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 nmutil.iocontrol import RecordObject
from nmutil.extend import exts
-from soc.decoder.power_regspec_map import regspec_decode
+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
+# see traptype (and trap main_stage.py)
+
+TT_FP = 1<<0
+TT_PRIV = 1<<1
+TT_TRAP = 1<<2
+TT_ADDR = 1<<3
+TT_ILLEG = 1<<4
+
+def decode_spr_num(spr):
+ return Cat(spr[5:10], spr[0:5])
-def instr_is_privileged(m, op, insn):
+
+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
- comb += is_priv_insn.eq(1)
+ with m.Case(MicrOp.OP_ATTN) : comb += is_priv_insn.eq(1)
+ with m.Case(MicrOp.OP_MFMSR) : comb += is_priv_insn.eq(1)
+ with m.Case(MicrOp.OP_MTMSRD): comb += is_priv_insn.eq(1)
+ with m.Case(MicrOp.OP_MTMSR): comb += is_priv_insn.eq(1)
+ with m.Case(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
+ """
+ def __init__(self):
+ self.spr_i = Signal(10, reset_less=True)
+ self.spr_o = Signal(SPR, reset_less=True)
+
+ 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.eq(i)
+ return m
+
+
class DecodeA(Elaboratable):
"""DecodeA from instruction
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)
# 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)
-
- # 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)
+ 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
+ comb += self.fast_out.data.eq(FastRegs.CTR) # constant: 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):
+ comb += self.fast_out.data.eq(FastRegs.CTR) # constant: 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
+ with m.Switch(spr):
+ # fast SPRs
+ with m.Case(SPR.CTR.value):
+ comb += self.fast_out.data.eq(FastRegs.CTR)
+ comb += self.fast_out.ok.eq(1)
+ with m.Case(SPR.LR.value):
+ comb += self.fast_out.data.eq(FastRegs.LR)
+ comb += self.fast_out.ok.eq(1)
+ with m.Case(SPR.TAR.value):
+ comb += self.fast_out.data.eq(FastRegs.TAR)
+ comb += self.fast_out.ok.eq(1)
+ with m.Case(SPR.SRR0.value):
+ comb += self.fast_out.data.eq(FastRegs.SRR0)
+ comb += self.fast_out.ok.eq(1)
+ with m.Case(SPR.SRR1.value):
+ comb += self.fast_out.data.eq(FastRegs.SRR1)
+ comb += self.fast_out.ok.eq(1)
+ with m.Case(SPR.XER.value):
+ pass # do nothing
+ # : map to internal SPR numbers
+ # XXX TODO: dec and tb not to go through mapping.
+ with m.Default():
+ comb += sprmap.spr_i.eq(spr)
+ comb += self.spr_out.data.eq(sprmap.spr_o)
+ comb += self.spr_out.ok.eq(1)
return m
-class Data(Record):
-
- def __init__(self, width, name):
- name_ok = "%s_ok" % name
- layout = ((name, width), (name_ok, 1))
- Record.__init__(self, layout)
- self.data = getattr(self, name) # convenience
- self.ok = getattr(self, name_ok) # convenience
- self.data.reset_less = True # grrr
- self.reset_less = True # grrr
-
- def ports(self):
- return [self.data, self.ok]
-
-
class DecodeB(Elaboratable):
"""DecodeB from instruction
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):
+ 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):
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)
+ spr = Signal(10, reset_less=True)
+ comb += spr.eq(decode_spr_num(self.dec.SPR)) # from XFX
# 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
+ with m.If(op.internal_op == MicrOp.OP_MTSPR):
+ with m.Switch(spr):
+ # fast SPRs
+ with m.Case(SPR.CTR.value):
+ comb += self.fast_out.data.eq(FastRegs.CTR)
+ comb += self.fast_out.ok.eq(1)
+ with m.Case(SPR.LR.value):
+ comb += self.fast_out.data.eq(FastRegs.LR)
+ comb += self.fast_out.ok.eq(1)
+ with m.Case(SPR.TAR.value):
+ comb += self.fast_out.data.eq(FastRegs.TAR)
+ comb += self.fast_out.ok.eq(1)
+ with m.Case(SPR.SRR0.value):
+ comb += self.fast_out.data.eq(FastRegs.SRR0)
+ comb += self.fast_out.ok.eq(1)
+ with m.Case(SPR.SRR1.value):
+ comb += self.fast_out.data.eq(FastRegs.SRR1)
+ comb += self.fast_out.ok.eq(1)
+ with m.Case(SPR.XER.value):
+ pass # do nothing
+ # : map to internal SPR numbers
+ # XXX TODO: dec and tb not to go through mapping.
+ with m.Default():
+ comb += sprmap.spr_i.eq(spr)
+ comb += self.spr_out.data.eq(sprmap.spr_o)
+ comb += self.spr_out.ok.eq(1)
+
+ 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
+ comb += self.fast_out.data.eq(FastRegs.CTR) # constant: 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):
+
+ # 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.If(op.internal_op == InternalOp.OP_RFID):
+ # 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)
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
+ with m.Case(MicrOp.OP_MUL_H64, MicrOp.OP_MUL_H32):
+ 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
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)
-
- def ports(self):
- return [self.ca, self.ov, self.so]
-
-
-class Decode2ToExecute1Type(RecordObject):
-
- def __init__(self, name=None):
-
- RecordObject.__init__(self, name=name)
-
- self.valid = Signal(reset_less=True)
- self.insn_type = Signal(InternalOp, reset_less=True)
- self.fn_unit = Signal(Function, reset_less=True)
- self.nia = Signal(64, reset_less=True)
- self.write_reg = Data(5, name="rego")
- self.write_ea = Data(5, name="ea") # for LD/ST in update mode
- self.read_reg1 = Data(5, name="reg1")
- self.read_reg2 = Data(5, name="reg2")
- self.read_reg3 = Data(5, name="reg3")
- self.imm_data = Data(64, name="imm")
- self.write_spr = Data(10, name="spro")
- self.read_spr1 = Data(10, name="spr1")
- self.read_spr2 = Data(10, name="spr2")
-
- self.read_fast1 = Data(3, name="fast1")
- self.read_fast2 = Data(3, name="fast2")
- self.write_fast1 = Data(3, name="fasto1")
- self.write_fast2 = Data(3, name="fasto2")
-
- self.read_cr1 = Data(3, name="cr_in1")
- self.read_cr2 = Data(3, name="cr_in2")
- self.read_cr3 = Data(3, name="cr_in2")
- self.read_cr_whole = Signal(reset_less=True)
- self.write_cr = Data(3, name="cr_out")
- self.write_cr_whole = Signal(reset_less=True)
- self.lk = Signal(reset_less=True)
- self.rc = Data(1, "rc")
- self.oe = Data(1, "oe")
- self.invert_a = Signal(reset_less=True)
- self.zero_a = Signal(reset_less=True)
- self.invert_out = Signal(reset_less=True)
- self.input_carry = Signal(CryIn, reset_less=True)
- self.output_carry = Signal(reset_less=True)
- self.input_cr = Signal(reset_less=True) # instr. has a CR as input
- self.output_cr = Signal(reset_less=True) # instr. has a CR as output
- self.is_32bit = Signal(reset_less=True)
- self.is_signed = Signal(reset_less=True)
- self.insn = Signal(32, reset_less=True)
- self.data_len = Signal(4, reset_less=True) # bytes
- self.byte_reverse = Signal(reset_less=True)
- self.sign_extend = Signal(reset_less=True)# do we need this?
- self.update = Signal(reset_less=True) # LD/ST is "update" variant
-
-
class PowerDecode2(Elaboratable):
+ """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 __init__(self, dec):
self.dec = dec
self.e = Decode2ToExecute1Type()
+ self.valid = Signal() # sync signal
+
+ # state information needed by the Decoder
+ self.msr = Signal(64, reset_less=True) # copy of MSR
def ports(self):
return self.dec.ports() + self.e.ports()
def elaborate(self, platform):
m = Module()
comb = m.d.comb
- e, op = self.e, self.dec.op
+ e, op, do, msr = self.e, self.dec.op, self.e.do, self.msr
# set up submodule decoders
m.submodules.dec = 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,
+ 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, dec_rc.insn_in,
dec_oe.insn_in, dec_cr_in.insn_in, dec_cr_out.insn_in]:
comb += i.eq(self.dec.opcode_in)
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_o2.lk.eq(do.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)
- # decode LD/ST length
- with m.Switch(op.ldst_len):
- with m.Case(LdstLen.is1B):
- comb += e.data_len.eq(1)
- with m.Case(LdstLen.is2B):
- comb += e.data_len.eq(2)
- with m.Case(LdstLen.is4B):
- comb += e.data_len.eq(4)
- with m.Case(LdstLen.is8B):
- comb += e.data_len.eq(8)
-
- 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)
+ # set up instruction, pick fn unit
+ comb += do.insn_type.eq(op.internal_op) # no op: defaults to OP_ILLEGAL
+ comb += do.fn_unit.eq(op.function_unit)
# 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
+ comb += do.imm_data.eq(dec_b.imm_out) # immediate in RB (usually)
+ comb += do.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)
+ comb += do.rc.eq(dec_rc.rc_out)
+ comb += do.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)
+ # condition registers (CR)
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)
+
+ comb += do.read_cr_whole.eq(dec_cr_in.whole_reg)
+ comb += do.write_cr_whole.eq(dec_cr_out.whole_reg)
+ comb += do.write_cr0.eq(dec_cr_out.cr_bitfield.ok)
# decoded/selected instruction flags
- 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)
+ comb += do.data_len.eq(op.ldst_len)
+ comb += do.invert_a.eq(op.inv_a)
+ comb += do.invert_out.eq(op.inv_out)
+ comb += do.input_carry.eq(op.cry_in) # carry comes in
+ comb += do.output_carry.eq(op.cry_out) # carry goes out
+ comb += do.is_32bit.eq(op.is_32b)
+ comb += do.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.
+ comb += do.lk.eq(self.dec.LK) # XXX TODO: accessor
+ comb += do.byte_reverse.eq(op.br)
+ comb += do.sign_extend.eq(op.sgn_ext)
+ comb += do.ldst_mode.eq(op.upd) # LD/ST mode (update, cache-inhibit)
# 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
-
+ comb += do.input_cr.eq(op.cr_in) # condition reg comes in
+ comb += do.output_cr.eq(op.cr_out) # condition reg goes in
+
+ # 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(1)
+ 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):
+ comb += do.trapaddr.eq(0x70) # addr=0x700 (strip first nibble)
+
+ # 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.If(op.internal_op == MicrOp.OP_ILLEGAL):
+ # illegal instruction trap
+ self.trap(m, TT_ILLEG, 0x700)
+
+ # 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.insn_type == MicrOp.OP_TRAP) |
+ (do.insn_type == MicrOp.OP_SC)):
+ # TRAP write fast1 = SRR0
+ comb += e.write_fast1.data.eq(FastRegs.SRR0) # constant: SRR0
+ comb += e.write_fast1.ok.eq(1)
+ # TRAP write fast2 = SRR1
+ comb += e.write_fast2.data.eq(FastRegs.SRR1) # constant: SRR1
+ comb += e.write_fast2.ok.eq(1)
+
+ # RFID: needs to read SRR0/1
+ with m.If(do.insn_type == MicrOp.OP_RFID):
+ # TRAP read fast1 = SRR0
+ comb += e.read_fast1.data.eq(FastRegs.SRR0) # constant: SRR0
+ comb += e.read_fast1.ok.eq(1)
+ # TRAP read fast2 = SRR1
+ comb += e.read_fast2.data.eq(FastRegs.SRR1) # constant: SRR1
+ comb += e.read_fast2.ok.eq(1)
+
+ # TODO: get msr, then can do privileged instruction
+ with m.If(instr_is_priv(m, op.internal_op, e.do.insn) & msr[MSR.PR]):
+ # privileged instruction trap
+ self.trap(m, TT_PRIV, 0x700)
return m
- def regspecmap(self, regfile, regname):
- """regspecmap: provides PowerDecode2 with an encoding relationship
+ def trap(self, m, traptype, trapaddr):
+ """trap: this basically "rewrites" the decoded instruction as a trap
+ """
+ comb = m.d.comb
+ e, op, do = self.e, self.dec.op, self.e.do
+ comb += e.eq(0) # reset eeeeeverything
+ # start again
+ comb += do.insn.eq(self.dec.opcode_in)
+ comb += do.insn_type.eq(MicrOp.OP_TRAP)
+ comb += do.fn_unit.eq(Function.TRAP)
+ comb += do.trapaddr.eq(trapaddr >> 4) # cut bottom 4 bits
+ comb += do.traptype.eq(traptype) # request type
+
+ 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.
"""
- return regspec_decode(self.e, regfile, regname)
+ return regspec_decode_read(self.e, regfile, regname)
+
+ 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)
def rdflags(self, cu):
rdl = []
for idx in range(cu.n_src):
regfile, regname, _ = cu.get_in_spec(idx)
- rdflag, read, write = self.regspecmap(regfile, regname)
+ rdflag, read = self.regspecmap_read(regfile, regname)
rdl.append(rdflag)
print ("rdflags", rdl)
return Cat(*rdl)
projects / soc.git / blobdiff