-- Instruction pre-decoder for microwatt
-- One cycle latency. Does 'WIDTH' instructions in parallel.
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.insn_helpers.all;
entity predecoder is
generic (
HAS_FPU : boolean := true;
WIDTH : natural := 2;
ICODE_LEN : natural := 10;
IMAGE_LEN : natural := 26
);
port (
clk : in std_ulogic;
valid_in : in std_ulogic;
insns_in : in std_ulogic_vector(WIDTH * 32 - 1 downto 0);
icodes_out : out std_ulogic_vector(WIDTH * (ICODE_LEN + IMAGE_LEN) - 1 downto 0)
);
end entity predecoder;
architecture behaviour of predecoder is
type predecoder_rom_t is array(0 to 2047) of insn_code;
constant major_predecode_rom : predecoder_rom_t := (
2#001100_00000# to 2#001100_11111# => INSN_addic,
2#001101_00000# to 2#001101_11111# => INSN_addic_dot,
2#001110_00000# to 2#001110_11111# => INSN_addi,
2#001111_00000# to 2#001111_11111# => INSN_addis,
2#010011_00100# to 2#010011_00101# => INSN_addpcis,
2#011100_00000# to 2#011100_11111# => INSN_andi_dot,
2#011101_00000# to 2#011101_11111# => INSN_andis_dot,
2#000000_00000# => INSN_attn,
2#010010_00000# to 2#010010_00001# => INSN_brel,
2#010010_00010# to 2#010010_00011# => INSN_babs,
2#010010_00100# to 2#010010_00101# => INSN_brel,
2#010010_00110# to 2#010010_00111# => INSN_babs,
2#010010_01000# to 2#010010_01001# => INSN_brel,
2#010010_01010# to 2#010010_01011# => INSN_babs,
2#010010_01100# to 2#010010_01101# => INSN_brel,
2#010010_01110# to 2#010010_01111# => INSN_babs,
2#010010_10000# to 2#010010_10001# => INSN_brel,
2#010010_10010# to 2#010010_10011# => INSN_babs,
2#010010_10100# to 2#010010_10101# => INSN_brel,
2#010010_10110# to 2#010010_10111# => INSN_babs,
2#010010_11000# to 2#010010_11001# => INSN_brel,
2#010010_11010# to 2#010010_11011# => INSN_babs,
2#010010_11100# to 2#010010_11101# => INSN_brel,
2#010010_11110# to 2#010010_11111# => INSN_babs,
2#010000_00000# to 2#010000_00001# => INSN_bcrel,
2#010000_00010# to 2#010000_00011# => INSN_bcabs,
2#010000_00100# to 2#010000_00101# => INSN_bcrel,
2#010000_00110# to 2#010000_00111# => INSN_bcabs,
2#010000_01000# to 2#010000_01001# => INSN_bcrel,
2#010000_01010# to 2#010000_01011# => INSN_bcabs,
2#010000_01100# to 2#010000_01101# => INSN_bcrel,
2#010000_01110# to 2#010000_01111# => INSN_bcabs,
2#010000_10000# to 2#010000_10001# => INSN_bcrel,
2#010000_10010# to 2#010000_10011# => INSN_bcabs,
2#010000_10100# to 2#010000_10101# => INSN_bcrel,
2#010000_10110# to 2#010000_10111# => INSN_bcabs,
2#010000_11000# to 2#010000_11001# => INSN_bcrel,
2#010000_11010# to 2#010000_11011# => INSN_bcabs,
2#010000_11100# to 2#010000_11101# => INSN_bcrel,
2#010000_11110# to 2#010000_11111# => INSN_bcabs,
2#001011_00000# to 2#001011_11111# => INSN_cmpi,
2#001010_00000# to 2#001010_11111# => INSN_cmpli,
2#100010_00000# to 2#100010_11111# => INSN_lbz,
2#100011_00000# to 2#100011_11111# => INSN_lbzu,
2#110010_00000# to 2#110010_11111# => INSN_lfd,
2#110011_00000# to 2#110011_11111# => INSN_lfdu,
2#110000_00000# to 2#110000_11111# => INSN_lfs,
2#110001_00000# to 2#110001_11111# => INSN_lfsu,
2#101010_00000# to 2#101010_11111# => INSN_lha,
2#101011_00000# to 2#101011_11111# => INSN_lhau,
2#101000_00000# to 2#101000_11111# => INSN_lhz,
2#101001_00000# to 2#101001_11111# => INSN_lhzu,
2#100000_00000# to 2#100000_11111# => INSN_lwz,
2#100001_00000# to 2#100001_11111# => INSN_lwzu,
2#000111_00000# to 2#000111_11111# => INSN_mulli,
2#011000_00000# to 2#011000_11111# => INSN_ori,
2#011001_00000# to 2#011001_11111# => INSN_oris,
2#010100_00000# to 2#010100_11111# => INSN_rlwimi,
2#010101_00000# to 2#010101_11111# => INSN_rlwinm,
2#010111_00000# to 2#010111_11111# => INSN_rlwnm,
2#010001_00000# to 2#010001_11111# => INSN_sc,
2#100110_00000# to 2#100110_11111# => INSN_stb,
2#100111_00000# to 2#100111_11111# => INSN_stbu,
2#110110_00000# to 2#110110_11111# => INSN_stfd,
2#110111_00000# to 2#110111_11111# => INSN_stfdu,
2#110100_00000# to 2#110100_11111# => INSN_stfs,
2#110101_00000# to 2#110101_11111# => INSN_stfsu,
2#101100_00000# to 2#101100_11111# => INSN_sth,
2#101101_00000# to 2#101101_11111# => INSN_sthu,
2#100100_00000# to 2#100100_11111# => INSN_stw,
2#100101_00000# to 2#100101_11111# => INSN_stwu,
2#001000_00000# to 2#001000_11111# => INSN_subfic,
2#000010_00000# to 2#000010_11111# => INSN_tdi,
2#000011_00000# to 2#000011_11111# => INSN_twi,
2#011010_00000# to 2#011010_11111# => INSN_xori,
2#011011_00000# to 2#011011_11111# => INSN_xoris,
-- major opcode 4
2#000100_10000# => INSN_maddhd,
2#000100_10001# => INSN_maddhdu,
2#000100_10011# => INSN_maddld,
-- major opcode 30
2#011110_01000# to 2#011110_01001# => INSN_rldic,
2#011110_01010# to 2#011110_01011# => INSN_rldic,
2#011110_00000# to 2#011110_00001# => INSN_rldicl,
2#011110_00010# to 2#011110_00011# => INSN_rldicl,
2#011110_00100# to 2#011110_00101# => INSN_rldicr,
2#011110_00110# to 2#011110_00111# => INSN_rldicr,
2#011110_01100# to 2#011110_01101# => INSN_rldimi,
2#011110_01110# to 2#011110_01111# => INSN_rldimi,
2#011110_10000# to 2#011110_10001# => INSN_rldcl,
2#011110_10010# to 2#011110_10011# => INSN_rldcr,
-- major opcode 58
2#111010_00000# => INSN_ld,
2#111010_00001# => INSN_ldu,
2#111010_00010# => INSN_lwa,
2#111010_00100# => INSN_ld,
2#111010_00101# => INSN_ldu,
2#111010_00110# => INSN_lwa,
2#111010_01000# => INSN_ld,
2#111010_01001# => INSN_ldu,
2#111010_01010# => INSN_lwa,
2#111010_01100# => INSN_ld,
2#111010_01101# => INSN_ldu,
2#111010_01110# => INSN_lwa,
2#111010_10000# => INSN_ld,
2#111010_10001# => INSN_ldu,
2#111010_10010# => INSN_lwa,
2#111010_10100# => INSN_ld,
2#111010_10101# => INSN_ldu,
2#111010_10110# => INSN_lwa,
2#111010_11000# => INSN_ld,
2#111010_11001# => INSN_ldu,
2#111010_11010# => INSN_lwa,
2#111010_11100# => INSN_ld,
2#111010_11101# => INSN_ldu,
2#111010_11110# => INSN_lwa,
-- major opcode 59
2#111011_00100# to 2#111011_00101# => INSN_fdivs,
2#111011_01000# to 2#111011_01001# => INSN_fsubs,
2#111011_01010# to 2#111011_01011# => INSN_fadds,
2#111011_01100# to 2#111011_01101# => INSN_fsqrts,
2#111011_10000# to 2#111011_10001# => INSN_fres,
2#111011_10010# to 2#111011_10011# => INSN_fmuls,
2#111011_10100# to 2#111011_10101# => INSN_frsqrtes,
2#111011_11000# to 2#111011_11001# => INSN_fmsubs,
2#111011_11010# to 2#111011_11011# => INSN_fmadds,
2#111011_11100# to 2#111011_11101# => INSN_fnmsubs,
2#111011_11110# to 2#111011_11111# => INSN_fnmadds,
-- major opcode 62
2#111110_00000# => INSN_std,
2#111110_00001# => INSN_stdu,
2#111110_00100# => INSN_std,
2#111110_00101# => INSN_stdu,
2#111110_01000# => INSN_std,
2#111110_01001# => INSN_stdu,
2#111110_01100# => INSN_std,
2#111110_01101# => INSN_stdu,
2#111110_10000# => INSN_std,
2#111110_10001# => INSN_stdu,
2#111110_10100# => INSN_std,
2#111110_10101# => INSN_stdu,
2#111110_11000# => INSN_std,
2#111110_11001# => INSN_stdu,
2#111110_11100# => INSN_std,
2#111110_11101# => INSN_stdu,
-- major opcode 63
2#111111_00100# to 2#111111_00101# => INSN_fdiv,
2#111111_01000# to 2#111111_01001# => INSN_fsub,
2#111111_01010# to 2#111111_01011# => INSN_fadd,
2#111111_01100# to 2#111111_01101# => INSN_fsqrt,
2#111111_01110# to 2#111111_01111# => INSN_fsel,
2#111111_10000# to 2#111111_10001# => INSN_fre,
2#111111_10010# to 2#111111_10011# => INSN_fmul,
2#111111_10100# to 2#111111_10101# => INSN_frsqrte,
2#111111_11000# to 2#111111_11001# => INSN_fmsub,
2#111111_11010# to 2#111111_11011# => INSN_fmadd,
2#111111_11100# to 2#111111_11101# => INSN_fnmsub,
2#111111_11110# to 2#111111_11111# => INSN_fnmadd,
-- prefix word, PO1
2#000001_00000# to 2#000001_11111# => INSN_prefix,
-- Major opcodes 57 and 61 are SFFS load/store instructions when prefixed
2#111001_00000# to 2#111001_11111# => INSN_op57,
2#111101_00000# to 2#111101_11111# => INSN_op61,
others => INSN_illegal
);
constant row_predecode_rom : predecoder_rom_t := (
-- Major opcode 31
-- Address bits are 0, insn(10:1)
2#0_01000_01010# => INSN_add,
2#0_11000_01010# => INSN_add, -- addo
2#0_00000_01010# => INSN_addc,
2#0_10000_01010# => INSN_addc, -- addco
2#0_00100_01010# => INSN_adde,
2#0_10100_01010# => INSN_adde, -- addeo
2#0_00101_01010# => INSN_addex,
2#0_00010_01010# => INSN_addg6s,
2#0_00111_01010# => INSN_addme,
2#0_10111_01010# => INSN_addme, -- addmeo
2#0_00110_01010# => INSN_addze,
2#0_10110_01010# => INSN_addze, -- addzeo
2#0_00000_11100# => INSN_and,
2#0_00001_11100# => INSN_andc,
2#0_00111_11100# => INSN_bperm,
2#0_00110_11011# => INSN_brh,
2#0_00100_11011# => INSN_brw,
2#0_00101_11011# => INSN_brd,
2#0_01001_11010# => INSN_cbcdtd,
2#0_01000_11010# => INSN_cdtbcd,
2#0_00000_00000# => INSN_cmp,
2#0_01111_11100# => INSN_cmpb,
2#0_00111_00000# => INSN_cmpeqb,
2#0_00001_00000# => INSN_cmpl,
2#0_00110_00000# => INSN_cmprb,
2#0_00001_11010# => INSN_cntlzd,
2#0_00000_11010# => INSN_cntlzw,
2#0_10001_11010# => INSN_cnttzd,
2#0_10000_11010# => INSN_cnttzw,
2#0_10111_10011# => INSN_darn,
2#0_00010_10110# => INSN_dcbf,
2#0_00001_10110# => INSN_dcbst,
2#0_01000_10110# => INSN_dcbt,
2#0_00111_10110# => INSN_dcbtst,
2#0_11111_10110# => INSN_dcbz,
2#0_01100_01001# => INSN_divdeu,
2#0_11100_01001# => INSN_divdeu, -- divdeuo
2#0_01100_01011# => INSN_divweu,
2#0_11100_01011# => INSN_divweu, -- divweuo
2#0_01101_01001# => INSN_divde,
2#0_11101_01001# => INSN_divde, -- divdeo
2#0_01101_01011# => INSN_divwe,
2#0_11101_01011# => INSN_divwe, -- divweo
2#0_01110_01001# => INSN_divdu,
2#0_11110_01001# => INSN_divdu, -- divduo
2#0_01110_01011# => INSN_divwu,
2#0_11110_01011# => INSN_divwu, -- divwuo
2#0_01111_01001# => INSN_divd,
2#0_11111_01001# => INSN_divd, -- divdo
2#0_01111_01011# => INSN_divw,
2#0_11111_01011# => INSN_divw, -- divwo
2#0_11001_10110# => INSN_rnop, -- dss
2#0_01010_10110# => INSN_rnop, -- dst
2#0_01011_10110# => INSN_rnop, -- dstst
2#0_11010_10110# => INSN_eieio,
2#0_01000_11100# => INSN_eqv,
2#0_11101_11010# => INSN_extsb,
2#0_11100_11010# => INSN_extsh,
2#0_11110_11010# => INSN_extsw,
2#0_11011_11010# => INSN_extswsli,
2#0_11011_11011# => INSN_extswsli,
2#0_11110_10110# => INSN_icbi,
2#0_00000_10110# => INSN_icbt,
2#0_00000_01111# => INSN_isel,
2#0_00001_01111# => INSN_isel,
2#0_00010_01111# => INSN_isel,
2#0_00011_01111# => INSN_isel,
2#0_00100_01111# => INSN_isel,
2#0_00101_01111# => INSN_isel,
2#0_00110_01111# => INSN_isel,
2#0_00111_01111# => INSN_isel,
2#0_01000_01111# => INSN_isel,
2#0_01001_01111# => INSN_isel,
2#0_01010_01111# => INSN_isel,
2#0_01011_01111# => INSN_isel,
2#0_01100_01111# => INSN_isel,
2#0_01101_01111# => INSN_isel,
2#0_01110_01111# => INSN_isel,
2#0_01111_01111# => INSN_isel,
2#0_10000_01111# => INSN_isel,
2#0_10001_01111# => INSN_isel,
2#0_10010_01111# => INSN_isel,
2#0_10011_01111# => INSN_isel,
2#0_10100_01111# => INSN_isel,
2#0_10101_01111# => INSN_isel,
2#0_10110_01111# => INSN_isel,
2#0_10111_01111# => INSN_isel,
2#0_11000_01111# => INSN_isel,
2#0_11001_01111# => INSN_isel,
2#0_11010_01111# => INSN_isel,
2#0_11011_01111# => INSN_isel,
2#0_11100_01111# => INSN_isel,
2#0_11101_01111# => INSN_isel,
2#0_11110_01111# => INSN_isel,
2#0_11111_01111# => INSN_isel,
2#0_00001_10100# => INSN_lbarx,
2#0_11010_10101# => INSN_lbzcix,
2#0_00011_10111# => INSN_lbzux,
2#0_00010_10111# => INSN_lbzx,
2#0_00010_10100# => INSN_ldarx,
2#0_10000_10100# => INSN_ldbrx,
2#0_11011_10101# => INSN_ldcix,
2#0_00001_10101# => INSN_ldux,
2#0_00000_10101# => INSN_ldx,
2#0_10010_10111# => INSN_lfdx,
2#0_10011_10111# => INSN_lfdux,
2#0_11010_10111# => INSN_lfiwax,
2#0_11011_10111# => INSN_lfiwzx,
2#0_10000_10111# => INSN_lfsx,
2#0_10001_10111# => INSN_lfsux,
2#0_00011_10100# => INSN_lharx,
2#0_01011_10111# => INSN_lhaux,
2#0_01010_10111# => INSN_lhax,
2#0_11000_10110# => INSN_lhbrx,
2#0_11001_10101# => INSN_lhzcix,
2#0_01001_10111# => INSN_lhzux,
2#0_01000_10111# => INSN_lhzx,
2#0_00000_10100# => INSN_lwarx,
2#0_01011_10101# => INSN_lwaux,
2#0_01010_10101# => INSN_lwax,
2#0_10000_10110# => INSN_lwbrx,
2#0_11000_10101# => INSN_lwzcix,
2#0_00001_10111# => INSN_lwzux,
2#0_00000_10111# => INSN_lwzx,
2#0_10010_00000# => INSN_mcrxrx,
2#0_00000_10011# => INSN_mfcr,
2#0_00010_10011# => INSN_mfmsr,
2#0_01010_10011# => INSN_mfspr,
2#0_01000_01001# => INSN_modud,
2#0_01000_01011# => INSN_moduw,
2#0_11000_01001# => INSN_modsd,
2#0_11000_01011# => INSN_modsw,
2#0_00100_10000# => INSN_mtcrf,
2#0_00100_10010# => INSN_mtmsr,
2#0_00101_10010# => INSN_mtmsrd,
2#0_01110_10011# => INSN_mtspr,
2#0_00010_01001# => INSN_mulhd,
2#0_00000_01001# => INSN_mulhdu,
2#0_00010_01011# => INSN_mulhw,
2#0_00000_01011# => INSN_mulhwu,
-- next 4 have reserved bit set
2#0_10010_01001# => INSN_mulhd,
2#0_10000_01001# => INSN_mulhdu,
2#0_10010_01011# => INSN_mulhw,
2#0_10000_01011# => INSN_mulhwu,
2#0_00111_01001# => INSN_mulld,
2#0_10111_01001# => INSN_mulld, -- mulldo
2#0_00111_01011# => INSN_mullw,
2#0_10111_01011# => INSN_mullw, -- mullwo
2#0_01110_11100# => INSN_nand,
2#0_00011_01000# => INSN_neg,
2#0_10011_01000# => INSN_neg, -- nego
-- next 8 are reserved no-op instructions
2#0_10000_10010# => INSN_rnop,
2#0_10001_10010# => INSN_rnop,
2#0_10010_10010# => INSN_rnop,
2#0_10011_10010# => INSN_rnop,
2#0_10100_10010# => INSN_rnop,
2#0_10101_10010# => INSN_rnop,
2#0_10110_10010# => INSN_rnop,
2#0_10111_10010# => INSN_rnop,
2#0_00011_11100# => INSN_nor,
2#0_01101_11100# => INSN_or,
2#0_01100_11100# => INSN_orc,
2#0_00011_11010# => INSN_popcntb,
2#0_01111_11010# => INSN_popcntd,
2#0_01011_11010# => INSN_popcntw,
2#0_00101_11010# => INSN_prtyd,
2#0_00100_11010# => INSN_prtyw,
2#0_00100_00000# => INSN_setb,
2#0_01100_00000# => INSN_setb, -- setbc
2#0_01101_00000# => INSN_setb, -- setbcr
2#0_01110_00000# => INSN_setb, -- setnbc
2#0_01111_00000# => INSN_setb, -- setnbcr
2#0_01111_10010# => INSN_slbia,
2#0_00000_11011# => INSN_sld,
2#0_00000_11000# => INSN_slw,
2#0_11000_11010# => INSN_srad,
2#0_11001_11010# => INSN_sradi,
2#0_11001_11011# => INSN_sradi,
2#0_11000_11000# => INSN_sraw,
2#0_11001_11000# => INSN_srawi,
2#0_10000_11011# => INSN_srd,
2#0_10000_11000# => INSN_srw,
2#0_11110_10101# => INSN_stbcix,
2#0_10101_10110# => INSN_stbcx,
2#0_00111_10111# => INSN_stbux,
2#0_00110_10111# => INSN_stbx,
2#0_10100_10100# => INSN_stdbrx,
2#0_11111_10101# => INSN_stdcix,
2#0_00110_10110# => INSN_stdcx,
2#0_00101_10101# => INSN_stdux,
2#0_00100_10101# => INSN_stdx,
2#0_10110_10111# => INSN_stfdx,
2#0_10111_10111# => INSN_stfdux,
2#0_11110_10111# => INSN_stfiwx,
2#0_10100_10111# => INSN_stfsx,
2#0_10101_10111# => INSN_stfsux,
2#0_11100_10110# => INSN_sthbrx,
2#0_11101_10101# => INSN_sthcix,
2#0_10110_10110# => INSN_sthcx,
2#0_01101_10111# => INSN_sthux,
2#0_01100_10111# => INSN_sthx,
2#0_10100_10110# => INSN_stwbrx,
2#0_11100_10101# => INSN_stwcix,
2#0_00100_10110# => INSN_stwcx,
2#0_00101_10111# => INSN_stwux,
2#0_00100_10111# => INSN_stwx,
2#0_00001_01000# => INSN_subf,
2#0_10001_01000# => INSN_subf, -- subfo
2#0_00000_01000# => INSN_subfc,
2#0_10000_01000# => INSN_subfc, -- subfco
2#0_00100_01000# => INSN_subfe,
2#0_10100_01000# => INSN_subfe, -- subfeo
2#0_00111_01000# => INSN_subfme,
2#0_10111_01000# => INSN_subfme, -- subfmeo
2#0_00110_01000# => INSN_subfze,
2#0_10110_01000# => INSN_subfze, -- subfzeo
2#0_10010_10110# => INSN_sync,
2#0_00010_00100# => INSN_td,
2#0_00000_00100# => INSN_tw,
2#0_01001_10010# => INSN_tlbie,
2#0_01000_10010# => INSN_tlbiel,
2#0_10001_10110# => INSN_tlbsync,
2#0_00000_11110# => INSN_wait,
2#0_01001_11100# => INSN_xor,
-- Major opcode 19
-- Columns with insn(4) = '1' are all illegal and not mapped here; to
-- fit into 2048 entries, the columns are remapped so that 16-24 are
-- stored here as 8-15; in other words the address bits are
-- 1, insn(10..6), 1, insn(5), insn(3..1)
-- Columns 16-17 here are opcode 19 columns 0-1
-- Columns 24-31 here are opcode 19 columns 16-23
2#1_10000_11000# => INSN_bcctr,
2#1_00000_11000# => INSN_bclr,
2#1_10001_11000# => INSN_bctar,
2#1_01000_10001# => INSN_crand,
2#1_00100_10001# => INSN_crandc,
2#1_01001_10001# => INSN_creqv,
2#1_00111_10001# => INSN_crnand,
2#1_00001_10001# => INSN_crnor,
2#1_01110_10001# => INSN_cror,
2#1_01101_10001# => INSN_crorc,
2#1_00110_10001# => INSN_crxor,
2#1_00100_11110# => INSN_isync,
2#1_00000_10000# => INSN_mcrf,
2#1_00000_11010# => INSN_rfid,
2#1_01000_11010# => INSN_rfid, -- hrfid
-- Major opcode 59
-- Address bits are 1, insn(10..6), 1, 0, insn(3..1)
-- Only column 14 is valid here; columns 16-31 are handled in the major table
-- Column 14 is mapped to column 22.
-- Columns 20-23 here are opcode 59 columns 12-15
2#1_11010_10110# => INSN_fcfids,
2#1_11110_10110# => INSN_fcfidus,
-- Major opcode 63
-- Columns 0-15 are mapped here; columns 16-31 are in the major table.
-- Address bits are 1, insn(10:6), 0, insn(4:1)
-- Columns 0-15 here are opcode 63 columns 0-15
2#1_00000_00000# => INSN_fcmpu,
2#1_00001_00000# => INSN_fcmpo,
2#1_00010_00000# => INSN_mcrfs,
2#1_00100_00000# => INSN_ftdiv,
2#1_00101_00000# => INSN_ftsqrt,
2#1_00001_00110# => INSN_mtfsb,
2#1_00010_00110# => INSN_mtfsb,
2#1_00100_00110# => INSN_mtfsfi,
2#1_11010_00110# => INSN_fmrgow,
2#1_11110_00110# => INSN_fmrgew,
2#1_10010_00111# => INSN_mffs,
2#1_10110_00111# => INSN_mtfsf,
2#1_00000_01000# => INSN_fcpsgn,
2#1_00001_01000# => INSN_fneg,
2#1_00010_01000# => INSN_fmr,
2#1_00100_01000# => INSN_fnabs,
2#1_01000_01000# => INSN_fabs,
2#1_01100_01000# => INSN_frin,
2#1_01101_01000# => INSN_friz,
2#1_01110_01000# => INSN_frip,
2#1_01111_01000# => INSN_frim,
2#1_00000_01100# => INSN_frsp,
2#1_00000_01110# => INSN_fctiw,
2#1_00100_01110# => INSN_fctiwu,
2#1_11001_01110# => INSN_fctid,
2#1_11010_01110# => INSN_fcfid,
2#1_11101_01110# => INSN_fctidu,
2#1_11110_01110# => INSN_fcfidu,
2#1_00000_01111# => INSN_fctiwz,
2#1_00100_01111# => INSN_fctiwuz,
2#1_11001_01111# => INSN_fctidz,
2#1_11101_01111# => INSN_fctiduz,
others => INSN_illegal
);
constant IOUT_LEN : natural := ICODE_LEN + IMAGE_LEN;
type predec_t is record
image : std_ulogic_vector(31 downto 0);
maj_predecode : unsigned(ICODE_LEN - 1 downto 0);
row_predecode : unsigned(ICODE_LEN - 1 downto 0);
end record;
subtype index_t is integer range 0 to WIDTH-1;
type predec_array is array(index_t) of predec_t;
signal pred : predec_array;
signal valid : std_ulogic;
begin
predecode_0: process(clk)
variable majaddr : std_ulogic_vector(10 downto 0);
variable rowaddr : std_ulogic_vector(10 downto 0);
variable iword : std_ulogic_vector(31 downto 0);
variable majcode : insn_code;
variable rowcode : insn_code;
begin
if rising_edge(clk) then
valid <= valid_in;
for i in index_t loop
iword := insns_in(i * 32 + 31 downto i * 32);
pred(i).image <= iword;
if is_X(iword) then
pred(i).maj_predecode <= (others => 'X');
pred(i).row_predecode <= (others => 'X');
else
majaddr := iword(31 downto 26) & iword(4 downto 0);
-- row_predecode_rom is used for op 19, 31, 59, 63
-- addr bit 10 is 0 for op 31, 1 for 19, 59, 63
rowaddr(10) := iword(31) or not iword(29);
rowaddr(9 downto 5) := iword(10 downto 6);
if iword(28) = '0' then
-- op 19 and op 59
rowaddr(4 downto 3) := '1' & iword(5);
else
-- op 31 and 63; for 63 we only use this when iword(5) = '0'
rowaddr(4 downto 3) := iword(5 downto 4);
end if;
rowaddr(2 downto 0) := iword(3 downto 1);
majcode := major_predecode_rom(to_integer(unsigned(majaddr)));
pred(i).maj_predecode <= to_unsigned(insn_code'pos(majcode), ICODE_LEN);
rowcode := row_predecode_rom(to_integer(unsigned(rowaddr)));
pred(i).row_predecode <= to_unsigned(insn_code'pos(rowcode), ICODE_LEN);
end if;
end loop;
end if;
end process;
predecode_1: process(all)
variable iword : std_ulogic_vector(31 downto 0);
variable use_row : std_ulogic;
variable illegal : std_ulogic;
variable ici : std_ulogic_vector(IOUT_LEN - 1 downto 0);
variable icode : unsigned(ICODE_LEN - 1 downto 0);
begin
for i in index_t loop
iword := pred(i).image;
icode := pred(i).maj_predecode;
use_row := '0';
illegal := '0';
case iword(31 downto 26) is
when "000100" => -- 4
-- major opcode 4, mostly VMX/VSX stuff but also some integer ops (madd*)
illegal := not iword(5);
when "010011" => -- 19
-- Columns 8-15 and 24-31 don't have any valid instructions
-- (where insn(5..1) is the column number).
-- addpcis (column 2) is in the major table
-- Other valid columns are mapped to columns in the second
-- half of the row table: columns 0-1 are mapped to 16-17
-- and 16-23 are mapped to 24-31.
illegal := iword(4);
use_row := iword(5) or (not iword(3) and not iword(2));
when "011000" => -- 24
-- ori, special-case the standard NOP
if std_match(iword, "01100000000000000000000000000000") then
icode := to_unsigned(insn_code'pos(INSN_nop), ICODE_LEN);
end if;
when "011111" => -- 31
-- major opcode 31, lots of things
-- Use the first half of the row table for all columns
use_row := '1';
when "111011" => -- 59
-- floating point operations, mostly single-precision
-- Columns 0-11 are illegal; columns 12-15 are mapped
-- to columns 20-23 in the second half of the row table,
-- and columns 16-31 are in the major table.
illegal := not iword(5) and (not iword(4) or not iword(3));
use_row := not iword(5);
when "111111" => -- 63
-- floating point operations, general and double-precision
-- Use columns 0-15 of the second half of the row table
-- for columns 0-15, and the major table for columns 16-31.
use_row := not iword(5);
when others =>
end case;
if use_row = '1' then
icode := pred(i).row_predecode;
end if;
-- Mark FP instructions as illegal if we don't have an FPU
if not HAS_FPU and not is_X(icode) and
to_integer(icode) >= insn_code'pos(INSN_first_frs) then
illegal := '1';
end if;
ici(31 downto 0) := iword;
ici(IOUT_LEN - 1 downto 32) := (others => '0');
if valid = '0' or illegal = '1' or is_X(icode) or
icode = to_unsigned(insn_code'pos(INSN_illegal), ICODE_LEN) then
-- Since an insn_code currently fits in 9 bits, use just
-- the most significant bit of ici to indicate illegal insns.
ici(IOUT_LEN - 1) := '1';
else
ici(IOUT_LEN - 1 downto IMAGE_LEN) := std_ulogic_vector(icode);
end if;
icodes_out(i * IOUT_LEN + IOUT_LEN - 1 downto i * IOUT_LEN) <= ici;
end loop;
end process;
end architecture behaviour;