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[/] [v65c816/] [trunk/] [intlog.vhd] - Blame information for rev 2

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library IEEE;
use IEEE.std_logic_1164.all;  -- defines std_logic types
use IEEE.STD_LOGIC_unsigned.all;
use IEEE.STD_LOGIC_arith.all;
 
-- interrupt request logic
entity intlog is
  port(    clk:  in STD_LOGIC;
          iack:  in STD_LOGIC;                    -- interrupt acknowledge by microcode 
             r:  in STD_LOGIC;                    -- RESET request
             n:  in STD_LOGIC;                    -- NMI request
             i:  in STD_LOGIC;                    -- IRQ request
           brk:  in STD_LOGIC;                    -- BRK opcode
                          cop:  in STD_LOGIC;                    -- COP opcode
                            e:  in STD_LOGIC;                    -- native\emulation mode
                        gmask:  in STD_LOGIC;                    -- global interrupt mask valid for IRQ and NMI (used by two byte instruction)   
         imask:  in STD_LOGIC;                    -- interrupt mask (valid only for IRQ)
         ioffs:  in STD_LOGIC_VECTOR(7 downto 0); -- interrupt servicing offset
          ireq: out STD_LOGIC;                    -- global interrupt requestb (IRQ/NMI)
         voffs: out STD_LOGIC_VECTOR(7 downto 0)  -- interrupt vector offset 
        );
end intlog;
 
architecture rtl of intlog is
signal irq_sync:   STD_LOGIC_VECTOR(1 downto 0);
signal nmi_sync:   STD_LOGIC_VECTOR(1 downto 0);
signal res_sync:   STD_LOGIC_VECTOR(1 downto 0);
signal irq_req:    STD_LOGIC;
signal i_nmi_req:  STD_LOGIC;
signal nmi_req:    STD_LOGIC;
signal res_req:    STD_LOGIC;
signal nmi_clr:    STD_LOGIC;
signal res_clr:    STD_LOGIC;
 
begin
  process(clk)                                                           -- IRQ/NMI synchronization
  begin
    if(clk'event and clk = '1')then
      res_sync <= res_sync(res_sync'left-1 downto res_sync'right) & r;   -- RES sampling
      nmi_sync <= nmi_sync(nmi_sync'left-1 downto nmi_sync'right) & n;   -- NMI sampling
      irq_sync <= irq_sync(irq_sync'left-1 downto irq_sync'right) & i;   -- IRQ sampling
      if res_clr = '1' then                                              -- RES ack
        res_req <= '0';
      else
        if res_sync = "11" then                                          -- level detection for RES
          res_req <= '1';
        else
          res_req <= res_req;
        end if;
      end if;
      if nmi_clr = '1' then                                              -- NMI ack
         i_nmi_req <= '0';
      else
        if nmi_sync = "01" then                                          -- edge detection for NMI
           i_nmi_req <= '1';
        else
           i_nmi_req <= i_nmi_req;
        end if;
      end if;
    end if;
  end process;
  nmi_req <= '1' when gmask = '0' and i_nmi_req = '1' else '0';
 
 
  process(gmask, imask, irq_sync)
  begin
    if gmask = '0' and imask = '0' then
      if irq_sync = "11" then
        irq_req <= '1';
      else
        irq_req <= '0';
      end if;
    else
      irq_req <= '0';
    end if;
  end process;
 
  -- priority encoder and vector offset generation (vector bits 7..0)
  process(e, res_req, nmi_req, irq_req, brk, cop)
  begin
          if e = '0' then                                                     -- native mode
        if res_req = '1' then
                voffs <= x"FC";                                               -- RESET 0x00FFFC 
                  else
           if nmi_req = '1' then
                   voffs <= x"EA";                                            -- NMI   0x00FFEA
                     else
                   if irq_req = '1' then
                           voffs <= x"EE";                                         -- IRQ   0x00FFEE 
                             else
                           if brk = '1' then
                                   voffs <= x"E6";                                      -- BRK   0x00FFE6
                                     else
                                   if cop = '1' then
                                      voffs <= x"E4";                                   -- COP   0x00FFE4 
                                                  else
                                                voffs <= "XXXXXXXX";
                                                  end if;
                                     end if;
                             end if;
                     end if;
             end if;
     else                                                                         -- emulation mode
        if res_req = '1' then
                voffs <= x"FC";                                               -- RESET 0x00FFFC
                  else
           if nmi_req = '1' then                                         -- NMI   0x00FFFA
                   voffs <= x"FA";
                     else
                   if irq_req = '1' then                                      -- IRQ   0x00FFFE
                           voffs <= x"FE";
                             else
                           if brk = '1' then                                       -- BRK   0x00FFFE 
                                   voffs <= x"FE";
                                     else
                                   if cop = '1' then                                    -- COP   0x00FFF4
                                      voffs <= x"F4";
                                                  else
                                                voffs <= "XXXXXXXX";
                                                  end if;
                                     end if;
                             end if;
                     end if;
             end if;
          end if;
 
  end process;
 
  process(iack,ioffs)                                                    -- interrupt acknowledge and flags clear
  begin
    if iack = '1' then
      case ioffs is
        when x"FC"  => res_clr <= '1';                                   -- RESET acknowledge
                       nmi_clr <= '1';                                   -- also NMI acknowledge
        when x"EA"  => nmi_clr <= '1';                                   -- NMI acknowledge (native mode)
                       res_clr <= '0';
        when x"FA"  => nmi_clr <= '1';                                   -- NMI acknowledge (emulation mode)
                       res_clr <= '0';
        when others => res_clr <= '0';
                       nmi_clr <= '0';
      end case;
    else
      res_clr <= '0';
      nmi_clr <= '0';
    end if;
  end process;
 
  ireq <= res_req or nmi_req or irq_req;
end rtl;
 
 

Line No.	Rev	Author	Line
1	2	Valerio63	`library IEEE;`
2			`use IEEE.std_logic_1164.all; -- defines std_logic types`
3			`use IEEE.STD_LOGIC_unsigned.all;`
4			`use IEEE.STD_LOGIC_arith.all;`
5
6			`-- interrupt request logic`
7			`entity intlog is`
8			`port( clk: in STD_LOGIC;`
9			`iack: in STD_LOGIC; -- interrupt acknowledge by microcode`
10			`r: in STD_LOGIC; -- RESET request`
11			`n: in STD_LOGIC; -- NMI request`
12			`i: in STD_LOGIC; -- IRQ request`
13			`brk: in STD_LOGIC; -- BRK opcode`
14			`cop: in STD_LOGIC; -- COP opcode`
15			`e: in STD_LOGIC; -- native\emulation mode`
16			`gmask: in STD_LOGIC; -- global interrupt mask valid for IRQ and NMI (used by two byte instruction)`
17			`imask: in STD_LOGIC; -- interrupt mask (valid only for IRQ)`
18			`ioffs: in STD_LOGIC_VECTOR(7 downto 0); -- interrupt servicing offset`
19			`ireq: out STD_LOGIC; -- global interrupt requestb (IRQ/NMI)`
20			`voffs: out STD_LOGIC_VECTOR(7 downto 0) -- interrupt vector offset`
21			`);`
22			`end intlog;`
23
24			`architecture rtl of intlog is`
25			`signal irq_sync: STD_LOGIC_VECTOR(1 downto 0);`
26			`signal nmi_sync: STD_LOGIC_VECTOR(1 downto 0);`
27			`signal res_sync: STD_LOGIC_VECTOR(1 downto 0);`
28			`signal irq_req: STD_LOGIC;`
29			`signal i_nmi_req: STD_LOGIC;`
30			`signal nmi_req: STD_LOGIC;`
31			`signal res_req: STD_LOGIC;`
32			`signal nmi_clr: STD_LOGIC;`
33			`signal res_clr: STD_LOGIC;`
34
35			`begin`
36			`process(clk) -- IRQ/NMI synchronization`
37			`begin`
38			`if(clk'event and clk = '1')then`
39			`res_sync <= res_sync(res_sync'left-1 downto res_sync'right) & r; -- RES sampling`
40			`nmi_sync <= nmi_sync(nmi_sync'left-1 downto nmi_sync'right) & n; -- NMI sampling`
41			`irq_sync <= irq_sync(irq_sync'left-1 downto irq_sync'right) & i; -- IRQ sampling`
42			`if res_clr = '1' then -- RES ack`
43			`res_req <= '0';`
44			`else`
45			`if res_sync = "11" then -- level detection for RES`
46			`res_req <= '1';`
47			`else`
48			`res_req <= res_req;`
49			`end if;`
50			`end if;`
51			`if nmi_clr = '1' then -- NMI ack`
52			`i_nmi_req <= '0';`
53			`else`
54			`if nmi_sync = "01" then -- edge detection for NMI`
55			`i_nmi_req <= '1';`
56			`else`
57			`i_nmi_req <= i_nmi_req;`
58			`end if;`
59			`end if;`
60			`end if;`
61			`end process;`
62			`nmi_req <= '1' when gmask = '0' and i_nmi_req = '1' else '0';`
63
64
65			`process(gmask, imask, irq_sync)`
66			`begin`
67			`if gmask = '0' and imask = '0' then`
68			`if irq_sync = "11" then`
69			`irq_req <= '1';`
70			`else`
71			`irq_req <= '0';`
72			`end if;`
73			`else`
74			`irq_req <= '0';`
75			`end if;`
76			`end process;`
77
78			`-- priority encoder and vector offset generation (vector bits 7..0)`
79			`process(e, res_req, nmi_req, irq_req, brk, cop)`
80			`begin`
81			`if e = '0' then -- native mode`
82			`if res_req = '1' then`
83			`voffs <= x"FC"; -- RESET 0x00FFFC`
84			`else`
85			`if nmi_req = '1' then`
86			`voffs <= x"EA"; -- NMI 0x00FFEA`
87			`else`
88			`if irq_req = '1' then`
89			`voffs <= x"EE"; -- IRQ 0x00FFEE`
90			`else`
91			`if brk = '1' then`
92			`voffs <= x"E6"; -- BRK 0x00FFE6`
93			`else`
94			`if cop = '1' then`
95			`voffs <= x"E4"; -- COP 0x00FFE4`
96			`else`
97			`voffs <= "XXXXXXXX";`
98			`end if;`
99			`end if;`
100			`end if;`
101			`end if;`
102			`end if;`
103			`else -- emulation mode`
104			`if res_req = '1' then`
105			`voffs <= x"FC"; -- RESET 0x00FFFC`
106			`else`
107			`if nmi_req = '1' then -- NMI 0x00FFFA`
108			`voffs <= x"FA";`
109			`else`
110			`if irq_req = '1' then -- IRQ 0x00FFFE`
111			`voffs <= x"FE";`
112			`else`
113			`if brk = '1' then -- BRK 0x00FFFE`
114			`voffs <= x"FE";`
115			`else`
116			`if cop = '1' then -- COP 0x00FFF4`
117			`voffs <= x"F4";`
118			`else`
119			`voffs <= "XXXXXXXX";`
120			`end if;`
121			`end if;`
122			`end if;`
123			`end if;`
124			`end if;`
125			`end if;`
126
127			`end process;`
128
129			`process(iack,ioffs) -- interrupt acknowledge and flags clear`
130			`begin`
131			`if iack = '1' then`
132			`case ioffs is`
133			`when x"FC" => res_clr <= '1'; -- RESET acknowledge`
134			`nmi_clr <= '1'; -- also NMI acknowledge`
135			`when x"EA" => nmi_clr <= '1'; -- NMI acknowledge (native mode)`
136			`res_clr <= '0';`
137			`when x"FA" => nmi_clr <= '1'; -- NMI acknowledge (emulation mode)`
138			`res_clr <= '0';`
139			`when others => res_clr <= '0';`
140			`nmi_clr <= '0';`
141			`end case;`
142			`else`
143			`res_clr <= '0';`
144			`nmi_clr <= '0';`
145			`end if;`
146			`end process;`
147
148			`ireq <= res_req or nmi_req or irq_req;`
149			`end rtl;`
150
151

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[/] [v65c816/] [trunk/] [intlog.vhd] - Blame information for rev 2