From 6d69d4aaa81f176ec97654b5103f6f59eb98c211 Mon Sep 17 00:00:00 2001 From: Clifford Wolf Date: Thu, 17 Jul 2014 13:13:21 +0200 Subject: [PATCH] Added support for constant bit- or part-select for memory writes --- frontends/ast/simplify.cc | 45 +++++++++++++++++++++++++++++++-------- tests/simple/memory.v | 20 +++++++++++++++++ 2 files changed, 56 insertions(+), 9 deletions(-) diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc index ba0dca139..320c80d72 100644 --- a/frontends/ast/simplify.cc +++ b/frontends/ast/simplify.cc @@ -607,9 +607,9 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage, } // split memory access with bit select to individual statements - if (type == AST_IDENTIFIER && children.size() == 2 && children[0]->type == AST_RANGE && children[1]->type == AST_RANGE) + if (type == AST_IDENTIFIER && children.size() == 2 && children[0]->type == AST_RANGE && children[1]->type == AST_RANGE && !in_lvalue) { - if (id2ast == NULL || id2ast->type != AST_MEMORY || children[0]->children.size() != 1 || in_lvalue) + if (id2ast == NULL || id2ast->type != AST_MEMORY || children[0]->children.size() != 1) log_error("Invalid bit-select on memory access at %s:%d!\n", filename.c_str(), linenum); int mem_width, mem_size, addr_bits; @@ -1150,9 +1150,9 @@ skip_dynamic_range_lvalue_expansion:; // assignment with memory in left-hand side expression -> replace with memory write port if (stage > 1 && (type == AST_ASSIGN_EQ || type == AST_ASSIGN_LE) && children[0]->type == AST_IDENTIFIER && - children[0]->children.size() == 1 && children[0]->id2ast && children[0]->id2ast->type == AST_MEMORY && - children[0]->id2ast->children.size() >= 2 && children[0]->id2ast->children[0]->range_valid && - children[0]->id2ast->children[1]->range_valid) + children[0]->id2ast && children[0]->id2ast->type == AST_MEMORY && children[0]->id2ast->children.size() >= 2 && + children[0]->id2ast->children[0]->range_valid && children[0]->id2ast->children[1]->range_valid && + (children[0]->children.size() == 1 || children[0]->children.size() == 2)) { std::stringstream sstr; sstr << "$memwr$" << children[0]->str << "$" << filename << ":" << linenum << "$" << (RTLIL::autoidx++); @@ -1209,11 +1209,38 @@ skip_dynamic_range_lvalue_expansion:; assign_addr = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), children[0]->children[0]->children[0]->clone()); assign_addr->children[0]->str = id_addr; - assign_data = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), children[1]->clone()); - assign_data->children[0]->str = id_data; + if (children[0]->children.size() == 2) + { + if (children[0]->children[1]->range_valid) + { + int offset = children[0]->children[1]->range_right; + int width = children[0]->children[1]->range_left - offset + 1; - assign_en = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), mkconst_bits(set_bits_en, false)); - assign_en->children[0]->str = id_en; + std::vector padding_x(offset, RTLIL::State::Sx); + + for (int i = 0; i < mem_width; i++) + set_bits_en[i] = offset <= i && i < offset+width ? RTLIL::State::S1 : RTLIL::State::S0; + + assign_data = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), + new AstNode(AST_CONCAT, mkconst_bits(padding_x, false), children[1]->clone())); + assign_data->children[0]->str = id_data; + + assign_en = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), mkconst_bits(set_bits_en, false)); + assign_en->children[0]->str = id_en; + } + else + { + log_error("Writing to memories with dynamic bit- or part-select is not supported yet at %s:%d.\n", filename.c_str(), linenum); + } + } + else + { + assign_data = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), children[1]->clone()); + assign_data->children[0]->str = id_data; + + assign_en = new AstNode(AST_ASSIGN_LE, new AstNode(AST_IDENTIFIER), mkconst_bits(set_bits_en, false)); + assign_en->children[0]->str = id_en; + } newNode = new AstNode(AST_BLOCK); newNode->children.push_back(assign_addr); diff --git a/tests/simple/memory.v b/tests/simple/memory.v index 927ee0438..aae3feace 100644 --- a/tests/simple/memory.v +++ b/tests/simple/memory.v @@ -114,3 +114,23 @@ assign rd_data = memory[rd_addr_buf]; endmodule +// ---------------------------------------------------------- + +module test05(clk, addr, wdata, rdata, wen); + +input clk; +input [1:0] addr; +input [7:0] wdata; +output reg [7:0] rdata; +input [3:0] wen; + +reg [7:0] mem [0:3]; + +integer i; +always @(posedge clk) begin + for (i = 0; i < 4; i = i+1) + if (wen[i]) mem[addr][i*2 +: 2] <= wdata[i*2 +: 2]; + rdata <= mem[addr]; +end + +endmodule -- 2.30.2