diff options
Diffstat (limited to 'backends/verilog')
| -rw-r--r-- | backends/verilog/verilog_backend.cc | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/backends/verilog/verilog_backend.cc b/backends/verilog/verilog_backend.cc index 368b76793..4f44a053a 100644 --- a/backends/verilog/verilog_backend.cc +++ b/backends/verilog/verilog_backend.cc @@ -740,6 +740,61 @@ bool dump_cell_expr(std::ostream &f, std::string indent, RTLIL::Cell *cell) #undef HANDLE_UNIOP #undef HANDLE_BINOP + if (cell->type == ID($divfloor)) + { + // wire [MAXLEN+1:0] _0_, _1_, _2_; + // assign _0_ = $signed(A); + // assign _1_ = $signed(B); + // assign _2_ = (A[-1] == B[-1]) || A == 0 ? _0_ : $signed(_0_ - (B[-1] ? _1_ + 1 : _1_ - 1)); + // assign Y = $signed(_2_) / $signed(_1_); + + if (cell->getParam(ID::A_SIGNED).as_bool() && cell->getParam(ID::B_SIGNED).as_bool()) { + SigSpec sig_a = cell->getPort(ID::A); + SigSpec sig_b = cell->getPort(ID::B); + + std::string buf_a = next_auto_id(); + std::string buf_b = next_auto_id(); + std::string buf_num = next_auto_id(); + int size_a = GetSize(sig_a); + int size_b = GetSize(sig_b); + int size_y = GetSize(cell->getPort(ID::Y)); + int size_max = std::max(size_a, std::max(size_b, size_y)); + + // intentionally one wider than maximum width + f << stringf("%s" "wire [%d:0] %s, %s, %s;\n", indent.c_str(), size_max, buf_a.c_str(), buf_b.c_str(), buf_num.c_str()); + f << stringf("%s" "assign %s = ", indent.c_str(), buf_a.c_str()); + dump_cell_expr_port(f, cell, "A", true); + f << stringf(";\n"); + f << stringf("%s" "assign %s = ", indent.c_str(), buf_b.c_str()); + dump_cell_expr_port(f, cell, "B", true); + f << stringf(";\n"); + + f << stringf("%s" "assign %s = ", indent.c_str(), buf_num.c_str()); + f << stringf("("); + dump_sigspec(f, sig_a.extract(sig_a.size()-1)); + f << stringf(" == "); + dump_sigspec(f, sig_b.extract(sig_b.size()-1)); + f << stringf(") || "); + dump_sigspec(f, sig_a); + f << stringf(" == 0 ? %s : ", buf_a.c_str()); + f << stringf("$signed(%s - (", buf_a.c_str()); + dump_sigspec(f, sig_b.extract(sig_b.size()-1)); + f << stringf(" ? %s + 1 : %s - 1));\n", buf_b.c_str(), buf_b.c_str()); + + + f << stringf("%s" "assign ", indent.c_str()); + dump_sigspec(f, cell->getPort(ID::Y)); + f << stringf(" = $signed(%s) / ", buf_num.c_str()); + dump_attributes(f, "", cell->attributes, ' '); + f << stringf("$signed(%s);\n", buf_b.c_str()); + return true; + } else { + // same as truncating division + dump_cell_expr_binop(f, indent, cell, "/"); + return true; + } + } + if (cell->type == ID($modfloor)) { // wire truncated = $signed(A) % $signed(B); |