547 revnorev
= Signal(64, reset_less
=True)
548 with m
.If(oper_r
.byte_reverse
):
549 # byte-reverse the data based on ld/st width (turn it to LE)
550 data_len
= oper_r
.data_len
551 lddata_r
= byte_reverse(m
, 'lddata_r', pi
.ld
.data
, data_len
)
552 comb
+= revnorev
.eq(lddata_r
) # put reversed- data out
554 comb
+= revnorev
.eq(pi
.ld
.data
) # put data out, straight (as BE)
556 # then check sign-extend
557 with m
.If(oper_r
.sign_extend
):
558 # okok really should "if data_len == 4" and so on here
559 with m
.If(oper_r
.data_len
== 2):
560 comb
+= ldd_o
.eq(exts(revnorev
, 16, 64)) # sign-extend hword
562 comb
+= ldd_o
.eq(exts(revnorev
, 32, 64)) # sign-extend dword
564 comb
+= ldd_o
.eq(revnorev
)
566 # ld - ld gets latched in via lod_l
567 comb
+= ld_ok
.eq(pi
.ld
.ok
) # ld.ok *closes* (freezes) ld data
570 op3
= srl
[2] # 3rd operand latch
571 with m
.If(oper_r
.byte_reverse
):
572 # byte-reverse the data based on width
573 data_len
= oper_r
.data_len
574 stdata_r
= byte_reverse(m
, 'stdata_r', op3
, data_len
)
575 comb
+= pi
.st
.data
.eq(stdata_r
)
577 comb
+= pi
.st
.data
.eq(op3
)
578 # store - data goes in based on go_st
579 comb
+= pi
.st
.ok
.eq(self
.st
.go_i
) # go store signals st data valid
583 def get_out(self
, i
):
584 """make LDSTCompUnit look like RegSpecALUAPI. these correspond
585 to LDSTOutputData o and o1 respectively.
588 return self
.o_data
# LDSTOutputData.regspec o
590 return self
.addr_o
# LDSTOutputData.regspec o1
591 # return self.dest[i]
593 def get_fu_out(self
, i
):
594 return self
.get_out(i
)
604 yield from self
.oper_i
.ports()
605 yield from self
.src_i
611 yield from self
.o_data
.ports()
612 yield from self
.addr_o
.ports()
613 yield self
.load_mem_o
614 yield self
.stwd_mem_o
620 def wait_for(sig
, wait
=True, test1st
=False):
622 print("wait for", sig
, v
, wait
, test1st
)
623 if test1st
and bool(v
) == wait
:
628 #print("...wait for", sig, v)
633 def store(dut
, src1
, src2
, src3
, imm
, imm_ok
=True, update
=False,
635 print("ST", src1
, src2
, src3
, imm
, imm_ok
, update
)
636 yield dut
.oper_i
.insn_type
.eq(MicrOp
.OP_STORE
)
637 yield dut
.oper_i
.data_len
.eq(2) # half-word
638 yield dut
.oper_i
.byte_reverse
.eq(byterev
)
639 yield dut
.src1_i
.eq(src1
)
640 yield dut
.src2_i
.eq(src2
)
641 yield dut
.src3_i
.eq(src3
)
642 yield dut
.oper_i
.imm_data
.data
.eq(imm
)
643 yield dut
.oper_i
.imm_data
.ok
.eq(imm_ok
)
644 #guess: this one was removed -- yield dut.oper_i.update.eq(update)
645 yield dut
.issue_i
.eq(1)
647 yield dut
.issue_i
.eq(0)
653 # wait for all active rel signals to come up
655 rel
= yield dut
.rd
.rel_o
656 if rel
== active_rel
:
659 yield dut
.rd
.go_i
.eq(active_rel
)
661 yield dut
.rd
.go_i
.eq(0)
663 yield from wait_for(dut
.adr_rel_o
, False, test1st
=True)
664 # yield from wait_for(dut.adr_rel_o)
665 # yield dut.ad.go.eq(1)
667 # yield dut.ad.go.eq(0)
670 yield from wait_for(dut
.wr
.rel_o
[1])
671 yield dut
.wr
.go
.eq(0b10)
673 addr
= yield dut
.addr_o
675 yield dut
.wr
.go
.eq(0)
679 yield from wait_for(dut
.sto_rel_o
)
680 yield dut
.go_st_i
.eq(1)
682 yield dut
.go_st_i
.eq(0)
683 yield from wait_for(dut
.busy_o
, False)
684 # wait_for(dut.stwd_mem_o)
689 def load(dut
, src1
, src2
, imm
, imm_ok
=True, update
=False, zero_a
=False,
691 print("LD", src1
, src2
, imm
, imm_ok
, update
)
692 yield dut
.oper_i
.insn_type
.eq(MicrOp
.OP_LOAD
)
693 yield dut
.oper_i
.data_len
.eq(2) # half-word
694 yield dut
.oper_i
.byte_reverse
.eq(byterev
)
695 yield dut
.src1_i
.eq(src1
)
696 yield dut
.src2_i
.eq(src2
)
697 yield dut
.oper_i
.zero_a
.eq(zero_a
)
698 yield dut
.oper_i
.imm_data
.data
.eq(imm
)
699 yield dut
.oper_i
.imm_data
.ok
.eq(imm_ok
)
700 yield dut
.issue_i
.eq(1)
702 yield dut
.issue_i
.eq(0)
705 # set up read-operand flags
707 if not imm_ok
: # no immediate means RB register needs to be read
709 if not zero_a
: # no zero-a means RA needs to be read
712 # wait for the operands (RA, RB, or both)
714 yield dut
.rd
.go_i
.eq(rd
)
715 yield from wait_for(dut
.rd
.rel_o
)
716 yield dut
.rd
.go_i
.eq(0)
718 yield from wait_for(dut
.adr_rel_o
, False, test1st
=True)
719 # yield dut.ad.go.eq(1)
721 # yield dut.ad.go.eq(0)
724 yield from wait_for(dut
.wr
.rel_o
[1])
725 yield dut
.wr
.go_i
.eq(0b10)
727 addr
= yield dut
.addr_o
729 yield dut
.wr
.go_i
.eq(0)
733 yield from wait_for(dut
.wr
.rel_o
[0], test1st
=True)
734 yield dut
.wr
.go_i
.eq(1)
736 data
= yield dut
.o_data
.o
737 data_ok
= yield dut
.o_data
.o_ok
738 yield dut
.wr
.go_i
.eq(0)
739 yield from wait_for(dut
.busy_o
)
741 # wait_for(dut.stwd_mem_o)
742 return data
, data_ok
, addr
750 # two STs (different addresses)
751 yield from store(dut
, 4, 0, 3, 2) # ST reg4 into addr rfile[reg3]+2
752 yield from store(dut
, 2, 0, 9, 2) # ST reg4 into addr rfile[reg9]+2
754 # two LDs (deliberately LD from the 1st address then 2nd)
755 data
, addr
= yield from load(dut
, 4, 0, 2)
756 assert data
== 0x0003, "returned %x" % data
757 data
, addr
= yield from load(dut
, 2, 0, 2)
758 assert data
== 0x0009, "returned %x" % data
762 yield from store(dut
, 9, 5, 3, 0, imm_ok
=False)
763 data
, addr
= yield from load(dut
, 9, 5, 0, imm_ok
=False)
764 assert data
== 0x0003, "returned %x" % data
766 # update-immediate version
767 addr
= yield from store(dut
, 9, 6, 3, 2, update
=True)
768 assert addr
== 0x000b, "returned %x" % addr
770 # update-indexed version
771 data
, addr
= yield from load(dut
, 9, 5, 0, imm_ok
=False, update
=True)
772 assert data
== 0x0003, "returned %x" % data
773 assert addr
== 0x000e, "returned %x" % addr
775 # immediate *and* zero version
776 data
, addr
= yield from load(dut
, 1, 4, 8, imm_ok
=True, zero_a
=True)
777 assert data
== 0x0008, "returned %x" % data
780 class TestLDSTCompUnit(LDSTCompUnit
):
782 def __init__(self
, rwid
, pspec
):
783 from soc
.experiment
.l0_cache
import TstL0CacheBuffer
784 self
.l0
= l0
= TstL0CacheBuffer(pspec
)
786 LDSTCompUnit
.__init
__(self
, pi
, rwid
, 4)
788 def elaborate(self
, platform
):
789 m
= LDSTCompUnit
.elaborate(self
, platform
)
790 m
.submodules
.l0
= self
.l0
791 # link addr-go direct to rel
792 m
.d
.comb
+= self
.ad
.go_i
.eq(self
.ad
.rel_o
)
796 def test_scoreboard():
799 pspec
= TestMemPspec(ldst_ifacetype
='bare_wb',
800 imem_ifacetype
='bare_wb',
806 dut
= TestLDSTCompUnit(16,pspec
)
807 vl
= rtlil
.convert(dut
, ports
=dut
.ports())
808 with
open("test_ldst_comp.il", "w") as f
:
811 run_simulation(dut
, ldst_sim(dut
), vcd_name
='test_ldst_comp.vcd')
814 class TestLDSTCompUnitRegSpec(LDSTCompUnit
):
816 def __init__(self
, pspec
):
817 from soc
.experiment
.l0_cache
import TstL0CacheBuffer
818 from soc
.fu
.ldst
.pipe_data
import LDSTPipeSpec
819 regspec
= LDSTPipeSpec
.regspec
820 self
.l0
= l0
= TstL0CacheBuffer(pspec
)
822 LDSTCompUnit
.__init
__(self
, pi
, regspec
, 4)
824 def elaborate(self
, platform
):
825 m
= LDSTCompUnit
.elaborate(self
, platform
)
826 m
.submodules
.l0
= self
.l0
827 # link addr-go direct to rel
828 m
.d
.comb
+= self
.ad
.go_i
.eq(self
.ad
.rel_o
)
832 def test_scoreboard_regspec():
835 pspec
= TestMemPspec(ldst_ifacetype
='bare_wb',
836 imem_ifacetype
='bare_wb',
842 dut
= TestLDSTCompUnitRegSpec(pspec
)
843 vl
= rtlil
.convert(dut
, ports
=dut
.ports())
844 with
open("test_ldst_comp.il", "w") as f
:
847 run_simulation(dut
, ldst_sim(dut
), vcd_name
='test_ldst_regspec.vcd')
850 if __name__
== '__main__':
851 test_scoreboard_regspec()