detect the case in Core bitvector when the Function Unit says:
[soc.git] / src / soc / simple / issuer.py
index aaed35085c3f407976ce3e1cb36d2e0c05173cd7..24830149a606a981f08e697e489a658fd7cea892 100644 (file)
@@ -16,32 +16,35 @@ improved.
 """
 
 from nmigen import (Elaboratable, Module, Signal, ClockSignal, ResetSignal,
-                    ClockDomain, DomainRenamer, Mux, Const, Repl)
+                    ClockDomain, DomainRenamer, Mux, Const, Repl, Cat)
 from nmigen.cli import rtlil
 from nmigen.cli import main
 import sys
 
-from soc.decoder.power_decoder import create_pdecode
-from soc.decoder.power_decoder2 import PowerDecode2, SVP64PrefixDecoder
-from soc.decoder.decode2execute1 import IssuerDecode2ToOperand
-from soc.decoder.decode2execute1 import Data
+from nmigen.lib.coding import PriorityEncoder
+
+from openpower.decoder.power_decoder import create_pdecode
+from openpower.decoder.power_decoder2 import PowerDecode2, SVP64PrefixDecoder
+from openpower.decoder.decode2execute1 import IssuerDecode2ToOperand
+from openpower.decoder.decode2execute1 import Data
+from openpower.decoder.power_enums import (MicrOp, SVP64PredInt, SVP64PredCR,
+                                     SVP64PredMode)
+from openpower.state import CoreState
+from openpower.consts import (CR, SVP64CROffs)
 from soc.experiment.testmem import TestMemory # test only for instructions
 from soc.regfile.regfiles import StateRegs, FastRegs
 from soc.simple.core import NonProductionCore
 from soc.config.test.test_loadstore import TestMemPspec
 from soc.config.ifetch import ConfigFetchUnit
-from soc.decoder.power_enums import (MicrOp, SVP64PredInt, SVP64PredCR,
-                                     SVP64PredMode)
 from soc.debug.dmi import CoreDebug, DMIInterface
 from soc.debug.jtag import JTAG
 from soc.config.pinouts import get_pinspecs
-from soc.config.state import CoreState
 from soc.interrupts.xics import XICS_ICP, XICS_ICS
 from soc.bus.simple_gpio import SimpleGPIO
 from soc.bus.SPBlock512W64B8W import SPBlock512W64B8W
 from soc.clock.select import ClockSelect
 from soc.clock.dummypll import DummyPLL
-from soc.sv.svstate import SVSTATERec
+from openpower.sv.svstate import SVSTATERec
 
 
 from nmutil.util import rising_edge
@@ -54,22 +57,23 @@ def get_insn(f_instr_o, pc):
         return f_instr_o.word_select(pc[2], 32)
 
 # gets state input or reads from state regfile
-def state_get(m, state_i, name, regfile, regnum):
+def state_get(m, core_rst, state_i, name, regfile, regnum):
     comb = m.d.comb
     sync = m.d.sync
     # read the PC
     res = Signal(64, reset_less=True, name=name)
     res_ok_delay = Signal(name="%s_ok_delay" % name)
-    sync += res_ok_delay.eq(~state_i.ok)
-    with m.If(state_i.ok):
-        # incoming override (start from pc_i)
-        comb += res.eq(state_i.data)
-    with m.Else():
-        # otherwise read StateRegs regfile for PC...
-        comb += regfile.ren.eq(1<<regnum)
-    # ... but on a 1-clock delay
-    with m.If(res_ok_delay):
-        comb += res.eq(regfile.data_o)
+    with m.If(~core_rst):
+        sync += res_ok_delay.eq(~state_i.ok)
+        with m.If(state_i.ok):
+            # incoming override (start from pc_i)
+            comb += res.eq(state_i.data)
+        with m.Else():
+            # otherwise read StateRegs regfile for PC...
+            comb += regfile.ren.eq(1<<regnum)
+        # ... but on a 1-clock delay
+        with m.If(res_ok_delay):
+            comb += res.eq(regfile.o_data)
     return res
 
 def get_predint(m, mask, name):
@@ -120,29 +124,29 @@ def get_predcr(m, mask, name):
     invert = Signal(name=name+"crinvert")
     with m.Switch(mask):
         with m.Case(SVP64PredCR.LT.value):
-            comb += idx.eq(0)
-            comb += invert.eq(1)
-        with m.Case(SVP64PredCR.GE.value):
-            comb += idx.eq(0)
+            comb += idx.eq(CR.LT)
             comb += invert.eq(0)
-        with m.Case(SVP64PredCR.GT.value):
-            comb += idx.eq(1)
+        with m.Case(SVP64PredCR.GE.value):
+            comb += idx.eq(CR.LT)
             comb += invert.eq(1)
-        with m.Case(SVP64PredCR.LE.value):
-            comb += idx.eq(1)
+        with m.Case(SVP64PredCR.GT.value):
+            comb += idx.eq(CR.GT)
             comb += invert.eq(0)
-        with m.Case(SVP64PredCR.EQ.value):
-            comb += idx.eq(2)
+        with m.Case(SVP64PredCR.LE.value):
+            comb += idx.eq(CR.GT)
             comb += invert.eq(1)
-        with m.Case(SVP64PredCR.NE.value):
-            comb += idx.eq(1)
+        with m.Case(SVP64PredCR.EQ.value):
+            comb += idx.eq(CR.EQ)
             comb += invert.eq(0)
-        with m.Case(SVP64PredCR.SO.value):
-            comb += idx.eq(3)
+        with m.Case(SVP64PredCR.NE.value):
+            comb += idx.eq(CR.EQ)
             comb += invert.eq(1)
-        with m.Case(SVP64PredCR.NS.value):
-            comb += idx.eq(3)
+        with m.Case(SVP64PredCR.SO.value):
+            comb += idx.eq(CR.SO)
             comb += invert.eq(0)
+        with m.Case(SVP64PredCR.NS.value):
+            comb += idx.eq(CR.SO)
+            comb += invert.eq(1)
     return idx, invert
 
 
@@ -158,14 +162,27 @@ class TestIssuerInternal(Elaboratable):
         # test is SVP64 is to be enabled
         self.svp64_en = hasattr(pspec, "svp64") and (pspec.svp64 == True)
 
+        # and if regfiles are reduced
+        self.regreduce_en = (hasattr(pspec, "regreduce") and
+                                            (pspec.regreduce == True))
+
         # JTAG interface.  add this right at the start because if it's
         # added it *modifies* the pspec, by adding enable/disable signals
         # for parts of the rest of the core
         self.jtag_en = hasattr(pspec, "debug") and pspec.debug == 'jtag'
+        self.dbg_domain = "sync" # sigh "dbgsunc" too problematic
+        #self.dbg_domain = "dbgsync" # domain for DMI/JTAG clock
         if self.jtag_en:
-            subset = {'uart', 'mtwi', 'eint', 'gpio', 'mspi0', 'mspi1',
-                      'pwm', 'sd0', 'sdr'}
-            self.jtag = JTAG(get_pinspecs(subset=subset))
+            # XXX MUST keep this up-to-date with litex, and
+            # soc-cocotb-sim, and err.. all needs sorting out, argh
+            subset = ['uart',
+                      'mtwi',
+                      'eint', 'gpio', 'mspi0',
+                      # 'mspi1', - disabled for now
+                      # 'pwm', 'sd0', - disabled for now
+                       'sdr']
+            self.jtag = JTAG(get_pinspecs(subset=subset),
+                             domain=self.dbg_domain)
             # add signals to pspec to enable/disable icache and dcache
             # (or data and intstruction wishbone if icache/dcache not included)
             # https://bugs.libre-soc.org/show_bug.cgi?id=520
@@ -184,7 +201,8 @@ class TestIssuerInternal(Elaboratable):
             self.sram4k = []
             for i in range(4):
                 self.sram4k.append(SPBlock512W64B8W(name="sram4k_%d" % i,
-                                                    features={'err'}))
+                                                    #features={'err'}
+                                                    ))
 
         # add interrupt controller?
         self.xics = hasattr(pspec, "xics") and pspec.xics == True
@@ -201,13 +219,17 @@ class TestIssuerInternal(Elaboratable):
 
         # main instruction core.  suitable for prototyping / demo only
         self.core = core = NonProductionCore(pspec)
+        self.core_rst = ResetSignal("coresync")
 
         # instruction decoder.  goes into Trap Record
-        pdecode = create_pdecode()
+        #pdecode = create_pdecode()
         self.cur_state = CoreState("cur") # current state (MSR/PC/SVSTATE)
-        self.pdecode2 = PowerDecode2(pdecode, state=self.cur_state,
+        self.pdecode2 = PowerDecode2(None, state=self.cur_state,
                                      opkls=IssuerDecode2ToOperand,
-                                     svp64_en=self.svp64_en)
+                                     svp64_en=self.svp64_en,
+                                     regreduce_en=self.regreduce_en)
+        pdecode = self.pdecode2.dec
+
         if self.svp64_en:
             self.svp64 = SVP64PrefixDecoder() # for decoding SVP64 prefix
 
@@ -220,7 +242,7 @@ class TestIssuerInternal(Elaboratable):
         # instruction go/monitor
         self.pc_o = Signal(64, reset_less=True)
         self.pc_i = Data(64, "pc_i") # set "ok" to indicate "please change me"
-        self.svstate_i = Data(32, "svstate_i") # ditto
+        self.svstate_i = Data(64, "svstate_i") # ditto
         self.core_bigendian_i = Signal() # TODO: set based on MSR.LE
         self.busy_o = Signal(reset_less=True)
         self.memerr_o = Signal(reset_less=True)
@@ -241,9 +263,10 @@ class TestIssuerInternal(Elaboratable):
         self.cr_r = crrf.r_ports['full_cr_dbg'] # CR read
         self.xer_r = xerrf.r_ports['full_xer'] # XER read
 
-        # for predication
-        self.int_pred = intrf.r_ports['pred'] # INT predicate read
-        self.cr_pred = crrf.r_ports['cr_pred'] # CR predicate read
+        if self.svp64_en:
+            # for predication
+            self.int_pred = intrf.r_ports['pred'] # INT predicate read
+            self.cr_pred = crrf.r_ports['cr_pred'] # CR predicate read
 
         # hack method of keeping an eye on whether branch/trap set the PC
         self.state_nia = self.core.regs.rf['state'].w_ports['nia']
@@ -258,8 +281,8 @@ class TestIssuerInternal(Elaboratable):
             self.dstmask = Signal(64)
 
     def fetch_fsm(self, m, core, pc, svstate, nia, is_svp64_mode,
-                        fetch_pc_ready_o, fetch_pc_valid_i,
-                        fetch_insn_valid_o, fetch_insn_ready_i):
+                        fetch_pc_o_ready, fetch_pc_i_valid,
+                        fetch_insn_o_valid, fetch_insn_i_ready):
         """fetch FSM
 
         this FSM performs fetch of raw instruction data, partial-decodes
@@ -278,15 +301,15 @@ class TestIssuerInternal(Elaboratable):
 
             # waiting (zzz)
             with m.State("IDLE"):
-                comb += fetch_pc_ready_o.eq(1)
-                with m.If(fetch_pc_valid_i):
+                comb += fetch_pc_o_ready.eq(1)
+                with m.If(fetch_pc_i_valid):
                     # instruction allowed to go: start by reading the PC
                     # capture the PC and also drop it into Insn Memory
                     # we have joined a pair of combinatorial memory
                     # lookups together.  this is Generally Bad.
                     comb += self.imem.a_pc_i.eq(pc)
-                    comb += self.imem.a_valid_i.eq(1)
-                    comb += self.imem.f_valid_i.eq(1)
+                    comb += self.imem.a_i_valid.eq(1)
+                    comb += self.imem.f_i_valid.eq(1)
                     sync += cur_state.pc.eq(pc)
                     sync += cur_state.svstate.eq(svstate) # and svstate
 
@@ -301,11 +324,11 @@ class TestIssuerInternal(Elaboratable):
                 # one cycle later, msr/sv read arrives.  valid only once.
                 with m.If(~msr_read):
                     sync += msr_read.eq(1) # yeah don't read it again
-                    sync += cur_state.msr.eq(self.state_r_msr.data_o)
+                    sync += cur_state.msr.eq(self.state_r_msr.o_data)
                 with m.If(self.imem.f_busy_o): # zzz...
                     # busy: stay in wait-read
-                    comb += self.imem.a_valid_i.eq(1)
-                    comb += self.imem.f_valid_i.eq(1)
+                    comb += self.imem.a_i_valid.eq(1)
+                    comb += self.imem.f_i_valid.eq(1)
                 with m.Else():
                     # not busy: instruction fetched
                     insn = get_insn(self.imem.f_instr_o, cur_state.pc)
@@ -316,6 +339,7 @@ class TestIssuerInternal(Elaboratable):
                         comb += svp64.bigendian.eq(self.core_bigendian_i)
                         # pass the decoded prefix (if any) to PowerDecoder2
                         sync += pdecode2.sv_rm.eq(svp64.svp64_rm)
+                        sync += pdecode2.is_svp64_mode.eq(is_svp64_mode)
                         # remember whether this is a prefixed instruction, so
                         # the FSM can readily loop when VL==0
                         sync += is_svp64_mode.eq(svp64.is_svp64_mode)
@@ -330,8 +354,8 @@ class TestIssuerInternal(Elaboratable):
                         with m.Else():
                             # fetch the rest of the instruction from memory
                             comb += self.imem.a_pc_i.eq(cur_state.pc + 4)
-                            comb += self.imem.a_valid_i.eq(1)
-                            comb += self.imem.f_valid_i.eq(1)
+                            comb += self.imem.a_i_valid.eq(1)
+                            comb += self.imem.f_i_valid.eq(1)
                             m.next = "INSN_READ2"
                     else:
                         # not SVP64 - 32-bit only
@@ -342,8 +366,8 @@ class TestIssuerInternal(Elaboratable):
             with m.State("INSN_READ2"):
                 with m.If(self.imem.f_busy_o):  # zzz...
                     # busy: stay in wait-read
-                    comb += self.imem.a_valid_i.eq(1)
-                    comb += self.imem.f_valid_i.eq(1)
+                    comb += self.imem.a_i_valid.eq(1)
+                    comb += self.imem.f_i_valid.eq(1)
                 with m.Else():
                     # not busy: instruction fetched
                     insn = get_insn(self.imem.f_instr_o, cur_state.pc+4)
@@ -367,13 +391,13 @@ class TestIssuerInternal(Elaboratable):
 
             with m.State("INSN_READY"):
                 # hand over the instruction, to be decoded
-                comb += fetch_insn_valid_o.eq(1)
-                with m.If(fetch_insn_ready_i):
+                comb += fetch_insn_o_valid.eq(1)
+                with m.If(fetch_insn_i_ready):
                     m.next = "IDLE"
 
     def fetch_predicate_fsm(self, m,
-                            pred_insn_valid_i, pred_insn_ready_o,
-                            pred_mask_valid_o, pred_mask_ready_i):
+                            pred_insn_i_valid, pred_insn_o_ready,
+                            pred_mask_o_valid, pred_mask_i_ready):
         """fetch_predicate_fsm - obtains (constructs in the case of CR)
            src/dest predicate masks
 
@@ -383,7 +407,9 @@ class TestIssuerInternal(Elaboratable):
         be done through multiple reads, extracting one relevant at a time.
         later, a faster way would be to use the 32-bit-wide CR port but
         this is more complex decoding, here.  equivalent code used in
-        ISACaller is "from soc.decoder.isa.caller import get_predcr"
+        ISACaller is "from openpower.decoder.isa.caller import get_predcr"
+
+        note: this ENTIRE FSM is not to be called when svp64 is disabled
         """
         comb = m.d.comb
         sync = m.d.sync
@@ -392,24 +418,11 @@ class TestIssuerInternal(Elaboratable):
         predmode = rm_dec.predmode
         srcpred, dstpred = rm_dec.srcpred, rm_dec.dstpred
         cr_pred, int_pred = self.cr_pred, self.int_pred   # read regfiles
-
-        # elif predmode == CR:
-        #    CR-src sidx, sinvert = get_predcr(m, srcpred)
-        #    CR-dst didx, dinvert = get_predcr(m, dstpred)
-        #    TODO read CR-src and CR-dst into self.srcmask+dstmask with loop
-        #         has to cope with first one then the other
-        #    for cr_idx = FSM-state-loop(0..VL-1):
-        #        FSM-state-trigger-CR-read:
-        #               cr_ren = (1<<7-(cr_idx+SVP64CROffs.CRPred))
-        #               comb += cr_pred.ren.eq(cr_ren)
-        #        FSM-state-1-clock-later-actual-Read:
-        #               cr_field = Signal(4)
-        #               cr_bit = Signal(1)
-        #               # read the CR field, select the appropriate bit
-        #               comb += cr_field.eq(cr_pred.data_o)
-        #               comb += cr_bit.eq(cr_field.bit_select(idx)))
-        #               # just like in branch BO tests
-        #               comd += self.srcmask[cr_idx].eq(inv ^ cr_bit)
+        # get src/dst step, so we can skip already used mask bits
+        cur_state = self.cur_state
+        srcstep = cur_state.svstate.srcstep
+        dststep = cur_state.svstate.dststep
+        cur_vl = cur_state.svstate.vl
 
         # decode predicates
         sregread, sinvert, sunary, sall1s = get_predint(m, srcpred, 's')
@@ -417,15 +430,21 @@ class TestIssuerInternal(Elaboratable):
         sidx, scrinvert = get_predcr(m, srcpred, 's')
         didx, dcrinvert = get_predcr(m, dstpred, 'd')
 
+        # store fetched masks, for either intpred or crpred
+        # when src/dst step is not zero, the skipped mask bits need to be
+        # shifted-out, before actually storing them in src/dest mask
+        new_srcmask = Signal(64, reset_less=True)
+        new_dstmask = Signal(64, reset_less=True)
+
         with m.FSM(name="fetch_predicate"):
 
             with m.State("FETCH_PRED_IDLE"):
-                comb += pred_insn_ready_o.eq(1)
-                with m.If(pred_insn_valid_i):
+                comb += pred_insn_o_ready.eq(1)
+                with m.If(pred_insn_i_valid):
                     with m.If(predmode == SVP64PredMode.INT):
                         # skip fetching destination mask register, when zero
                         with m.If(dall1s):
-                            sync += self.dstmask.eq(-1)
+                            sync += new_dstmask.eq(-1)
                             # directly go to fetch source mask register
                             # guaranteed not to be zero (otherwise predmode
                             # would be SVP64PredMode.ALWAYS, not INT)
@@ -437,6 +456,11 @@ class TestIssuerInternal(Elaboratable):
                             comb += int_pred.addr.eq(dregread)
                             comb += int_pred.ren.eq(1)
                             m.next = "INT_DST_READ"
+                    with m.Elif(predmode == SVP64PredMode.CR):
+                        # go fetch masks from the CR register file
+                        sync += new_srcmask.eq(0)
+                        sync += new_dstmask.eq(0)
+                        m.next = "CR_READ"
                     with m.Else():
                         sync += self.srcmask.eq(-1)
                         sync += self.dstmask.eq(-1)
@@ -445,11 +469,18 @@ class TestIssuerInternal(Elaboratable):
             with m.State("INT_DST_READ"):
                 # store destination mask
                 inv = Repl(dinvert, 64)
-                sync += self.dstmask.eq(self.int_pred.data_o ^ inv)
+                with m.If(dunary):
+                    # set selected mask bit for 1<<r3 mode
+                    dst_shift = Signal(range(64))
+                    comb += dst_shift.eq(self.int_pred.o_data & 0b111111)
+                    sync += new_dstmask.eq(1 << dst_shift)
+                with m.Else():
+                    # invert mask if requested
+                    sync += new_dstmask.eq(self.int_pred.o_data ^ inv)
                 # skip fetching source mask register, when zero
                 with m.If(sall1s):
-                    sync += self.srcmask.eq(-1)
-                    m.next = "FETCH_PRED_DONE"
+                    sync += new_srcmask.eq(-1)
+                    m.next = "FETCH_PRED_SHIFT_MASK"
                 # fetch source predicate register
                 with m.Else():
                     comb += int_pred.addr.eq(sregread)
@@ -459,22 +490,86 @@ class TestIssuerInternal(Elaboratable):
             with m.State("INT_SRC_READ"):
                 # store source mask
                 inv = Repl(sinvert, 64)
-                sync += self.srcmask.eq(self.int_pred.data_o ^ inv)
+                with m.If(sunary):
+                    # set selected mask bit for 1<<r3 mode
+                    src_shift = Signal(range(64))
+                    comb += src_shift.eq(self.int_pred.o_data & 0b111111)
+                    sync += new_srcmask.eq(1 << src_shift)
+                with m.Else():
+                    # invert mask if requested
+                    sync += new_srcmask.eq(self.int_pred.o_data ^ inv)
+                m.next = "FETCH_PRED_SHIFT_MASK"
+
+            # fetch masks from the CR register file
+            # implements the following loop:
+            # idx, inv = get_predcr(mask)
+            # mask = 0
+            # for cr_idx in range(vl):
+            #     cr = crl[cr_idx + SVP64CROffs.CRPred]  # takes one cycle
+            #     if cr[idx] ^ inv:
+            #         mask |= 1 << cr_idx
+            # return mask
+            with m.State("CR_READ"):
+                # CR index to be read, which will be ready by the next cycle
+                cr_idx = Signal.like(cur_vl, reset_less=True)
+                # submit the read operation to the regfile
+                with m.If(cr_idx != cur_vl):
+                    # the CR read port is unary ...
+                    # ren = 1 << cr_idx
+                    # ... in MSB0 convention ...
+                    # ren = 1 << (7 - cr_idx)
+                    # ... and with an offset:
+                    # ren = 1 << (7 - off - cr_idx)
+                    idx = SVP64CROffs.CRPred + cr_idx
+                    comb += cr_pred.ren.eq(1 << (7 - idx))
+                    # signal data valid in the next cycle
+                    cr_read = Signal(reset_less=True)
+                    sync += cr_read.eq(1)
+                    # load the next index
+                    sync += cr_idx.eq(cr_idx + 1)
+                with m.Else():
+                    # exit on loop end
+                    sync += cr_read.eq(0)
+                    sync += cr_idx.eq(0)
+                    m.next = "FETCH_PRED_SHIFT_MASK"
+                with m.If(cr_read):
+                    # compensate for the one cycle delay on the regfile
+                    cur_cr_idx = Signal.like(cur_vl)
+                    comb += cur_cr_idx.eq(cr_idx - 1)
+                    # read the CR field, select the appropriate bit
+                    cr_field = Signal(4)
+                    scr_bit = Signal()
+                    dcr_bit = Signal()
+                    comb += cr_field.eq(cr_pred.o_data)
+                    comb += scr_bit.eq(cr_field.bit_select(sidx, 1) ^ scrinvert)
+                    comb += dcr_bit.eq(cr_field.bit_select(didx, 1) ^ dcrinvert)
+                    # set the corresponding mask bit
+                    bit_to_set = Signal.like(self.srcmask)
+                    comb += bit_to_set.eq(1 << cur_cr_idx)
+                    with m.If(scr_bit):
+                        sync += new_srcmask.eq(new_srcmask | bit_to_set)
+                    with m.If(dcr_bit):
+                        sync += new_dstmask.eq(new_dstmask | bit_to_set)
+
+            with m.State("FETCH_PRED_SHIFT_MASK"):
+                # shift-out skipped mask bits
+                sync += self.srcmask.eq(new_srcmask >> srcstep)
+                sync += self.dstmask.eq(new_dstmask >> dststep)
                 m.next = "FETCH_PRED_DONE"
 
             with m.State("FETCH_PRED_DONE"):
-                comb += pred_mask_valid_o.eq(1)
-                with m.If(pred_mask_ready_i):
+                comb += pred_mask_o_valid.eq(1)
+                with m.If(pred_mask_i_ready):
                     m.next = "FETCH_PRED_IDLE"
 
     def issue_fsm(self, m, core, pc_changed, sv_changed, nia,
                   dbg, core_rst, is_svp64_mode,
-                  fetch_pc_ready_o, fetch_pc_valid_i,
-                  fetch_insn_valid_o, fetch_insn_ready_i,
-                  pred_insn_valid_i, pred_insn_ready_o,
-                  pred_mask_valid_o, pred_mask_ready_i,
-                  exec_insn_valid_i, exec_insn_ready_o,
-                  exec_pc_valid_o, exec_pc_ready_i):
+                  fetch_pc_o_ready, fetch_pc_i_valid,
+                  fetch_insn_o_valid, fetch_insn_i_ready,
+                  pred_insn_i_valid, pred_insn_o_ready,
+                  pred_mask_o_valid, pred_mask_i_ready,
+                  exec_insn_i_valid, exec_insn_o_ready,
+                  exec_pc_o_valid, exec_pc_i_ready):
         """issue FSM
 
         decode / issue FSM.  this interacts with the "fetch" FSM
@@ -507,6 +602,10 @@ class TestIssuerInternal(Elaboratable):
         comb += next_srcstep.eq(cur_state.svstate.srcstep+1)
         comb += next_dststep.eq(cur_state.svstate.dststep+1)
 
+        # note if an exception happened.  in a pipelined or OoO design
+        # this needs to be accompanied by "shadowing" (or stalling)
+        exc_happened = self.core.o.exc_happened
+
         with m.FSM(name="issue_fsm"):
 
             # sync with the "fetch" phase which is reading the instruction
@@ -516,34 +615,26 @@ class TestIssuerInternal(Elaboratable):
                 # wait on "core stop" release, before next fetch
                 # need to do this here, in case we are in a VL==0 loop
                 with m.If(~dbg.core_stop_o & ~core_rst):
-                    comb += fetch_pc_valid_i.eq(1) # tell fetch to start
-                    with m.If(fetch_pc_ready_o):   # fetch acknowledged us
+                    comb += fetch_pc_i_valid.eq(1) # tell fetch to start
+                    with m.If(fetch_pc_o_ready):   # fetch acknowledged us
                         m.next = "INSN_WAIT"
                 with m.Else():
                     # tell core it's stopped, and acknowledge debug handshake
-                    comb += core.core_stopped_i.eq(1)
                     comb += dbg.core_stopped_i.eq(1)
                     # while stopped, allow updating the PC and SVSTATE
                     with m.If(self.pc_i.ok):
                         comb += self.state_w_pc.wen.eq(1 << StateRegs.PC)
-                        comb += self.state_w_pc.data_i.eq(self.pc_i.data)
+                        comb += self.state_w_pc.i_data.eq(self.pc_i.data)
                         sync += pc_changed.eq(1)
                     with m.If(self.svstate_i.ok):
                         comb += new_svstate.eq(self.svstate_i.data)
                         comb += update_svstate.eq(1)
                         sync += sv_changed.eq(1)
 
-            # decode the instruction when it arrives
+            # wait for an instruction to arrive from Fetch
             with m.State("INSN_WAIT"):
-                comb += fetch_insn_ready_i.eq(1)
-                with m.If(fetch_insn_valid_o):
-                    # decode the instruction
-                    sync += core.e.eq(pdecode2.e)
-                    sync += core.state.eq(cur_state)
-                    sync += core.raw_insn_i.eq(dec_opcode_i)
-                    sync += core.bigendian_i.eq(self.core_bigendian_i)
-                    # set RA_OR_ZERO detection in satellite decoders
-                    sync += core.sv_a_nz.eq(pdecode2.sv_a_nz)
+                comb += fetch_insn_i_ready.eq(1)
+                with m.If(fetch_insn_o_valid):
                     # loop into ISSUE_START if it's a SVP64 instruction
                     # and VL == 0.  this because VL==0 is a for-loop
                     # from 0 to 0 i.e. always, always a NOP.
@@ -553,79 +644,156 @@ class TestIssuerInternal(Elaboratable):
                         # since we are in a VL==0 loop, no instruction was
                         # executed that we could be overwriting
                         comb += self.state_w_pc.wen.eq(1 << StateRegs.PC)
-                        comb += self.state_w_pc.data_i.eq(nia)
+                        comb += self.state_w_pc.i_data.eq(nia)
                         comb += self.insn_done.eq(1)
                         m.next = "ISSUE_START"
                     with m.Else():
                         if self.svp64_en:
                             m.next = "PRED_START"  # start fetching predicate
                         else:
-                            m.next = "INSN_EXECUTE" # skip predication
+                            m.next = "DECODE_SV"  # skip predication
 
             with m.State("PRED_START"):
-                comb += pred_insn_valid_i.eq(1)  # tell fetch_pred to start
-                with m.If(pred_insn_ready_o):  # fetch_pred acknowledged us
+                comb += pred_insn_i_valid.eq(1)  # tell fetch_pred to start
+                with m.If(pred_insn_o_ready):  # fetch_pred acknowledged us
                     m.next = "MASK_WAIT"
 
             with m.State("MASK_WAIT"):
-                comb += pred_mask_ready_i.eq(1) # ready to receive the masks
-                with m.If(pred_mask_valid_o): # predication masks are ready
-                    m.next = "INSN_EXECUTE"
-
-            # handshake with execution FSM, move to "wait" once acknowledged
-            with m.State("INSN_EXECUTE"):
-                # with m.If(is_svp64_mode):
-                #    TODO advance src/dst step to "skip" over predicated-out
-                #    from self.srcmask and self.dstmask
-                #    https://bugs.libre-soc.org/show_bug.cgi?id=617#c3
-                #    but still without exceeding VL in either case
-                # IMPORTANT: when changing src/dest step, have to
-                # jump to m.next = "DECODE_SV" to deal with the change in
-                # SVSTATE
-
-                with m.If(is_svp64_mode):
-
+                comb += pred_mask_i_ready.eq(1) # ready to receive the masks
+                with m.If(pred_mask_o_valid): # predication masks are ready
+                    m.next = "PRED_SKIP"
+
+            # skip zeros in predicate
+            with m.State("PRED_SKIP"):
+                with m.If(~is_svp64_mode):
+                    m.next = "DECODE_SV"  # nothing to do
+                with m.Else():
                     if self.svp64_en:
                         pred_src_zero = pdecode2.rm_dec.pred_sz
                         pred_dst_zero = pdecode2.rm_dec.pred_dz
 
-                    """
-                    if not pred_src_zero:
-                        if (((1<<cur_srcstep) & self.srcmask) == 0) and
-                              (cur_srcstep != vl):
+                        # new srcstep, after skipping zeros
+                        skip_srcstep = Signal.like(cur_srcstep)
+                        # value to be added to the current srcstep
+                        src_delta = Signal.like(cur_srcstep)
+                        # add leading zeros to srcstep, if not in zero mode
+                        with m.If(~pred_src_zero):
+                            # priority encoder (count leading zeros)
+                            # append guard bit, in case the mask is all zeros
+                            pri_enc_src = PriorityEncoder(65)
+                            m.submodules.pri_enc_src = pri_enc_src
+                            comb += pri_enc_src.i.eq(Cat(self.srcmask,
+                                                         Const(1, 1)))
+                            comb += src_delta.eq(pri_enc_src.o)
+                        # apply delta to srcstep
+                        comb += skip_srcstep.eq(cur_srcstep + src_delta)
+                        # shift-out all leading zeros from the mask
+                        # plus the leading "one" bit
+                        # TODO count leading zeros and shift-out the zero
+                        #      bits, in the same step, in hardware
+                        sync += self.srcmask.eq(self.srcmask >> (src_delta+1))
+
+                        # same as above, but for dststep
+                        skip_dststep = Signal.like(cur_dststep)
+                        dst_delta = Signal.like(cur_dststep)
+                        with m.If(~pred_dst_zero):
+                            pri_enc_dst = PriorityEncoder(65)
+                            m.submodules.pri_enc_dst = pri_enc_dst
+                            comb += pri_enc_dst.i.eq(Cat(self.dstmask,
+                                                         Const(1, 1)))
+                            comb += dst_delta.eq(pri_enc_dst.o)
+                        comb += skip_dststep.eq(cur_dststep + dst_delta)
+                        sync += self.dstmask.eq(self.dstmask >> (dst_delta+1))
+
+                        # TODO: initialize mask[VL]=1 to avoid passing past VL
+                        with m.If((skip_srcstep >= cur_vl) |
+                                  (skip_dststep >= cur_vl)):
+                            # end of VL loop. Update PC and reset src/dst step
+                            comb += self.state_w_pc.wen.eq(1 << StateRegs.PC)
+                            comb += self.state_w_pc.i_data.eq(nia)
+                            comb += new_svstate.srcstep.eq(0)
+                            comb += new_svstate.dststep.eq(0)
                             comb += update_svstate.eq(1)
-                            comb += new_svstate.srcstep.eq(next_srcstep)
-
-                    if not pred_dst_zero:
-                        if (((1<<cur_dststep) & self.dstmask) == 0) and
-                              (cur_dststep != vl):
-                            comb += new_svstate.dststep.eq(next_dststep)
+                            # synchronize with the simulator
+                            comb += self.insn_done.eq(1)
+                            # go back to Issue
+                            m.next = "ISSUE_START"
+                        with m.Else():
+                            # update new src/dst step
+                            comb += new_svstate.srcstep.eq(skip_srcstep)
+                            comb += new_svstate.dststep.eq(skip_dststep)
                             comb += update_svstate.eq(1)
+                            # proceed to Decode
+                            m.next = "DECODE_SV"
 
-                    if update_svstate:
-                        m.next = "DECODE_SV"
-                    """
+                        # pass predicate mask bits through to satellite decoders
+                        # TODO: for SIMD this will be *multiple* bits
+                        sync += core.i.sv_pred_sm.eq(self.srcmask[0])
+                        sync += core.i.sv_pred_dm.eq(self.dstmask[0])
+
+            # after src/dst step have been updated, we are ready
+            # to decode the instruction
+            with m.State("DECODE_SV"):
+                # decode the instruction
+                sync += core.i.e.eq(pdecode2.e)
+                sync += core.i.state.eq(cur_state)
+                sync += core.i.raw_insn_i.eq(dec_opcode_i)
+                sync += core.i.bigendian_i.eq(self.core_bigendian_i)
+                if self.svp64_en:
+                    sync += core.i.sv_rm.eq(pdecode2.sv_rm)
+                    # set RA_OR_ZERO detection in satellite decoders
+                    sync += core.i.sv_a_nz.eq(pdecode2.sv_a_nz)
+                    # and svp64 detection
+                    sync += core.i.is_svp64_mode.eq(is_svp64_mode)
+                    # and svp64 bit-rev'd ldst mode
+                    ldst_dec = pdecode2.use_svp64_ldst_dec
+                    sync += core.i.use_svp64_ldst_dec.eq(ldst_dec)
+                # after decoding, reset any previous exception condition,
+                # allowing it to be set again during the next execution
+                sync += pdecode2.ldst_exc.eq(0)
+
+                m.next = "INSN_EXECUTE"  # move to "execute"
 
-                comb += exec_insn_valid_i.eq(1) # trigger execute
-                with m.If(exec_insn_ready_o):   # execute acknowledged us
+            # handshake with execution FSM, move to "wait" once acknowledged
+            with m.State("INSN_EXECUTE"):
+                comb += exec_insn_i_valid.eq(1) # trigger execute
+                with m.If(exec_insn_o_ready):   # execute acknowledged us
                     m.next = "EXECUTE_WAIT"
 
             with m.State("EXECUTE_WAIT"):
                 # wait on "core stop" release, at instruction end
                 # need to do this here, in case we are in a VL>1 loop
                 with m.If(~dbg.core_stop_o & ~core_rst):
-                    comb += exec_pc_ready_i.eq(1)
-                    with m.If(exec_pc_valid_o):
+                    comb += exec_pc_i_ready.eq(1)
+                    # see https://bugs.libre-soc.org/show_bug.cgi?id=636
+                    # the exception info needs to be blatted into
+                    # pdecode.ldst_exc, and the instruction "re-run".
+                    # when ldst_exc.happened is set, the PowerDecoder2
+                    # reacts very differently: it re-writes the instruction
+                    # with a "trap" (calls PowerDecoder2.trap()) which
+                    # will *overwrite* whatever was requested and jump the
+                    # PC to the exception address, as well as alter MSR.
+                    # nothing else needs to be done other than to note
+                    # the change of PC and MSR (and, later, SVSTATE)
+                    with m.If(exc_happened):
+                        sync += pdecode2.ldst_exc.eq(core.fus.get_exc("ldst0"))
+
+                    with m.If(exec_pc_o_valid):
 
                         # was this the last loop iteration?
                         is_last = Signal()
                         cur_vl = cur_state.svstate.vl
                         comb += is_last.eq(next_srcstep == cur_vl)
 
+                        # return directly to Decode if Execute generated an
+                        # exception.
+                        with m.If(pdecode2.ldst_exc.happened):
+                            m.next = "DECODE_SV"
+
                         # if either PC or SVSTATE were changed by the previous
                         # instruction, go directly back to Fetch, without
                         # updating either PC or SVSTATE
-                        with m.If(pc_changed | sv_changed):
+                        with m.Elif(pc_changed | sv_changed):
                             m.next = "ISSUE_START"
 
                         # also return to Fetch, when no output was a vector
@@ -638,9 +806,14 @@ class TestIssuerInternal(Elaboratable):
                             # TODO: this just blithely overwrites whatever
                             #       pipeline updated the PC
                             comb += self.state_w_pc.wen.eq(1 << StateRegs.PC)
-                            comb += self.state_w_pc.data_i.eq(nia)
+                            comb += self.state_w_pc.i_data.eq(nia)
                             # reset SRCSTEP before returning to Fetch
-                            with m.If(pdecode2.loop_continue):
+                            if self.svp64_en:
+                                with m.If(pdecode2.loop_continue):
+                                    comb += new_svstate.srcstep.eq(0)
+                                    comb += new_svstate.dststep.eq(0)
+                                    comb += update_svstate.eq(1)
+                            else:
                                 comb += new_svstate.srcstep.eq(0)
                                 comb += new_svstate.dststep.eq(0)
                                 comb += update_svstate.eq(1)
@@ -651,41 +824,30 @@ class TestIssuerInternal(Elaboratable):
                             comb += new_svstate.srcstep.eq(next_srcstep)
                             comb += new_svstate.dststep.eq(next_dststep)
                             comb += update_svstate.eq(1)
-                            m.next = "DECODE_SV"
+                            # return to mask skip loop
+                            m.next = "PRED_SKIP"
 
                 with m.Else():
-                    comb += core.core_stopped_i.eq(1)
                     comb += dbg.core_stopped_i.eq(1)
                     # while stopped, allow updating the PC and SVSTATE
                     with m.If(self.pc_i.ok):
                         comb += self.state_w_pc.wen.eq(1 << StateRegs.PC)
-                        comb += self.state_w_pc.data_i.eq(self.pc_i.data)
+                        comb += self.state_w_pc.i_data.eq(self.pc_i.data)
                         sync += pc_changed.eq(1)
                     with m.If(self.svstate_i.ok):
                         comb += new_svstate.eq(self.svstate_i.data)
                         comb += update_svstate.eq(1)
                         sync += sv_changed.eq(1)
 
-            # need to decode the instruction again, after updating SRCSTEP
-            # in the previous state.
-            # mostly a copy of INSN_WAIT, but without the actual wait
-            with m.State("DECODE_SV"):
-                # decode the instruction
-                sync += core.e.eq(pdecode2.e)
-                sync += core.state.eq(cur_state)
-                sync += core.bigendian_i.eq(self.core_bigendian_i)
-                sync += core.sv_a_nz.eq(pdecode2.sv_a_nz)
-                m.next = "INSN_EXECUTE"  # move to "execute"
-
         # check if svstate needs updating: if so, write it to State Regfile
         with m.If(update_svstate):
             comb += self.state_w_sv.wen.eq(1<<StateRegs.SVSTATE)
-            comb += self.state_w_sv.data_i.eq(new_svstate)
+            comb += self.state_w_sv.i_data.eq(new_svstate)
             sync += cur_state.svstate.eq(new_svstate) # for next clock
 
     def execute_fsm(self, m, core, pc_changed, sv_changed,
-                    exec_insn_valid_i, exec_insn_ready_o,
-                    exec_pc_valid_o, exec_pc_ready_i):
+                    exec_insn_i_valid, exec_insn_o_ready,
+                    exec_pc_o_valid, exec_pc_i_ready):
         """execute FSM
 
         execute FSM. this interacts with the "issue" FSM
@@ -699,46 +861,59 @@ class TestIssuerInternal(Elaboratable):
         pdecode2 = self.pdecode2
 
         # temporaries
-        core_busy_o = core.busy_o                 # core is busy
-        core_ivalid_i = core.ivalid_i             # instruction is valid
-        core_issue_i = core.issue_i               # instruction is issued
-        insn_type = core.e.do.insn_type           # instruction MicroOp type
+        core_busy_o = ~core.p.o_ready | core.n.o_data.busy_o # core is busy
+        core_ivalid_i = core.p.i_valid              # instruction is valid
 
         with m.FSM(name="exec_fsm"):
 
             # waiting for instruction bus (stays there until not busy)
             with m.State("INSN_START"):
-                comb += exec_insn_ready_o.eq(1)
-                with m.If(exec_insn_valid_i):
-                    comb += core_ivalid_i.eq(1)  # instruction is valid
-                    comb += core_issue_i.eq(1)  # and issued
+                comb += exec_insn_o_ready.eq(1)
+                with m.If(exec_insn_i_valid):
+                    comb += core_ivalid_i.eq(1)  # instruction is valid/issued
                     sync += sv_changed.eq(0)
                     sync += pc_changed.eq(0)
                     m.next = "INSN_ACTIVE"  # move to "wait completion"
 
             # instruction started: must wait till it finishes
             with m.State("INSN_ACTIVE"):
-                with m.If(insn_type != MicrOp.OP_NOP):
-                    comb += core_ivalid_i.eq(1) # instruction is valid
                 # note changes to PC and SVSTATE
                 with m.If(self.state_nia.wen & (1<<StateRegs.SVSTATE)):
                     sync += sv_changed.eq(1)
                 with m.If(self.state_nia.wen & (1<<StateRegs.PC)):
                     sync += pc_changed.eq(1)
                 with m.If(~core_busy_o): # instruction done!
-                    comb += exec_pc_valid_o.eq(1)
-                    with m.If(exec_pc_ready_i):
-                        comb += self.insn_done.eq(1)
+                    comb += exec_pc_o_valid.eq(1)
+                    with m.If(exec_pc_i_ready):
+                        # when finished, indicate "done".
+                        # however, if there was an exception, the instruction
+                        # is *not* yet done.  this is an implementation
+                        # detail: we choose to implement exceptions by
+                        # taking the exception information from the LDST
+                        # unit, putting that *back* into the PowerDecoder2,
+                        # and *re-running the entire instruction*.
+                        # if we erroneously indicate "done" here, it is as if
+                        # there were *TWO* instructions:
+                        # 1) the failed LDST 2) a TRAP.
+                        with m.If(~pdecode2.ldst_exc.happened):
+                            comb += self.insn_done.eq(1)
                         m.next = "INSN_START"  # back to fetch
 
     def setup_peripherals(self, m):
         comb, sync = m.d.comb, m.d.sync
 
-        m.submodules.core = core = DomainRenamer("coresync")(self.core)
-        m.submodules.imem = imem = self.imem
-        m.submodules.dbg = dbg = self.dbg
+        # okaaaay so the debug module must be in coresync clock domain
+        # but NOT its reset signal. to cope with this, set every single
+        # submodule explicitly in coresync domain, debug and JTAG
+        # in their own one but using *external* reset.
+        csd = DomainRenamer("coresync")
+        dbd = DomainRenamer(self.dbg_domain)
+
+        m.submodules.core = core = csd(self.core)
+        m.submodules.imem = imem = csd(self.imem)
+        m.submodules.dbg = dbg = dbd(self.dbg)
         if self.jtag_en:
-            m.submodules.jtag = jtag = self.jtag
+            m.submodules.jtag = jtag = dbd(self.jtag)
             # TODO: UART2GDB mux, here, from external pin
             # see https://bugs.libre-soc.org/show_bug.cgi?id=499
             sync += dbg.dmi.connect_to(jtag.dmi)
@@ -748,19 +923,19 @@ class TestIssuerInternal(Elaboratable):
         # 4x 4k SRAM blocks.  these simply "exist", they get routed in litex
         if self.sram4x4k:
             for i, sram in enumerate(self.sram4k):
-                m.submodules["sram4k_%d" % i] = sram
+                m.submodules["sram4k_%d" % i] = csd(sram)
                 comb += sram.enable.eq(self.wb_sram_en)
 
         # XICS interrupt handler
         if self.xics:
-            m.submodules.xics_icp = icp = self.xics_icp
-            m.submodules.xics_ics = ics = self.xics_ics
+            m.submodules.xics_icp = icp = csd(self.xics_icp)
+            m.submodules.xics_ics = ics = csd(self.xics_ics)
             comb += icp.ics_i.eq(ics.icp_o)           # connect ICS to ICP
             sync += cur_state.eint.eq(icp.core_irq_o) # connect ICP to core
 
         # GPIO test peripheral
         if self.gpio:
-            m.submodules.simple_gpio = simple_gpio = self.simple_gpio
+            m.submodules.simple_gpio = simple_gpio = csd(self.simple_gpio)
 
         # connect one GPIO output to ICS bit 15 (like in microwatt soc.vhdl)
         # XXX causes litex ECP5 test to get wrong idea about input and output
@@ -770,9 +945,9 @@ class TestIssuerInternal(Elaboratable):
 
         # instruction decoder
         pdecode = create_pdecode()
-        m.submodules.dec2 = pdecode2 = self.pdecode2
+        m.submodules.dec2 = pdecode2 = csd(self.pdecode2)
         if self.svp64_en:
-            m.submodules.svp64 = svp64 = self.svp64
+            m.submodules.svp64 = svp64 = csd(self.svp64)
 
         # convenience
         dmi, d_reg, d_cr, d_xer, = dbg.dmi, dbg.d_gpr, dbg.d_cr, dbg.d_xer
@@ -783,6 +958,9 @@ class TestIssuerInternal(Elaboratable):
         cd_sync = ClockDomain()
         core_sync = ClockDomain("coresync")
         m.domains += cd_por, cd_sync, core_sync
+        if self.dbg_domain != "sync":
+            dbg_sync = ClockDomain(self.dbg_domain)
+            m.domains += dbg_sync
 
         ti_rst = Signal(reset_less=True)
         delay = Signal(range(4), reset=3)
@@ -795,8 +973,14 @@ class TestIssuerInternal(Elaboratable):
         comb += ti_rst.eq(delay != 0 | dbg.core_rst_o | ResetSignal())
         comb += core_rst.eq(ti_rst)
 
+        # debug clock is same as coresync, but reset is *main external*
+        if self.dbg_domain != "sync":
+            dbg_rst = ResetSignal(self.dbg_domain)
+            comb += dbg_rst.eq(ResetSignal())
+
         # busy/halted signals from core
-        comb += self.busy_o.eq(core.busy_o)
+        core_busy_o = ~core.p.o_ready | core.n.o_data.busy_o # core is busy
+        comb += self.busy_o.eq(core_busy_o)
         comb += pdecode2.dec.bigendian.eq(self.core_bigendian_i)
 
         # temporary hack: says "go" immediately for both address gen and ST
@@ -806,8 +990,6 @@ class TestIssuerInternal(Elaboratable):
         m.d.comb += ldst.ad.go_i.eq(ldst.ad.rel_o) # link addr-go direct to rel
         m.d.comb += ldst.st.go_i.eq(st_go_edge) # link store-go to rising rel
 
-        return core_rst
-
     def elaborate(self, platform):
         m = Module()
         # convenience
@@ -818,7 +1000,12 @@ class TestIssuerInternal(Elaboratable):
         core = self.core
 
         # set up peripherals and core
-        core_rst = self.setup_peripherals(m)
+        core_rst = self.core_rst
+        self.setup_peripherals(m)
+
+        # reset current state if core reset requested
+        with m.If(core_rst):
+            m.d.sync += self.cur_state.eq(0)
 
         # PC and instruction from I-Memory
         comb += self.pc_o.eq(cur_state.pc)
@@ -827,25 +1014,27 @@ class TestIssuerInternal(Elaboratable):
 
         # read state either from incoming override or from regfile
         # TODO: really should be doing MSR in the same way
-        pc = state_get(m, self.pc_i, "pc",                  # read PC
+        pc = state_get(m, core_rst, self.pc_i,
+                            "pc",                  # read PC
                             self.state_r_pc, StateRegs.PC)
-        svstate = state_get(m, self.svstate_i, "svstate",   # read SVSTATE
+        svstate = state_get(m, core_rst, self.svstate_i,
+                            "svstate",   # read SVSTATE
                             self.state_r_sv, StateRegs.SVSTATE)
 
         # don't write pc every cycle
         comb += self.state_w_pc.wen.eq(0)
-        comb += self.state_w_pc.data_i.eq(0)
+        comb += self.state_w_pc.i_data.eq(0)
 
         # don't read msr every cycle
         comb += self.state_r_msr.ren.eq(0)
 
         # address of the next instruction, in the absence of a branch
         # depends on the instruction size
-        nia = Signal(64, reset_less=True)
+        nia = Signal(64)
 
         # connect up debug signals
         # TODO comb += core.icache_rst_i.eq(dbg.icache_rst_o)
-        comb += dbg.terminate_i.eq(core.core_terminate_o)
+        comb += dbg.terminate_i.eq(core.o.core_terminate_o)
         comb += dbg.state.pc.eq(pc)
         comb += dbg.state.svstate.eq(svstate)
         comb += dbg.state.msr.eq(cur_state.msr)
@@ -854,32 +1043,33 @@ class TestIssuerInternal(Elaboratable):
         # on VL==0
         is_svp64_mode = Signal()
 
-        # there are *THREE* FSMs, fetch (32/64-bit) issue, decode/execute.
-        # these are the handshake signals between fetch and decode/execute
+        # there are *THREE^WFOUR-if-SVP64-enabled* FSMs, fetch (32/64-bit)
+        # issue, decode/execute, now joined by "Predicate fetch/calculate".
+        # these are the handshake signals between each
 
         # fetch FSM can run as soon as the PC is valid
-        fetch_pc_valid_i = Signal() # Execute tells Fetch "start next read"
-        fetch_pc_ready_o = Signal() # Fetch Tells SVSTATE "proceed"
+        fetch_pc_i_valid = Signal() # Execute tells Fetch "start next read"
+        fetch_pc_o_ready = Signal() # Fetch Tells SVSTATE "proceed"
 
         # fetch FSM hands over the instruction to be decoded / issued
-        fetch_insn_valid_o = Signal()
-        fetch_insn_ready_i = Signal()
+        fetch_insn_o_valid = Signal()
+        fetch_insn_i_ready = Signal()
 
         # predicate fetch FSM decodes and fetches the predicate
-        pred_insn_valid_i = Signal()
-        pred_insn_ready_o = Signal()
+        pred_insn_i_valid = Signal()
+        pred_insn_o_ready = Signal()
 
         # predicate fetch FSM delivers the masks
-        pred_mask_valid_o = Signal()
-        pred_mask_ready_i = Signal()
+        pred_mask_o_valid = Signal()
+        pred_mask_i_ready = Signal()
 
         # issue FSM delivers the instruction to the be executed
-        exec_insn_valid_i = Signal()
-        exec_insn_ready_o = Signal()
+        exec_insn_i_valid = Signal()
+        exec_insn_o_ready = Signal()
 
         # execute FSM, hands over the PC/SVSTATE back to the issue FSM
-        exec_pc_valid_o = Signal()
-        exec_pc_ready_i = Signal()
+        exec_pc_o_valid = Signal()
+        exec_pc_i_ready = Signal()
 
         # the FSMs here are perhaps unusual in that they detect conditions
         # then "hold" information, combinatorially, for the core
@@ -891,26 +1081,30 @@ class TestIssuerInternal(Elaboratable):
         # signalling is used to communicate between the four.
 
         self.fetch_fsm(m, core, pc, svstate, nia, is_svp64_mode,
-                       fetch_pc_ready_o, fetch_pc_valid_i,
-                       fetch_insn_valid_o, fetch_insn_ready_i)
+                       fetch_pc_o_ready, fetch_pc_i_valid,
+                       fetch_insn_o_valid, fetch_insn_i_ready)
 
         self.issue_fsm(m, core, pc_changed, sv_changed, nia,
                        dbg, core_rst, is_svp64_mode,
-                       fetch_pc_ready_o, fetch_pc_valid_i,
-                       fetch_insn_valid_o, fetch_insn_ready_i,
-                       pred_insn_valid_i, pred_insn_ready_o,
-                       pred_mask_valid_o, pred_mask_ready_i,
-                       exec_insn_valid_i, exec_insn_ready_o,
-                       exec_pc_valid_o, exec_pc_ready_i)
+                       fetch_pc_o_ready, fetch_pc_i_valid,
+                       fetch_insn_o_valid, fetch_insn_i_ready,
+                       pred_insn_i_valid, pred_insn_o_ready,
+                       pred_mask_o_valid, pred_mask_i_ready,
+                       exec_insn_i_valid, exec_insn_o_ready,
+                       exec_pc_o_valid, exec_pc_i_ready)
 
         if self.svp64_en:
             self.fetch_predicate_fsm(m,
-                                     pred_insn_valid_i, pred_insn_ready_o,
-                                     pred_mask_valid_o, pred_mask_ready_i)
+                                     pred_insn_i_valid, pred_insn_o_ready,
+                                     pred_mask_o_valid, pred_mask_i_ready)
 
         self.execute_fsm(m, core, pc_changed, sv_changed,
-                         exec_insn_valid_i, exec_insn_ready_o,
-                         exec_pc_valid_o, exec_pc_ready_i)
+                         exec_insn_i_valid, exec_insn_o_ready,
+                         exec_pc_o_valid, exec_pc_i_ready)
+
+        # whatever was done above, over-ride it if core reset is held
+        with m.If(core_rst):
+            sync += nia.eq(0)
 
         # this bit doesn't have to be in the FSM: connect up to read
         # regfiles on demand from DMI
@@ -945,7 +1139,7 @@ class TestIssuerInternal(Elaboratable):
         sync += d_reg_delay.eq(d_reg.req)
         with m.If(d_reg_delay):
             # data arrives one clock later
-            comb += d_reg.data.eq(self.int_r.data_o)
+            comb += d_reg.data.eq(self.int_r.o_data)
             comb += d_reg.ack.eq(1)
 
         # sigh same thing for CR debug
@@ -955,7 +1149,7 @@ class TestIssuerInternal(Elaboratable):
         sync += d_cr_delay.eq(d_cr.req)
         with m.If(d_cr_delay):
             # data arrives one clock later
-            comb += d_cr.data.eq(self.cr_r.data_o)
+            comb += d_cr.data.eq(self.cr_r.o_data)
             comb += d_cr.ack.eq(1)
 
         # aaand XER...
@@ -965,7 +1159,7 @@ class TestIssuerInternal(Elaboratable):
         sync += d_xer_delay.eq(d_xer.req)
         with m.If(d_xer_delay):
             # data arrives one clock later
-            comb += d_xer.data.eq(self.xer_r.data_o)
+            comb += d_xer.data.eq(self.xer_r.o_data)
             comb += d_xer.ack.eq(1)
 
     def tb_dec_fsm(self, m, spr_dec):
@@ -996,10 +1190,10 @@ class TestIssuerInternal(Elaboratable):
             with m.State("DEC_WRITE"):
                 new_dec = Signal(64)
                 # TODO: MSR.LPCR 32-bit decrement mode
-                comb += new_dec.eq(fast_r_dectb.data_o - 1)
+                comb += new_dec.eq(fast_r_dectb.o_data - 1)
                 comb += fast_w_dectb.addr.eq(FastRegs.DEC)
                 comb += fast_w_dectb.wen.eq(1)
-                comb += fast_w_dectb.data_i.eq(new_dec)
+                comb += fast_w_dectb.i_data.eq(new_dec)
                 sync += spr_dec.eq(new_dec) # copy into cur_state for decoder
                 m.next = "TB_READ"
 
@@ -1012,10 +1206,10 @@ class TestIssuerInternal(Elaboratable):
             # waits for read TB to arrive, initiates write of current TB
             with m.State("TB_WRITE"):
                 new_tb = Signal(64)
-                comb += new_tb.eq(fast_r_dectb.data_o + 1)
+                comb += new_tb.eq(fast_r_dectb.o_data + 1)
                 comb += fast_w_dectb.addr.eq(FastRegs.TB)
                 comb += fast_w_dectb.wen.eq(1)
-                comb += fast_w_dectb.data_i.eq(new_tb)
+                comb += fast_w_dectb.i_data.eq(new_tb)
                 m.next = "DEC_READ"
 
         return m
@@ -1044,7 +1238,7 @@ class TestIssuerInternal(Elaboratable):
             ports += list(self.dbg.dmi.ports())
 
         ports += list(self.imem.ibus.fields.values())
-        ports += list(self.core.l0.cmpi.lsmem.lsi.slavebus.fields.values())
+        ports += list(self.core.l0.cmpi.wb_bus().fields.values())
 
         if self.sram4x4k:
             for sram in self.sram4k:
@@ -1068,25 +1262,28 @@ class TestIssuerInternal(Elaboratable):
 class TestIssuer(Elaboratable):
     def __init__(self, pspec):
         self.ti = TestIssuerInternal(pspec)
-
-        self.pll = DummyPLL()
+        self.pll = DummyPLL(instance=True)
 
         # PLL direct clock or not
         self.pll_en = hasattr(pspec, "use_pll") and pspec.use_pll
         if self.pll_en:
-            self.pll_18_o = Signal(reset_less=True)
+            self.pll_test_o = Signal(reset_less=True)
+            self.pll_vco_o = Signal(reset_less=True)
+            self.clk_sel_i = Signal(2, reset_less=True)
+            self.ref_clk =  ClockSignal() # can't rename it but that's ok
+            self.pllclk_clk = ClockSignal("pllclk")
 
     def elaborate(self, platform):
         m = Module()
         comb = m.d.comb
 
-        # TestIssuer runs at direct clock
+        # TestIssuer nominally runs at main clock, actually it is
+        # all combinatorial internally except for coresync'd components
         m.submodules.ti = ti = self.ti
-        cd_int = ClockDomain("coresync")
 
         if self.pll_en:
             # ClockSelect runs at PLL output internal clock rate
-            m.submodules.pll = pll = self.pll
+            m.submodules.wrappll = pll = self.pll
 
             # add clock domains from PLL
             cd_pll = ClockDomain("pllclk")
@@ -1094,14 +1291,17 @@ class TestIssuer(Elaboratable):
 
             # PLL clock established.  has the side-effect of running clklsel
             # at the PLL's speed (see DomainRenamer("pllclk") above)
-            pllclk = ClockSignal("pllclk")
+            pllclk = self.pllclk_clk
             comb += pllclk.eq(pll.clk_pll_o)
 
             # wire up external 24mhz to PLL
-            comb += pll.clk_24_i.eq(ClockSignal())
+            #comb += pll.clk_24_i.eq(self.ref_clk)
+            # output 18 mhz PLL test signal, and analog oscillator out
+            comb += self.pll_test_o.eq(pll.pll_test_o)
+            comb += self.pll_vco_o.eq(pll.pll_vco_o)
 
-            # output 18 mhz PLL test signal
-            comb += self.pll_18_o.eq(pll.pll_18_o)
+            # input to pll clock selection
+            comb += pll.clk_sel_i.eq(self.clk_sel_i)
 
             # now wire up ResetSignals.  don't mind them being in this domain
             pll_rst = ResetSignal("pllclk")
@@ -1109,11 +1309,24 @@ class TestIssuer(Elaboratable):
 
         # internal clock is set to selector clock-out.  has the side-effect of
         # running TestIssuer at this speed (see DomainRenamer("intclk") above)
+        # debug clock runs at coresync internal clock
+        cd_coresync = ClockDomain("coresync")
+        #m.domains += cd_coresync
+        if self.ti.dbg_domain != 'sync':
+            cd_dbgsync = ClockDomain("dbgsync")
+            #m.domains += cd_dbgsync
         intclk = ClockSignal("coresync")
+        dbgclk = ClockSignal(self.ti.dbg_domain)
+        # XXX BYPASS PLL XXX
+        # XXX BYPASS PLL XXX
+        # XXX BYPASS PLL XXX
         if self.pll_en:
-            comb += intclk.eq(pll.clk_pll_o)
+            comb += intclk.eq(self.ref_clk)
         else:
             comb += intclk.eq(ClockSignal())
+        if self.ti.dbg_domain != 'sync':
+            dbgclk = ClockSignal(self.ti.dbg_domain)
+            comb += dbgclk.eq(intclk)
 
         return m
 
@@ -1126,9 +1339,12 @@ class TestIssuer(Elaboratable):
         ports.append(ClockSignal())
         ports.append(ResetSignal())
         if self.pll_en:
-            ports.append(self.pll.clk_sel_i)
-            ports.append(self.pll_18_o)
-            ports.append(self.pll.pll_lck_o)
+            ports.append(self.clk_sel_i)
+            ports.append(self.pll.clk_24_i)
+            ports.append(self.pll_test_o)
+            ports.append(self.pll_vco_o)
+            ports.append(self.pllclk_clk)
+            ports.append(self.ref_clk)
         return ports