clk : in std_ulogic;
rst : in std_ulogic;
- complete_in : in std_ulogic;
+ complete_in : in instr_tag_t;
busy_in : in std_ulogic;
stall_out : out std_ulogic;
c_in : in CrFileToDecode2Type;
c_out : out Decode2ToCrFileType;
+ execute_bypass : in bypass_data_t;
+ execute_cr_bypass : in cr_bypass_data_t;
+
log_out : out std_ulogic_vector(9 downto 0)
);
end entity decode2;
end case;
end;
- -- For now, use "rc" in the decode table to decide whether oe exists.
- -- This is not entirely correct architecturally: For mulhd and
- -- mulhdu, the OE field is reserved. It remains to be seen what an
- -- actual POWER9 does if we set it on those instructions, for now we
- -- test that further down when assigning to the multiplier oe input.
- --
- function decode_oe (t : rc_t; insn_in : std_ulogic_vector(31 downto 0)) return std_ulogic is
- begin
- case t is
- when RC =>
- return insn_oe(insn_in);
- when OTHERS =>
- return '0';
- end case;
- end;
-
-- control signals that are derived from insn_type
type mux_select_array_t is array(insn_type_t) of std_ulogic_vector(2 downto 0);
OP_MOD => "011",
OP_CNTZ => "100", -- countzero_result
OP_MFSPR => "101", -- spr_result
+ OP_B => "110", -- next_nia
+ OP_BC => "110",
+ OP_BCREG => "110",
OP_ADDG6S => "111", -- misc_result
OP_ISEL => "111",
OP_DARN => "111",
OP_MFMSR => "100",
OP_MFCR => "101",
OP_SETB => "110",
+ OP_CMP => "000", -- cr_result
+ OP_CMPRB => "001",
+ OP_CMPEQB => "010",
+ OP_CROP => "011",
+ OP_MCRXRX => "100",
+ OP_MTCRF => "101",
others => "000"
);
signal gpr_write_valid : std_ulogic;
signal gpr_write : gspr_index_t;
- signal gpr_bypassable : std_ulogic;
-
- signal update_gpr_write_valid : std_ulogic;
- signal update_gpr_write_reg : gspr_index_t;
signal gpr_a_read_valid : std_ulogic;
- signal gpr_a_read :gspr_index_t;
- signal gpr_a_bypass : std_ulogic;
+ signal gpr_a_read : gspr_index_t;
+ signal gpr_a_bypass : std_ulogic;
signal gpr_b_read_valid : std_ulogic;
- signal gpr_b_read : gspr_index_t;
- signal gpr_b_bypass : std_ulogic;
+ signal gpr_b_read : gspr_index_t;
+ signal gpr_b_bypass : std_ulogic;
signal gpr_c_read_valid : std_ulogic;
- signal gpr_c_read : gspr_index_t;
- signal gpr_c_bypass : std_ulogic;
+ signal gpr_c_read : gspr_index_t;
+ signal gpr_c_bypass : std_ulogic;
+ signal cr_read_valid : std_ulogic;
signal cr_write_valid : std_ulogic;
signal cr_bypass : std_ulogic;
- signal cr_bypass_avail : std_ulogic;
+
+ signal instr_tag : instr_tag_t;
begin
control_0: entity work.control
generic map (
- PIPELINE_DEPTH => 1
+ EX1_BYPASS => EX1_BYPASS
)
port map (
clk => clk,
gpr_write_valid_in => gpr_write_valid,
gpr_write_in => gpr_write,
- gpr_bypassable => gpr_bypassable,
-
- update_gpr_write_valid => update_gpr_write_valid,
- update_gpr_write_reg => update_gpr_write_reg,
gpr_a_read_valid_in => gpr_a_read_valid,
gpr_a_read_in => gpr_a_read,
gpr_c_read_valid_in => gpr_c_read_valid,
gpr_c_read_in => gpr_c_read,
- cr_read_in => d_in.decode.input_cr,
+ execute_next_tag => execute_bypass.tag,
+ execute_next_cr_tag => execute_cr_bypass.tag,
+
+ cr_read_in => cr_read_valid,
cr_write_in => cr_write_valid,
cr_bypass => cr_bypass,
- cr_bypassable => cr_bypass_avail,
valid_out => control_valid_out,
stall_out => control_stall_out,
gpr_bypass_a => gpr_a_bypass,
gpr_bypass_b => gpr_b_bypass,
- gpr_bypass_c => gpr_c_bypass
+ gpr_bypass_c => gpr_c_bypass,
+
+ instr_tag_out => instr_tag
);
deferred <= r.e.valid and busy_in;
variable decoded_reg_c : decode_input_reg_t;
variable decoded_reg_o : decode_output_reg_t;
variable length : std_ulogic_vector(3 downto 0);
+ variable op : insn_type_t;
begin
v := r;
--v.e.input_cr := d_in.decode.input_cr;
v.e.output_cr := d_in.decode.output_cr;
-
+
+ -- Work out whether XER common bits are set
+ v.e.output_xer := d_in.decode.output_carry;
+ case d_in.decode.insn_type is
+ when OP_ADD | OP_MUL_L64 | OP_DIV | OP_DIVE =>
+ -- OE field is valid in OP_ADD/OP_MUL_L64 with major opcode 31 only
+ if d_in.insn(31 downto 26) = "011111" and insn_oe(d_in.insn) = '1' then
+ v.e.oe := '1';
+ v.e.output_xer := '1';
+ end if;
+ when OP_MTSPR =>
+ if decode_spr_num(d_in.insn) = SPR_XER then
+ v.e.output_xer := '1';
+ end if;
+ when others =>
+ end case;
+
decoded_reg_a := decode_input_reg_a (d_in.decode.input_reg_a, d_in.insn, r_in.read1_data, d_in.ispr1,
d_in.nia);
decoded_reg_b := decode_input_reg_b (d_in.decode.input_reg_b, d_in.insn, r_in.read2_data, d_in.ispr2);
decoded_reg_c := decode_input_reg_c (d_in.decode.input_reg_c, d_in.insn, r_in.read3_data);
- decoded_reg_o := decode_output_reg (d_in.decode.output_reg_a, d_in.insn, d_in.ispr1);
+ decoded_reg_o := decode_output_reg (d_in.decode.output_reg_a, d_in.insn, d_in.ispro);
+
+ if d_in.decode.lr = '1' then
+ v.e.lr := insn_lk(d_in.insn);
+ -- b and bc have even major opcodes; bcreg is considered absolute
+ v.e.br_abs := insn_aa(d_in.insn) or d_in.insn(26);
+ end if;
+ op := d_in.decode.insn_type;
if d_in.decode.repeat /= NONE then
v.e.repeat := '1';
if r.repeat = d_in.big_endian then
decoded_reg_o.reg(0) := '1';
end if;
+ when DUPD =>
+ -- update-form loads, 2nd instruction writes RA
+ if r.repeat = '1' then
+ decoded_reg_o.reg := decoded_reg_a.reg;
+ end if;
when others =>
end case;
+ elsif v.e.lr = '1' and decoded_reg_a.reg_valid = '1' then
+ -- bcl/bclrl/bctarl that needs to write both CTR and LR has to be doubled
+ v.e.repeat := '1';
+ v.e.second := r.repeat;
+ -- first one does CTR, second does LR
+ decoded_reg_o.reg(0) := not r.repeat;
end if;
r_out.read1_enable <= decoded_reg_a.reg_valid and d_in.valid;
v.e.nia := d_in.nia;
v.e.unit := d_in.decode.unit;
v.e.fac := d_in.decode.facility;
- v.e.insn_type := d_in.decode.insn_type;
+ v.e.instr_tag := instr_tag;
v.e.read_reg1 := decoded_reg_a.reg;
- v.e.read_data1 := decoded_reg_a.data;
- v.e.bypass_data1 := gpr_a_bypass;
v.e.read_reg2 := decoded_reg_b.reg;
- v.e.read_data2 := decoded_reg_b.data;
- v.e.bypass_data2 := gpr_b_bypass;
- v.e.read_data3 := decoded_reg_c.data;
- v.e.bypass_data3 := gpr_c_bypass;
v.e.write_reg := decoded_reg_o.reg;
v.e.write_reg_enable := decoded_reg_o.reg_valid;
v.e.rc := decode_rc(d_in.decode.rc, d_in.insn);
- if not (d_in.decode.insn_type = OP_MUL_H32 or d_in.decode.insn_type = OP_MUL_H64) then
- v.e.oe := decode_oe(d_in.decode.rc, d_in.insn);
- end if;
- v.e.cr := c_in.read_cr_data;
- v.e.bypass_cr := cr_bypass;
v.e.xerc := c_in.read_xerc_data;
v.e.invert_a := d_in.decode.invert_a;
v.e.addm1 := '0';
- if d_in.decode.insn_type = OP_BC or d_in.decode.insn_type = OP_BCREG then
- -- add -1 to CTR
- v.e.addm1 := '1';
- if d_in.insn(23) = '1' or
- (d_in.decode.insn_type = OP_BCREG and d_in.insn(10) = '0') then
- -- don't write decremented CTR if BO(2) = 1 or bcctr
- v.e.write_reg_enable := '0';
- end if;
- end if;
+ v.e.insn_type := op;
v.e.invert_out := d_in.decode.invert_out;
v.e.input_carry := d_in.decode.input_carry;
v.e.output_carry := d_in.decode.output_carry;
v.e.is_32bit := d_in.decode.is_32bit;
v.e.is_signed := d_in.decode.is_signed;
- if d_in.decode.lr = '1' then
- v.e.lr := insn_lk(d_in.insn);
- end if;
v.e.insn := d_in.insn;
v.e.data_len := length;
v.e.byte_reverse := d_in.decode.byte_reverse;
v.e.update := d_in.decode.update;
v.e.reserve := d_in.decode.reserve;
v.e.br_pred := d_in.br_pred;
- v.e.result_sel := result_select(d_in.decode.insn_type);
- v.e.sub_select := subresult_select(d_in.decode.insn_type);
+ v.e.result_sel := result_select(op);
+ v.e.sub_select := subresult_select(op);
+ if op = OP_BC or op = OP_BCREG then
+ if d_in.insn(23) = '0' and r.repeat = '0' and
+ not (d_in.decode.insn_type = OP_BCREG and d_in.insn(10) = '0') then
+ -- decrement CTR if BO(2) = 0 and not bcctr
+ v.e.addm1 := '1';
+ v.e.result_sel := "000"; -- select adder output
+ end if;
+ end if;
+
+ -- See if any of the operands can get their value via the bypass path.
+ case gpr_a_bypass is
+ when '1' =>
+ v.e.read_data1 := execute_bypass.data;
+ when others =>
+ v.e.read_data1 := decoded_reg_a.data;
+ end case;
+ case gpr_b_bypass is
+ when '1' =>
+ v.e.read_data2 := execute_bypass.data;
+ when others =>
+ v.e.read_data2 := decoded_reg_b.data;
+ end case;
+ case gpr_c_bypass is
+ when '1' =>
+ v.e.read_data3 := execute_bypass.data;
+ when others =>
+ v.e.read_data3 := decoded_reg_c.data;
+ end case;
+
+ v.e.cr := c_in.read_cr_data;
+ if cr_bypass = '1' then
+ v.e.cr := execute_cr_bypass.data;
+ end if;
-- issue control
control_valid_in <= d_in.valid;
gpr_write_valid <= v.e.write_reg_enable;
gpr_write <= decoded_reg_o.reg;
- gpr_bypassable <= '0';
- if EX1_BYPASS and d_in.decode.unit = ALU then
- gpr_bypassable <= '1';
- end if;
- update_gpr_write_valid <= d_in.decode.update;
- update_gpr_write_reg <= decoded_reg_a.reg;
- if v.e.lr = '1' then
- -- there are no instructions that have both update=1 and lr=1
- update_gpr_write_valid <= '1';
- update_gpr_write_reg <= fast_spr_num(SPR_LR);
- end if;
gpr_a_read_valid <= decoded_reg_a.reg_valid;
gpr_a_read <= decoded_reg_a.reg;
gpr_c_read <= decoded_reg_c.reg;
cr_write_valid <= d_in.decode.output_cr or decode_rc(d_in.decode.rc, d_in.insn);
- cr_bypass_avail <= '0';
- if EX1_BYPASS and d_in.decode.unit = ALU then
- cr_bypass_avail <= d_in.decode.output_cr;
- end if;
+ -- Since ops that write CR only write some of the fields,
+ -- any op that writes CR effectively also reads it.
+ cr_read_valid <= cr_write_valid or d_in.decode.input_cr;
v.e.valid := control_valid_out;
if control_valid_out = '1' then
r.e.valid &
stopped_out &
stall_out &
- r.e.bypass_data3 &
- r.e.bypass_data2 &
- r.e.bypass_data1;
+ gpr_a_bypass &
+ gpr_b_bypass &
+ gpr_c_bypass;
end if;
end process;
log_out <= log_data;
projects / microwatt.git / blobdiff