"""
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 nmigen.lib.coding import PriorityEncoder
+
from soc.decoder.power_decoder import create_pdecode
from soc.decoder.power_decoder2 import PowerDecode2, SVP64PrefixDecoder
from soc.decoder.decode2execute1 import IssuerDecode2ToOperand
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.data_o)
return res
def get_predint(m, mask, name):
# 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'
if self.jtag_en:
- subset = {'uart', 'mtwi', 'eint', 'gpio', 'mspi0', 'mspi1',
- 'pwm', 'sd0', 'sdr'}
+ # 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))
# add signals to pspec to enable/disable icache and dcache
# (or data and intstruction wishbone if icache/dcache not included)
self.cur_state = CoreState("cur") # current state (MSR/PC/SVSTATE)
self.pdecode2 = PowerDecode2(pdecode, state=self.cur_state,
opkls=IssuerDecode2ToOperand,
- svp64_en=self.svp64_en)
+ svp64_en=self.svp64_en,
+ regreduce_en=self.regreduce_en)
if self.svp64_en:
self.svp64 = SVP64PrefixDecoder() # for decoding SVP64 prefix
predmode = rm_dec.predmode
srcpred, dstpred = rm_dec.srcpred, rm_dec.dstpred
cr_pred, int_pred = self.cr_pred, self.int_pred # read regfiles
+ # 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
# elif predmode == CR:
# CR-src sidx, sinvert = get_predcr(m, srcpred)
with m.State("INT_DST_READ"):
# store destination mask
inv = Repl(dinvert, 64)
- sync += self.dstmask.eq(self.int_pred.data_o ^ inv)
+ new_dstmask = Signal(64)
+ with m.If(dunary):
+ # set selected mask bit for 1<<r3 mode
+ dst_shift = Signal(range(64))
+ comb += dst_shift.eq(self.int_pred.data_o & 0b111111)
+ comb += new_dstmask.eq(1 << dst_shift)
+ with m.Else():
+ # invert mask if requested
+ comb += new_dstmask.eq(self.int_pred.data_o ^ inv)
+ # shift-out already used mask bits
+ sync += self.dstmask.eq(new_dstmask >> dststep)
# skip fetching source mask register, when zero
with m.If(sall1s):
sync += self.srcmask.eq(-1)
with m.State("INT_SRC_READ"):
# store source mask
inv = Repl(sinvert, 64)
- sync += self.srcmask.eq(self.int_pred.data_o ^ inv)
+ new_srcmask = Signal(64)
+ with m.If(sunary):
+ # set selected mask bit for 1<<r3 mode
+ src_shift = Signal(range(64))
+ comb += src_shift.eq(self.int_pred.data_o & 0b111111)
+ comb += new_srcmask.eq(1 << src_shift)
+ with m.Else():
+ # invert mask if requested
+ comb += new_srcmask.eq(self.int_pred.data_o ^ inv)
+ # shift-out already used mask bits
+ sync += self.srcmask.eq(new_srcmask >> srcstep)
m.next = "FETCH_PRED_DONE"
with m.State("FETCH_PRED_DONE"):
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 += 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)
# 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.
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.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):
+ 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
- """
- TODO: actually, can use
- PriorityEncoder(self.srcmask | (1<<cur_srcstep))
-
- 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.data_i.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"
- """
+ # after src/dst step have been updated, we are ready
+ # to decode the instruction
+ with m.State("DECODE_SV"):
+ # 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)
+ m.next = "INSN_EXECUTE" # move to "execute"
+ # handshake with execution FSM, move to "wait" once acknowledged
+ with m.State("INSN_EXECUTE"):
comb += exec_insn_valid_i.eq(1) # trigger execute
with m.If(exec_insn_ready_o): # execute acknowledged us
m.next = "EXECUTE_WAIT"
comb += self.state_w_pc.wen.eq(1 << StateRegs.PC)
comb += self.state_w_pc.data_i.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)
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 += 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)
# set up peripherals and core
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)
pc_changed = Signal() # note write to PC
# 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
# 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)
exec_insn_valid_i, exec_insn_ready_o,
exec_pc_valid_o, exec_pc_ready_i)
+ # 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
self.do_dmi(m, dbg)
projects / soc.git / blobdiff