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microwatt/multiply.vhdl

102 lines
2.7 KiB
VHDL

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
library work;
use work.common.all;
use work.decode_types.all;
use work.ppc_fx_insns.all;
use work.crhelpers.all;
entity multiply is
generic (
PIPELINE_DEPTH : natural := 2
);
port (
clk : in std_logic;
m_in : in Decode2ToMultiplyType;
m_out : out MultiplyToWritebackType
);
end entity multiply;
architecture behaviour of multiply is
signal m: Decode2ToMultiplyType;
type multiply_pipeline_stage is record
valid : std_ulogic;
insn_type : insn_type_t;
data : signed(129 downto 0);
write_reg : std_ulogic_vector(4 downto 0);
rc : std_ulogic;
end record;
constant MultiplyPipelineStageInit : multiply_pipeline_stage := (valid => '0', insn_type => OP_ILLEGAL, rc => '0', data => (others => '0'), others => (others => '0'));
type multiply_pipeline_type is array(0 to PIPELINE_DEPTH-1) of multiply_pipeline_stage;
constant MultiplyPipelineInit : multiply_pipeline_type := (others => MultiplyPipelineStageInit);
type reg_type is record
multiply_pipeline : multiply_pipeline_type;
end record;
signal r, rin : reg_type := (multiply_pipeline => MultiplyPipelineInit);
begin
multiply_0: process(clk)
begin
if rising_edge(clk) then
m <= m_in;
r <= rin;
end if;
end process;
multiply_1: process(all)
variable v : reg_type;
variable d : std_ulogic_vector(129 downto 0);
variable d2 : std_ulogic_vector(63 downto 0);
begin
v := r;
m_out <= MultiplyToWritebackInit;
v.multiply_pipeline(0).valid := m.valid;
v.multiply_pipeline(0).insn_type := m.insn_type;
v.multiply_pipeline(0).data := signed(m.data1) * signed(m.data2);
v.multiply_pipeline(0).write_reg := m.write_reg;
v.multiply_pipeline(0).rc := m.rc;
loop_0: for i in 1 to PIPELINE_DEPTH-1 loop
v.multiply_pipeline(i) := r.multiply_pipeline(i-1);
end loop;
d := std_ulogic_vector(v.multiply_pipeline(PIPELINE_DEPTH-1).data);
case_0: case v.multiply_pipeline(PIPELINE_DEPTH-1).insn_type is
when OP_MUL_L64 =>
d2 := d(63 downto 0);
when OP_MUL_H32 =>
d2 := d(63 downto 32) & d(63 downto 32);
when OP_MUL_H64 =>
d2 := d(127 downto 64);
when others =>
--report "Illegal insn type in multiplier";
d2 := (others => '0');
end case;
m_out.write_reg_data <= d2;
m_out.write_reg_nr <= v.multiply_pipeline(PIPELINE_DEPTH-1).write_reg;
if v.multiply_pipeline(PIPELINE_DEPTH-1).valid = '1' then
m_out.valid <= '1';
m_out.write_reg_enable <= '1';
if v.multiply_pipeline(PIPELINE_DEPTH-1).rc = '1' then
m_out.write_cr_enable <= '1';
m_out.write_cr_mask <= num_to_fxm(0);
m_out.write_cr_data <= ppc_cmpi('1', d2, x"0000") & x"0000000";
end if;
end if;
rin <= v;
end process;
end architecture behaviour;