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/macc/Makefile

@@ -0,0 +1,12 @@
+PROGRAM_PREFIX :=
+
+YOSYS ?= ../../../$(PROGRAM_PREFIX)yosys
+
+all: macc_simple_xmap.pdf macc_xilinx_xmap.pdf
+
+macc_simple_xmap.pdf: macc_simple_*.v macc_simple_test.ys
+	$(YOSYS) macc_simple_test.ys
+
+macc_xilinx_xmap.pdf: macc_xilinx_*.v macc_xilinx_test.ys
+	$(YOSYS) macc_xilinx_test.ys
+

docs/source/code_examples/macc/macc_simple_test.v

@@ -0,0 +1,6 @@
+module test(a, b, c, d, y);
+input [15:0] a, b;
+input [31:0] c, d;
+output [31:0] y;
+assign y = a * b + c + d;
+endmodule

docs/source/code_examples/macc/macc_simple_test.ys

@@ -0,0 +1,37 @@
+read_verilog macc_simple_test.v
+hierarchy -check -top test;;
+
+show -prefix macc_simple_test_00a -format pdf -notitle -lib macc_simple_xmap.v
+
+extract -constports -map macc_simple_xmap.v;;
+show -prefix macc_simple_test_00b -format pdf -notitle -lib macc_simple_xmap.v
+
+#################################################
+
+design -reset
+read_verilog macc_simple_test_01.v
+hierarchy -check -top test;;
+
+show -prefix macc_simple_test_01a -format pdf -notitle -lib macc_simple_xmap.v
+
+extract -map macc_simple_xmap.v;;
+show -prefix macc_simple_test_01b -format pdf -notitle -lib macc_simple_xmap.v
+
+#################################################
+
+design -reset
+read_verilog macc_simple_test_02.v
+hierarchy -check -top test;;
+
+show -prefix macc_simple_test_02a -format pdf -notitle -lib macc_simple_xmap.v
+
+extract -map macc_simple_xmap.v;;
+show -prefix macc_simple_test_02b -format pdf -notitle -lib macc_simple_xmap.v
+
+#################################################
+
+design -reset
+read_verilog macc_simple_xmap.v
+hierarchy -check -top macc_16_16_32;;
+
+show -prefix macc_simple_xmap -format pdf -notitle

docs/source/code_examples/macc/macc_simple_test_01.v

@@ -0,0 +1,6 @@
+module test(a, b, c, d, x, y);
+input [15:0] a, b, c, d;
+input [31:0] x;
+output [31:0] y;
+assign y = a*b + c*d + x;
+endmodule

docs/source/code_examples/macc/macc_simple_test_02.v

@@ -0,0 +1,6 @@
+module test(a, b, c, d, x, y);
+input [15:0] a, b, c, d;
+input [31:0] x;
+output [31:0] y;
+assign y = a*b + (c*d + x);
+endmodule

docs/source/code_examples/macc/macc_simple_xmap.v

@@ -0,0 +1,6 @@
+module macc_16_16_32(a, b, c, y);
+input [15:0] a, b;
+input [31:0] c;
+output [31:0] y;
+assign y = a*b + c;
+endmodule

docs/source/code_examples/macc/macc_xilinx_swap_map.v

@@ -0,0 +1,28 @@
+(* techmap_celltype = "$mul" *)
+module mul_swap_ports (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;
+
+\$mul #(
+	.A_SIGNED(B_SIGNED),
+	.B_SIGNED(A_SIGNED),
+	.A_WIDTH(B_WIDTH),
+	.B_WIDTH(A_WIDTH),
+	.Y_WIDTH(Y_WIDTH)
+) _TECHMAP_REPLACE_ (
+	.A(B),
+	.B(A),
+	.Y(Y)
+);
+
+endmodule

docs/source/code_examples/macc/macc_xilinx_test.v

@@ -0,0 +1,13 @@
+module test1(a, b, c, d, e, f, y);
+    input [19:0] a, b, c;
+    input [15:0] d, e, f;
+    output [41:0] y;
+    assign y = a*b + c*d + e*f;
+endmodule
+
+module test2(a, b, c, d, e, f, y);
+    input [19:0] a, b, c;
+    input [15:0] d, e, f;
+    output [41:0] y;
+    assign y = a*b + (c*d + e*f);
+endmodule

docs/source/code_examples/macc/macc_xilinx_test.ys

@@ -0,0 +1,43 @@
+read_verilog macc_xilinx_test.v
+read_verilog -lib -icells macc_xilinx_unwrap_map.v
+read_verilog -lib -icells macc_xilinx_xmap.v
+hierarchy -check ;;
+
+show -prefix macc_xilinx_test1a -format pdf -notitle test1
+show -prefix macc_xilinx_test2a -format pdf -notitle test2
+
+techmap -map macc_xilinx_swap_map.v;;
+
+show -prefix macc_xilinx_test1b -format pdf -notitle test1
+show -prefix macc_xilinx_test2b -format pdf -notitle test2
+
+techmap -map macc_xilinx_wrap_map.v
+
+connwrappers -unsigned $__mul_wrapper Y Y_WIDTH \
+             -unsigned $__add_wrapper Y Y_WIDTH;;
+
+show -prefix macc_xilinx_test1c -format pdf -notitle test1
+show -prefix macc_xilinx_test2c -format pdf -notitle test2
+
+design -push
+read_verilog macc_xilinx_xmap.v
+techmap -map macc_xilinx_swap_map.v
+techmap -map macc_xilinx_wrap_map.v;;
+design -save __macc_xilinx_xmap
+design -pop
+
+extract -constports -ignore_parameters \
+        -map %__macc_xilinx_xmap       \
+        -swap $__add_wrapper A,B ;;
+
+show -prefix macc_xilinx_test1d -format pdf -notitle test1
+show -prefix macc_xilinx_test2d -format pdf -notitle test2
+
+techmap -map macc_xilinx_unwrap_map.v;;
+
+show -prefix macc_xilinx_test1e -format pdf -notitle test1
+show -prefix macc_xilinx_test2e -format pdf -notitle test2
+
+design -load __macc_xilinx_xmap
+show -prefix macc_xilinx_xmap -format pdf -notitle
+

docs/source/code_examples/macc/macc_xilinx_unwrap_map.v

@@ -0,0 +1,61 @@
+module \$__mul_wrapper (A, B, Y);
+
+parameter A_SIGNED = 0;
+parameter B_SIGNED = 0;
+parameter A_WIDTH = 1;
+parameter B_WIDTH = 1;
+parameter Y_WIDTH = 1;
+
+input [17:0] A;
+input [24:0] B;
+output [47:0] Y;
+
+wire [A_WIDTH-1:0] A_ORIG = A;
+wire [B_WIDTH-1:0] B_ORIG = B;
+wire [Y_WIDTH-1:0] Y_ORIG;
+assign Y = Y_ORIG;
+
+\$mul #(
+	.A_SIGNED(A_SIGNED),
+	.B_SIGNED(B_SIGNED),
+	.A_WIDTH(A_WIDTH),
+	.B_WIDTH(B_WIDTH),
+	.Y_WIDTH(Y_WIDTH)
+) _TECHMAP_REPLACE_ (
+	.A(A_ORIG),
+	.B(B_ORIG),
+	.Y(Y_ORIG)
+);
+
+endmodule
+
+module \$__add_wrapper (A, B, Y);
+
+parameter A_SIGNED = 0;
+parameter B_SIGNED = 0;
+parameter A_WIDTH = 1;
+parameter B_WIDTH = 1;
+parameter Y_WIDTH = 1;
+
+input [47:0] A;
+input [47:0] B;
+output [47:0] Y;
+
+wire [A_WIDTH-1:0] A_ORIG = A;
+wire [B_WIDTH-1:0] B_ORIG = B;
+wire [Y_WIDTH-1:0] Y_ORIG;
+assign Y = Y_ORIG;
+
+\$add #(
+	.A_SIGNED(A_SIGNED),
+	.B_SIGNED(B_SIGNED),
+	.A_WIDTH(A_WIDTH),
+	.B_WIDTH(B_WIDTH),
+	.Y_WIDTH(Y_WIDTH)
+) _TECHMAP_REPLACE_ (
+	.A(A_ORIG),
+	.B(B_ORIG),
+	.Y(Y_ORIG)
+);
+
+endmodule

docs/source/code_examples/macc/macc_xilinx_wrap_map.v

@@ -0,0 +1,89 @@
+(* techmap_celltype = "$mul" *)
+module mul_wrap (A, B, Y);
+
+parameter A_SIGNED = 0;
+parameter B_SIGNED = 0;
+parameter A_WIDTH = 1;
+parameter B_WIDTH = 1;
+parameter Y_WIDTH = 1;
+
+input [A_WIDTH-1:0] A;
+input [B_WIDTH-1:0] B;
+output [Y_WIDTH-1:0] Y;
+
+wire [17:0] A_18 = A;
+wire [24:0] B_25 = B;
+wire [47:0] Y_48;
+assign Y = Y_48;
+
+wire [1023:0] _TECHMAP_DO_ = "proc; clean";
+
+reg _TECHMAP_FAIL_;
+initial begin
+	_TECHMAP_FAIL_ <= 0;
+	if (A_SIGNED || B_SIGNED)
+		_TECHMAP_FAIL_ <= 1;
+	if (A_WIDTH < 4 || B_WIDTH < 4)
+		_TECHMAP_FAIL_ <= 1;
+	if (A_WIDTH > 18 || B_WIDTH > 25)
+		_TECHMAP_FAIL_ <= 1;
+	if (A_WIDTH*B_WIDTH < 100)
+		_TECHMAP_FAIL_ <= 1;
+end
+
+\$__mul_wrapper #(
+	.A_SIGNED(A_SIGNED),
+	.B_SIGNED(B_SIGNED),
+	.A_WIDTH(A_WIDTH),
+	.B_WIDTH(B_WIDTH),
+	.Y_WIDTH(Y_WIDTH)
+) _TECHMAP_REPLACE_ (
+	.A(A_18),
+	.B(B_25),
+	.Y(Y_48)
+);
+
+endmodule
+
+(* techmap_celltype = "$add" *)
+module add_wrap (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 [47:0] A_48 = A;
+wire [47:0] B_48 = B;
+wire [47:0] Y_48;
+assign Y = Y_48;
+
+wire [1023:0] _TECHMAP_DO_ = "proc; clean";
+
+reg _TECHMAP_FAIL_;
+initial begin
+	_TECHMAP_FAIL_ <= 0;
+	if (A_SIGNED || B_SIGNED)
+		_TECHMAP_FAIL_ <= 1;
+	if (A_WIDTH < 10 && B_WIDTH < 10)
+		_TECHMAP_FAIL_ <= 1;
+end
+
+\$__add_wrapper #(
+	.A_SIGNED(A_SIGNED),
+	.B_SIGNED(B_SIGNED),
+	.A_WIDTH(A_WIDTH),
+	.B_WIDTH(B_WIDTH),
+	.Y_WIDTH(Y_WIDTH)
+) _TECHMAP_REPLACE_ (
+	.A(A_48),
+	.B(B_48),
+	.Y(Y_48)
+);
+
+endmodule

docs/source/code_examples/macc/macc_xilinx_xmap.v

@@ -0,0 +1,10 @@
+module DSP48_MACC (a, b, c, y);
+
+input [17:0] a;
+input [24:0] b;
+input [47:0] c;
+output [47:0] y;
+
+assign y = a*b + c;
+
+endmodule