based on Anton Blanchard microwatt decode2.vhdl
+Note: OP_TRAP is used for exceptions and interrupts (micro-code style) by
+over-riding the internal opcode when an exception is needed.
"""
+
from nmigen import Module, Elaboratable, Signal, Mux, Const, Cat, Repl, Record
from nmigen.cli import rtlil
+from soc.regfile.regfiles import XERRegs
+from nmutil.picker import PriorityPicker
from nmutil.iocontrol import RecordObject
from nmutil.extend import exts
from soc.decoder.power_regspec_map import regspec_decode_read
from soc.decoder.power_regspec_map import regspec_decode_write
from soc.decoder.power_decoder import create_pdecode
-from soc.decoder.power_enums import (InternalOp, CryIn, Function,
+from soc.decoder.power_enums import (MicrOp, CryIn, Function,
CRInSel, CROutSel,
LdstLen, In1Sel, In2Sel, In3Sel,
- OutSel, SPR, RC)
+ OutSel, SPR, RC, LDSTMode)
from soc.decoder.decode2execute1 import Decode2ToExecute1Type, Data
+from soc.consts import MSR
from soc.regfile.regfiles import FastRegs
+from soc.consts import TT
+from soc.config.state import CoreState
+from soc.regfile.util import spr_to_fast
-# see traptype (and trap main_stage.py)
-TT_FP = 1<<0
-TT_PRIV = 1<<1
-TT_TRAP = 1<<2
-TT_ADDR = 1<<3
+def decode_spr_num(spr):
+ return Cat(spr[5:10], spr[0:5])
def instr_is_priv(m, op, insn):
"""determines if the instruction is privileged or not
"""
comb = m.d.comb
- Signal = is_priv_insn(reset_less=True)
+ is_priv_insn = Signal(reset_less=True)
with m.Switch(op):
- with m.Case(InternalOp.OP_ATTN) : comb += is_priv_insn.eq(1)
- with m.Case(InternalOp.OP_MFMSR) : comb += is_priv_insn.eq(1)
- with m.Case(InternalOp.OP_MTMSRD): comb += is_priv_insn.eq(1)
- with m.Case(InternalOp.OP_RFID) : comb += is_priv_insn.eq(1)
- with m.Case(InternalOp.OP_TLBIE) : comb += is_priv_insn.eq(1)
- with m.If(op == OP_MFSPR | op == OP_MTSPR):
- with m.If(insn[20]): # field XFX.spr[-1] i think
+ with m.Case(MicrOp.OP_ATTN, MicrOp.OP_MFMSR, MicrOp.OP_MTMSRD,
+ MicrOp.OP_MTMSR, MicrOp.OP_RFID):
comb += is_priv_insn.eq(1)
+ # XXX TODO
+ #with m.Case(MicrOp.OP_TLBIE) : comb += is_priv_insn.eq(1)
+ with m.Case(MicrOp.OP_MFSPR, MicrOp.OP_MTSPR):
+ with m.If(insn[20]): # field XFX.spr[-1] i think
+ comb += is_priv_insn.eq(1)
return is_priv_insn
+class SPRMap(Elaboratable):
+ """SPRMap: maps POWER9 SPR numbers to internal enum values, fast and slow
+ """
+
+ def __init__(self):
+ self.spr_i = Signal(10, reset_less=True)
+ self.spr_o = Data(SPR, name="spr_o")
+ self.fast_o = Data(3, name="fast_o")
+
+ def elaborate(self, platform):
+ m = Module()
+ with m.Switch(self.spr_i):
+ for i, x in enumerate(SPR):
+ with m.Case(x.value):
+ m.d.comb += self.spr_o.data.eq(i)
+ m.d.comb += self.spr_o.ok.eq(1)
+ for x, v in spr_to_fast.items():
+ with m.Case(x.value):
+ m.d.comb += self.fast_o.data.eq(v)
+ m.d.comb += self.fast_o.ok.eq(1)
+ return m
+
+
class DecodeA(Elaboratable):
"""DecodeA from instruction
- decodes register RA, whether immediate-zero, implicit and
- explicit CSRs
+ decodes register RA, implicit and explicit CSRs
"""
def __init__(self, dec):
self.sel_in = Signal(In1Sel, reset_less=True)
self.insn_in = Signal(32, reset_less=True)
self.reg_out = Data(5, name="reg_a")
- self.immz_out = Signal(reset_less=True)
- self.spr_out = Data(10, "spr_a")
+ self.spr_out = Data(SPR, "spr_a")
self.fast_out = Data(3, "fast_a")
def elaborate(self, platform):
m = Module()
comb = m.d.comb
+ m.submodules.sprmap = sprmap = SPRMap()
# select Register A field
ra = Signal(5, reset_less=True)
comb += self.reg_out.data.eq(ra)
comb += self.reg_out.ok.eq(1)
- # zero immediate requested
- with m.If((self.sel_in == In1Sel.RA_OR_ZERO) &
- (self.reg_out.data == Const(0, 5))):
- comb += self.immz_out.eq(1)
-
# some Logic/ALU ops have RS as the 3rd arg, but no "RA".
with m.If(self.sel_in == In1Sel.RS):
comb += self.reg_out.data.eq(self.dec.RS)
# decode Fast-SPR based on instruction type
op = self.dec.op
- # BC or BCREG: potential implicit register (CTR) NOTE: same in DecodeOut
- with m.If(op.internal_op == InternalOp.OP_BC):
- with m.If(~self.dec.BO[2]): # 3.0B p38 BO2=0, use CTR reg
- comb += self.fast_out.data.eq(FastRegs.CTR) # constant: CTR
- comb += self.fast_out.ok.eq(1)
- with m.Elif(op.internal_op == InternalOp.OP_BCREG):
- xo9 = self.dec.FormXL.XO[9] # 3.0B p38 top bit of XO
- xo5 = self.dec.FormXL.XO[5] # 3.0B p38
- with m.If(xo9 & ~xo5):
- comb += self.fast_out.data.eq(FastRegs.CTR) # constant: CTR
- comb += self.fast_out.ok.eq(1)
+ with m.Switch(op.internal_op):
+
+ # BC or BCREG: implicit register (CTR) NOTE: same in DecodeOut
+ with m.Case(MicrOp.OP_BC):
+ with m.If(~self.dec.BO[2]): # 3.0B p38 BO2=0, use CTR reg
+ # constant: CTR
+ comb += self.fast_out.data.eq(FastRegs.CTR)
+ comb += self.fast_out.ok.eq(1)
+ with m.Case(MicrOp.OP_BCREG):
+ xo9 = self.dec.FormXL.XO[9] # 3.0B p38 top bit of XO
+ xo5 = self.dec.FormXL.XO[5] # 3.0B p38
+ with m.If(xo9 & ~xo5):
+ # constant: CTR
+ comb += self.fast_out.data.eq(FastRegs.CTR)
+ comb += self.fast_out.ok.eq(1)
+
+ # MFSPR move from SPRs
+ with m.Case(MicrOp.OP_MFSPR):
+ spr = Signal(10, reset_less=True)
+ comb += spr.eq(decode_spr_num(self.dec.SPR)) # from XFX
+ comb += sprmap.spr_i.eq(spr)
+ comb += self.spr_out.eq(sprmap.spr_o)
+ comb += self.fast_out.eq(sprmap.fast_o)
+
+ return m
- # MFSPR move from SPRs
- with m.If(op.internal_op == InternalOp.OP_MFSPR):
- # XXX TODO: fast/slow SPR decoding and mapping
- comb += self.spr_out.data.eq(self.dec.SPR) # SPR field, XFX
- comb += self.spr_out.ok.eq(1)
+
+class DecodeAImm(Elaboratable):
+ """DecodeA immediate from instruction
+
+ decodes register RA, whether immediate-zero, implicit and
+ explicit CSRs
+ """
+
+ def __init__(self, dec):
+ self.dec = dec
+ self.sel_in = Signal(In1Sel, reset_less=True)
+ self.immz_out = Signal(reset_less=True)
+
+ def elaborate(self, platform):
+ m = Module()
+ comb = m.d.comb
+
+ # zero immediate requested
+ ra = Signal(5, reset_less=True)
+ comb += ra.eq(self.dec.RA)
+ with m.If((self.sel_in == In1Sel.RA_OR_ZERO) & (ra == Const(0, 5))):
+ comb += self.immz_out.eq(1)
return m
self.sel_in = Signal(In2Sel, reset_less=True)
self.insn_in = Signal(32, reset_less=True)
self.reg_out = Data(5, "reg_b")
- self.imm_out = Data(64, "imm_b")
self.fast_out = Data(3, "fast_b")
def elaborate(self, platform):
comb += self.reg_out.data.eq(self.dec.RB)
comb += self.reg_out.ok.eq(1)
with m.Case(In2Sel.RS):
- comb += self.reg_out.data.eq(self.dec.RS) # for M-Form shiftrot
+ # for M-Form shiftrot
+ comb += self.reg_out.data.eq(self.dec.RS)
comb += self.reg_out.ok.eq(1)
- with m.Case(In2Sel.CONST_UI):
+
+ # decode SPR2 based on instruction type
+ op = self.dec.op
+ # BCREG implicitly uses LR or TAR for 2nd reg
+ # CTR however is already in fast_spr1 *not* 2.
+ with m.If(op.internal_op == MicrOp.OP_BCREG):
+ xo9 = self.dec.FormXL.XO[9] # 3.0B p38 top bit of XO
+ xo5 = self.dec.FormXL.XO[5] # 3.0B p38
+ with m.If(~xo9):
+ comb += self.fast_out.data.eq(FastRegs.LR)
+ comb += self.fast_out.ok.eq(1)
+ with m.Elif(xo5):
+ comb += self.fast_out.data.eq(FastRegs.TAR)
+ comb += self.fast_out.ok.eq(1)
+
+ return m
+
+
+class DecodeBImm(Elaboratable):
+ """DecodeB immediate from instruction
+ """
+ def __init__(self, dec):
+ self.dec = dec
+ self.sel_in = Signal(In2Sel, reset_less=True)
+ self.imm_out = Data(64, "imm_b")
+
+ def elaborate(self, platform):
+ m = Module()
+ comb = m.d.comb
+
+ # select Register B Immediate
+ with m.Switch(self.sel_in):
+ with m.Case(In2Sel.CONST_UI): # unsigned
comb += self.imm_out.data.eq(self.dec.UI)
comb += self.imm_out.ok.eq(1)
- with m.Case(In2Sel.CONST_SI): # TODO: sign-extend here?
- comb += self.imm_out.data.eq(
- exts(self.dec.SI, 16, 64))
+ with m.Case(In2Sel.CONST_SI): # sign-extended 16-bit
+ si = Signal(16, reset_less=True)
+ comb += si.eq(self.dec.SI)
+ comb += self.imm_out.data.eq(exts(si, 16, 64))
comb += self.imm_out.ok.eq(1)
- with m.Case(In2Sel.CONST_UI_HI):
- comb += self.imm_out.data.eq(self.dec.UI<<16)
+ with m.Case(In2Sel.CONST_SI_HI): # sign-extended 16+16=32 bit
+ si_hi = Signal(32, reset_less=True)
+ comb += si_hi.eq(self.dec.SI << 16)
+ comb += self.imm_out.data.eq(exts(si_hi, 32, 64))
comb += self.imm_out.ok.eq(1)
- with m.Case(In2Sel.CONST_SI_HI): # TODO: sign-extend here?
- comb += self.imm_out.data.eq(self.dec.SI<<16)
- comb += self.imm_out.data.eq(
- exts(self.dec.SI << 16, 32, 64))
+ with m.Case(In2Sel.CONST_UI_HI): # unsigned
+ ui = Signal(16, reset_less=True)
+ comb += ui.eq(self.dec.UI)
+ comb += self.imm_out.data.eq(ui << 16)
comb += self.imm_out.ok.eq(1)
- with m.Case(In2Sel.CONST_LI):
- comb += self.imm_out.data.eq(self.dec.LI<<2)
+ with m.Case(In2Sel.CONST_LI): # sign-extend 24+2=26 bit
+ li = Signal(26, reset_less=True)
+ comb += li.eq(self.dec.LI << 2)
+ comb += self.imm_out.data.eq(exts(li, 26, 64))
comb += self.imm_out.ok.eq(1)
- with m.Case(In2Sel.CONST_BD):
- comb += self.imm_out.data.eq(self.dec.BD<<2)
+ with m.Case(In2Sel.CONST_BD): # sign-extend (14+2)=16 bit
+ bd = Signal(16, reset_less=True)
+ comb += bd.eq(self.dec.BD << 2)
+ comb += self.imm_out.data.eq(exts(bd, 16, 64))
comb += self.imm_out.ok.eq(1)
- with m.Case(In2Sel.CONST_DS):
- comb += self.imm_out.data.eq(self.dec.DS<<2)
+ with m.Case(In2Sel.CONST_DS): # sign-extended (14+2=16) bit
+ ds = Signal(16, reset_less=True)
+ comb += ds.eq(self.dec.DS << 2)
+ comb += self.imm_out.data.eq(exts(ds, 16, 64))
comb += self.imm_out.ok.eq(1)
- with m.Case(In2Sel.CONST_M1):
- comb += self.imm_out.data.eq(~Const(0, 64)) # all 1s
+ with m.Case(In2Sel.CONST_M1): # signed (-1)
+ comb += self.imm_out.data.eq(~Const(0, 64)) # all 1s
comb += self.imm_out.ok.eq(1)
- with m.Case(In2Sel.CONST_SH):
+ with m.Case(In2Sel.CONST_SH): # unsigned - for shift
comb += self.imm_out.data.eq(self.dec.sh)
comb += self.imm_out.ok.eq(1)
- with m.Case(In2Sel.CONST_SH32):
+ with m.Case(In2Sel.CONST_SH32): # unsigned - for shift
comb += self.imm_out.data.eq(self.dec.SH32)
comb += self.imm_out.ok.eq(1)
- # decode SPR2 based on instruction type
- op = self.dec.op
- # BCREG implicitly uses LR or TAR for 2nd reg
- # CTR however is already in fast_spr1 *not* 2.
- with m.If(op.internal_op == InternalOp.OP_BCREG):
- xo9 = self.dec.FormXL.XO[9] # 3.0B p38 top bit of XO
- xo5 = self.dec.FormXL.XO[5] # 3.0B p38
- with m.If(~xo9):
- comb += self.fast_out.data.eq(FastRegs.LR)
- comb += self.fast_out.ok.eq(1)
- with m.Elif(xo5):
- comb += self.fast_out.data.eq(FastRegs.TAR)
- comb += self.fast_out.ok.eq(1)
-
return m
# select Register C field
with m.Switch(self.sel_in):
with m.Case(In3Sel.RB):
- comb += self.reg_out.data.eq(self.dec.RB) # for M-Form shiftrot
+ # for M-Form shiftrot
+ comb += self.reg_out.data.eq(self.dec.RB)
comb += self.reg_out.ok.eq(1)
with m.Case(In3Sel.RS):
comb += self.reg_out.data.eq(self.dec.RS)
self.sel_in = Signal(OutSel, reset_less=True)
self.insn_in = Signal(32, reset_less=True)
self.reg_out = Data(5, "reg_o")
- self.spr_out = Data(10, "spr_o")
+ self.spr_out = Data(SPR, "spr_o")
self.fast_out = Data(3, "fast_o")
def elaborate(self, platform):
m = Module()
comb = m.d.comb
+ m.submodules.sprmap = sprmap = SPRMap()
op = self.dec.op
# select Register out field
comb += self.reg_out.data.eq(self.dec.RA)
comb += self.reg_out.ok.eq(1)
with m.Case(OutSel.SPR):
- comb += self.spr_out.data.eq(self.dec.SPR) # from XFX
- comb += self.spr_out.ok.eq(1)
- # TODO MTSPR 1st spr (fast)
- with m.If(op.internal_op == InternalOp.OP_MTSPR):
- pass
- """
- sprn := decode_spr_num(f_in.insn);
- v.ispr1 := fast_spr_num(sprn);
- -- Make slow SPRs single issue
- if is_fast_spr(v.ispr1) = '0' then
- v.decode.sgl_pipe := '1';
- -- send MMU-related SPRs to loadstore1
- case sprn is
- when SPR_DAR | SPR_DSISR | SPR_PID | SPR_PRTBL =>
- v.decode.unit := LDST;
- when others =>
- end case;
- end if;
- """
-
-
- # BC or BCREG: potential implicit register (CTR) NOTE: same in DecodeA
- op = self.dec.op
- with m.If((op.internal_op == InternalOp.OP_BC) |
- (op.internal_op == InternalOp.OP_BCREG)):
- with m.If(~self.dec.BO[2]): # 3.0B p38 BO2=0, use CTR reg
- comb += self.fast_out.data.eq(FastRegs.CTR) # constant: CTR
+ spr = Signal(10, reset_less=True)
+ comb += spr.eq(decode_spr_num(self.dec.SPR)) # from XFX
+ # MFSPR move to SPRs - needs mapping
+ with m.If(op.internal_op == MicrOp.OP_MTSPR):
+ comb += sprmap.spr_i.eq(spr)
+ comb += self.spr_out.eq(sprmap.spr_o)
+ comb += self.fast_out.eq(sprmap.fast_o)
+
+ with m.Switch(op.internal_op):
+
+ # BC or BCREG: implicit register (CTR) NOTE: same in DecodeA
+ with m.Case(MicrOp.OP_BC, MicrOp.OP_BCREG):
+ with m.If(~self.dec.BO[2]): # 3.0B p38 BO2=0, use CTR reg
+ # constant: CTR
+ comb += self.fast_out.data.eq(FastRegs.CTR)
+ comb += self.fast_out.ok.eq(1)
+
+ # RFID 1st spr (fast)
+ with m.Case(MicrOp.OP_RFID):
+ comb += self.fast_out.data.eq(FastRegs.SRR0) # constant: SRR0
comb += self.fast_out.ok.eq(1)
- # RFID 1st spr (fast)
- with m.If(op.internal_op == InternalOp.OP_RFID):
- comb += self.fast_out.data.eq(FastRegs.SRR0) # constant: SRR0
- comb += self.fast_out.ok.eq(1)
-
return m
comb = m.d.comb
# update mode LD/ST uses read-reg A also as an output
- with m.If(self.dec.op.upd):
+ with m.If(self.dec.op.upd == LDSTMode.update):
comb += self.reg_out.eq(self.dec.RA)
comb += self.reg_out.ok.eq(1)
- # BC or BCREG: potential implicit register (LR) output
+ # B, BC or BCREG: potential implicit register (LR) output
+ # these give bl, bcl, bclrl, etc.
op = self.dec.op
- with m.If((op.internal_op == InternalOp.OP_BC) |
- (op.internal_op == InternalOp.OP_BCREG)):
- with m.If(self.lk): # "link" mode
- comb += self.fast_out.data.eq(FastRegs.LR) # constant: LR
- comb += self.fast_out.ok.eq(1)
+ with m.Switch(op.internal_op):
- # RFID 2nd spr (fast)
- with m.If(op.internal_op == InternalOp.OP_RFID):
- comb += self.fast_out.data.eq(FastRegs.SRR1) # constant: SRR1
+ # BC* implicit register (LR)
+ with m.Case(MicrOp.OP_BC, MicrOp.OP_B, MicrOp.OP_BCREG):
+ with m.If(self.lk): # "link" mode
+ comb += self.fast_out.data.eq(FastRegs.LR) # constant: LR
+ comb += self.fast_out.ok.eq(1)
+
+ # RFID 2nd spr (fast)
+ with m.Case(MicrOp.OP_RFID):
+ comb += self.fast_out.data.eq(FastRegs.SRR1) # constant: SRR1
comb += self.fast_out.ok.eq(1)
return m
decodes Record bit Rc
"""
+
def __init__(self, dec):
self.dec = dec
self.sel_in = Signal(RC, reset_less=True)
-- actual POWER9 does if we set it on those instructions, for now we
-- test that further down when assigning to the multiplier oe input.
"""
+
def __init__(self, dec):
self.dec = dec
self.sel_in = Signal(RC, reset_less=True)
def elaborate(self, platform):
m = Module()
comb = m.d.comb
+ op = self.dec.op
- # select OE bit out field
- with m.Switch(self.sel_in):
- with m.Case(RC.RC):
- comb += self.oe_out.data.eq(self.dec.OE)
- comb += self.oe_out.ok.eq(1)
+ with m.Switch(op.internal_op):
+
+ # mulhw, mulhwu, mulhd, mulhdu - these *ignore* OE
+ # also rotate
+ # XXX ARGH! ignoring OE causes incompatibility with microwatt
+ # http://lists.libre-soc.org/pipermail/libre-soc-dev/2020-August/000302.html
+ with m.Case(MicrOp.OP_MUL_H64, MicrOp.OP_MUL_H32,
+ MicrOp.OP_EXTS, MicrOp.OP_CNTZ,
+ MicrOp.OP_SHL, MicrOp.OP_SHR, MicrOp.OP_RLC,
+ MicrOp.OP_LOAD, MicrOp.OP_STORE,
+ MicrOp.OP_RLCL, MicrOp.OP_RLCR,
+ MicrOp.OP_EXTSWSLI):
+ pass
+
+ # all other ops decode OE field
+ with m.Default():
+ # select OE bit out field
+ with m.Switch(self.sel_in):
+ with m.Case(RC.RC):
+ comb += self.oe_out.data.eq(self.dec.OE)
+ comb += self.oe_out.ok.eq(1)
return m
+
class DecodeCRIn(Elaboratable):
"""Decodes input CR from instruction
self.cr_bitfield = Data(3, "cr_bitfield")
self.cr_bitfield_b = Data(3, "cr_bitfield_b")
self.cr_bitfield_o = Data(3, "cr_bitfield_o")
- self.whole_reg = Signal(reset_less=True)
+ self.whole_reg = Data(8, "cr_fxm")
def elaborate(self, platform):
m = Module()
+ m.submodules.ppick = ppick = PriorityPicker(8, reverse_i=True,
+ reverse_o=True)
+
comb = m.d.comb
+ op = self.dec.op
comb += self.cr_bitfield.ok.eq(0)
comb += self.cr_bitfield_b.ok.eq(0)
- comb += self.whole_reg.eq(0)
+ comb += self.whole_reg.ok.eq(0)
with m.Switch(self.sel_in):
with m.Case(CRInSel.NONE):
- pass # No bitfield activated
+ pass # No bitfield activated
with m.Case(CRInSel.CR0):
- comb += self.cr_bitfield.data.eq(0)
+ comb += self.cr_bitfield.data.eq(0) # CR0 (MSB0 numbering)
comb += self.cr_bitfield.ok.eq(1)
with m.Case(CRInSel.BI):
comb += self.cr_bitfield.data.eq(self.dec.BI[2:5])
comb += self.cr_bitfield.data.eq(self.dec.BC[2:5])
comb += self.cr_bitfield.ok.eq(1)
with m.Case(CRInSel.WHOLE_REG):
- comb += self.whole_reg.eq(1)
+ comb += self.whole_reg.ok.eq(1)
+ move_one = Signal(reset_less=True)
+ comb += move_one.eq(self.insn_in[20]) # MSB0 bit 11
+ with m.If((op.internal_op == MicrOp.OP_MFCR) & move_one):
+ # must one-hot the FXM field
+ comb += ppick.i.eq(self.dec.FXM)
+ comb += self.whole_reg.data.eq(ppick.o)
+ with m.Else():
+ # otherwise use all of it
+ comb += self.whole_reg.data.eq(0xff)
return m
self.sel_in = Signal(CROutSel, reset_less=True)
self.insn_in = Signal(32, reset_less=True)
self.cr_bitfield = Data(3, "cr_bitfield")
- self.whole_reg = Signal(reset_less=True)
+ self.whole_reg = Data(8, "cr_fxm")
def elaborate(self, platform):
m = Module()
comb = m.d.comb
+ op = self.dec.op
+ m.submodules.ppick = ppick = PriorityPicker(8, reverse_i=True,
+ reverse_o=True)
comb += self.cr_bitfield.ok.eq(0)
- comb += self.whole_reg.eq(0)
+ comb += self.whole_reg.ok.eq(0)
with m.Switch(self.sel_in):
with m.Case(CROutSel.NONE):
- pass # No bitfield activated
+ pass # No bitfield activated
with m.Case(CROutSel.CR0):
- comb += self.cr_bitfield.data.eq(0)
- comb += self.cr_bitfield.ok.eq(self.rc_in) # only when RC=1
+ comb += self.cr_bitfield.data.eq(0) # CR0 (MSB0 numbering)
+ comb += self.cr_bitfield.ok.eq(self.rc_in) # only when RC=1
with m.Case(CROutSel.BF):
comb += self.cr_bitfield.data.eq(self.dec.FormX.BF)
comb += self.cr_bitfield.ok.eq(1)
comb += self.cr_bitfield.data.eq(self.dec.FormXL.BT[2:5])
comb += self.cr_bitfield.ok.eq(1)
with m.Case(CROutSel.WHOLE_REG):
- comb += self.whole_reg.eq(1)
+ comb += self.whole_reg.ok.eq(1)
+ move_one = Signal(reset_less=True)
+ comb += move_one.eq(self.insn_in[20])
+ with m.If((op.internal_op == MicrOp.OP_MTCRF)):
+ with m.If(move_one):
+ # must one-hot the FXM field
+ comb += ppick.i.eq(self.dec.FXM)
+ with m.If(ppick.en_o):
+ comb += self.whole_reg.data.eq(ppick.o)
+ with m.Else():
+ comb += self.whole_reg.data.eq(0b00000001) # CR7
+ with m.Else():
+ comb += self.whole_reg.data.eq(self.dec.FXM)
+ with m.Else():
+ # otherwise use all of it
+ comb += self.whole_reg.data.eq(0xff)
return m
-class XerBits:
- def __init__(self):
- self.ca = Signal(2, reset_less=True)
- self.ov = Signal(2, reset_less=True)
- self.so = Signal(reset_less=True)
+class PowerDecodeSubset(Elaboratable):
+ """PowerDecodeSubset: dynamic subset decoder
- def ports(self):
- return [self.ca, self.ov, self.so]
+ """
+ def __init__(self, dec, opkls=None, fn_name=None, col_subset=None):
-class PowerDecode2(Elaboratable):
+ if dec is None:
+ self.opkls = opkls
+ self.fn_name = fn_name
+ self.dec = create_pdecode(name=fn_name, col_subset=col_subset,
+ row_subset=self.rowsubsetfn)
+ else:
+ self.dec = dec
+ self.opkls = None
+ self.fn_name = None
+ self.e = Decode2ToExecute1Type(name=self.fn_name, opkls=self.opkls)
- def __init__(self, dec):
+ # state information needed by the Decoder (TODO: this as a Record)
+ self.state = CoreState("dec2")
- self.dec = dec
- self.e = Decode2ToExecute1Type()
+ def rowsubsetfn(self, opcode, row):
+ return row['unit'] == self.fn_name
def ports(self):
return self.dec.ports() + self.e.ports()
+ def needs_field(self, field, op_field):
+ do = self.e_tmp.do
+ return hasattr(do, field) and self.op_get(op_field)
+
+ def do_copy(self, field, val, final=False):
+ if final:
+ do = self.e.do
+ else:
+ do = self.e_tmp.do
+ if hasattr(do, field) and val is not None:
+ return getattr(do, field).eq(val)
+ return []
+
+ def op_get(self, op_field):
+ return getattr(self.dec.op, op_field, None)
+
def elaborate(self, platform):
m = Module()
comb = m.d.comb
- e, op = self.e, self.dec.op
+ state = self.state
+ e_out, op, do_out = self.e, self.dec.op, self.e.do
+ dec_spr, msr, cia, ext_irq = state.dec, state.msr, state.pc, state.eint
+
+ # fill in for a normal instruction (not an exception)
+ # copy over if non-exception, non-privileged etc. is detected
+ self.e_tmp = e = Decode2ToExecute1Type(name=self.fn_name,
+ opkls=self.opkls)
+ do = e.do
# set up submodule decoders
m.submodules.dec = self.dec
+ m.submodules.dec_ai = dec_ai = DecodeAImm(self.dec)
+ m.submodules.dec_bi = dec_bi = DecodeBImm(self.dec)
+ m.submodules.dec_rc = dec_rc = DecodeRC(self.dec)
+ m.submodules.dec_oe = dec_oe = DecodeOE(self.dec)
+ m.submodules.dec_cr_in = self.dec_cr_in = DecodeCRIn(self.dec)
+ m.submodules.dec_cr_out = self.dec_cr_out = DecodeCROut(self.dec)
+
+ # copy instruction through...
+ for i in [do.insn,
+ dec_rc.insn_in, dec_oe.insn_in,
+ self.dec_cr_in.insn_in, self.dec_cr_out.insn_in]:
+ comb += i.eq(self.dec.opcode_in)
+
+ # ...and subdecoders' input fields
+ comb += dec_ai.sel_in.eq(op.in1_sel)
+ comb += dec_bi.sel_in.eq(op.in2_sel)
+ comb += dec_rc.sel_in.eq(op.rc_sel)
+ comb += dec_oe.sel_in.eq(op.rc_sel) # XXX should be OE sel
+ comb += self.dec_cr_in.sel_in.eq(op.cr_in)
+ comb += self.dec_cr_out.sel_in.eq(op.cr_out)
+ comb += self.dec_cr_out.rc_in.eq(dec_rc.rc_out.data)
+
+ # copy "state" over
+ comb += self.do_copy("msr", msr)
+ comb += self.do_copy("cia", cia)
+
+ # set up instruction, pick fn unit
+ # no op: defaults to OP_ILLEGAL
+ comb += self.do_copy("insn_type", self.op_get("internal_op"))
+ comb += self.do_copy("fn_unit", self.op_get("function_unit"))
+
+ # immediates
+ comb += self.do_copy("imm_data", dec_bi.imm_out) # imm in RB
+ comb += self.do_copy("zero_a", dec_ai.immz_out) # RA==0 detected
+
+ # rc and oe out
+ comb += self.do_copy("rc", dec_rc.rc_out)
+ comb += self.do_copy("oe", dec_oe.oe_out)
+
+ comb += self.do_copy("read_cr_whole", self.dec_cr_in.whole_reg)
+ comb += self.do_copy("write_cr_whole", self.dec_cr_out.whole_reg)
+ comb += self.do_copy("write_cr0", self.dec_cr_out.cr_bitfield.ok)
+
+ # decoded/selected instruction flags
+ comb += self.do_copy("data_len", self.op_get("ldst_len"))
+ comb += self.do_copy("invert_in", self.op_get("inv_a"))
+ comb += self.do_copy("invert_out", self.op_get("inv_out"))
+ comb += self.do_copy("input_carry", self.op_get("cry_in"))
+ comb += self.do_copy("output_carry", self.op_get("cry_out"))
+ comb += self.do_copy("is_32bit", self.op_get("is_32b"))
+ comb += self.do_copy("is_signed", self.op_get("sgn"))
+ lk = self.op_get("lk")
+ if lk is not None:
+ with m.If(lk):
+ comb += self.do_copy("lk", self.dec.LK) # XXX TODO: accessor
+
+ comb += self.do_copy("byte_reverse", self.op_get("br"))
+ comb += self.do_copy("sign_extend", self.op_get("sgn_ext"))
+ comb += self.do_copy("ldst_mode", self.op_get("upd")) # LD/ST mode
+
+ # These should be removed eventually
+ comb += self.do_copy("input_cr", self.op_get("cr_in")) # CR in
+ comb += self.do_copy("output_cr", self.op_get("cr_out")) # CR out
+
+ return m
+
+
+class PowerDecode2(PowerDecodeSubset):
+ """PowerDecode2: the main instruction decoder.
+
+ whilst PowerDecode is responsible for decoding the actual opcode, this
+ module encapsulates further specialist, sparse information and
+ expansion of fields that is inconvenient to have in the CSV files.
+ for example: the encoding of the immediates, which are detected
+ and expanded out to their full value from an annotated (enum)
+ representation.
+
+ implicit register usage is also set up, here. for example: OP_BC
+ requires implicitly reading CTR, OP_RFID requires implicitly writing
+ to SRR1 and so on.
+
+ in addition, PowerDecoder2 is responsible for detecting whether
+ instructions are illegal (or privileged) or not, and instead of
+ just leaving at that, *replacing* the instruction to execute with
+ a suitable alternative (trap).
+ """
+
+ def elaborate(self, platform):
+ m = super().elaborate(platform)
+ comb = m.d.comb
+ state = self.state
+ e_out, op, do_out = self.e, self.dec.op, self.e.do
+ dec_spr, msr, cia, ext_irq = state.dec, state.msr, state.pc, state.eint
+ e = self.e_tmp
+ do = e.do
+
+ # fill in for a normal instruction (not an exception)
+ # copy over if non-exception, non-privileged etc. is detected
+
+ # set up submodule decoders
m.submodules.dec_a = dec_a = DecodeA(self.dec)
m.submodules.dec_b = dec_b = DecodeB(self.dec)
m.submodules.dec_c = dec_c = DecodeC(self.dec)
m.submodules.dec_o = dec_o = DecodeOut(self.dec)
m.submodules.dec_o2 = dec_o2 = DecodeOut2(self.dec)
- m.submodules.dec_rc = dec_rc = DecodeRC(self.dec)
- m.submodules.dec_oe = dec_oe = DecodeOE(self.dec)
- m.submodules.dec_cr_in = dec_cr_in = DecodeCRIn(self.dec)
- m.submodules.dec_cr_out = dec_cr_out = DecodeCROut(self.dec)
# copy instruction through...
- for i in [e.insn, dec_a.insn_in, dec_b.insn_in,
- dec_c.insn_in, dec_o.insn_in, dec_o2.insn_in, dec_rc.insn_in,
- dec_oe.insn_in, dec_cr_in.insn_in, dec_cr_out.insn_in]:
+ for i in [do.insn, dec_a.insn_in, dec_b.insn_in,
+ dec_c.insn_in, dec_o.insn_in, dec_o2.insn_in]:
comb += i.eq(self.dec.opcode_in)
# ...and subdecoders' input fields
comb += dec_c.sel_in.eq(op.in3_sel)
comb += dec_o.sel_in.eq(op.out_sel)
comb += dec_o2.sel_in.eq(op.out_sel)
- comb += dec_o2.lk.eq(e.lk)
- comb += dec_rc.sel_in.eq(op.rc_sel)
- comb += dec_oe.sel_in.eq(op.rc_sel) # XXX should be OE sel
- comb += dec_cr_in.sel_in.eq(op.cr_in)
- comb += dec_cr_out.sel_in.eq(op.cr_out)
- comb += dec_cr_out.rc_in.eq(dec_rc.rc_out.data)
-
-
- comb += e.nia.eq(0) # XXX TODO (or remove? not sure yet)
- fu = op.function_unit
- itype = Mux(fu == Function.NONE, InternalOp.OP_ILLEGAL, op.internal_op)
- comb += e.insn_type.eq(itype)
- comb += e.fn_unit.eq(fu)
+ if hasattr(do, "lk"):
+ comb += dec_o2.lk.eq(do.lk)
# registers a, b, c and out and out2 (LD/ST EA)
comb += e.read_reg1.eq(dec_a.reg_out)
comb += e.read_reg3.eq(dec_c.reg_out)
comb += e.write_reg.eq(dec_o.reg_out)
comb += e.write_ea.eq(dec_o2.reg_out)
- comb += e.imm_data.eq(dec_b.imm_out) # immediate in RB (usually)
- comb += e.zero_a.eq(dec_a.immz_out) # RA==0 detected
-
- # rc and oe out
- comb += e.rc.eq(dec_rc.rc_out)
- comb += e.oe.eq(dec_oe.oe_out)
# SPRs out
comb += e.read_spr1.eq(dec_a.spr_out)
comb += e.write_fast1.eq(dec_o.fast_out)
comb += e.write_fast2.eq(dec_o2.fast_out)
- comb += e.read_cr1.eq(dec_cr_in.cr_bitfield)
- comb += e.read_cr2.eq(dec_cr_in.cr_bitfield_b)
- comb += e.read_cr3.eq(dec_cr_in.cr_bitfield_o)
- comb += e.read_cr_whole.eq(dec_cr_in.whole_reg)
-
- comb += e.write_cr.eq(dec_cr_out.cr_bitfield)
- comb += e.write_cr_whole.eq(dec_cr_out.whole_reg)
-
- # decoded/selected instruction flags
- comb += e.data_len.eq(op.ldst_len)
- comb += e.invert_a.eq(op.inv_a)
- comb += e.invert_out.eq(op.inv_out)
- comb += e.input_carry.eq(op.cry_in) # carry comes in
- comb += e.output_carry.eq(op.cry_out) # carry goes out
- comb += e.is_32bit.eq(op.is_32b)
- comb += e.is_signed.eq(op.sgn)
- with m.If(op.lk):
- comb += e.lk.eq(self.dec.LK) # XXX TODO: accessor
-
- comb += e.byte_reverse.eq(op.br)
- comb += e.sign_extend.eq(op.sgn_ext)
- comb += e.update.eq(op.upd) # LD/ST "update" mode.
+ # condition registers (CR)
+ comb += e.read_cr1.eq(self.dec_cr_in.cr_bitfield)
+ comb += e.read_cr2.eq(self.dec_cr_in.cr_bitfield_b)
+ comb += e.read_cr3.eq(self.dec_cr_in.cr_bitfield_o)
+ comb += e.write_cr.eq(self.dec_cr_out.cr_bitfield)
+
+ # sigh this is exactly the sort of thing for which the
+ # decoder is designed to not need. MTSPR, MFSPR and others need
+ # access to the XER bits. however setting e.oe is not appropriate
+ with m.If(op.internal_op == MicrOp.OP_MFSPR):
+ comb += e.xer_in.eq(0b111) # SO, CA, OV
+ with m.If(op.internal_op == MicrOp.OP_CMP):
+ comb += e.xer_in.eq(1<<XERRegs.SO) # SO
+ with m.If(op.internal_op == MicrOp.OP_MTSPR):
+ comb += e.xer_out.eq(1)
+
+ # set the trapaddr to 0x700 for a td/tw/tdi/twi operation
+ with m.If(op.internal_op == MicrOp.OP_TRAP):
+ # *DO NOT* call self.trap here. that would reset absolutely
+ # rverything including destroying read of RA and RB.
+ comb += self.do_copy("trapaddr", 0x70, True) # strip first nibble
+
+ # check if instruction is privileged
+ is_priv_insn = instr_is_priv(m, op.internal_op, e.do.insn)
+
+ # external interrupt? only if MSR.EE set
+ with m.If(ext_irq & msr[MSR.EE]): # v3.0B p944 (MSR.EE)
+ self.trap(m, TT.EINT, 0x500)
+
+ # decrement counter (v3.0B p1099): TODO 32-bit version (MSR.LPCR)
+ with m.If(dec_spr[63] & msr[MSR.EE]): # v3.0B 6.5.11 p1076
+ self.trap(m, TT.DEC, 0x900) # v3.0B 6.5 p1065
+
+ # privileged instruction trap
+ with m.Elif(is_priv_insn & msr[MSR.PR]):
+ self.trap(m, TT.PRIV, 0x700)
+
+ # illegal instruction must redirect to trap. this is done by
+ # *overwriting* the decoded instruction and starting again.
+ # (note: the same goes for interrupts and for privileged operations,
+ # just with different trapaddr and traptype)
+ with m.Elif(op.internal_op == MicrOp.OP_ILLEGAL):
+ # illegal instruction trap
+ self.trap(m, TT.ILLEG, 0x700)
+
+ # no exception, just copy things to the output
+ with m.Else():
+ comb += e_out.eq(e)
+
+ # trap: (note e.insn_type so this includes OP_ILLEGAL) set up fast regs
+ # Note: OP_SC could actually be modified to just be a trap
+ with m.If((do_out.insn_type == MicrOp.OP_TRAP) |
+ (do_out.insn_type == MicrOp.OP_SC)):
+ # TRAP write fast1 = SRR0
+ comb += e_out.write_fast1.data.eq(FastRegs.SRR0) # constant: SRR0
+ comb += e_out.write_fast1.ok.eq(1)
+ # TRAP write fast2 = SRR1
+ comb += e_out.write_fast2.data.eq(FastRegs.SRR1) # constant: SRR1
+ comb += e_out.write_fast2.ok.eq(1)
+
+ # RFID: needs to read SRR0/1
+ with m.If(do_out.insn_type == MicrOp.OP_RFID):
+ # TRAP read fast1 = SRR0
+ comb += e_out.read_fast1.data.eq(FastRegs.SRR0) # constant: SRR0
+ comb += e_out.read_fast1.ok.eq(1)
+ # TRAP read fast2 = SRR1
+ comb += e_out.read_fast2.data.eq(FastRegs.SRR1) # constant: SRR1
+ comb += e_out.read_fast2.ok.eq(1)
-
- # These should be removed eventually
- comb += e.input_cr.eq(op.cr_in) # condition reg comes in
- comb += e.output_cr.eq(op.cr_out) # condition reg goes in
-
- return m
-
- # privileged instruction
- with m.If(instr_is_priv(m, op.internal_op, e.insn) & msr[MSR_PR]):
- # don't request registers RA/RT
- comb += e.read_reg1.eq(0)
- comb += e.read_reg2.eq(0)
- comb += e.read_reg3.eq(0)
- comb += e.write_reg.eq(0)
- comb += e.write_ea.eq(0)
- # privileged instruction trap
- comb += op.internal_op.eq(InternalOp.OP_TRAP)
- comb += e.traptype.eq(TT_PRIV) # request privileged instruction
- comb += e.trapaddr.eq(0x70) # addr=0x700 (strip first nibble)
return m
- def regspecmap_read(self, regfile, regname):
- """regspecmap_read: provides PowerDecode2 with an encoding relationship
- to Function Unit port regfiles (read-enable, read regnum, write regnum)
- regfile and regname arguments are fields 1 and 2 from a given regspec.
+ def trap(self, m, traptype, trapaddr):
+ """trap: this basically "rewrites" the decoded instruction as a trap
"""
- return regspec_decode_read(self.e, regfile, regname)
+ comb = m.d.comb
+ op, e = self.dec.op, self.e
+ comb += e.eq(0) # reset eeeeeverything
- def regspecmap_write(self, regfile, regname):
- """regspecmap_write: provides PowerDecode2 with an encoding relationship
- to Function Unit port regfiles (write port, write regnum)
- regfile and regname arguments are fields 1 and 2 from a given regspec.
- """
- return regspec_decode_write(self.e, regfile, regname)
+ # start again
+ comb += self.do_copy("insn", self.dec.opcode_in, True)
+ comb += self.do_copy("insn_type", MicrOp.OP_TRAP, True)
+ comb += self.do_copy("fn_unit", Function.TRAP, True)
+ comb += self.do_copy("trapaddr", trapaddr >> 4, True) # bottom 4 bits
+ comb += self.do_copy("traptype", traptype, True) # request type
+ comb += self.do_copy("msr", self.state.msr, True) # copy of MSR "state"
+ comb += self.do_copy("cia", self.state.pc, True) # copy of PC "state"
- def rdflags(self, cu):
- rdl = []
- for idx in range(cu.n_src):
- regfile, regname, _ = cu.get_in_spec(idx)
- rdflag, read = self.regspecmap_read(regfile, regname)
- rdl.append(rdflag)
- print ("rdflags", rdl)
- return Cat(*rdl)
+
+def get_rdflags(e, cu):
+ rdl = []
+ for idx in range(cu.n_src):
+ regfile, regname, _ = cu.get_in_spec(idx)
+ rdflag, read = regspec_decode_read(e, regfile, regname)
+ rdl.append(rdflag)
+ print("rdflags", rdl)
+ return Cat(*rdl)
if __name__ == '__main__':
vl = rtlil.convert(dec2, ports=dec2.ports() + pdecode.ports())
with open("dec2.il", "w") as f:
f.write(vl)
-
projects / soc.git / blobdiff