Merge pull request #425 from udif/udif_dollar_bits

Add $bits() and $size()

2 files changed, 103 insertions, 1 deletions

diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc
index 28c9945ab..678951850 100644
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -387,7 +387,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		}
 		for (size_t i = 0; i < children.size(); i++) {
 			AstNode *node = children[i];
-			if (node->type == AST_PARAMETER || node->type == AST_LOCALPARAM || node->type == AST_WIRE || node->type == AST_AUTOWIRE)
+			if (node->type == AST_PARAMETER || node->type == AST_LOCALPARAM || node->type == AST_WIRE || node->type == AST_AUTOWIRE || node->type == AST_MEMORY)
 				while (node->simplify(true, false, false, 1, -1, false, node->type == AST_PARAMETER || node->type == AST_LOCALPARAM))
 					did_something = true;
 		}
@@ -1870,6 +1870,76 @@ skip_dynamic_range_lvalue_expansion:;
 				goto apply_newNode;
 			}
 
+			if (VERILOG_FRONTEND::sv_mode && (str == "\\$size" || str == "\\$bits"))
+			{
+				if (str == "\\$bits" && children.size() != 1)
+					log_error("System function %s got %d arguments, expected 1 at %s:%d.\n",
+							RTLIL::unescape_id(str).c_str(), int(children.size()), filename.c_str(), linenum);
+
+				if (str == "\\$size" && children.size() != 1 && children.size() != 2)
+					log_error("System function %s got %d arguments, expected 1 or 2 at %s:%d.\n",
+							RTLIL::unescape_id(str).c_str(), int(children.size()), filename.c_str(), linenum);
+
+				int dim = 1;
+				if (str == "\\$size" && children.size() == 2) {
+					AstNode *buf = children[1]->clone();
+					// Evaluate constant expression
+					while (buf->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
+					dim = buf->asInt(false);
+					delete buf;
+				}
+				AstNode *buf = children[0]->clone();
+				int mem_depth = 1;
+				AstNode *id_ast = NULL;
+
+				// Is this needed?
+				//while (buf->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
+				buf->detectSignWidth(width_hint, sign_hint);
+
+				if (buf->type == AST_IDENTIFIER) {
+					id_ast = buf->id2ast;
+					if (id_ast == NULL && current_scope.count(buf->str))
+						id_ast = current_scope.at(buf->str);
+					if (!id_ast)
+						log_error("Failed to resolve identifier %s for width detection at %s:%d!\n", buf->str.c_str(), filename.c_str(), linenum);
+					if (id_ast->type == AST_MEMORY) {
+						// We got here only if the argument is a memory
+						// Otherwise $size() and $bits() return the expression width
+						AstNode *mem_range = id_ast->children[1];
+						if (str == "\\$bits") {
+							if (mem_range->type == AST_RANGE) {
+								if (!mem_range->range_valid)
+									log_error("Failed to detect width of memory access `%s' at %s:%d!\n", buf->str.c_str(), filename.c_str(), linenum);
+								mem_depth = mem_range->range_left - mem_range->range_right + 1;
+							} else
+								log_error("Unknown memory depth AST type in `%s' at %s:%d!\n", buf->str.c_str(), filename.c_str(), linenum);
+						} else {
+							// $size()
+							if (mem_range->type == AST_RANGE) {
+								if (!mem_range->range_valid)
+									log_error("Failed to detect width of memory access `%s' at %s:%d!\n", buf->str.c_str(), filename.c_str(), linenum);
+								int dims;
+								if (id_ast->multirange_dimensions.empty())
+									dims = 1;
+								else
+									dims = GetSize(id_ast->multirange_dimensions)/2;
+								if (dim == 1)
+									width_hint = (dims > 1) ? id_ast->multirange_dimensions[1] : (mem_range->range_left - mem_range->range_right + 1);
+								else if (dim <= dims) {
+									width_hint = id_ast->multirange_dimensions[2*dim-1];
+								} else if ((dim > dims+1) || (dim < 0))
+									log_error("Dimension %d out of range in `%s', as it only has dimensions 1..%d at %s:%d!\n", dim, buf->str.c_str(), dims+1, filename.c_str(), linenum);
+							} else
+								log_error("Unknown memory depth AST type in `%s' at %s:%d!\n", buf->str.c_str(), filename.c_str(), linenum);
+						}
+					}
+				}
+				delete buf;
+
+				newNode = mkconst_int(width_hint * mem_depth, false);
+				goto apply_newNode;
+			}
+
 			if (str == "\\$ln" || str == "\\$log10" || str == "\\$exp" || str == "\\$sqrt" || str == "\\$pow" ||
 					str == "\\$floor" || str == "\\$ceil" || str == "\\$sin" || str == "\\$cos" || str == "\\$tan" ||
 					str == "\\$asin" || str == "\\$acos" || str == "\\$atan" || str == "\\$atan2" || str == "\\$hypot" ||
diff --git a/tests/simple/functions01.sv b/tests/simple/functions01.sv
new file mode 100644
index 000000000..d7ce2326e
--- /dev/null
+++ b/tests/simple/functions01.sv
@@ -0,0 +1,32 @@
+module functions01;
+
+wire [5:2]x;
+wire [3:0]y[2:7];
+wire [3:0]z[7:2][2:9];
+
+//wire [$size(x)-1:0]x_size;
+//wire [$size({x, x})-1:0]xx_size;
+//wire [$size(y)-1:0]y_size;
+//wire [$size(z)-1:0]z_size;
+
+assert property ($size(x) == 4);
+assert property ($size({3{x}}) == 3*4);
+assert property ($size(y) == 6);
+assert property ($size(y, 1) == 6);
+assert property ($size(y, (1+1)) == 4);
+
+assert property ($size(z) == 6);
+assert property ($size(z, 1) == 6);
+assert property ($size(z, 2) == 8);
+assert property ($size(z, 3) == 4);
+// This should trigger an error if enabled (it does).
+//assert property ($size(z, 4) == 4);
+
+//wire [$bits(x)-1:0]x_bits;
+//wire [$bits({x, x})-1:0]xx_bits;
+
+assert property ($bits(x) == 4);
+assert property ($bits(y) == 4*6);
+assert property ($bits(z) == 4*6*8);
+
+endmodule