i80386.vhd

Intel微处理器80386的vhdl模拟

    -- Internal Control Logic Processes End

    -- Instruction Pre-Fetch, Decode and Execution Unit Begin
    InstDecode: PROCESS
    VARIABLE InstQueue:         vlbit_2d(1 to 16,7 downto 0);
    VARIABLE InstQueueRd_Addr:  INTEGER := 1;       -- Address used by the decode unit to read the queue.
    VARIABLE InstQueueWr_Addr:  INTEGER := 1;       -- Address used by the Pre-fetch unit to fill the queue.
    VARIABLE InstQueueLimit:    INTEGER := 16;      -- Maximum length of the Queue.
    VARIABLE InstAddrPointer:   INTEGER := 0;       -- Allways points to the current instruction's Address.
    VARIABLE PhyAddrPointer:    INTEGER := 0;       -- Allways points to the Systems Physical Address.
    VARIABLE Extended:          BOOLEAN := FALSE;   -- True if an extended op-code prefix was detected.
    VARIABLE More:              BOOLEAN := FALSE;   -- True if instruction was decoded correctly and
                                                    -- another read is needed for data.
    VARIABLE Flush:             BOOLEAN := FALSE;   -- True if JMP was executed, flush the Queue.
    VARIABLE First:             BOOLEAN := TRUE;    -- First time thru.
    VARIABLE Byte:              vlbit_1d(7 downto 0);
    VARIABLE lWord:             vlbit_1d(15 downto 0);
    VARIABLE uWord:             vlbit_1d(15 downto 0);
    VARIABLE fWord:             vlbit_1d(31 downto 0);
    VARIABLE Dummy:             INTEGER;

    BEGIN
        IF First THEN
            PhyAddrPointer := integer(rEIP);
            InstAddrPointer := PhyAddrPointer;
            First := FALSE;
        END IF;
        RequestPending <= Pending;
        ReadRequest <= Pending;
        MemoryFetch <= Pending;
        CodeFetch <= Pending;
        IF Debug THEN
            put("DEBUG: Fetching 1st Word @ Addr=");Dummy := tohex(PhyAddrPointer,4);putline("");
        END IF;
        WAIT UNTIL pfalling(READY_n);
        RequestPending <= NotPending;
        WAIT UNTIL pfalling(CLK);
        InstQueue(InstQueueWr_Addr) := Data(7 downto 0);
        InstQueueWr_Addr := InstQueueWr_Addr + 1;
        InstQueue(InstQueueWr_Addr) := Data(15 downto 8);
        InstQueueWr_Addr := InstQueueWr_Addr + 1;
        IF StateBS16 = '1' THEN  -- A dWord code fetch
            InstQueue(InstQueueWr_Addr) := Data(23 downto 16);
            InstQueueWr_Addr := InstQueueWr_Addr + 1;
            InstQueue(InstQueueWr_Addr) := Data(31 downto 24);
            InstQueueWr_Addr := InstQueueWr_Addr + 1;
            PhyAddrPointer := PhyAddrPointer + 4; -- Point to next dWord since BS16- = 1
        ELSE
            PhyAddrPointer := PhyAddrPointer + 2; -- Point to next word since BS16- = 0
            IF Debug THEN
                put("DEBUG: Fetching 2nd Word @ Addr=");Dummy := tohex(PhyAddrPointer,4);putline("");
            END IF;
            rEIP <= vlbit_vector(PhyAddrPointer);
            WAIT UNTIL prising(CLK);
            RequestPending <= Pending;
            WAIT UNTIL pfalling(READY_n);
            RequestPending <= NotPending;
            WAIT UNTIL pfalling(CLK);
            InstQueue(InstQueueWr_Addr) := Data(7 downto 0);
            InstQueueWr_Addr := InstQueueWr_Addr + 1;
            InstQueue(InstQueueWr_Addr) := Data(15 downto 8);
            InstQueueWr_Addr := InstQueueWr_Addr + 1;
            PhyAddrPointer := PhyAddrPointer + 2; -- Point to next word since BS16- = 0
        END IF;
        Decode: WHILE InstQueueRd_Addr < InstQueueWr_Addr LOOP
            IF DEBUG THEN
                putline("DEBUG: InstQueueRd_Addr=",InstQueueRd_Addr);
                putline("DEBUG: InstQueueWr_Addr=",InstQueueWr_Addr);
                putline("DEBUG: InstQueueLimit=",InstQueueLimit);
                put("DEBUG: InstAddrPointer=");Dummy := tohex(InstAddrPointer,4);putline("");
                put("DEBUG: PhyAddrPointer=");Dummy := tohex(PhyAddrPointer,4);putline("");
                putline("DEBUG: Extended=",Extended);
                putline("DEBUG: Flush=",Flush);
                putline("DEBUG: More=",More);
                put("DEBUG: InstQueue( 1)=");Dummy := tohex(integer(InstQueue(1)),1);putline("");
                put("DEBUG: InstQueue( 2)=");Dummy := tohex(integer(InstQueue(2)),1);putline("");
                put("DEBUG: InstQueue( 3)=");Dummy := tohex(integer(InstQueue(3)),1);putline("");
                put("DEBUG: InstQueue( 4)=");Dummy := tohex(integer(InstQueue(4)),1);putline("");
                put("DEBUG: InstQueue( 5)=");Dummy := tohex(integer(InstQueue(5)),1);putline("");
                put("DEBUG: InstQueue( 6)=");Dummy := tohex(integer(InstQueue(6)),1);putline("");
                put("DEBUG: InstQueue( 7)=");Dummy := tohex(integer(InstQueue(7)),1);putline("");
                put("DEBUG: InstQueue( 8)=");Dummy := tohex(integer(InstQueue(8)),1);putline("");
                put("DEBUG: InstQueue( 9)=");Dummy := tohex(integer(InstQueue(9)),1);putline("");
                put("DEBUG: InstQueue(10)=");Dummy := tohex(integer(InstQueue(10)),1);putline("");
                put("DEBUG: InstQueue(11)=");Dummy := tohex(integer(InstQueue(11)),1);putline("");
                put("DEBUG: InstQueue(12)=");Dummy := tohex(integer(InstQueue(12)),1);putline("");
                put("DEBUG: InstQueue(13)=");Dummy := tohex(integer(InstQueue(13)),1);putline("");
                put("DEBUG: InstQueue(14)=");Dummy := tohex(integer(InstQueue(14)),1);putline("");
                put("DEBUG: InstQueue(15)=");Dummy := tohex(integer(InstQueue(15)),1);putline("");
                put("DEBUG: InstQueue(16)=");Dummy := tohex(integer(InstQueue(16)),1);putline("");
            END IF;
            CASE integer(InstQueue(InstQueueRd_Addr)) is
                WHEN NOP =>
                    InstAddrPointer := InstAddrPointer + 1;
                    InstQueueRd_Addr := InstQueueRd_Addr + 1;
                    Flush := FALSE;
                    More := FALSE;
                    IF Debug OR Inst THEN
                        putline("DEBUG: Executing NOP");
                    END IF;
                WHEN OPsop =>
                    InstAddrPointer := InstAddrPointer + 1;
                    InstQueueRd_Addr := InstQueueRd_Addr + 1;
                    Extended := TRUE;
                    Flush := FALSE;
                    More := FALSE;
                    IF Debug OR Inst THEN
                        put("DEBUG: Extended Op-Code Read:");Dummy := tohex(OPsop,1);putline("");
                    END IF;
                WHEN JMP_rel_short =>
                    IF (InstQueueWr_Addr - InstQueueRd_Addr) >= 3 THEN
                        IF Debug OR Inst THEN
                            put("DEBUG: Executing JMP-Rel-Short from:");Dummy := tohex(InstAddrPointer,4);
                        END IF;
                        IF InstQueue(InstQueueRd_Addr+1,7) = '1' THEN -- Negative Offset
                            PhyAddrPointer := InstAddrPointer + 1 - (16#FF# - integer(extendum(InstQueue(InstQueueRd_Addr+1),32)));
                            InstAddrPointer := PhyAddrPointer;
                            IF Debug OR Inst THEN
                                put(" (-)To:");Dummy := tohex(PhyAddrPointer,4);putline("");
                            END IF;
                        ELSE -- Positive Offset
                            PhyAddrPointer := InstAddrPointer + 2 + integer(extendum(InstQueue(InstQueueRd_Addr+1),32));
                            InstAddrPointer := PhyAddrPointer;
                            IF Debug OR Inst THEN
                                put(" (+)To:");Dummy := tohex(PhyAddrPointer,4);putline("");
                            END IF;
                        END IF;
                        Flush := TRUE;
                        More := FALSE;
                    ELSE
                        Flush := FALSE;
                        More := TRUE;
                    END IF;
                WHEN JMP_rel_near =>
                    IF (InstQueueWr_Addr - InstQueueRd_Addr) >= 5 THEN
                        IF Debug OR Inst THEN
                            put("DEBUG: Executing JMP-Rel-Near from:");Dummy := tohex(InstAddrPointer,4);
                        END IF;
                        PhyAddrPointer := InstAddrPointer + 5 + integer(extendum(InstQueue(InstQueueRd_Addr+1),32));
                        InstAddrPointer := PhyAddrPointer;
                        IF Debug OR Inst THEN
                            put(" To:");Dummy := tohex(PhyAddrPointer,4);putline("");
                        END IF;
                        Flush := TRUE;
                        More := FALSE;
                    ELSE
                        Flush := FALSE;
                        More := TRUE;
                    END IF;
                WHEN JMP_intseg_immed =>
-- To be Implemented (mad/8-23-1988)
                    IF Debug OR Inst THEN
                        putline("DEBUG: {TBD} Executing JMP-IntSeg-Immed from:",InstAddrPointer);
                    END IF;
                    InstAddrPointer := InstAddrPointer + 1;
                    InstQueueRd_Addr := InstQueueRd_Addr + 1;
                    Flush := FALSE;
                    More := FALSE;
                WHEN MOV_al_b =>
-- To be Implemented (mad/8-23-1988)
                    IF Debug OR Inst THEN
                        putline("DEBUG: {TBD} Executing MOV-al<-byte");
                    END IF;
                    InstAddrPointer := InstAddrPointer + 1;
                    InstQueueRd_Addr := InstQueueRd_Addr + 1;
                    Flush := FALSE;
                    More := FALSE;
                WHEN MOV_eax_dw =>
                    IF (InstQueueWr_Addr - InstQueueRd_Addr) >= 5 THEN
                        IF Debug OR Inst THEN
                            put("DEBUG: Executing MOV-eax<-dw");
                        END IF;
                        -- Note Word position is swaped
                        EAX <= InstQueue(InstQueueRd_Addr+4) & InstQueue(InstQueueRd_Addr+3)
                                     & InstQueue(InstQueueRd_Addr+2) & InstQueue(InstQueueRd_Addr+1);
                        WAIT FOR 1;
                        IF Debug OR Inst THEN
                            put(" of:");Dummy := tohex(integer(EAX),4);putline("");
                        END IF;
                        More := FALSE;
                        Flush := FALSE;
                        InstAddrPointer := InstAddrPointer + 5;
                        InstQueueRd_Addr := InstQueueRd_Addr + 5;
                    ELSE
                        Flush := FALSE;
                        More := TRUE;
                        IF Debug THEN
                            putline("DEBUG: Executing MOV-eax<-dw but ...");
                            putline("DEBUG: all of the immediate data is not in queue.");
                        END IF;
                    END IF;
                WHEN MOV_ebx_dw =>
                    IF (InstQueueWr_Addr - InstQueueRd_Addr) >= 5 THEN
                        IF Debug OR Inst THEN
                            put("DEBUG: Executing MOV-ebx<-dw");
                        END IF;
                        -- Note Word position is swaped
                        EBX <= InstQueue(InstQueueRd_Addr+4) & InstQueue(InstQueueRd_Addr+3)
                                     & InstQueue(InstQueueRd_Addr+2) & InstQueue(InstQueueRd_Addr+1);
                        WAIT FOR 1;
                        IF Debug OR Inst THEN
                            put(" of:");Dummy := tohex(integer(EBX),4);putline("");
                        END IF;
                        More := FALSE;
                        Flush := FALSE;
                        InstAddrPointer := InstAddrPointer + 5;
                        InstQueueRd_Addr := InstQueueRd_Addr + 5;
                    ELSE
                        Flush := FALSE;
                        More := TRUE;
                        IF Debug THEN
                            putline("DEBUG: Executing MOV-ebx<-dw but ...");
                            putline("DEBUG: all of the immediate data is not in queue.");
                        END IF;
                    END IF;
                WHEN MOV_eax_ebx =>  -- Read at [ebx] to eax register
                    IF (InstQueueWr_Addr - InstQueueRd_Addr) >= 2 THEN
                        IF Debug OR Inst THEN
                            put("DEBUG: Executing MOV-eax,[ebx]");
                        END IF;
                        IF Debug OR Inst THEN
                            put(" at address:");Dummy := tohex(integer(EBX),4);putline("");
                        END IF;
                        rEIP <= EBX;
                        RequestPending <= Pending;
                        ReadRequest <= Pending;
                        MemoryFetch <= Pending;
                        CodeFetch <= NotPending;
                        WAIT UNTIL pfalling(READY_n);
                        RequestPending <= NotPending;
                        WAIT UNTIL pfalling(CLK);
                        uWord := Data(15 downto 0);
                        IF StateBS16 = '1' THEN
                            lWord := Data(31 downto 16);
                        ELSE
                            rEIP <= vlbit_vector(integer(rEIP) + 2);
                            WAIT FOR 1;
                            IF Debug THEN
                                put("DEBUG: Reading Second Word at Addr=");Dummy := tohex(integer(rEIP),4);putline("");
                            END IF;
                            WAIT UNTIL prising(CLK);
                            RequestPending <= Pending;
                            WAIT UNTIL pfalling(READY_n);
                            RequestPending <= NotPending;
                            WAIT UNTIL pfalling(CLK);
                            lWord := Data(15 downto 0);
                        END IF;
                        EAX <= uWord & lWord;
                        WAIT FOR 1;
                        IF Debug OR Inst THEN
                            put("DEBUG: Data=");Dummy := tohex(integer(EAX),4);putline("");
                        END IF;
                        More := FALSE;
                        Flush := FALSE;
                        InstAddrPointer := InstAddrPointer + 2;
                        InstQueueRd_Addr := InstQueueRd_Addr + 2;
                    ELSE
                        Flush := FALSE;
                        More := TRUE;
                    END IF;
                WHEN MOV_ebx_eax =>  -- Write at [ebx] from eax register
                    IF (InstQueueWr_Addr - InstQueueRd_Addr) >= 2 THEN
                        IF Debug OR Inst THEN
                            put("DEBUG: Executing MOV-[ebx],eax");
                        END IF;
                        IF Debug OR Inst THEN
                            put(" at address:");Dummy := tohex(integer(EBX),4);putline("");
                        END IF;
                        rEIP <= EBX;
                        lWord := EAX(15 downto 0);
                        uWord := EAX(31 downto 16);
                        IF Debug OR Inst THEN
                            put("DEBUG: Data=");Dummy := tohex(integer(EAX),4);putline("");
                        END IF;
                        RequestPending <= Pending;
                        ReadRequest <= NotPending;
                        MemoryFetch <= Pending;
                        CodeFetch <= NotPending;
                        IF Debug THEN
                            put("DEBUG: Writing First Word at Addr=");Dummy := tohex(integer(EBX),4);putline("");
                        END IF;
                        WAIT UNTIL (integer(State) = StateT1 OR integer(State) = StateT1P);
                        WAIT UNTIL prising(CLK);
                        Data <= (uWord & lWord) after 480;
                        WAIT UNTIL pfalling(READY_n);
                        RequestPending <= NotPending;
                        WAIT UNTIL prising(CLK);
                        Data <= X"ZZZZZZZZ" after 480;
                        WAIT FOR 1;
                        IF StateBS16 = '0' THEN
                            IF Debug THEN
                                put("DEBUG: Writing Second Word at Addr=");Dummy := tohex(integer(EBX),4);putline("");
                            END IF;
                            rEIP <= vlbit_vector(integer(rEIP) + 2);
                            RequestPending <= Pending;
                            ReadRequest <= NotPending;
                            MemoryFetch <= Pending;
                            CodeFetch <= NotPending;
                            WAIT UNTIL (integer(State) = StateT1 OR integer(State) = StateT1P);
                            WAIT UNTIL prising(CLK);
                            Data <= (uWord & lWord) after 480;
                            WAIT UNTIL pfalling(READY_n);
                            RequestPending <= NotPending;
                            WAIT UNTIL prising(CLK);
                            Data <= X"ZZZZZZZZ" after 480;