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
, C
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
=64, 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
= 3 # RA, RT/RS, CR0
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
.cr_o
= Data(4, name
="cr0") # CR0 (for stdcx etc)
249 self
.exc_o
= cu
.exc_o
250 self
.done_o
= cu
.done_o
251 self
.busy_o
= cu
.busy_o
256 self
.load_mem_o
= cu
.load_mem_o
257 self
.stwd_mem_o
= cu
.stwd_mem_o
259 def elaborate(self
, platform
):
265 issue_i
= self
.issue_i
267 #####################
268 # latches for the FSM.
269 m
.submodules
.opc_l
= opc_l
= SRLatch(sync
=False, name
="opc")
270 m
.submodules
.src_l
= src_l
= SRLatch(False, self
.n_src
, name
="src")
271 m
.submodules
.alu_l
= alu_l
= SRLatch(sync
=False, name
="alu")
272 m
.submodules
.adr_l
= adr_l
= SRLatch(sync
=False, name
="adr")
273 m
.submodules
.lod_l
= lod_l
= SRLatch(sync
=False, name
="lod")
274 m
.submodules
.sto_l
= sto_l
= SRLatch(sync
=False, name
="sto")
275 m
.submodules
.wri_l
= wri_l
= SRLatch(sync
=False, name
="wri")
276 m
.submodules
.upd_l
= upd_l
= SRLatch(sync
=False, name
="upd")
277 m
.submodules
.cr0_l
= cr0_l
= SRLatch(sync
=False, name
="cr0")
278 m
.submodules
.rst_l
= rst_l
= SRLatch(sync
=False, name
="rst")
279 m
.submodules
.lsd_l
= lsd_l
= SRLatch(sync
=False, name
="lsd") # done
285 op_is_ld
= Signal(reset_less
=True)
286 op_is_st
= Signal(reset_less
=True)
287 op_is_dcbz
= Signal(reset_less
=True)
288 op_is_st_or_dcbz
= Signal(reset_less
=True)
289 op_is_atomic
= Signal(reset_less
=True)
291 # ALU/LD data output control
292 alu_valid
= Signal(reset_less
=True) # ALU operands are valid
293 alu_ok
= Signal(reset_less
=True) # ALU out ok (1 clock delay valid)
294 addr_ok
= Signal(reset_less
=True) # addr ok (from PortInterface)
295 ld_ok
= Signal(reset_less
=True) # LD out ok from PortInterface
296 wr_any
= Signal(reset_less
=True) # any write (incl. store)
297 rda_any
= Signal(reset_less
=True) # any read for address ops
298 rd_done
= Signal(reset_less
=True) # all *necessary* operands read
299 wr_reset
= Signal(reset_less
=True) # final reset condition
300 canceln
= Signal(reset_less
=True) # cancel (active low)
301 store_done
= Signal(reset_less
=True) # store has been actioned
304 alu_o
= Signal(self
.data_wid
, reset_less
=True)
305 ldd_o
= Signal(self
.data_wid
, reset_less
=True)
307 ##############################
308 # reset conditions for latches
310 # temporaries (also convenient when debugging)
311 reset_o
= Signal(reset_less
=True) # reset opcode
312 reset_w
= Signal(reset_less
=True) # reset write
313 reset_u
= Signal(reset_less
=True) # reset update
314 reset_c
= Signal(reset_less
=True) # reset cr0
315 reset_a
= Signal(reset_less
=True) # reset adr latch
316 reset_i
= Signal(reset_less
=True) # issue|die (use a lot)
317 reset_r
= Signal(self
.n_src
, reset_less
=True) # reset src
318 reset_s
= Signal(reset_less
=True) # reset store
320 # end execution when a terminating condition is detected:
321 # - go_die_i: a speculative operation was cancelled
322 # - exc_o.happened: an exception has occurred
324 comb
+= terminate
.eq(self
.go_die_i | self
.exc_o
.happened
)
326 comb
+= reset_i
.eq(issue_i | terminate
) # various
327 comb
+= reset_o
.eq(self
.done_o | terminate
) # opcode reset
328 comb
+= reset_w
.eq(self
.wr
.go_i
[0] | terminate
) # write reg 1
329 comb
+= reset_u
.eq(self
.wr
.go_i
[1] | terminate
) # update (reg 2)
330 comb
+= reset_c
.eq(self
.wr
.go_i
[2] | terminate
) # cr0 (reg 3)
331 comb
+= reset_s
.eq(self
.go_st_i | terminate
) # store reset
332 comb
+= reset_r
.eq(self
.rd
.go_i |
Repl(terminate
, self
.n_src
))
333 comb
+= reset_a
.eq(self
.go_ad_i | terminate
)
335 p_st_go
= Signal(reset_less
=True)
336 sync
+= p_st_go
.eq(self
.st
.go_i
)
338 # decode bits of operand (latched)
339 oper_r
= CompLDSTOpSubset(name
="oper_r") # Dest register
340 comb
+= op_is_st
.eq(oper_r
.insn_type
== MicrOp
.OP_STORE
) # ST
341 comb
+= op_is_ld
.eq(oper_r
.insn_type
== MicrOp
.OP_LOAD
) # LD
342 comb
+= op_is_dcbz
.eq(oper_r
.insn_type
== MicrOp
.OP_DCBZ
) # DCBZ
343 comb
+= op_is_atomic
.eq(oper_r
.reserve
) # atomic LR/SC
344 comb
+= op_is_st_or_dcbz
.eq(op_is_st | op_is_dcbz
)
345 # dcbz is special case of store
347 #comb += Display("compldst_multi: op_is_dcbz = %i",
348 # (oper_r.insn_type == MicrOp.OP_DCBZ))
349 op_is_update
= oper_r
.ldst_mode
== LDSTMode
.update
# UPDATE
350 op_is_cix
= oper_r
.ldst_mode
== LDSTMode
.cix
# cache-inhibit
351 comb
+= self
.load_mem_o
.eq(op_is_ld
& self
.go_ad_i
)
352 comb
+= self
.stwd_mem_o
.eq(op_is_st
& self
.go_st_i
)
353 comb
+= self
.ld_o
.eq(op_is_ld
)
354 comb
+= self
.st_o
.eq(op_is_st
)
356 ##########################
357 # FSM implemented through sequence of latches. approximately this:
359 # - src_l[0] : operands
361 # - alu_l : looks after add of src1/2/imm (EA)
362 # - adr_l : waits for add (EA)
363 # - upd_l : waits for adr and Regfile (port 2)
364 # - cr0_l : waits for Rc=1 and CR0 Regfile (port 3)
366 # - lod_l : waits for adr (EA) and for LD Data
367 # - wri_l : waits for LD Data and Regfile (port 1)
368 # - st_l : waits for alu and operand2
369 # - rst_l : waits for all FSM paths to converge.
370 # NOTE: use sync to stop combinatorial loops.
372 # opcode latch - inverted so that busy resets to 0
373 # note this MUST be sync so as to avoid a combinatorial loop
374 # between busy_o and issue_i on the reset latch (rst_l)
375 sync
+= opc_l
.s
.eq(issue_i
) # XXX NOTE: INVERTED FROM book!
376 sync
+= opc_l
.r
.eq(reset_o
) # XXX NOTE: INVERTED FROM book!
379 sync
+= src_l
.s
.eq(Repl(issue_i
, self
.n_src
) & ~self
.rdmaskn
)
380 sync
+= src_l
.r
.eq(reset_r
)
381 #### sync += Display("reset_r = %i",reset_r)
383 # alu latch. use sync-delay between alu_ok and valid to generate pulse
384 comb
+= alu_l
.s
.eq(reset_i
)
385 comb
+= alu_l
.r
.eq(alu_ok
& ~alu_valid
& ~rda_any
)
388 comb
+= adr_l
.s
.eq(reset_i
)
389 sync
+= adr_l
.r
.eq(reset_a
)
392 comb
+= lod_l
.s
.eq(reset_i
)
393 comb
+= lod_l
.r
.eq(ld_ok
)
396 comb
+= wri_l
.s
.eq(issue_i
)
397 sync
+= wri_l
.r
.eq(reset_w |
Repl(wr_reset |
398 (~self
.pi
.busy_o
& op_is_update
),
399 #(self.pi.busy_o & op_is_update),
400 #self.done_o | (self.pi.busy_o & op_is_update),
403 # CR0 operand latch (CR0 written to reg 3 if Rc=1)
404 op_is_rc1
= self
.oper_i
.rc
.rc
& self
.oper_i
.rc
.ok
405 comb
+= cr0_l
.s
.eq(issue_i
& op_is_rc1
)
406 sync
+= cr0_l
.r
.eq(reset_c
)
408 # update-mode operand latch (EA written to reg 2)
409 sync
+= upd_l
.s
.eq(reset_i
)
410 sync
+= upd_l
.r
.eq(reset_u
)
413 comb
+= sto_l
.s
.eq(addr_ok
& op_is_st_or_dcbz
)
414 sync
+= sto_l
.r
.eq(reset_s | p_st_go
)
416 # ld/st done. needed to stop LD/ST from activating repeatedly
417 comb
+= lsd_l
.s
.eq(issue_i
)
418 sync
+= lsd_l
.r
.eq(reset_s | p_st_go | ld_ok
)
421 comb
+= rst_l
.s
.eq(addr_ok
) # start when address is ready
422 comb
+= rst_l
.r
.eq(issue_i
)
424 # create a latch/register for the operand
425 with m
.If(self
.issue_i
):
426 sync
+= oper_r
.eq(self
.oper_i
)
427 with m
.If(self
.done_o | terminate
):
430 # and for LD and store-done
431 ldd_r
= Signal(self
.data_wid
, reset_less
=True) # Dest register
432 latchregister(m
, ldd_o
, ldd_r
, ld_ok
, name
="ldo_r")
434 # store actioned, communicate through CR0 (for atomic LR/SC)
435 latchregister(m
, self
.pi
.store_done
.data
, store_done
,
436 self
.pi
.store_done
.ok
,
439 # and for each input from the incoming src operands
441 for i
in range(self
.n_src
):
443 src_r
= Signal(self
.data_wid
, name
=name
, reset_less
=True)
444 with m
.If(self
.rd
.go_i
[i
]):
445 sync
+= src_r
.eq(self
.src_i
[i
])
446 with m
.If(self
.issue_i
):
450 # and one for the output from the ADD (for the EA)
451 addr_r
= Signal(self
.data_wid
, reset_less
=True) # Effective Address
452 latchregister(m
, alu_o
, addr_r
, alu_l
.q
, "ea_r")
454 # select either zero or src1 if opcode says so
455 op_is_z
= oper_r
.zero_a
456 src1_or_z
= Signal(self
.data_wid
, reset_less
=True)
457 m
.d
.comb
+= src1_or_z
.eq(Mux(op_is_z
, 0, srl
[0]))
459 # select either immediate or src2 if opcode says so
460 op_is_imm
= oper_r
.imm_data
.ok
461 src2_or_imm
= Signal(self
.data_wid
, reset_less
=True)
462 m
.d
.comb
+= src2_or_imm
.eq(Mux(op_is_imm
, oper_r
.imm_data
.data
, srl
[1]))
464 # now do the ALU addr add: one cycle, and say "ready" (next cycle, too)
465 comb
+= alu_o
.eq(src1_or_z
+ src2_or_imm
) # actual EA
466 m
.d
.sync
+= alu_ok
.eq(alu_valid
& canceln
) # keep ack in sync with EA
468 ############################
469 # Control Signal calculation
473 comb
+= self
.busy_o
.eq(opc_l
.q
) # | self.pi.busy_o) # busy out
475 # 1st operand read-request only when zero not active
476 # 2nd operand only needed when immediate is not active
477 slg
= Cat(op_is_z
, op_is_imm
) #is this correct ?
478 bro
= Repl(self
.busy_o
, self
.n_src
)
479 comb
+= self
.rd
.rel_o
.eq(src_l
.q
& bro
& ~slg
)
481 # note when the address-related read "go" signals are active
482 comb
+= rda_any
.eq(self
.rd
.go_i
[0] | self
.rd
.go_i
[1])
484 # alu input valid when 1st and 2nd ops done (or imm not active)
485 comb
+= alu_valid
.eq(busy_o
& ~
(self
.rd
.rel_o
[0] | self
.rd
.rel_o
[1]) &
488 # 3rd operand only needed when operation is a store
489 comb
+= self
.rd
.rel_o
[2].eq(src_l
.q
[2] & busy_o
& op_is_st
)
491 # all reads done when alu is valid and 3rd operand needed
492 comb
+= rd_done
.eq(alu_valid
& ~self
.rd
.rel_o
[2])
494 # address release only if addr ready, but Port must be idle
495 comb
+= self
.adr_rel_o
.eq(alu_valid
& adr_l
.q
& busy_o
)
497 # the write/store (etc) all must be cancelled if an exception occurs
498 # note: cancel is active low, like shadown_i,
499 # while exc_o.happpened is active high
500 comb
+= canceln
.eq(~self
.exc_o
.happened
& self
.shadown_i
)
502 # store release when st ready *and* all operands read (and no shadow)
503 # dcbz is special case of store -- TODO verify shadows
504 comb
+= self
.st
.rel_o
.eq(sto_l
.q
& busy_o
& rd_done
& op_is_st_or_dcbz
&
507 # request write of LD result. waits until shadow is dropped.
508 comb
+= self
.wr
.rel_o
[0].eq(rd_done
& wri_l
.q
& busy_o
& lod_l
.qn
&
511 # request write of EA result only in update mode
512 comb
+= self
.wr
.rel_o
[1].eq(upd_l
.q
& busy_o
& op_is_update
&
515 # request write of CR0 result only in reserve and Rc=1
516 comb
+= self
.wr
.rel_o
[2].eq(cr0_l
.q
& busy_o
& op_is_atomic
&
519 # provide "done" signal: select req_rel for non-LD/ST, adr_rel for LD/ST
520 comb
+= wr_any
.eq(self
.st
.go_i | p_st_go |
522 comb
+= wr_reset
.eq(rst_l
.q
& busy_o
& canceln
&
523 ~
(self
.st
.rel_o | self
.wr
.rel_o
.bool()) &
524 (lod_l
.qn | op_is_st_or_dcbz
)
526 comb
+= self
.done_o
.eq(wr_reset
& (~self
.pi
.busy_o | op_is_ld
))
528 ######################
529 # Data/Address outputs
531 # put the LD-output register directly onto the output bus on a go_write
532 comb
+= self
.o_data
.data
.eq(self
.dest
[0])
533 comb
+= self
.o_data
.ok
.eq(self
.wr
.rel_o
[0])
534 with m
.If(self
.wr
.go_i
[0]):
535 comb
+= self
.dest
[0].eq(ldd_r
)
537 # "update" mode, put address out on 2nd go-write
538 comb
+= self
.addr_o
.data
.eq(self
.dest
[1])
539 comb
+= self
.addr_o
.ok
.eq(self
.wr
.rel_o
[1])
540 with m
.If(op_is_update
& self
.wr
.go_i
[1]):
541 comb
+= self
.dest
[1].eq(addr_r
)
543 # fun-fun-fun, calculate CR0 when Rc=1 requested.
545 comb
+= self
.cr_o
.data
.eq(cr0
)
546 comb
+= self
.cr_o
.ok
.eq(self
.wr
.rel_o
[2])
548 comb
+= cr0
.eq(Cat(C(0, 1), store_done
, C(0, 2)))
550 # need to look like MultiCompUnit: put wrmask out.
551 # XXX may need to make this enable only when write active
552 comb
+= self
.wrmask
.eq(bro
& Cat(op_is_ld
, op_is_update
, cr0_l
.q
))
554 ###########################
555 # PortInterface connections
558 # connect to LD/ST PortInterface.
559 comb
+= pi
.is_ld_i
.eq(op_is_ld
& busy_o
) # decoded-LD
560 comb
+= pi
.is_nc
.eq(op_is_cix
& busy_o
) # cache-inhibited
561 comb
+= pi
.is_st_i
.eq(op_is_st_or_dcbz
& busy_o
) # decoded-ST
562 comb
+= pi
.is_dcbz_i
.eq(op_is_dcbz
& busy_o
) # decoded-DCBZ
563 comb
+= pi
.reserve
.eq(oper_r
.reserve
& busy_o
) # atomic LR/SC
564 comb
+= pi
.data_len
.eq(oper_r
.data_len
) # data_len
565 # address: use sync to avoid long latency
566 sync
+= pi
.addr
.data
.eq(addr_r
) # EA from adder
567 with m
.If(op_is_dcbz
):
568 sync
+= Display("LDSTCompUnit.DCBZ: EA from adder %x", addr_r
)
570 sync
+= pi
.addr
.ok
.eq(alu_ok
& lsd_l
.q
) # "do address stuff" (once)
571 comb
+= self
.exc_o
.eq(pi
.exc_o
) # exception occurred
572 comb
+= addr_ok
.eq(self
.pi
.addr_ok_o
) # no exc, address fine
573 # connect MSR.PR etc. for priv/virt operation
574 comb
+= pi
.priv_mode
.eq(~oper_r
.msr
[MSR
.PR
])
575 comb
+= pi
.virt_mode
.eq(oper_r
.msr
[MSR
.DR
])
576 comb
+= pi
.mode_32bit
.eq(~oper_r
.msr
[MSR
.SF
])
577 with m
.If(self
.issue_i
): # display this only once
578 sync
+= Display("LDSTCompUnit: oper_r.msr %x pr=%x dr=%x sf=%x",
585 revnorev
= Signal(64, reset_less
=True)
586 with m
.If(oper_r
.byte_reverse
):
587 # byte-reverse the data based on ld/st width (turn it to LE)
588 data_len
= oper_r
.data_len
589 lddata_r
= byte_reverse(m
, 'lddata_r', pi
.ld
.data
, data_len
)
590 comb
+= revnorev
.eq(lddata_r
) # put reversed- data out
592 comb
+= revnorev
.eq(pi
.ld
.data
) # put data out, straight (as BE)
594 # then check sign-extend
595 with m
.If(oper_r
.sign_extend
):
596 # okok really should "if data_len == 4" and so on here
597 with m
.If(oper_r
.data_len
== 2):
598 comb
+= ldd_o
.eq(exts(revnorev
, 16, 64)) # sign-extend hword
600 comb
+= ldd_o
.eq(exts(revnorev
, 32, 64)) # sign-extend dword
602 comb
+= ldd_o
.eq(revnorev
)
604 # ld - ld gets latched in via lod_l
605 comb
+= ld_ok
.eq(pi
.ld
.ok
) # ld.ok *closes* (freezes) ld data
608 op3
= srl
[2] # 3rd operand latch
609 with m
.If(oper_r
.byte_reverse
):
610 # byte-reverse the data based on width
611 data_len
= oper_r
.data_len
612 stdata_r
= byte_reverse(m
, 'stdata_r', op3
, data_len
)
613 comb
+= pi
.st
.data
.eq(stdata_r
)
615 comb
+= pi
.st
.data
.eq(op3
)
617 # store - data goes in based on go_st
618 comb
+= pi
.st
.ok
.eq(self
.st
.go_i
) # go store signals st data valid
622 def get_out(self
, i
):
623 """make LDSTCompUnit look like RegSpecALUAPI. these correspond
624 to LDSTOutputData o and o1 respectively.
627 return self
.o_data
# LDSTOutputData.regspec o
629 return self
.addr_o
# LDSTOutputData.regspec o1
631 return self
.cr_o
# LDSTOutputData.regspec cr_a
632 # return self.dest[i]
634 def get_fu_out(self
, i
):
635 return self
.get_out(i
)
645 yield from self
.oper_i
.ports()
646 yield from self
.src_i
652 yield from self
.o_data
.ports()
653 yield from self
.addr_o
.ports()
654 yield from self
.cr_o
.ports()
655 yield self
.load_mem_o
656 yield self
.stwd_mem_o
662 def wait_for(sig
, wait
=True, test1st
=False):
664 print("wait for", sig
, v
, wait
, test1st
)
665 if test1st
and bool(v
) == wait
:
670 #print("...wait for", sig, v)
675 def store(dut
, src1
, src2
, src3
, imm
, imm_ok
=True, update
=False,
677 print("ST", src1
, src2
, src3
, imm
, imm_ok
, update
)
678 yield dut
.oper_i
.insn_type
.eq(MicrOp
.OP_STORE
)
679 yield dut
.oper_i
.data_len
.eq(2) # half-word
680 yield dut
.oper_i
.byte_reverse
.eq(byterev
)
681 yield dut
.src1_i
.eq(src1
)
682 yield dut
.src2_i
.eq(src2
)
683 yield dut
.src3_i
.eq(src3
)
684 yield dut
.oper_i
.imm_data
.data
.eq(imm
)
685 yield dut
.oper_i
.imm_data
.ok
.eq(imm_ok
)
686 #guess: this one was removed -- yield dut.oper_i.update.eq(update)
687 yield dut
.issue_i
.eq(1)
689 yield dut
.issue_i
.eq(0)
695 # wait for all active rel signals to come up
697 rel
= yield dut
.rd
.rel_o
698 if rel
== active_rel
:
701 yield dut
.rd
.go_i
.eq(active_rel
)
703 yield dut
.rd
.go_i
.eq(0)
705 yield from wait_for(dut
.adr_rel_o
, False, test1st
=True)
706 # yield from wait_for(dut.adr_rel_o)
707 # yield dut.ad.go.eq(1)
709 # yield dut.ad.go.eq(0)
712 yield from wait_for(dut
.wr
.rel_o
[1])
713 yield dut
.wr
.go
.eq(0b10)
715 addr
= yield dut
.addr_o
717 yield dut
.wr
.go
.eq(0)
721 yield from wait_for(dut
.sto_rel_o
)
722 yield dut
.go_st_i
.eq(1)
724 yield dut
.go_st_i
.eq(0)
725 yield from wait_for(dut
.busy_o
, False)
726 # wait_for(dut.stwd_mem_o)
731 def load(dut
, src1
, src2
, imm
, imm_ok
=True, update
=False, zero_a
=False,
733 print("LD", src1
, src2
, imm
, imm_ok
, update
)
734 yield dut
.oper_i
.insn_type
.eq(MicrOp
.OP_LOAD
)
735 yield dut
.oper_i
.data_len
.eq(2) # half-word
736 yield dut
.oper_i
.byte_reverse
.eq(byterev
)
737 yield dut
.src1_i
.eq(src1
)
738 yield dut
.src2_i
.eq(src2
)
739 yield dut
.oper_i
.zero_a
.eq(zero_a
)
740 yield dut
.oper_i
.imm_data
.data
.eq(imm
)
741 yield dut
.oper_i
.imm_data
.ok
.eq(imm_ok
)
742 yield dut
.issue_i
.eq(1)
744 yield dut
.issue_i
.eq(0)
747 # set up read-operand flags
749 if not imm_ok
: # no immediate means RB register needs to be read
751 if not zero_a
: # no zero-a means RA needs to be read
754 # wait for the operands (RA, RB, or both)
756 yield dut
.rd
.go_i
.eq(rd
)
757 yield from wait_for(dut
.rd
.rel_o
)
758 yield dut
.rd
.go_i
.eq(0)
760 yield from wait_for(dut
.adr_rel_o
, False, test1st
=True)
761 # yield dut.ad.go.eq(1)
763 # yield dut.ad.go.eq(0)
766 yield from wait_for(dut
.wr
.rel_o
[1])
767 yield dut
.wr
.go_i
.eq(0b10)
769 addr
= yield dut
.addr_o
771 yield dut
.wr
.go_i
.eq(0)
775 yield from wait_for(dut
.wr
.rel_o
[0], test1st
=True)
776 yield dut
.wr
.go_i
.eq(1)
778 data
= yield dut
.o_data
.o
779 data_ok
= yield dut
.o_data
.o_ok
780 yield dut
.wr
.go_i
.eq(0)
781 yield from wait_for(dut
.busy_o
)
783 # wait_for(dut.stwd_mem_o)
784 return data
, data_ok
, addr
792 # two STs (different addresses)
793 yield from store(dut
, 4, 0, 3, 2) # ST reg4 into addr rfile[reg3]+2
794 yield from store(dut
, 2, 0, 9, 2) # ST reg4 into addr rfile[reg9]+2
796 # two LDs (deliberately LD from the 1st address then 2nd)
797 data
, addr
= yield from load(dut
, 4, 0, 2)
798 assert data
== 0x0003, "returned %x" % data
799 data
, addr
= yield from load(dut
, 2, 0, 2)
800 assert data
== 0x0009, "returned %x" % data
804 yield from store(dut
, 9, 5, 3, 0, imm_ok
=False)
805 data
, addr
= yield from load(dut
, 9, 5, 0, imm_ok
=False)
806 assert data
== 0x0003, "returned %x" % data
808 # update-immediate version
809 addr
= yield from store(dut
, 9, 6, 3, 2, update
=True)
810 assert addr
== 0x000b, "returned %x" % addr
812 # update-indexed version
813 data
, addr
= yield from load(dut
, 9, 5, 0, imm_ok
=False, update
=True)
814 assert data
== 0x0003, "returned %x" % data
815 assert addr
== 0x000e, "returned %x" % addr
817 # immediate *and* zero version
818 data
, addr
= yield from load(dut
, 1, 4, 8, imm_ok
=True, zero_a
=True)
819 assert data
== 0x0008, "returned %x" % data
822 class TestLDSTCompUnit(LDSTCompUnit
):
824 def __init__(self
, rwid
, pspec
):
825 from soc
.experiment
.l0_cache
import TstL0CacheBuffer
826 self
.l0
= l0
= TstL0CacheBuffer(pspec
)
828 LDSTCompUnit
.__init
__(self
, pi
, rwid
, 4)
830 def elaborate(self
, platform
):
831 m
= LDSTCompUnit
.elaborate(self
, platform
)
832 m
.submodules
.l0
= self
.l0
833 # link addr-go direct to rel
834 m
.d
.comb
+= self
.ad
.go_i
.eq(self
.ad
.rel_o
)
838 def test_scoreboard():
841 pspec
= TestMemPspec(ldst_ifacetype
='bare_wb',
842 imem_ifacetype
='bare_wb',
848 dut
= TestLDSTCompUnit(16,pspec
)
849 vl
= rtlil
.convert(dut
, ports
=dut
.ports())
850 with
open("test_ldst_comp.il", "w") as f
:
853 run_simulation(dut
, ldst_sim(dut
), vcd_name
='test_ldst_comp.vcd')
856 class TestLDSTCompUnitRegSpec(LDSTCompUnit
):
858 def __init__(self
, pspec
):
859 from soc
.experiment
.l0_cache
import TstL0CacheBuffer
860 from soc
.fu
.ldst
.pipe_data
import LDSTPipeSpec
861 regspec
= LDSTPipeSpec
.regspec
862 self
.l0
= l0
= TstL0CacheBuffer(pspec
)
864 LDSTCompUnit
.__init
__(self
, pi
, regspec
, 4)
866 def elaborate(self
, platform
):
867 m
= LDSTCompUnit
.elaborate(self
, platform
)
868 m
.submodules
.l0
= self
.l0
869 # link addr-go direct to rel
870 m
.d
.comb
+= self
.ad
.go_i
.eq(self
.ad
.rel_o
)
874 def test_scoreboard_regspec():
877 pspec
= TestMemPspec(ldst_ifacetype
='bare_wb',
878 imem_ifacetype
='bare_wb',
884 dut
= TestLDSTCompUnitRegSpec(pspec
)
885 vl
= rtlil
.convert(dut
, ports
=dut
.ports())
886 with
open("test_ldst_comp.il", "w") as f
:
889 run_simulation(dut
, ldst_sim(dut
), vcd_name
='test_ldst_regspec.vcd')
892 if __name__
== '__main__':
893 test_scoreboard_regspec()