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Valerio63 |
----------------------------------------------------------------------
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Valerio63 |
-- 8/16 bit microprocessor (65C816) VHDL project --
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Valerio63 |
-- Full RTL synchronous pipelined architecture --
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-- Project by Valerio Venturi (Italy) --
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Valerio63 |
-- Start date: 5/04/2020 --
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-- Last revision: 5/04/2023 --
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Valerio63 |
----------------------------------------------------------------------
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Valerio63 |
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Valerio63 |
library IEEE;
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use IEEE.std_logic_1164.all; -- defines std_logic types
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use IEEE.STD_LOGIC_unsigned.all;
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use IEEE.STD_LOGIC_arith.all;
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-- global architecture
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entity v65c816 is
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port( clk0: in STD_LOGIC; -- PHASE0 clock input
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res: in STD_LOGIC; -- reset input
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irq: in STD_LOGIC; -- interrupt request input
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nmi: in STD_LOGIC; -- not maskable interrupt input
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rdy: in STD_LOGIC; -- wait state request input (read/write)
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rdy_out: out STD_LOGIC; -- CPU in wait state (WAI instruction)
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stp_out: out STD_LOGIC; -- CPU in stop state (STP instruction)
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rw: out STD_LOGIC; -- read/write out
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vpa: out STD_LOGIC; -- vpa
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vda: out STD_LOGIC; -- vda
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ml: out STD_LOGIC; -- ml
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vp: out STD_LOGIC; -- vector pull
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ope: out STD_LOGIC; -- microcode end
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e: out STD_LOGIC; -- emulation (1)/native mode (0)
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m: out STD_LOGIC; -- M status
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x: out STD_LOGIC; -- X status
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op_exp: out STD_LOGIC; -- two byte instruction running
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addr: out STD_LOGIC_VECTOR(23 downto 0); -- 16 bit address bus out
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data_in: in STD_LOGIC_VECTOR(7 downto 0); -- 8 bit input data bus
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data_out: out STD_LOGIC_VECTOR(7 downto 0) -- 8 bit output data bus
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-- DEBUG
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-- a_reg: out STD_LOGIC_VECTOR(15 downto 0); -- 16 bit A register
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-- x_reg: out STD_LOGIC_VECTOR(15 downto 0); -- 16 bit X register
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-- y_reg: out STD_LOGIC_VECTOR(15 downto 0); -- 16 bit Y register
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-- s_reg: out STD_LOGIC_VECTOR(15 downto 0); -- 16 bit S register
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-- op_reg: out STD_LOGIC_VECTOR(15 downto 0); -- 16 bit Operand register
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-- p_reg: out STD_LOGIC_VECTOR(7 downto 0); -- 8 bit P register
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-- k_reg: out STD_LOGIC_VECTOR(7 downto 0); -- 8 bit K register
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-- b_reg: out STD_LOGIC_VECTOR(7 downto 0); -- 8 bit B register
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-- o_reg: out STD_LOGIC_VECTOR(7 downto 0); -- 8 bit Opcode register
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-- mcode: out STD_LOGIC_VECTOR(3 downto 0) -- 4 bit microcode sequence register
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);
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end v65c816;
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architecture struct of v65c816 is
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signal i_res: STD_LOGIC; -- internal global reset RES
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signal i_irq: STD_LOGIC; -- internal interrupt request IRQ
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signal i_nmi: STD_LOGIC; -- internal interrupt request NMI
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signal i_rdy: STD_LOGIC; -- internal wait request RDY
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signal e_rdy: STD_LOGIC; -- external invertedf RDY
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signal i_vp: STD_LOGIC; -- internal VP (vector pull)
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signal int: STD_LOGIC; -- internal global interrupt (instruction boundary synchronized)
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signal we: STD_LOGIC; -- write enable (combinatorial from PLA)
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signal we_r: STD_LOGIC; -- write enable (registered)
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signal ien: STD_LOGIC; -- interrupt IRQ enable
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signal emu: STD_LOGIC; -- emulation mode
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signal two_byte_op: STD_LOGIC; -- two byte instruction
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-- microcode signals (register control)
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signal regop: STD_LOGIC_VECTOR(5 downto 0); -- register operation microcode
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signal rsel: STD_LOGIC_VECTOR(4 downto 0); -- register select microcode
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signal a_l_lsb: STD_LOGIC; -- A load lsb
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signal a_l_msb: STD_LOGIC; -- A load msb
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signal a_dec: STD_LOGIC; -- A decrement (MVN/MVP)
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signal x_l_lsb: STD_LOGIC; -- X load lsb
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signal x_l_msb: STD_LOGIC; -- X load msb
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signal x_d: STD_LOGIC; -- X decrement
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signal x_u: STD_LOGIC; -- X increment
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signal y_d: STD_LOGIC; -- Y decrement
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signal y_u: STD_LOGIC; -- Y increment
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signal y_l_lsb: STD_LOGIC; -- Y load lsb
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signal y_l_msb: STD_LOGIC; -- Y load msb
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signal d_l_lsb: STD_LOGIC; -- D load lsb
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signal d_l_msb: STD_LOGIC; -- D load msb
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signal p_l: STD_LOGIC; -- P load
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signal k_l: STD_LOGIC; -- program bank register PBR K load
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signal b_l: STD_LOGIC; -- data bank register DBR B load
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signal k_cl: STD_LOGIC; -- program bank register PBR K clear
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signal b_cl: STD_LOGIC; -- data bank register DBR B clear
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signal o_l: STD_LOGIC; -- OPE load msb & lsb
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signal o_l_lsb: STD_LOGIC; -- OPE load lsb
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signal o_l_msb: STD_LOGIC; -- OPE load msb
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signal sp_ll: STD_LOGIC; -- SP load lsb
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signal sp_lh: STD_LOGIC; -- SP load msb
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signal sp_u: STD_LOGIC; -- SP increment
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signal sp_d: STD_LOGIC; -- SP decrement
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signal dmux_sel: STD_LOGIC_VECTOR(2 downto 0); -- ALU operand #2 data multiplexer
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signal kr_clear: STD_LOGIC; -- K clear
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signal br_clear: STD_LOGIC; -- B clear
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signal sp_emu: STD_LOGIC; -- '1' when S must be set in emulation mode
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-- microcode signals (ALU control)
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signal aluop: STD_LOGIC_VECTOR(4 downto 0); -- ALU operation code
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-- microcode signals CPU control logic
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signal mc_addr: STD_LOGIC_VECTOR(12 downto 0); -- microcode PLA address
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signal opfetch: STD_LOGIC; -- opcode fetch
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signal i_sync: STD_LOGIC; -- internal SYNC not latched
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signal m_sync: STD_LOGIC; -- internal SYNC latched
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signal opdec: STD_LOGIC; -- opcode decode
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signal pcmp: STD_LOGIC_VECTOR(2 downto 0); -- PC/MP out control effective
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signal pcmp_mc: STD_LOGIC_VECTOR(2 downto 0); -- PC/MP out control microcode
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signal pcinc: STD_LOGIC; -- PC increment
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signal e_eop: STD_LOGIC; -- early microcode sequence end (for some opcodes)
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signal mc_eop: STD_LOGIC; -- microcode sequence end
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signal eop: STD_LOGIC; -- microcode sequence end (effective)
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signal we_mc: STD_LOGIC; -- microcode write enable
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signal we_mc_l: STD_LOGIC; -- microcode write enable to latch
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signal fbrk: STD_LOGIC; -- force BRK opcode (used by hardware interrupts)
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signal opbrk: STD_LOGIC; -- BRK opcode (used for distinguish between hardware/software interrupts)
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signal opcop: STD_LOGIC; -- COP opcode
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signal sw_int: STD_LOGIC; -- software interrupt request
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signal branch_taken: STD_LOGIC; -- branch condition resolved
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signal pcc: STD_LOGIC; -- PC carry
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signal clri: STD_LOGIC; -- clear interrupt request pending microcode
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signal mc_vda: STD_LOGIC; -- microcode VDA
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signal mc_vpa: STD_LOGIC; -- microcode VPA
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signal mc_ml: STD_LOGIC; -- microcode ML
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signal adc_sbc_mc: STD_LOGIC; -- ADC/SBC opcode (used for decimal adjustment)
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signal ai_op: STD_LOGIC; -- opcode with absolute indexed addressing mode
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signal daa_req: STD_LOGIC; -- DAA required
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signal mcad: STD_LOGIC_VECTOR(11 downto 0); -- microcode address
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signal mcscan: STD_LOGIC_VECTOR(3 downto 0); -- microcode pointer control
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signal p_op: STD_LOGIC_VECTOR(4 downto 0); -- microcode control bits register P
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signal pcr_fc: STD_LOGIC_VECTOR(3 downto 0); -- microcode control PC
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signal mpr_fc: STD_LOGIC_VECTOR(4 downto 0); -- microcode control MP
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signal mcbit: STD_LOGIC_VECTOR(44 downto 0); -- microcode control bits
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signal regbit: STD_LOGIC_VECTOR(29 downto 0); -- microcode control bits on registers
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signal ivoffs: STD_LOGIC_VECTOR(7 downto 0); -- interrupt vector offset encoding
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signal mcn: STD_LOGIC; -- microcode does NOPs
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signal add_sub_op: STD_LOGIC; -- ADC/SBC opcode
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signal m_bit: STD_LOGIC; -- M bit of status register
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signal x_bit: STD_LOGIC; -- X bit of status register
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signal index_size: STD_LOGIC; -- index register size: 1 = 8 bit, 0 = 16 bit
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signal m_size8: STD_LOGIC; -- memory operation size: 1 = 8 bit
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signal m_size16: STD_LOGIC; -- memory operation size: 1 = 16 bit
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signal s_size16: STD_LOGIC; -- memory operation size: 1 = 16 bit for special cases
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signal m_size: STD_LOGIC; -- memory operation size: 1 = 8 bit, 0 = 16 bit
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signal acc_size: STD_LOGIC; -- accumulator C size: 1 = 8 bit, 0 = 16 bit
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signal mov_end: STD_LOGIC; -- MVN/MVP end transfer
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signal ld_acc: STD_LOGIC; -- load accumulator C register (16 bit)
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signal ld_xy: STD_LOGIC; -- load X/Y registers (16 bit)
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-- ALU signals
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signal c_flg: STD_LOGIC; -- ALU carry flag
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signal z_flg: STD_LOGIC; -- ALU zero flag
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signal v_flg: STD_LOGIC; -- ALU overflow flag
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signal n_flg: STD_LOGIC; -- ALU negative flag
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signal pc_c_alu_flg: STD_LOGIC; -- ALU PC carry flag
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signal acr_reg: STD_LOGIC; -- ALU auxiliary carry (registered)
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-- multiplier signals
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signal mul_init: STD_LOGIC; -- multiplier initialize
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signal mul_start_u: STD_LOGIC; -- multiplier unsigned start
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signal mul_start_s: STD_LOGIC; -- multiplier signed start
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signal mul_busy: STD_LOGIC; -- multiplier busy
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signal mul_r_lsb: STD_LOGIC_VECTOR(15 downto 0); -- multiplier lsb result
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signal mul_r_msb: STD_LOGIC_VECTOR(15 downto 0); -- multiplier msb result
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signal mul_l_res: STD_LOGIC; -- load multiplier lsb result on register A/B and multiplier msb result on register X
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signal mul_z_flg: STD_LOGIC; -- multiplier Z flag
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signal mul_n_flg: STD_LOGIC; -- multiplier N flag
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-- WAI/STP signals
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signal wai_ff: STD_LOGIC; -- WAI instruction flipflop
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signal stp_ff: STD_LOGIC; -- STP instruction flipflop
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signal wai_set: STD_LOGIC; -- WAI flipflop set
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signal stp_set: STD_LOGIC; -- STP flipflop set
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-- bus
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signal dbin: STD_LOGIC_VECTOR(7 downto 0); -- input data bus D0..D7
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signal dbout: STD_LOGIC_VECTOR(7 downto 0); -- output data bus D0..D7
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signal a_bus: STD_LOGIC_VECTOR(15 downto 0); -- accumulator register A/B/C bus
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signal x_bus: STD_LOGIC_VECTOR(15 downto 0); -- index register X bus
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signal y_bus: STD_LOGIC_VECTOR(15 downto 0); -- index register Y bus
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signal k_bus: STD_LOGIC_VECTOR(7 downto 0); -- program bank PBR K bus
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signal b_bus: STD_LOGIC_VECTOR(7 downto 0); -- program data DBR B bus
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signal d_bus: STD_LOGIC_VECTOR(15 downto 0); -- zero page/direct register D bus
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signal sp_bus: STD_LOGIC_VECTOR(15 downto 0); -- stack pointer register S bus
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signal p_bus: STD_LOGIC_VECTOR(7 downto 0); -- status register P bus
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signal op_bus: STD_LOGIC_VECTOR(7 downto 0); -- opcode register bus
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signal o_bus: STD_LOGIC_VECTOR(15 downto 0); -- operand register bus
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signal oper_bus: STD_LOGIC_VECTOR(15 downto 0); -- operand bus (ALU operand #2 bus)
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signal r_bus: STD_LOGIC_VECTOR(15 downto 0); -- general register bus (ALU operand #2 bus)
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signal alu_bus: STD_LOGIC_VECTOR(15 downto 0); -- ALU output bus
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signal pc_bus: STD_LOGIC_VECTOR(15 downto 0); -- program counter register PC bus
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signal mp_bus: STD_LOGIC_VECTOR(23 downto 0); -- memory data pointer register bus
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signal ad_bus: STD_LOGIC_VECTOR(15 downto 0); -- address bus
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signal i_addr_bus: STD_LOGIC_VECTOR(23 downto 0); -- internal 24 bit address bus
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-- 16 bit program counter register (PC)
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component pcr
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port( clk: in STD_LOGIC; -- clock
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i: in STD_LOGIC; -- increment
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fwait: in STD_LOGIC; -- wait
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brk_op: in STD_LOGIC; -- forced BRK (by interrupt request)
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branch_flg: in STD_LOGIC; -- branch flag
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mov_f: in STD_LOGIC; -- MVN/MVP end transfer
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fc: in STD_LOGIC_VECTOR(3 downto 0); -- function code
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din1: in STD_LOGIC_VECTOR(7 downto 0); -- input
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din2: in STD_LOGIC_VECTOR(15 downto 0); -- input
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dout: out STD_LOGIC_VECTOR(15 downto 0) -- output
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);
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end component;
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-- 8 bit PBR program bank register K
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component kr
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port( clk: in STD_LOGIC; -- clock
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clr: in STD_LOGIC; -- reset
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fwait: in STD_LOGIC;
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ld: in STD_LOGIC; -- load
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din: in STD_LOGIC_VECTOR(7 downto 0); -- input
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dout: out STD_LOGIC_VECTOR(7 downto 0) -- output
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);
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end component;
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-- 8 bit DBR program bank register B
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component br
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port( clk: in STD_LOGIC; -- clock
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clr: in STD_LOGIC; -- reset
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fwait: in STD_LOGIC;
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ld: in STD_LOGIC; -- load
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din: in STD_LOGIC_VECTOR(7 downto 0); -- input
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dout: out STD_LOGIC_VECTOR(7 downto 0) -- output
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);
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end component;
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-- 16 bit memory pointer register (MP)
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component mpr
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port( clk: in STD_LOGIC; -- clock
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fwait: in STD_LOGIC; -- wait
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dbr_ld: in STD_LOGIC; -- load DBR
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c: in STD_LOGIC; -- carry
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fc: in STD_LOGIC_VECTOR(4 downto 0); -- function code
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din_l: in STD_LOGIC_VECTOR(7 downto 0); -- input LSB
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din_h: in STD_LOGIC_VECTOR(7 downto 0); -- input MSB
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dbr: in STD_LOGIC_VECTOR(7 downto 0);
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dr: in STD_LOGIC_VECTOR(15 downto 0);
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op: in STD_LOGIC_VECTOR(15 downto 0);
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xr: in STD_LOGIC_VECTOR(15 downto 0);
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yr: in STD_LOGIC_VECTOR(15 downto 0);
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sr: in STD_LOGIC_VECTOR(15 downto 0);
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v: in STD_LOGIC_VECTOR(7 downto 0); -- vector offset input
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dout: out STD_LOGIC_VECTOR(23 downto 0) -- output
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);
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end component;
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|
|
-- 8 bit opcode register opr (pipeline opcode prefetch register)
|
| 255 |
|
|
component opr
|
| 256 |
|
|
port( clk: in STD_LOGIC; -- clock
|
| 257 |
|
|
clr: in STD_LOGIC; -- force BRK opcode
|
| 258 |
|
|
fwait: in STD_LOGIC; -- wait
|
| 259 |
|
|
ld: in STD_LOGIC; -- load
|
| 260 |
|
|
din: in STD_LOGIC_VECTOR(7 downto 0); -- input
|
| 261 |
|
|
brk_f: out STD_LOGIC; -- BRK opcode
|
| 262 |
|
|
cop_f: out STD_LOGIC; -- COP opcode
|
| 263 |
|
|
dout: out STD_LOGIC_VECTOR(7 downto 0) -- output
|
| 264 |
|
|
);
|
| 265 |
|
|
end component;
|
| 266 |
|
|
|
| 267 |
|
|
-- 16 bit operand hold register oper
|
| 268 |
|
|
component oper
|
| 269 |
|
|
port( clk: in STD_LOGIC; -- clock
|
| 270 |
|
|
clr: in STD_LOGIC; -- clear
|
| 271 |
|
|
fwait: in STD_LOGIC; -- wait
|
| 272 |
|
|
ld: in STD_LOGIC;
|
| 273 |
|
|
ld_lsb: in STD_LOGIC; -- load lsb
|
| 274 |
|
|
ld_msb: in STD_LOGIC; -- load msb
|
| 275 |
|
|
din: in STD_LOGIC_VECTOR(15 downto 0); -- input
|
| 276 |
|
|
dout: out STD_LOGIC_VECTOR(15 downto 0) -- output
|
| 277 |
|
|
);
|
| 278 |
|
|
end component;
|
| 279 |
|
|
|
| 280 |
|
|
-- 16 bit accumulator register A
|
| 281 |
|
|
component ar
|
| 282 |
|
|
port( clk: in STD_LOGIC; -- clock
|
| 283 |
|
|
fwait: in STD_LOGIC;
|
| 284 |
|
|
size: in STD_LOGIC; -- accumulator register size: 1 = 8 bit, 0 = 16 bit
|
| 285 |
|
|
ld_lsb: in STD_LOGIC; -- load lsb
|
| 286 |
|
|
ld_msb: in STD_LOGIC; -- load msb
|
| 287 |
|
|
ld_mul_lsb: in STD_LOGIC; -- load multiplication lsb result
|
| 288 |
|
|
d: in STD_LOGIC; -- decrement
|
| 289 |
|
|
end_count: out STD_LOGIC; -- '1' when a is 0xFF or 0xFFFF
|
| 290 |
|
|
din: in STD_LOGIC_VECTOR(15 downto 0); -- input
|
| 291 |
|
|
mul_lsb: in STD_LOGIC_VECTOR(15 downto 0); -- input multiplication lsb result
|
| 292 |
|
|
dout: out STD_LOGIC_VECTOR(15 downto 0) -- output
|
| 293 |
|
|
);
|
| 294 |
|
|
end component;
|
| 295 |
|
|
|
| 296 |
|
|
-- 16 bit index register X
|
| 297 |
|
|
component xr
|
| 298 |
|
|
port( clk: in STD_LOGIC; -- clock
|
| 299 |
|
|
fwait: in STD_LOGIC;
|
| 300 |
|
|
size: in STD_LOGIC; -- index register size: 1 = 8 bit, 0 = 16 bit
|
| 301 |
|
|
ld_lsb: in STD_LOGIC; -- load lsb
|
| 302 |
|
|
ld_msb: in STD_LOGIC; -- load msb
|
| 303 |
|
|
ld_mul_msb: in STD_LOGIC;
|
| 304 |
|
|
u: in STD_LOGIC; -- increment
|
| 305 |
|
|
d: in STD_LOGIC; -- decrement
|
| 306 |
|
|
din: in STD_LOGIC_VECTOR(15 downto 0); -- input
|
| 307 |
|
|
mul_msb: in STD_LOGIC_VECTOR(15 downto 0); -- input multiplication msb result
|
| 308 |
|
|
dout: out STD_LOGIC_VECTOR(15 downto 0) -- output
|
| 309 |
|
|
);
|
| 310 |
|
|
end component;
|
| 311 |
|
|
|
| 312 |
|
|
-- 16 bit index register Y
|
| 313 |
|
|
component yr
|
| 314 |
|
|
port( clk: in STD_LOGIC; -- clock
|
| 315 |
|
|
fwait: in STD_LOGIC;
|
| 316 |
|
|
size: in STD_LOGIC; -- index register size: 1 = 8 bit, 0 = 16 bit
|
| 317 |
|
|
ld_lsb: in STD_LOGIC; -- load lsb
|
| 318 |
|
|
ld_msb: in STD_LOGIC; -- load msb
|
| 319 |
|
|
u: in STD_LOGIC; -- increment
|
| 320 |
|
|
d: in STD_LOGIC; -- decrement
|
| 321 |
|
|
din: in STD_LOGIC_VECTOR(15 downto 0); -- input
|
| 322 |
|
|
dout: out STD_LOGIC_VECTOR(15 downto 0) -- output
|
| 323 |
|
|
);
|
| 324 |
|
|
end component;
|
| 325 |
|
|
|
| 326 |
|
|
-- 16 bit zero page/direct register D
|
| 327 |
|
|
component dr
|
| 328 |
|
|
port( clk: in STD_LOGIC; -- clock
|
| 329 |
|
|
clr: in STD_LOGIC; -- reset
|
| 330 |
|
|
fwait: in STD_LOGIC;
|
| 331 |
|
|
ld_lsb: in STD_LOGIC; -- load lsb
|
| 332 |
|
|
ld_msb: in STD_LOGIC; -- load msb
|
| 333 |
|
|
din: in STD_LOGIC_VECTOR(15 downto 0); -- input
|
| 334 |
|
|
dout: out STD_LOGIC_VECTOR(15 downto 0) -- output
|
| 335 |
|
|
);
|
| 336 |
|
|
end component;
|
| 337 |
|
|
|
| 338 |
|
|
-- 16 bit stack pointer SP
|
| 339 |
|
|
component spr
|
| 340 |
|
|
port( clk: in STD_LOGIC; -- clock
|
| 341 |
|
|
fwait: in STD_LOGIC; -- wait
|
| 342 |
|
|
em: in STD_LOGIC; -- emulation mode (1)/native mode (0)
|
| 343 |
|
|
clr: in STD_LOGIC; -- load init value
|
| 344 |
|
|
ld_l: in STD_LOGIC; -- load lsb
|
| 345 |
|
|
ld_h: in STD_LOGIC; -- load msb
|
| 346 |
|
|
u: in STD_LOGIC; -- increment
|
| 347 |
|
|
d: in STD_LOGIC; -- decrement
|
| 348 |
|
|
din: in STD_LOGIC_VECTOR(15 downto 0); -- input
|
| 349 |
|
|
dout: out STD_LOGIC_VECTOR(15 downto 0) -- output
|
| 350 |
|
|
);
|
| 351 |
|
|
end component;
|
| 352 |
|
|
|
| 353 |
|
|
-- 8 bit processor status register P
|
| 354 |
|
|
-- NV1BDIZC
|
| 355 |
|
|
-- 76543210
|
| 356 |
|
|
-- ||||||||
|
| 357 |
|
|
-- ||||||||--- C/E = carry/borrow flag (emulation bit: 1 = emulation mode, 0 = native mode)
|
| 358 |
|
|
-- |||||||---- Z = zero flag
|
| 359 |
|
|
-- ||||||----- I = interrupt mask
|
| 360 |
|
|
-- |||||------ D = decimal/binary alu mode
|
| 361 |
|
|
-- ||||------- B/X = index reg. select (1 = 8 bit, 0 = 16 bit) (B Break: 0 on stack after interrupt if E emulation mode = 1)
|
| 362 |
|
|
-- |||-------- M = memory/acc. select (1 = 8 bit, 0 = 16 bit) (always 1 if E = 1)
|
| 363 |
|
|
-- ||--------- V = overflow flag
|
| 364 |
|
|
-- |---------- N = negative flag
|
| 365 |
|
|
-- The P register also contains an additional carry/borrow flag (ACR) used for effective address calculation but
|
| 366 |
|
|
-- it is not visible at program level
|
| 367 |
|
|
component pr
|
| 368 |
|
|
port( clk: in STD_LOGIC; -- clock
|
| 369 |
|
|
clr: in STD_LOGIC; -- clear
|
| 370 |
|
|
fwait: in STD_LOGIC; -- wait
|
| 371 |
|
|
n: in STD_LOGIC; -- N input
|
| 372 |
|
|
v: in STD_LOGIC; -- V input
|
| 373 |
|
|
z: in STD_LOGIC; -- Z input
|
| 374 |
|
|
c: in STD_LOGIC; -- C input
|
| 375 |
|
|
mpy_z: in STD_LOGIC; -- Z input from multiplier
|
| 376 |
|
|
mpy_n: in STD_LOGIC; -- N input from multiplier
|
| 377 |
|
|
swi: in STD_LOGIC; -- software interrupt (BRK/COP opcode)
|
| 378 |
|
|
acr_in: in STD_LOGIC; -- auxiliary carry in
|
| 379 |
|
|
fc: in STD_LOGIC_VECTOR(4 downto 0); -- function code
|
| 380 |
|
|
din: in STD_LOGIC_VECTOR(7 downto 0); -- input
|
| 381 |
|
|
dout: out STD_LOGIC_VECTOR(7 downto 0); -- output
|
| 382 |
|
|
acr_out: out STD_LOGIC; -- auxiliary carry out
|
| 383 |
|
|
em: out STD_LOGIC; -- emulation (1)/native mode (0)
|
| 384 |
|
|
two_op: out STD_LOGIC -- two byte instruction
|
| 385 |
|
|
);
|
| 386 |
|
|
end component;
|
| 387 |
|
|
|
| 388 |
|
|
-- 16 bit (binary/bcd) two-way through pass ALU
|
| 389 |
|
|
component alu_bin
|
| 390 |
|
|
port( alu_byp: in STD_LOGIC; -- ALU bypass (no operation)
|
| 391 |
|
|
bcd: in STD_LOGIC; -- BCD mode
|
| 392 |
|
|
size: in STD_LOGIC; -- ALU size operation: 1 = 8 bit, 0 = 16 bit
|
| 393 |
|
|
cin: in STD_LOGIC; -- carry/borrow in
|
| 394 |
|
|
vin: in STD_LOGIC; -- overflow in
|
| 395 |
|
|
op1: in STD_LOGIC_VECTOR(15 downto 0); -- 16 bit operand #1
|
| 396 |
|
|
op2: in STD_LOGIC_VECTOR(15 downto 0); -- 16 bit operand #2
|
| 397 |
|
|
fc: in STD_LOGIC_VECTOR(4 downto 0); -- function code
|
| 398 |
|
|
cf: out STD_LOGIC; -- carry/borrow (byte) out
|
| 399 |
|
|
zf: out STD_LOGIC; -- zero flag out
|
| 400 |
|
|
nf: out STD_LOGIC; -- negative flag out
|
| 401 |
|
|
vf: out STD_LOGIC; -- overflow flag out
|
| 402 |
|
|
pc_cf: out STD_LOGIC; -- carry/borrow out for PC operation
|
| 403 |
|
|
dout: out STD_LOGIC_VECTOR(15 downto 0) -- 16 bit result out
|
| 404 |
|
|
);
|
| 405 |
|
|
end component;
|
| 406 |
|
|
|
| 407 |
|
|
-- PC/MP address multiplexer
|
| 408 |
|
|
component addrmux
|
| 409 |
|
|
port( sel: in STD_LOGIC_VECTOR(2 downto 0);
|
| 410 |
|
|
a: in STD_LOGIC_VECTOR(23 downto 0);
|
| 411 |
|
|
b: in STD_LOGIC_VECTOR(23 downto 0);
|
| 412 |
|
|
dbr: in STD_LOGIC_VECTOR(7 downto 0);
|
| 413 |
|
|
s: in STD_LOGIC_VECTOR(15 downto 0);
|
| 414 |
|
|
xr: in STD_LOGIC_VECTOR(15 downto 0);
|
| 415 |
|
|
yr: in STD_LOGIC_VECTOR(15 downto 0);
|
| 416 |
|
|
y: out STD_LOGIC_VECTOR(23 downto 0)
|
| 417 |
|
|
);
|
| 418 |
|
|
end component;
|
| 419 |
|
|
|
| 420 |
|
|
-- register multiplexer
|
| 421 |
|
|
component regmux
|
| 422 |
|
|
port( sel: in STD_LOGIC_VECTOR(4 downto 0);
|
| 423 |
|
|
a: in STD_LOGIC_VECTOR(7 downto 0);
|
| 424 |
|
|
b: in STD_LOGIC_VECTOR(15 downto 0);
|
| 425 |
|
|
c: in STD_LOGIC_VECTOR(15 downto 0);
|
| 426 |
|
|
d: in STD_LOGIC_VECTOR(15 downto 0);
|
| 427 |
|
|
e: in STD_LOGIC_VECTOR(15 downto 0);
|
| 428 |
|
|
g: in STD_LOGIC_VECTOR(7 downto 0);
|
| 429 |
|
|
h: in STD_LOGIC_VECTOR(7 downto 0);
|
| 430 |
|
|
i: in STD_LOGIC_VECTOR(7 downto 0);
|
| 431 |
|
|
j: in STD_LOGIC_VECTOR(15 downto 0);
|
| 432 |
|
|
k: in STD_LOGIC_VECTOR(15 downto 0);
|
| 433 |
|
|
l: in STD_LOGIC_VECTOR(7 downto 0);
|
| 434 |
|
|
m: in STD_LOGIC_VECTOR(7 downto 0);
|
| 435 |
|
|
y: out STD_LOGIC_VECTOR(15 downto 0)
|
| 436 |
|
|
);
|
| 437 |
|
|
end component;
|
| 438 |
|
|
|
| 439 |
|
|
-- data multiplexer (register "O" bypass)
|
| 440 |
|
|
component dmux is
|
| 441 |
|
|
port( sel: in STD_LOGIC_VECTOR(2 downto 0);
|
| 442 |
|
|
a: in STD_LOGIC_VECTOR(15 downto 0);
|
| 443 |
|
|
b: in STD_LOGIC_VECTOR(7 downto 0);
|
| 444 |
|
|
y: out STD_LOGIC_VECTOR(15 downto 0)
|
| 445 |
|
|
);
|
| 446 |
|
|
end component dmux;
|
| 447 |
|
|
|
| 448 |
|
|
-- microcode sequencer logic
|
| 449 |
|
|
component mcseq
|
| 450 |
|
|
port( clk: in STD_LOGIC;
|
| 451 |
|
|
clr: in STD_LOGIC;
|
| 452 |
|
|
mc_nop: in STD_LOGIC;
|
| 453 |
|
|
fwait: in STD_LOGIC;
|
| 454 |
|
|
q: out STD_LOGIC_VECTOR(3 downto 0)
|
| 455 |
|
|
);
|
| 456 |
|
|
end component;
|
| 457 |
|
|
|
| 458 |
|
|
-- micropla logic
|
| 459 |
|
|
-- output fields format:
|
| 460 |
|
|
-- a[12] is two byte instruction bit
|
| 461 |
|
|
-- a[11..4] is 8 bit opcode
|
| 462 |
|
|
-- a[3..0] is 4 bit microinstruction counter
|
| 463 |
|
|
component mcpla
|
| 464 |
|
|
port( em: in STD_LOGIC; -- emulation mode (1)/native mode (0)
|
| 465 |
|
|
m: in STD_LOGIC; -- M memory/acc. 8 bit (1), M memory/acc. 16 bit (0)
|
| 466 |
|
|
x: in STD_LOGIC; -- X index reg. 8 bit (1), X index reg. 16 bit (0)
|
| 467 |
|
|
a: in STD_LOGIC_VECTOR(12 downto 0); -- two byte bit & 8 bit opcode & 4 bit microinstruction counter
|
| 468 |
|
|
q: out STD_LOGIC_VECTOR(44 downto 0) -- microcode output
|
| 469 |
|
|
);
|
| 470 |
|
|
end component;
|
| 471 |
|
|
|
| 472 |
|
|
-- register operation decoding logic
|
| 473 |
|
|
component decreg
|
| 474 |
|
|
port( r: in STD_LOGIC_VECTOR(5 downto 0);
|
| 475 |
|
|
y: out STD_LOGIC_VECTOR(29 downto 0)
|
| 476 |
|
|
);
|
| 477 |
|
|
end component;
|
| 478 |
|
|
|
| 479 |
|
|
-- cpu main state machine
|
| 480 |
|
|
component cpufsm
|
| 481 |
|
|
port( clk: in STD_LOGIC;
|
| 482 |
|
|
clr: in STD_LOGIC;
|
| 483 |
|
|
fwait: in STD_LOGIC;
|
| 484 |
|
|
ireq: in STD_LOGIC;
|
| 485 |
|
|
aim: in STD_LOGIC;
|
| 486 |
|
|
bcarry: in STD_LOGIC;
|
| 487 |
|
|
icarry: in STD_LOGIC;
|
| 488 |
|
|
p1: in STD_LOGIC_VECTOR(2 downto 0);
|
| 489 |
|
|
e_ei: in STD_LOGIC;
|
| 490 |
|
|
mc_ei: in STD_LOGIC;
|
| 491 |
|
|
addsub: in STD_LOGIC;
|
| 492 |
|
|
dec_mode: in STD_LOGIC;
|
| 493 |
|
|
fetch: out STD_LOGIC;
|
| 494 |
|
|
op_sync: out STD_LOGIC;
|
| 495 |
|
|
pci: out STD_LOGIC;
|
| 496 |
|
|
pq: out STD_LOGIC_VECTOR(2 downto 0);
|
| 497 |
|
|
fb: out STD_LOGIC;
|
| 498 |
|
|
od: out STD_LOGIC;
|
| 499 |
|
|
mc_nop: out STD_LOGIC
|
| 500 |
|
|
);
|
| 501 |
|
|
end component;
|
| 502 |
|
|
|
| 503 |
|
|
-- interrupt logic
|
| 504 |
|
|
component intlog
|
| 505 |
|
|
port( clk: in STD_LOGIC;
|
| 506 |
|
|
iack: in STD_LOGIC; -- interrupt acknowledge by microcode
|
| 507 |
|
|
r: in STD_LOGIC; -- RESET request
|
| 508 |
|
|
n: in STD_LOGIC; -- NMI request
|
| 509 |
|
|
i: in STD_LOGIC; -- IRQ request
|
| 510 |
|
|
brk: in STD_LOGIC; -- BRK opcode
|
| 511 |
|
|
cop: in STD_LOGIC; -- COP opcode
|
| 512 |
|
|
e: in STD_LOGIC; -- native\emulation mode
|
| 513 |
|
|
gmask: in STD_LOGIC; -- interrupt mask valid for IRQ and NMI (used by two byte instruction)
|
| 514 |
|
|
imask: in STD_LOGIC; -- interrupt mask (valid only for IRQ)
|
| 515 |
|
|
ioffs: in STD_LOGIC_VECTOR(7 downto 0); -- interrupt servicing offset
|
| 516 |
|
|
ireq: out STD_LOGIC; -- global interrupt requestb (IRQ/NMI)
|
| 517 |
|
|
voffs: out STD_LOGIC_VECTOR(7 downto 0) -- interrupt vector offset
|
| 518 |
|
|
);
|
| 519 |
|
|
end component;
|
| 520 |
|
|
|
| 521 |
|
|
-- branch logic
|
| 522 |
|
|
component branch
|
| 523 |
|
|
port( op: in STD_LOGIC_VECTOR(3 downto 0);
|
| 524 |
|
|
n: in STD_LOGIC;
|
| 525 |
|
|
v: in STD_LOGIC;
|
| 526 |
|
|
z: in STD_LOGIC;
|
| 527 |
|
|
c: in STD_LOGIC;
|
| 528 |
|
|
bres: out STD_LOGIC
|
| 529 |
|
|
);
|
| 530 |
|
|
end component;
|
| 531 |
|
|
|
| 532 |
|
|
-- opcode decimal instructions and prefetch prediction logic
|
| 533 |
|
|
component pre_dec
|
| 534 |
|
|
port( op: in STD_LOGIC_VECTOR(7 downto 0);
|
| 535 |
|
|
fetch: in STD_LOGIC;
|
| 536 |
|
|
ei: out STD_LOGIC;
|
| 537 |
|
|
dec: out STD_LOGIC
|
| 538 |
|
|
);
|
| 539 |
|
|
end component;
|
| 540 |
|
|
|
| 541 |
|
|
-- 16X16->32 bit multiplier signed/unsigned
|
| 542 |
|
|
component multiplier
|
| 543 |
|
|
port( clk: in STD_LOGIC;
|
| 544 |
|
|
clr: in STD_LOGIC;
|
| 545 |
|
|
init: in STD_LOGIC;
|
| 546 |
|
|
start_u: in STD_LOGIC;
|
| 547 |
|
|
start_s: in STD_LOGIC;
|
| 548 |
|
|
mpcand: in STD_LOGIC_VECTOR(15 downto 0);
|
| 549 |
|
|
mplier: in STD_LOGIC_VECTOR(15 downto 0);
|
| 550 |
|
|
busy: out STD_LOGIC;
|
| 551 |
|
|
res_lsb: out STD_LOGIC_VECTOR(15 downto 0);
|
| 552 |
|
|
res_msb: out STD_LOGIC_VECTOR(15 downto 0);
|
| 553 |
|
|
z_flg: out STD_LOGIC;
|
| 554 |
|
|
n_flg: out STD_LOGIC
|
| 555 |
|
|
);
|
| 556 |
|
|
end component;
|
| 557 |
|
|
|
| 558 |
|
|
begin
|
| 559 |
|
|
u1:pcr port map(clk=>clk0,
|
| 560 |
|
|
i=>pcinc,
|
| 561 |
|
|
fwait=>i_rdy,
|
| 562 |
|
|
brk_op=>opbrk,
|
| 563 |
|
|
branch_flg=>branch_taken,
|
| 564 |
|
|
mov_f=>mov_end,
|
| 565 |
|
|
fc=>pcr_fc,
|
| 566 |
|
|
din1=>alu_bus(7 downto 0),
|
| 567 |
|
|
din2=>o_bus,
|
| 568 |
|
|
dout=>pc_bus
|
| 569 |
|
|
);
|
| 570 |
|
|
|
| 571 |
|
|
u2:kr port map(clk=>clk0,
|
| 572 |
|
|
clr=>kr_clear,
|
| 573 |
|
|
fwait=>i_rdy,
|
| 574 |
|
|
ld=>k_l,
|
| 575 |
|
|
din=>alu_bus(7 downto 0),
|
| 576 |
|
|
dout=>k_bus
|
| 577 |
|
|
);
|
| 578 |
|
|
|
| 579 |
|
|
u3:br port map(clk=>clk0,
|
| 580 |
|
|
clr=>br_clear,
|
| 581 |
|
|
fwait=>i_rdy,
|
| 582 |
|
|
ld=>b_l,
|
| 583 |
|
|
din=>alu_bus(7 downto 0),
|
| 584 |
|
|
dout=>b_bus
|
| 585 |
|
|
);
|
| 586 |
|
|
|
| 587 |
|
|
u4:mpr port map(clk=>clk0,
|
| 588 |
|
|
fwait=>i_rdy,
|
| 589 |
|
|
dbr_ld=>opfetch,
|
| 590 |
|
|
c=>acr_reg,
|
| 591 |
|
|
fc=>mpr_fc,
|
| 592 |
|
|
din_l=>alu_bus(7 downto 0),
|
| 593 |
|
|
din_h=>dbin,
|
| 594 |
|
|
dbr=>b_bus,
|
| 595 |
|
|
dr=>d_bus,
|
| 596 |
|
|
op=>o_bus,
|
| 597 |
|
|
xr=>x_bus,
|
| 598 |
|
|
yr=>y_bus,
|
| 599 |
|
|
sr=>sp_bus,
|
| 600 |
|
|
v=>ivoffs,
|
| 601 |
|
|
dout=>mp_bus
|
| 602 |
|
|
);
|
| 603 |
|
|
|
| 604 |
|
|
u5:ar port map(clk=>clk0,
|
| 605 |
|
|
fwait=>i_rdy,
|
| 606 |
|
|
size=>acc_size,
|
| 607 |
|
|
ld_lsb=>a_l_lsb,
|
| 608 |
|
|
ld_msb=>a_l_msb,
|
| 609 |
|
|
ld_mul_lsb=>mul_l_res,
|
| 610 |
|
|
d=>a_dec,
|
| 611 |
|
|
end_count=>mov_end,
|
| 612 |
|
|
din=>alu_bus,
|
| 613 |
|
|
mul_lsb=>mul_r_lsb,
|
| 614 |
|
|
dout=>a_bus
|
| 615 |
|
|
);
|
| 616 |
|
|
|
| 617 |
|
|
u6:xr port map(clk=>clk0,
|
| 618 |
|
|
fwait=>i_rdy,
|
| 619 |
|
|
size=>index_size,
|
| 620 |
|
|
ld_lsb=>x_l_lsb,
|
| 621 |
|
|
ld_msb=>x_l_msb,
|
| 622 |
|
|
ld_mul_msb=>mul_l_res,
|
| 623 |
|
|
u=>x_u,
|
| 624 |
|
|
d=>x_d,
|
| 625 |
|
|
din=>alu_bus,
|
| 626 |
|
|
mul_msb=>mul_r_msb,
|
| 627 |
|
|
dout=>x_bus
|
| 628 |
|
|
);
|
| 629 |
|
|
|
| 630 |
|
|
u7:yr port map(clk=>clk0,
|
| 631 |
|
|
fwait=>i_rdy,
|
| 632 |
|
|
size=>index_size,
|
| 633 |
|
|
ld_lsb=>y_l_lsb,
|
| 634 |
|
|
ld_msb=>y_l_msb,
|
| 635 |
|
|
u=>y_u,
|
| 636 |
|
|
d=>y_d,
|
| 637 |
|
|
din=>alu_bus,
|
| 638 |
|
|
dout=>y_bus
|
| 639 |
|
|
);
|
| 640 |
|
|
|
| 641 |
|
|
u8:dr port map(clk=>clk0,
|
| 642 |
|
|
clr=>i_res,
|
| 643 |
|
|
fwait=>i_rdy,
|
| 644 |
|
|
ld_lsb=>d_l_lsb,
|
| 645 |
|
|
ld_msb=>d_l_msb,
|
| 646 |
|
|
din=>alu_bus,
|
| 647 |
|
|
dout=>d_bus
|
| 648 |
|
|
);
|
| 649 |
|
|
|
| 650 |
|
|
u9:spr port map(clk=>clk0,
|
| 651 |
|
|
clr=>i_res,
|
| 652 |
|
|
fwait=>i_rdy,
|
| 653 |
|
|
em=>sp_emu,
|
| 654 |
|
|
ld_l=>sp_ll,
|
| 655 |
|
|
ld_h=>sp_lh,
|
| 656 |
|
|
u=>sp_u,
|
| 657 |
|
|
d=>sp_d,
|
| 658 |
|
|
din=>alu_bus,
|
| 659 |
|
|
dout=>sp_bus
|
| 660 |
|
|
);
|
| 661 |
|
|
|
| 662 |
|
|
u10:pr port map(clk=>clk0,
|
| 663 |
|
|
clr=>i_res,
|
| 664 |
|
|
fwait=>i_rdy,
|
| 665 |
|
|
n=>n_flg,
|
| 666 |
|
|
v=>v_flg,
|
| 667 |
|
|
z=>z_flg,
|
| 668 |
|
|
c=>c_flg,
|
| 669 |
|
|
mpy_z=>mul_z_flg,
|
| 670 |
|
|
mpy_n=>mul_n_flg,
|
| 671 |
|
|
swi=>sw_int,
|
| 672 |
|
|
acr_in=>pc_c_alu_flg,
|
| 673 |
|
|
fc=>p_op,
|
| 674 |
|
|
din=>dbin,
|
| 675 |
|
|
dout=>p_bus,
|
| 676 |
|
|
acr_out=>acr_reg,
|
| 677 |
|
|
em=>emu,
|
| 678 |
|
|
two_op=>two_byte_op
|
| 679 |
|
|
);
|
| 680 |
|
|
|
| 681 |
|
|
u11:opr port map(clk=>clk0,
|
| 682 |
|
|
clr=>fbrk,
|
| 683 |
|
|
fwait=>i_rdy,
|
| 684 |
|
|
ld=>opfetch,
|
| 685 |
|
|
din=>dbin,
|
| 686 |
|
|
brk_f=>opbrk,
|
| 687 |
|
|
cop_f=>opcop,
|
| 688 |
|
|
dout=>op_bus
|
| 689 |
|
|
);
|
| 690 |
|
|
|
| 691 |
|
|
u12:oper port map(clk=>clk0,
|
| 692 |
|
|
clr=>opfetch,
|
| 693 |
|
|
fwait=>i_rdy,
|
| 694 |
|
|
ld=>o_l,
|
| 695 |
|
|
ld_lsb=>o_l_lsb,
|
| 696 |
|
|
ld_msb=>o_l_msb,
|
| 697 |
|
|
din=>alu_bus,
|
| 698 |
|
|
dout=>o_bus
|
| 699 |
|
|
);
|
| 700 |
|
|
|
| 701 |
|
|
u13:alu_bin port map(alu_byp=>acr_reg,
|
| 702 |
|
|
bcd=>p_bus(3),
|
| 703 |
|
|
size=>m_size,
|
| 704 |
|
|
cin=>p_bus(0),
|
| 705 |
|
|
vin=>p_bus(6),
|
| 706 |
|
|
op1=>r_bus,
|
| 707 |
|
|
op2=>oper_bus,
|
| 708 |
|
|
fc=>aluop,
|
| 709 |
|
|
cf=>c_flg,
|
| 710 |
|
|
zf=>z_flg,
|
| 711 |
|
|
nf=>n_flg,
|
| 712 |
|
|
vf=>v_flg,
|
| 713 |
|
|
pc_cf=>pc_c_alu_flg,
|
| 714 |
|
|
dout=>alu_bus
|
| 715 |
|
|
);
|
| 716 |
|
|
|
| 717 |
|
|
u14:addrmux port map(sel=>pcmp,
|
| 718 |
|
|
a=>i_addr_bus,
|
| 719 |
|
|
b=>mp_bus,
|
| 720 |
|
|
dbr=>b_bus,
|
| 721 |
|
|
s=>sp_bus,
|
| 722 |
|
|
xr=>x_bus,
|
| 723 |
|
|
yr=>y_bus,
|
| 724 |
|
|
y=>addr
|
| 725 |
|
|
);
|
| 726 |
|
|
|
| 727 |
|
|
u15:regmux port map(sel=>rsel,
|
| 728 |
|
|
a=>dbin,
|
| 729 |
|
|
b=>a_bus,
|
| 730 |
|
|
c=>x_bus,
|
| 731 |
|
|
d=>y_bus,
|
| 732 |
|
|
e=>sp_bus,
|
| 733 |
|
|
g=>p_bus,
|
| 734 |
|
|
h=>pc_bus(7 downto 0),
|
| 735 |
|
|
i=>pc_bus(15 downto 8),
|
| 736 |
|
|
j=>o_bus,
|
| 737 |
|
|
k=>d_bus,
|
| 738 |
|
|
l=>k_bus,
|
| 739 |
|
|
m=>b_bus,
|
| 740 |
|
|
y=>r_bus
|
| 741 |
|
|
);
|
| 742 |
|
|
|
| 743 |
|
|
u16:dmux port map(sel=>dmux_sel,
|
| 744 |
|
|
a=>o_bus,
|
| 745 |
|
|
b=>dbin,
|
| 746 |
|
|
y=>oper_bus
|
| 747 |
|
|
);
|
| 748 |
|
|
|
| 749 |
|
|
u17:mcseq port map(clk=>clk0,
|
| 750 |
|
|
clr=>opdec,
|
| 751 |
|
|
mc_nop=>mcn,
|
| 752 |
|
|
fwait=>i_rdy or mul_busy,
|
| 753 |
|
|
q=>mcscan
|
| 754 |
|
|
);
|
| 755 |
|
|
|
| 756 |
|
|
u18:mcpla port map(em=>emu,
|
| 757 |
|
|
m=>m_bit,
|
| 758 |
|
|
x=>x_bit,
|
| 759 |
|
|
a=>mc_addr,
|
| 760 |
|
|
q=>mcbit
|
| 761 |
|
|
);
|
| 762 |
|
|
|
| 763 |
|
|
u19:decreg port map(r=>regop,
|
| 764 |
|
|
y=>regbit
|
| 765 |
|
|
);
|
| 766 |
|
|
|
| 767 |
|
|
u20:cpufsm port map(clk=>clk0,
|
| 768 |
|
|
clr=>i_res,
|
| 769 |
|
|
fwait=>i_rdy,
|
| 770 |
|
|
ireq=>int,
|
| 771 |
|
|
aim=>ai_op,
|
| 772 |
|
|
bcarry=>pcc,
|
| 773 |
|
|
icarry=>acr_reg,
|
| 774 |
|
|
p1=>pcmp_mc,
|
| 775 |
|
|
e_ei=>e_eop,
|
| 776 |
|
|
mc_ei=>mc_eop,
|
| 777 |
|
|
addsub=>add_sub_op,
|
| 778 |
|
|
dec_mode=>p_bus(3),
|
| 779 |
|
|
fetch=>opfetch,
|
| 780 |
|
|
op_sync=>i_sync,
|
| 781 |
|
|
pci=>pcinc,
|
| 782 |
|
|
pq=>pcmp,
|
| 783 |
|
|
fb=>fbrk,
|
| 784 |
|
|
od=>opdec,
|
| 785 |
|
|
mc_nop=>mcn
|
| 786 |
|
|
);
|
| 787 |
|
|
|
| 788 |
|
|
u21:intlog port map(clk=>clk0,
|
| 789 |
|
|
iack=>clri,
|
| 790 |
|
|
r=>i_res,
|
| 791 |
|
|
n=>i_nmi,
|
| 792 |
|
|
i=>i_irq,
|
| 793 |
|
|
brk=>opbrk,
|
| 794 |
|
|
cop=>opcop,
|
| 795 |
|
|
e=>emu,
|
| 796 |
|
|
gmask=>two_byte_op,
|
| 797 |
|
|
imask=>ien,
|
| 798 |
|
|
ioffs=>mp_bus(7 downto 0),
|
| 799 |
|
|
ireq=>int,
|
| 800 |
|
|
voffs=>ivoffs
|
| 801 |
|
|
);
|
| 802 |
|
|
|
| 803 |
|
|
u22:branch port map(op=>op_bus(7 downto 4),
|
| 804 |
|
|
n=>p_bus(7),
|
| 805 |
|
|
v=>p_bus(6),
|
| 806 |
|
|
z=>p_bus(1),
|
| 807 |
|
|
c=>p_bus(0),
|
| 808 |
|
|
bres=>branch_taken
|
| 809 |
|
|
);
|
| 810 |
|
|
|
| 811 |
|
|
u23:pre_dec port map(op=>dbin,
|
| 812 |
|
|
fetch=>opfetch,
|
| 813 |
|
|
ei=>e_eop,
|
| 814 |
|
|
dec=>add_sub_op
|
| 815 |
|
|
);
|
| 816 |
|
|
|
| 817 |
|
|
u24:multiplier port map(clk=>clk0,
|
| 818 |
|
|
clr=>i_res,
|
| 819 |
|
|
init=>mul_init,
|
| 820 |
|
|
start_u=>mul_start_u,
|
| 821 |
|
|
start_s=>mul_start_s,
|
| 822 |
|
|
mpcand=>a_bus,
|
| 823 |
|
|
mplier=>x_bus,
|
| 824 |
|
|
busy=>mul_busy,
|
| 825 |
|
|
res_lsb=>mul_r_lsb,
|
| 826 |
|
|
res_msb=>mul_r_msb,
|
| 827 |
|
|
z_flg=>mul_z_flg,
|
| 828 |
|
|
n_flg=>mul_n_flg
|
| 829 |
|
|
);
|
| 830 |
|
|
|
| 831 |
|
|
-- asynchronous CPU link section
|
| 832 |
|
|
mc_addr <= two_byte_op & mcad;
|
| 833 |
|
|
e <= emu; -- emulation mode
|
| 834 |
|
|
ien <= p_bus(2); -- P(I) flag
|
| 835 |
|
|
i_res <= not res; -- internal reset
|
| 836 |
|
|
i_nmi <= not nmi; -- internal NMI
|
| 837 |
|
|
i_irq <= not irq; -- internal IRQ
|
| 838 |
|
|
e_rdy <= not rdy; -- external RDY inverted
|
| 839 |
|
|
i_rdy <= e_rdy or wai_ff or stp_ff; -- internal RDY
|
| 840 |
|
|
mcad <= op_bus & mcscan; -- microcode address
|
| 841 |
|
|
rsel <= mcbit(4 downto 0); -- registers read microcode
|
| 842 |
|
|
regop <= mcbit(10 downto 5); -- registers operation microcode
|
| 843 |
|
|
aluop <= mcbit(15 downto 11); -- ALU microcode
|
| 844 |
|
|
p_op <= mcbit(20 downto 16); -- register P microcode
|
| 845 |
|
|
mpr_fc <= mcbit(25 downto 21); -- MPR microcode
|
| 846 |
|
|
pcr_fc <= mcbit(29 downto 26); -- PCR microcode
|
| 847 |
|
|
pcmp_mc <= mcbit(32 downto 30); -- PCR/MPR multiplexer microcode
|
| 848 |
|
|
clri <= mcbit(33); -- clear interrupt request
|
| 849 |
|
|
we_mc <= mcbit(34); -- write enable (combinatorial) microcode
|
| 850 |
|
|
we_mc_l <= mcbit(35); -- write enable (latched) microcode
|
| 851 |
|
|
mc_eop <= mcbit(36); -- end of instruction reached
|
| 852 |
|
|
mc_vda <= mcbit(37); -- microcode VDA
|
| 853 |
|
|
mc_vpa <= mcbit(38); -- microcode VPA
|
| 854 |
|
|
mc_ml <= mcbit(39); -- microcode ML
|
| 855 |
|
|
i_vp <= mcbit(40); -- vector pull
|
| 856 |
|
|
ai_op <= mcbit(41); -- opcode with addressing indexed microcode
|
| 857 |
|
|
dmux_sel <= mcbit(44 downto 42); -- data multiplexer microcode
|
| 858 |
|
|
ope <= eop;
|
| 859 |
|
|
i_addr_bus <= k_bus & pc_bus;
|
| 860 |
|
|
eop <= '1' when mc_eop = '1' or e_eop = '1' else '0';
|
| 861 |
|
|
vp <= not i_vp;
|
| 862 |
|
|
op_exp <= two_byte_op;
|
| 863 |
|
|
vda <= m_sync or mc_vda;
|
| 864 |
|
|
vpa <= m_sync or mc_vpa;
|
| 865 |
|
|
ml <= mc_ml;
|
| 866 |
|
|
sw_int <= opbrk or opcop;
|
| 867 |
|
|
|
| 868 |
|
|
-- ALU/memory size
|
| 869 |
|
|
m_size8 <= '1' when emu = '1' or m_bit = '1' else
|
| 870 |
|
|
'1' when op_bus = x"EB" or op_bus = x"AB" else -- when XBA and PLB opcodes the ALU size is always 8 bit
|
| 871 |
|
|
'1' when (op_bus = x"AA" or op_bus = x"A8") and x_bit = '1' else -- when TAX and TAY opcodes and X is '1' the ALU size is 8 bit
|
| 872 |
|
|
'1' when (op_bus = x"8A" or op_bus = x"98") and m_bit = '1' else -- when TXA and TXA opcodes and M is '1' the ALU size is 8 bit
|
| 873 |
|
|
'1' when op_bus = x"68" and m_bit = '1' else -- when PLA opcode and M is '1' the ALU size is 8 bit
|
| 874 |
|
|
'1' when (op_bus = x"FA" or op_bus = x"7A") and x_bit = '1' else -- when PLX or PLY opcode and X = '1' the ALU size is 8 bit
|
| 875 |
|
|
'0';
|
| 876 |
|
|
m_size16 <= '0' when (op_bus = x"5B" or op_bus = x"7B") else -- when TCD or TDC opcodes the transfer size is always 16 bit
|
| 877 |
|
|
'0' when (op_bus = x"1B" or op_bus = x"3B") else -- when TCS or TSC opcodes the transfer size is always 16 bit
|
| 878 |
|
|
'0' when (op_bus = x"82" or op_bus = x"62") else -- when BRL or PER opcodes the transfer size is always 16 bit
|
| 879 |
|
|
'0' when op_bus = x"2B" else -- when PLD opcode the transfer size is always 16 bit
|
| 880 |
|
|
'0' when (op_bus = x"AB" and two_byte_op = '1') and emu = '0' else -- when PLR opcode and native mode
|
| 881 |
|
|
'0' when ld_acc = '1' and m_bit = '0' else -- when load accumulator C register
|
| 882 |
|
|
'0' when ld_xy = '1' and x_bit = '0' else -- when load X/Y registers (16 bit size)
|
| 883 |
|
|
'1';
|
| 884 |
|
|
s_size16 <= '0' when op_bus = x"EB" else '1'; -- special case for XBA: accumulator size is 16 bit so it can reloads itself swapped in only one cycle
|
| 885 |
|
|
m_size <= m_size8 and m_size16; -- ALU size
|
| 886 |
|
|
acc_size <= m_size8 and m_size16 and s_size16; -- accumulator register C size
|
| 887 |
|
|
index_size <= emu or x_bit; -- index registers size
|
| 888 |
|
|
|
| 889 |
|
|
-- S native/emulation mode (set by XCE opcode and E bit)
|
| 890 |
|
|
sp_emu <= p_bus(0) when op_bus = x"FB" else emu;
|
| 891 |
|
|
|
| 892 |
|
|
-- register operations
|
| 893 |
|
|
a_l_lsb <= regbit(0); -- A load lsb
|
| 894 |
|
|
a_l_msb <= regbit(1); -- A load msb
|
| 895 |
|
|
a_dec <= regbit(2); -- A decrement
|
| 896 |
|
|
x_l_lsb <= regbit(3); -- X load lsb
|
| 897 |
|
|
x_l_msb <= regbit(4); -- X load msb
|
| 898 |
|
|
x_d <= regbit(5); -- X -= 1
|
| 899 |
|
|
x_u <= regbit(6); -- X += 1
|
| 900 |
|
|
y_l_lsb <= regbit(7); -- Y load lsb
|
| 901 |
|
|
y_l_msb <= regbit(8); -- Y load msb
|
| 902 |
|
|
y_d <= regbit(9); -- Y -= 1
|
| 903 |
|
|
y_u <= regbit(10); -- Y += 1
|
| 904 |
|
|
d_l_lsb <= regbit(11); -- D load lsb
|
| 905 |
|
|
d_l_msb <= regbit(12); -- D load msb
|
| 906 |
|
|
o_l <= regbit(13); -- O load msb & lsb
|
| 907 |
|
|
o_l_lsb <= regbit(14); -- O load lsb
|
| 908 |
|
|
o_l_msb <= regbit(15); -- O load msb
|
| 909 |
|
|
sp_ll <= regbit(16); -- S load lsb
|
| 910 |
|
|
sp_lh <= regbit(17); -- S load msb
|
| 911 |
|
|
sp_u <= regbit(18); -- S += 1
|
| 912 |
|
|
sp_d <= regbit(19); -- S -= 1
|
| 913 |
|
|
k_l <= regbit(20); -- PBR K load
|
| 914 |
|
|
b_l <= regbit(21); -- DBR B load
|
| 915 |
|
|
k_cl <= regbit(22); -- PBR K clear
|
| 916 |
|
|
b_cl <= regbit(23); -- DBR B clear
|
| 917 |
|
|
mul_l_res <= regbit(24); -- load multiplication result on A/B and X
|
| 918 |
|
|
mul_init <= regbit(25); -- init multiplier
|
| 919 |
|
|
mul_start_u <= regbit(26); -- start multiplier unsigned
|
| 920 |
|
|
mul_start_s <= regbit(27); -- start multiplier signed
|
| 921 |
|
|
wai_set <= regbit(28); -- WAI enter wait
|
| 922 |
|
|
stp_set <= regbit(29); -- STP enter wait
|
| 923 |
|
|
we <= we_mc or opfetch; -- write enable
|
| 924 |
|
|
m_bit <= p_bus(5) or emu; -- M bit
|
| 925 |
|
|
x_bit <= p_bus(4) or emu; -- X bit
|
| 926 |
|
|
m <= m_bit;
|
| 927 |
|
|
x <= x_bit;
|
| 928 |
|
|
kr_clear <= i_res or k_cl;
|
| 929 |
|
|
br_clear <= i_res or b_cl;
|
| 930 |
|
|
ld_acc <= regbit(0) and regbit(1);
|
| 931 |
|
|
ld_xy <= (regbit(3) and regbit(4)) or (regbit(7) and regbit(8));
|
| 932 |
|
|
-- VPA latched
|
| 933 |
|
|
process(clk0)
|
| 934 |
|
|
begin
|
| 935 |
|
|
if (clk0'event and clk0 = '1') then
|
| 936 |
|
|
if i_rdy = '0' then
|
| 937 |
|
|
m_sync <= i_sync;
|
| 938 |
|
|
else
|
| 939 |
|
|
m_sync <= m_sync;
|
| 940 |
|
|
end if;
|
| 941 |
|
|
end if;
|
| 942 |
|
|
end process;
|
| 943 |
|
|
|
| 944 |
|
|
-- PC carry logic
|
| 945 |
|
|
process(o_bus,pc_c_alu_flg)
|
| 946 |
|
|
begin
|
| 947 |
|
|
if o_bus(7) = '0' then -- check for positive/negative branch offset (bit 7)
|
| 948 |
|
|
pcc <= pc_c_alu_flg;
|
| 949 |
|
|
else
|
| 950 |
|
|
pcc <= not pc_c_alu_flg;
|
| 951 |
|
|
end if;
|
| 952 |
|
|
end process;
|
| 953 |
|
|
|
| 954 |
|
|
-- write enable registered
|
| 955 |
|
|
process(clk0)
|
| 956 |
|
|
begin
|
| 957 |
|
|
if (clk0'event and clk0 = '1') then
|
| 958 |
|
|
if i_res = '1' then
|
| 959 |
|
|
we_r <= '1';
|
| 960 |
|
|
else
|
| 961 |
|
|
if i_rdy = '0' then
|
| 962 |
|
|
we_r <= we_mc_l;
|
| 963 |
|
|
else
|
| 964 |
|
|
we_r <= we_r;
|
| 965 |
|
|
end if;
|
| 966 |
|
|
end if;
|
| 967 |
|
|
end if;
|
| 968 |
|
|
end process;
|
| 969 |
|
|
|
| 970 |
|
|
rw <= we and we_r;
|
| 971 |
|
|
|
| 972 |
|
|
-- WAI
|
| 973 |
|
|
process(clk0)
|
| 974 |
|
|
begin
|
| 975 |
|
|
if (clk0'event and clk0 = '1') then
|
| 976 |
|
|
if wai_ff = '0' then
|
| 977 |
|
|
if wai_set then
|
| 978 |
|
|
wai_ff <= '1';
|
| 979 |
|
|
else
|
| 980 |
|
|
wai_ff <= wai_ff;
|
| 981 |
|
|
end if;
|
| 982 |
|
|
else
|
| 983 |
|
|
if i_res = '1' or i_nmi = '1' or i_irq = '1' then
|
| 984 |
|
|
wai_ff <= '0';
|
| 985 |
|
|
else
|
| 986 |
|
|
wai_ff <= wai_ff;
|
| 987 |
|
|
end if;
|
| 988 |
|
|
end if;
|
| 989 |
|
|
end if;
|
| 990 |
|
|
end process;
|
| 991 |
|
|
rdy_out <= not wai_ff;
|
| 992 |
|
|
|
| 993 |
|
|
-- STP
|
| 994 |
|
|
process(clk0)
|
| 995 |
|
|
begin
|
| 996 |
|
|
if (clk0'event and clk0 = '1') then
|
| 997 |
|
|
if stp_ff = '0' then
|
| 998 |
|
|
if stp_set then
|
| 999 |
|
|
stp_ff <= '1';
|
| 1000 |
|
|
else
|
| 1001 |
|
|
stp_ff <= stp_ff;
|
| 1002 |
|
|
end if;
|
| 1003 |
|
|
else
|
| 1004 |
|
|
if i_res = '1' then
|
| 1005 |
|
|
stp_ff <= '0';
|
| 1006 |
|
|
else
|
| 1007 |
|
|
stp_ff <= stp_ff;
|
| 1008 |
|
|
end if;
|
| 1009 |
|
|
end if;
|
| 1010 |
|
|
end if;
|
| 1011 |
|
|
end process;
|
| 1012 |
|
|
stp_out <= not stp_ff;
|
| 1013 |
|
|
|
| 1014 |
|
|
|
| 1015 |
|
|
-- data bus tristate (buffer ring gated) control logic
|
| 1016 |
|
|
--process(clk0,we,we_r,alu_bus)
|
| 1017 |
|
|
--begin
|
| 1018 |
|
|
-- if clock = '0' and (we = '0' or we_r = '0') then
|
| 1019 |
|
|
-- data <= alu_bus;
|
| 1020 |
|
|
-- else
|
| 1021 |
|
|
-- data <= "ZZZZZZZZ";
|
| 1022 |
|
|
-- end if;
|
| 1023 |
|
|
--end process;
|
| 1024 |
|
|
|
| 1025 |
|
|
|
| 1026 |
|
|
data_out <= alu_bus(7 downto 0);
|
| 1027 |
|
|
dbin <= data_in or "00000000";
|
| 1028 |
|
|
-- DEBUG
|
| 1029 |
|
|
-- a_reg <= a_bus;
|
| 1030 |
|
|
-- x_reg <= x_bus;
|
| 1031 |
|
|
-- y_reg <= y_bus;
|
| 1032 |
|
|
-- s_reg <= sp_bus;
|
| 1033 |
|
|
-- op_reg <= o_bus;
|
| 1034 |
|
|
-- p_reg <= p_bus;
|
| 1035 |
|
|
-- k_reg <= k_bus;
|
| 1036 |
|
|
-- b_reg <= b_bus;
|
| 1037 |
|
|
-- o_reg <= op_bus;
|
| 1038 |
|
|
-- mcode <= mcscan;
|
| 1039 |
|
|
|
| 1040 |
|
|
end struct;
|
| 1041 |
|
|
|
| 1042 |
|
|
|
| 1043 |
|
|
|
