docs: moving code examples

Code now resides in `docs/source/code_examples`.
`CHAPTER_Prog` -> `stubnets`
`APPNOTE_011_Design_Investigation` -> `selections` and `show`
`resources/PRESENTATION_Intro` -> `intro`
`resources/PRESENTATION_ExSyn` -> `synth_flow`
`resources/PRESENTATION_ExAdv` -> `techmap`,  `macc`, and `selections`
`resources/PRESENTATION_ExOth` -> `scrambler` and `axis`

Note that generated images are not yet configured to build from the new code locations.

docs/source/code_examples/techmap/Makefile

@@ -0,0 +1,21 @@
+PROGRAM_PREFIX :=
+
+YOSYS ?= ../../../$(PROGRAM_PREFIX)yosys
+
+all: red_or3x1.dot sym_mul.dot mymul.dot mulshift.dot addshift.dot
+
+red_or3x1.dot: red_or3x1_*
+	$(YOSYS) red_or3x1_test.ys
+
+sym_mul.dot: sym_mul_*
+	$(YOSYS) sym_mul_test.ys
+
+mymul.dot: mymul_*
+	$(YOSYS) mymul_test.ys
+
+mulshift.dot: mulshift_*
+	$(YOSYS) mulshift_test.ys
+
+addshift.dot: addshift_*
+	$(YOSYS) addshift_test.ys
+

docs/source/code_examples/techmap/addshift_map.v

@@ -0,0 +1,20 @@
+module \$add (A, B, Y);
+  parameter A_SIGNED = 0;
+  parameter B_SIGNED = 0;
+  parameter A_WIDTH = 1;
+  parameter B_WIDTH = 1;
+  parameter Y_WIDTH = 1;
+
+  input [A_WIDTH-1:0] A;
+  input [B_WIDTH-1:0] B;
+  output [Y_WIDTH-1:0] Y;
+
+  parameter _TECHMAP_BITS_CONNMAP_ = 0;
+  parameter _TECHMAP_CONNMAP_A_ = 0;
+  parameter _TECHMAP_CONNMAP_B_ = 0;
+
+  wire _TECHMAP_FAIL_ = A_WIDTH != B_WIDTH || B_WIDTH < Y_WIDTH ||
+                        _TECHMAP_CONNMAP_A_ != _TECHMAP_CONNMAP_B_;
+
+  assign Y = A << 1;
+endmodule

docs/source/code_examples/techmap/addshift_test.v

@@ -0,0 +1,5 @@
+module test (A, B, X, Y);
+input [7:0] A, B;
+output [7:0] X = A + B;
+output [7:0] Y = A + A;
+endmodule

docs/source/code_examples/techmap/addshift_test.ys

@@ -0,0 +1,6 @@
+read_verilog addshift_test.v
+hierarchy -check -top test
+
+techmap -map addshift_map.v;;
+
+show -prefix addshift -format dot -notitle

docs/source/code_examples/techmap/mulshift_map.v

@@ -0,0 +1,26 @@
+module MYMUL(A, B, Y);
+    parameter WIDTH = 1;
+    input [WIDTH-1:0] A, B;
+    output reg [WIDTH-1:0] Y;
+
+    parameter _TECHMAP_CONSTVAL_A_ = WIDTH'bx;
+    parameter _TECHMAP_CONSTVAL_B_ = WIDTH'bx;
+
+    reg _TECHMAP_FAIL_;
+    wire [1023:0] _TECHMAP_DO_ = "proc; clean";
+
+    integer i;
+    always @* begin
+    	_TECHMAP_FAIL_ <= 1;
+        for (i = 0; i < WIDTH; i=i+1) begin
+            if (_TECHMAP_CONSTVAL_A_ === WIDTH'd1 << i) begin
+	        _TECHMAP_FAIL_ <= 0;
+                Y <= B << i;
+	    end
+            if (_TECHMAP_CONSTVAL_B_ === WIDTH'd1 << i) begin
+	        _TECHMAP_FAIL_ <= 0;
+                Y <= A << i;
+	    end
+	end
+    end
+endmodule

docs/source/code_examples/techmap/mulshift_test.v

@@ -0,0 +1,5 @@
+module test (A, X, Y);
+input [7:0] A;
+output [7:0] X = A * 8'd 6;
+output [7:0] Y = A * 8'd 8;
+endmodule

docs/source/code_examples/techmap/mulshift_test.ys

@@ -0,0 +1,7 @@
+read_verilog mulshift_test.v
+hierarchy -check -top test
+
+techmap -map sym_mul_map.v \
+        -map mulshift_map.v;;
+
+show -prefix mulshift -format dot -notitle -lib sym_mul_cells.v

docs/source/code_examples/techmap/mymul_map.v

@@ -0,0 +1,15 @@
+module MYMUL(A, B, Y);
+    parameter WIDTH = 1;
+    input [WIDTH-1:0] A, B;
+    output reg [WIDTH-1:0] Y;
+
+    wire [1023:0] _TECHMAP_DO_ = "proc; clean";
+
+    integer i;
+    always @* begin
+        Y = 0;
+        for (i = 0; i < WIDTH; i=i+1)
+            if (A[i])
+                Y = Y + (B << i);
+    end
+endmodule

docs/source/code_examples/techmap/mymul_test.v

@@ -0,0 +1,4 @@
+module test(A, B, Y);
+    input  [1:0] A, B;
+    output [1:0] Y = A * B;
+endmodule

docs/source/code_examples/techmap/mymul_test.ys

@@ -0,0 +1,15 @@
+read_verilog mymul_test.v
+hierarchy -check -top test
+
+techmap -map sym_mul_map.v \
+        -map mymul_map.v;;
+
+rename test test_mapped
+read_verilog mymul_test.v
+miter -equiv test test_mapped miter
+flatten miter
+
+sat -verify -prove trigger 0 miter
+
+splitnets -ports test_mapped/A
+show -prefix mymul -format dot -notitle test_mapped

docs/source/code_examples/techmap/red_or3x1_cells.v

@@ -0,0 +1,5 @@
+module OR3X1(A, B, C, Y);
+    input A, B, C;
+    output Y;
+    assign Y = A | B | C;
+endmodule

docs/source/code_examples/techmap/red_or3x1_map.v

@@ -0,0 +1,48 @@
+module \$reduce_or (A, Y);
+
+    parameter A_SIGNED = 0;
+    parameter A_WIDTH = 0;
+    parameter Y_WIDTH = 0;
+
+    input [A_WIDTH-1:0] A;
+    output [Y_WIDTH-1:0] Y;
+
+    function integer min;
+        input integer a, b;
+        begin
+            if (a < b)
+                min = a;
+            else
+                min = b;
+        end
+    endfunction
+
+    genvar i;
+    generate begin
+        if (A_WIDTH == 0) begin
+            assign Y = 0;
+        end
+        if (A_WIDTH == 1) begin
+            assign Y = A;
+        end
+        if (A_WIDTH == 2) begin
+            wire ybuf;
+            OR3X1 g (.A(A[0]), .B(A[1]), .C(1'b0), .Y(ybuf));
+            assign Y = ybuf;
+        end
+        if (A_WIDTH == 3) begin
+            wire ybuf;
+            OR3X1 g (.A(A[0]), .B(A[1]), .C(A[2]), .Y(ybuf));
+            assign Y = ybuf;
+        end
+        if (A_WIDTH > 3) begin
+            localparam next_stage_sz = (A_WIDTH+2) / 3;
+            wire [next_stage_sz-1:0] next_stage;
+            for (i = 0; i < next_stage_sz; i = i+1) begin
+                localparam bits = min(A_WIDTH - 3*i, 3);
+                assign next_stage[i] = |A[3*i +: bits];
+            end
+            assign Y = |next_stage;
+        end
+    end endgenerate
+endmodule

docs/source/code_examples/techmap/red_or3x1_test.v

@@ -0,0 +1,5 @@
+module test (A, Y);
+    input [6:0] A;
+    output Y;
+    assign Y = |A;
+endmodule

docs/source/code_examples/techmap/red_or3x1_test.ys

@@ -0,0 +1,7 @@
+read_verilog red_or3x1_test.v
+hierarchy -check -top test
+
+techmap -map red_or3x1_map.v;;
+
+splitnets -ports
+show -prefix red_or3x1 -format dot -notitle -lib red_or3x1_cells.v

docs/source/code_examples/techmap/sym_mul_cells.v

@@ -0,0 +1,6 @@
+module MYMUL(A, B, Y);
+    parameter WIDTH = 1;
+    input [WIDTH-1:0] A, B;
+    output [WIDTH-1:0] Y;
+    assign Y = A * B;
+endmodule

docs/source/code_examples/techmap/sym_mul_map.v

@@ -0,0 +1,15 @@
+module \$mul (A, B, Y);
+    parameter A_SIGNED = 0;
+    parameter B_SIGNED = 0;
+    parameter A_WIDTH = 1;
+    parameter B_WIDTH = 1;
+    parameter Y_WIDTH = 1;
+
+    input [A_WIDTH-1:0] A;
+    input [B_WIDTH-1:0] B;
+    output [Y_WIDTH-1:0] Y;
+
+    wire _TECHMAP_FAIL_ = A_WIDTH != B_WIDTH || B_WIDTH != Y_WIDTH;
+
+    MYMUL #( .WIDTH(Y_WIDTH) ) g ( .A(A), .B(B), .Y(Y) );
+endmodule

docs/source/code_examples/techmap/sym_mul_test.v

@@ -0,0 +1,5 @@
+module test(A, B, C, Y1, Y2);
+    input   [7:0] A, B, C;
+    output  [7:0] Y1 = A * B;
+    output [15:0] Y2 = A * C;
+endmodule

docs/source/code_examples/techmap/sym_mul_test.ys

@@ -0,0 +1,6 @@
+read_verilog sym_mul_test.v
+hierarchy -check -top test
+
+techmap -map sym_mul_map.v;;
+
+show -prefix sym_mul -format dot -notitle -lib sym_mul_cells.v