76.025MHz, ship it

[mandelfpga.git] / Main.v

diff --git a/Main.v b/Main.v
index 61cb8f1d9991a72ae15261f8b2bd8781e6840108..b034663f746a74b01b00874ac28c4bdbe5ff17fa 100644 (file)
--- a/Main.v
+++ b/Main.v
@@ -64,22 +64,23 @@ module NaiveMultiplier(
        input xsign, ysign,
        output reg [12:0] out,
        output reg sign,
-       output reg [1:0] ovf);
+       output reg ovf);
 
        always @(posedge clk)
        begin
                {ovf,out} <=
                        (((y[12] ? (x     ) : 0)  +
                          (y[11] ? (x >> 1) : 0)  +
-                         (y[10] ? (x >> 2) : 0)  +
-                         (y[9]  ? (x >> 3) : 0)) +
-                        ((y[8]  ? (x >> 4) : 0)  +
-                         (y[7]  ? (x >> 5) : 0)  +
-                         (y[6]  ? (x >> 6) : 0)))+
+                         (y[10] ? (x >> 2) : 0)) +
+                       (((y[9]  ? (x >> 3) : 0)  +
+                         (y[8]  ? (x >> 4) : 0))+
+                   ((y[7]  ? (x >> 5) : 0)  +
+                         (y[6]  ? (x >> 6) : 0))))+
+                         
                        (((y[5]  ? (x >> 7) : 0)  +
-                         (y[4]  ? (x >> 8) : 0)  +
+                         (y[4]  ? (x >> 8) : 0)+
                          (y[3]  ? (x >> 9) : 0)) +
-                        ((y[2]  ? (x >> 10): 0)  +
+                        ((y[2]  ? (x >> 10): 0) +
                          (y[1]  ? (x >> 11): 0)  +
                          (y[0]  ? (x >> 12): 0)));
                sign <= xsign ^ ysign;
@@ -93,12 +94,13 @@ module Multiplier(
        input xsign, ysign,
        output wire [12:0] out,
        output wire sign,
-       output wire [1:0] overflow);
+       output wire overflow);
 
        NaiveMultiplier nm(clk, x, y, xsign, ysign, out, sign, overflow);
 
 endmodule
 
+// Yuq.
 module MandelUnit(
        input clk,
        input [12:0] x, y,
@@ -230,11 +232,6 @@ module Mandelbrot(
        
        reg [2:0] state = 3'b001;       // One-hot encoded state.
        
-       // On pixclk = 1,
-       //    A new value to be loaded comes in, and a value in need of loopback comes out.
-       // On pixclk = 0,
-       //    A new value in need of loopback comes in, and a completed value comes out.
-       
        assign initx = state[0] ? rx :
                       state[1] ? stagex[1] :
                       stagex[2];
@@ -263,34 +260,34 @@ module Mandelbrot(
                       state[1] ? stageb[1] :
                       stageb[2];
        assign initci = state[0] ? 8'b00000000 :
-                       state[1] ? stageb[1] : 
-                       stageb[2];
+                       state[1] ? stageci[1] : 
+                       stageci[2];
        
        reg [7:0] out;
-       reg typethea = 0;       // Whether we have typed the A.
-       reg statekick = 0;      // State needs to be kicked back to 3'b010 on the next mclk.
-
-       // This is guaranteed to converge after two pixclks.
-       //always @(negedge mclk)
-       //      if (pixclk && !typethea) begin
-       //              typethea <= 1;
-       //              statekick <= 1;
-       //      end else if (typethea) begin // This is the edge of the falling anus.
-       //              typethea <= 0;
-       //              statekick <= 0;
-       //      end
+       
+       // We detect when the state should be poked by a high negedge followed
+       // by a high posedge -- if that happens, then we're guaranteed that the
+       // state following the current state will be 3'b100.
+       reg lastneg;
+       always @(negedge mclk)
+               lastneg <= pixclk;
        
        always @(posedge mclk)
        begin
+               if (lastneg && pixclk)  // If a pixclk has happened, the state should be reset.
+                       state <= 3'b100;
+               else                                            // Otherwise, just poke it forward.
+                       state <= {state[1], state[0], state[2]};
+       
                // Data output handling
                if (state[0]) begin
                        {red, green, blue} <= {out[0],out[3],out[6],out[1],out[4],out[7],out[2],out[5]};
                end
-               if (state[2]) begin
+               if (state[1]) begin
                        out <= ~mb[`MAXOUTN] + colorofs;
                end
                
-               if (state[1]) begin             // PnR0 in, PnR2 out
+               if (state[0]) begin             // PnR0 in, PnR2 out
                        stagex[2] <= xprop[`MAXOUTN];
                        stagey[2] <= yprop[`MAXOUTN];
                        stager[2] <= mr[`MAXOUTN];
@@ -303,7 +300,7 @@ module Mandelbrot(
                        stageci[2] <= curiter[`MAXOUTN];
                end
                
-               if (state[0]) begin     // PnR2 in, PnR1 out
+               if (state[2]) begin     // PnR2 in, PnR1 out
                        stagex[1] <= xprop[`MAXOUTN];
                        stagey[1] <= yprop[`MAXOUTN];
                        stager[1] <= mr[`MAXOUTN];
@@ -315,11 +312,6 @@ module Mandelbrot(
                        stageb[1] <= mb[`MAXOUTN];
                        stageci[1] <= curiter[`MAXOUTN];
                end
-               
-               if (statekick)          // If a pixclk has happened, the state should be reset.
-                       state <= 3'b010;
-               else                                            // Otherwise, just poke it forward.
-                       state <= {state[1], state[0], state[2]};
        end
 
        MandelUnit mu0(