src/soc/experiment/compldst_multi.py

   1 """LOAD / STORE Computation Unit.
   2
   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.
   8
   9 ----
  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.
  13 ----
  14
  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)
  18
  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.
  22
  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.
  27
  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).
  31
  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.
  35
  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:
  39
  40     * LD-imm         1R1W
  41     * LD-imm-update  1R2W
  42     * LD-idx         2R1W
  43     * LD-idx-update  2R2W
  44
  45     * ST-imm         2R
  46     * ST-imm-update  2R1W
  47     * ST-idx         3R
  48     * ST-idx-update  3R1W
  49
  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*).
  53
  54     * One FSM covers Operand collection and communication address-side
  55       with the LD/ST PortInterface.  its role ends when "RD_DONE" is asserted
  56
  57     * A second FSM activates to cover LD.  it activates if op_is_ld is true
  58
  59     * A third FSM activates to cover ST.  it activates if op_is_st is true
  60
  61     * TODO document DCBZ (not complete yet)
  62
  63     * The "overall" (fourth) FSM coordinates the progression and completion
  64       of the three other FSMs, firing "WR_RESET" which switches off "busy"
  65
  66 Full diagram:
  67
  68     https://libre-soc.org/3d_gpu/ld_st_comp_unit.jpg
  69
  70 Links including to walk-through videos:
  71
  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
  75
  76 Related Bugreports:
  77
  78     * https://bugs.libre-soc.org/show_bug.cgi?id=302
  79     * https://bugs.libre-soc.org/show_bug.cgi?id=216
  80
  81 Terminology:
  82
  83     * EA - Effective Address
  84     * LD - Load
  85     * ST - Store
  86 """
  87
  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
  92
  93 from nmutil.latch import SRLatch, latchregister
  94 from nmutil.byterev import byte_reverse
  95 from nmutil.extend import exts
  96
  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
 101
 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
 107
 108 # for debugging dcbz
 109 from nmutil.util import Display
 110
 111
 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
 115
 116
 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)
 121
 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
 124
 125         self.exc_o = LDSTException("exc_o")
 126
 127         self.ld_o = Signal(reset_less=True)  # operation is a LD
 128         self.st_o = Signal(reset_less=True)  # operation is a ST
 129
 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
 133
 134
 135 class LDSTCompUnit(RegSpecAPI, Elaboratable):
 136     """LOAD / STORE Computation Unit
 137
 138     Inputs
 139     ------
 140
 141     * :pi:     a PortInterface to the memory subsystem (read-write capable)
 142     * :rwid:   register width
 143     * :awid:   address width
 144
 145     Data inputs
 146     -----------
 147     * :src_i:  Source Operands (RA/RB/RC) - managed by rd[0-3] go/req
 148
 149     Data (outputs)
 150     --------------
 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
 154
 155     TODO: make exc_o a data-type rather than a single-bit signal
 156           (see bug #302)
 157
 158     Control Signals (In)
 159     --------------------
 160
 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"
 169
 170     Control Signals (Out)
 171     ---------------------
 172
 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
 180
 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.
 185
 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
 190     """
 191
 192     def __init__(self, pi=None, rwid=64, awid=64, opsubset=CompLDSTOpSubset,
 193                  debugtest=False, name=None):
 194         super().__init__(rwid)
 195         self.awid = awid
 196         self.pi = pi
 197         self.cu = cu = LDSTCompUnitRecord(rwid, opsubset, name=name)
 198         self.debugtest = debugtest # enable debug output for unit testing
 199
 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
 203
 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
 207             name = "src%d_i" % j
 208             setattr(self, name, getattr(cu, name))
 209
 210         dst = []
 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))
 215
 216         # convenience names
 217         self.rd = cu.rd
 218         self.wr = cu.wr
 219         self.rdmaskn = cu.rdmaskn
 220         self.wrmask = cu.wrmask
 221         self.ad = cu.ad
 222         self.st = cu.st
 223         self.dest = cu._dest
 224
 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()
 228
 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
 233
 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)
 238
 239         self.issue_i = cu.issue_i
 240         self.shadown_i = cu.shadown_i
 241         self.go_die_i = cu.go_die_i
 242
 243         self.oper_i = cu.oper_i
 244         self.src_i = cu._src_i
 245
 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
 251
 252         self.ld_o = cu.ld_o
 253         self.st_o = cu.st_o
 254
 255         self.load_mem_o = cu.load_mem_o
 256         self.stwd_mem_o = cu.stwd_mem_o
 257
 258     def elaborate(self, platform):
 259         m = Module()
 260
 261         # temp/convenience
 262         comb = m.d.comb
 263         sync = m.d.sync
 264         issue_i = self.issue_i
 265
 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
 278
 279         ####################
 280         # signals
 281
 282         # opcode decode
 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)
 287
 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)
 298
 299         # LD and ALU out
 300         alu_o = Signal(self.data_wid, reset_less=True)
 301         ldd_o = Signal(self.data_wid, reset_less=True)
 302
 303         ##############################
 304         # reset conditions for latches
 305
 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
 314
 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
 318         terminate = Signal()
 319         comb += terminate.eq(self.go_die_i | self.exc_o.happened)
 320
 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)
 328
 329         p_st_go = Signal(reset_less=True)
 330         sync += p_st_go.eq(self.st.go_i)
 331
 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
 339         #uncomment if needed
 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)
 348
 349         ##########################
 350         # FSM implemented through sequence of latches.  approximately this:
 351         # - opc_l       : opcode
 352         #    - src_l[0] : operands
 353         #    - src_l[1]
 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)
 357         #    - src_l[2] : ST
 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.
 363
 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!
 369
 370         # src operand latch
 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)
 374
 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)
 378
 379         # addr latch
 380         comb += adr_l.s.eq(reset_i)
 381         sync += adr_l.r.eq(reset_a)
 382
 383         # ld latch
 384         comb += lod_l.s.eq(reset_i)
 385         comb += lod_l.r.eq(ld_ok)
 386
 387         # dest operand latch
 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),
 393                                           self.n_dst))
 394
 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)
 398
 399         # store latch
 400         comb += sto_l.s.eq(addr_ok & op_is_st_or_dcbz)
 401         sync += sto_l.r.eq(reset_s | p_st_go)
 402
 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)
 406
 407         # reset latch
 408         comb += rst_l.s.eq(addr_ok)  # start when address is ready
 409         comb += rst_l.r.eq(issue_i)
 410
 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):
 415             sync += oper_r.eq(0)
 416
 417         # and for LD
 418         ldd_r = Signal(self.data_wid, reset_less=True)  # Dest register
 419         latchregister(m, ldd_o, ldd_r, ld_ok, name="ldo_r")
 420
 421         # and for each input from the incoming src operands
 422         srl = []
 423         for i in range(self.n_src):
 424             name = "src_r%d" % i
 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):
 429                 sync += src_r.eq(0)
 430             srl.append(src_r)
 431
 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")
 435
 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]))
 440
 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]))
 445
 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
 449
 450         ############################
 451         # Control Signal calculation
 452
 453         # busy signal
 454         busy_o = self.busy_o
 455         comb += self.busy_o.eq(opc_l.q)  # | self.pi.busy_o)  # busy out
 456
 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)
 462
 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])
 465
 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]) &
 468                              canceln)
 469
 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)
 472
 473         # all reads done when alu is valid and 3rd operand needed
 474         comb += rd_done.eq(alu_valid & ~self.rd.rel_o[2])
 475
 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)
 478
 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)
 483
 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 &
 487                                canceln)
 488
 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 &
 491                                   op_is_ld & canceln)
 492
 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 &
 495                                   alu_valid & canceln)
 496
 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] |
 502                               self.wr.rel_o[1]) &
 503                             (lod_l.qn | op_is_st_or_dcbz)
 504                             )
 505         comb += self.done_o.eq(wr_reset & (~self.pi.busy_o | op_is_ld))
 506
 507         ######################
 508         # Data/Address outputs
 509
 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)
 514
 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)
 519
 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))
 523
 524         ###########################
 525         # PortInterface connections
 526         pi = self.pi
 527
 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)
 537
 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 etc. for priv/virt operation
 542         comb += pi.priv_mode.eq(~oper_r.msr[MSR.PR])
 543         comb += pi.virt_mode.eq(oper_r.msr[MSR.DR])
 544         comb += pi.mode_32bit.eq(~oper_r.msr[MSR.SF])
 545         with m.If(self.issue_i): # display this only once
 546             sync += Display("LDSTCompUnit: oper_r.msr %x pr=%x dr=%x sf=%x",
 547                                       oper_r.msr,
 548                                       oper_r.msr[MSR.PR],
 549                                       oper_r.msr[MSR.DR],
 550                                       oper_r.msr[MSR.SF])
 551
 552         # byte-reverse on LD
 553         revnorev = Signal(64, reset_less=True)
 554         with m.If(oper_r.byte_reverse):
 555             # byte-reverse the data based on ld/st width (turn it to LE)
 556             data_len = oper_r.data_len
 557             lddata_r = byte_reverse(m, 'lddata_r', pi.ld.data, data_len)
 558             comb += revnorev.eq(lddata_r)  # put reversed- data out
 559         with m.Else():
 560             comb += revnorev.eq(pi.ld.data)  # put data out, straight (as BE)
 561
 562         # then check sign-extend
 563         with m.If(oper_r.sign_extend):
 564             # okok really should "if data_len == 4" and so on here
 565             with m.If(oper_r.data_len == 2):
 566                 comb += ldd_o.eq(exts(revnorev, 16, 64))  # sign-extend hword
 567             with m.Else():
 568                 comb += ldd_o.eq(exts(revnorev, 32, 64))  # sign-extend dword
 569         with m.Else():
 570             comb += ldd_o.eq(revnorev)
 571
 572         # ld - ld gets latched in via lod_l
 573         comb += ld_ok.eq(pi.ld.ok)  # ld.ok *closes* (freezes) ld data
 574
 575         # byte-reverse on ST
 576         op3 = srl[2] # 3rd operand latch
 577         with m.If(oper_r.byte_reverse):
 578             # byte-reverse the data based on width
 579             data_len = oper_r.data_len
 580             stdata_r = byte_reverse(m, 'stdata_r', op3, data_len)
 581             comb += pi.st.data.eq(stdata_r)
 582         with m.Else():
 583             comb += pi.st.data.eq(op3)
 584         # store - data goes in based on go_st
 585         comb += pi.st.ok.eq(self.st.go_i)  # go store signals st data valid
 586
 587         return m
 588
 589     def get_out(self, i):
 590         """make LDSTCompUnit look like RegSpecALUAPI.  these correspond
 591         to LDSTOutputData o and o1 respectively.
 592         """
 593         if i == 0:
 594             return self.o_data # LDSTOutputData.regspec o
 595         if i == 1:
 596             return self.addr_o # LDSTOutputData.regspec o1
 597         # return self.dest[i]
 598
 599     def get_fu_out(self, i):
 600         return self.get_out(i)
 601
 602     def __iter__(self):
 603         yield self.rd.go_i
 604         yield self.go_ad_i
 605         yield self.wr.go_i
 606         yield self.go_st_i
 607         yield self.issue_i
 608         yield self.shadown_i
 609         yield self.go_die_i
 610         yield from self.oper_i.ports()
 611         yield from self.src_i
 612         yield self.busy_o
 613         yield self.rd.rel_o
 614         yield self.adr_rel_o
 615         yield self.sto_rel_o
 616         yield self.wr.rel_o
 617         yield from self.o_data.ports()
 618         yield from self.addr_o.ports()
 619         yield self.load_mem_o
 620         yield self.stwd_mem_o
 621
 622     def ports(self):
 623         return list(self)
 624
 625
 626 def wait_for(sig, wait=True, test1st=False):
 627     v = (yield sig)
 628     print("wait for", sig, v, wait, test1st)
 629     if test1st and bool(v) == wait:
 630         return
 631     while True:
 632         yield
 633         v = (yield sig)
 634         #print("...wait for", sig, v)
 635         if bool(v) == wait:
 636             break
 637
 638
 639 def store(dut, src1, src2, src3, imm, imm_ok=True, update=False,
 640           byterev=True):
 641     print("ST", src1, src2, src3, imm, imm_ok, update)
 642     yield dut.oper_i.insn_type.eq(MicrOp.OP_STORE)
 643     yield dut.oper_i.data_len.eq(2)  # half-word
 644     yield dut.oper_i.byte_reverse.eq(byterev)
 645     yield dut.src1_i.eq(src1)
 646     yield dut.src2_i.eq(src2)
 647     yield dut.src3_i.eq(src3)
 648     yield dut.oper_i.imm_data.data.eq(imm)
 649     yield dut.oper_i.imm_data.ok.eq(imm_ok)
 650     #guess: this one was removed -- yield dut.oper_i.update.eq(update)
 651     yield dut.issue_i.eq(1)
 652     yield
 653     yield dut.issue_i.eq(0)
 654
 655     if imm_ok:
 656         active_rel = 0b101
 657     else:
 658         active_rel = 0b111
 659     # wait for all active rel signals to come up
 660     while True:
 661         rel = yield dut.rd.rel_o
 662         if rel == active_rel:
 663             break
 664         yield
 665     yield dut.rd.go_i.eq(active_rel)
 666     yield
 667     yield dut.rd.go_i.eq(0)
 668
 669     yield from wait_for(dut.adr_rel_o, False, test1st=True)
 670     # yield from wait_for(dut.adr_rel_o)
 671     # yield dut.ad.go.eq(1)
 672     # yield
 673     # yield dut.ad.go.eq(0)
 674
 675     if update:
 676         yield from wait_for(dut.wr.rel_o[1])
 677         yield dut.wr.go.eq(0b10)
 678         yield
 679         addr = yield dut.addr_o
 680         print("addr", addr)
 681         yield dut.wr.go.eq(0)
 682     else:
 683         addr = None
 684
 685     yield from wait_for(dut.sto_rel_o)
 686     yield dut.go_st_i.eq(1)
 687     yield
 688     yield dut.go_st_i.eq(0)
 689     yield from wait_for(dut.busy_o, False)
 690     # wait_for(dut.stwd_mem_o)
 691     yield
 692     return addr
 693
 694
 695 def load(dut, src1, src2, imm, imm_ok=True, update=False, zero_a=False,
 696          byterev=True):
 697     print("LD", src1, src2, imm, imm_ok, update)
 698     yield dut.oper_i.insn_type.eq(MicrOp.OP_LOAD)
 699     yield dut.oper_i.data_len.eq(2)  # half-word
 700     yield dut.oper_i.byte_reverse.eq(byterev)
 701     yield dut.src1_i.eq(src1)
 702     yield dut.src2_i.eq(src2)
 703     yield dut.oper_i.zero_a.eq(zero_a)
 704     yield dut.oper_i.imm_data.data.eq(imm)
 705     yield dut.oper_i.imm_data.ok.eq(imm_ok)
 706     yield dut.issue_i.eq(1)
 707     yield
 708     yield dut.issue_i.eq(0)
 709     yield
 710
 711     # set up read-operand flags
 712     rd = 0b00
 713     if not imm_ok:  # no immediate means RB register needs to be read
 714         rd |= 0b10
 715     if not zero_a:  # no zero-a means RA needs to be read
 716         rd |= 0b01
 717
 718     # wait for the operands (RA, RB, or both)
 719     if rd:
 720         yield dut.rd.go_i.eq(rd)
 721         yield from wait_for(dut.rd.rel_o)
 722         yield dut.rd.go_i.eq(0)
 723
 724     yield from wait_for(dut.adr_rel_o, False, test1st=True)
 725     # yield dut.ad.go.eq(1)
 726     # yield
 727     # yield dut.ad.go.eq(0)
 728
 729     if update:
 730         yield from wait_for(dut.wr.rel_o[1])
 731         yield dut.wr.go_i.eq(0b10)
 732         yield
 733         addr = yield dut.addr_o
 734         print("addr", addr)
 735         yield dut.wr.go_i.eq(0)
 736     else:
 737         addr = None
 738
 739     yield from wait_for(dut.wr.rel_o[0], test1st=True)
 740     yield dut.wr.go_i.eq(1)
 741     yield
 742     data = yield dut.o_data.o
 743     data_ok = yield dut.o_data.o_ok
 744     yield dut.wr.go_i.eq(0)
 745     yield from wait_for(dut.busy_o)
 746     yield
 747     # wait_for(dut.stwd_mem_o)
 748     return data, data_ok, addr
 749
 750
 751 def ldst_sim(dut):
 752
 753     ###################
 754     # immediate version
 755
 756     # two STs (different addresses)
 757     yield from store(dut, 4, 0, 3, 2)  # ST reg4 into addr rfile[reg3]+2
 758     yield from store(dut, 2, 0, 9, 2)  # ST reg4 into addr rfile[reg9]+2
 759     yield
 760     # two LDs (deliberately LD from the 1st address then 2nd)
 761     data, addr = yield from load(dut, 4, 0, 2)
 762     assert data == 0x0003, "returned %x" % data
 763     data, addr = yield from load(dut, 2, 0, 2)
 764     assert data == 0x0009, "returned %x" % data
 765     yield
 766
 767     # indexed version
 768     yield from store(dut, 9, 5, 3, 0, imm_ok=False)
 769     data, addr = yield from load(dut, 9, 5, 0, imm_ok=False)
 770     assert data == 0x0003, "returned %x" % data
 771
 772     # update-immediate version
 773     addr = yield from store(dut, 9, 6, 3, 2, update=True)
 774     assert addr == 0x000b, "returned %x" % addr
 775
 776     # update-indexed version
 777     data, addr = yield from load(dut, 9, 5, 0, imm_ok=False, update=True)
 778     assert data == 0x0003, "returned %x" % data
 779     assert addr == 0x000e, "returned %x" % addr
 780
 781     # immediate *and* zero version
 782     data, addr = yield from load(dut, 1, 4, 8, imm_ok=True, zero_a=True)
 783     assert data == 0x0008, "returned %x" % data
 784
 785
 786 class TestLDSTCompUnit(LDSTCompUnit):
 787
 788     def __init__(self, rwid, pspec):
 789         from soc.experiment.l0_cache import TstL0CacheBuffer
 790         self.l0 = l0 = TstL0CacheBuffer(pspec)
 791         pi = l0.l0.dports[0]
 792         LDSTCompUnit.__init__(self, pi, rwid, 4)
 793
 794     def elaborate(self, platform):
 795         m = LDSTCompUnit.elaborate(self, platform)
 796         m.submodules.l0 = self.l0
 797         # link addr-go direct to rel
 798         m.d.comb += self.ad.go_i.eq(self.ad.rel_o)
 799         return m
 800
 801
 802 def test_scoreboard():
 803
 804     units = {}
 805     pspec = TestMemPspec(ldst_ifacetype='bare_wb',
 806                          imem_ifacetype='bare_wb',
 807                          addr_wid=64,
 808                          mask_wid=8,
 809                          reg_wid=64,
 810                          units=units)
 811
 812     dut = TestLDSTCompUnit(16,pspec)
 813     vl = rtlil.convert(dut, ports=dut.ports())
 814     with open("test_ldst_comp.il", "w") as f:
 815         f.write(vl)
 816
 817     run_simulation(dut, ldst_sim(dut), vcd_name='test_ldst_comp.vcd')
 818
 819
 820 class TestLDSTCompUnitRegSpec(LDSTCompUnit):
 821
 822     def __init__(self, pspec):
 823         from soc.experiment.l0_cache import TstL0CacheBuffer
 824         from soc.fu.ldst.pipe_data import LDSTPipeSpec
 825         regspec = LDSTPipeSpec.regspec
 826         self.l0 = l0 = TstL0CacheBuffer(pspec)
 827         pi = l0.l0.dports[0]
 828         LDSTCompUnit.__init__(self, pi, regspec, 4)
 829
 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)
 835         return m
 836
 837
 838 def test_scoreboard_regspec():
 839
 840     units = {}
 841     pspec = TestMemPspec(ldst_ifacetype='bare_wb',
 842                          imem_ifacetype='bare_wb',
 843                          addr_wid=64,
 844                          mask_wid=8,
 845                          reg_wid=64,
 846                          units=units)
 847
 848     dut = TestLDSTCompUnitRegSpec(pspec)
 849     vl = rtlil.convert(dut, ports=dut.ports())
 850     with open("test_ldst_comp.il", "w") as f:
 851         f.write(vl)
 852
 853     run_simulation(dut, ldst_sim(dut), vcd_name='test_ldst_regspec.vcd')
 854
 855
 856 if __name__ == '__main__':
 857     test_scoreboard_regspec()
 858     test_scoreboard()