- Add to kernel/celltypes.h (incl. eval() handling for non-mem cells)
- Add to InternalCellChecker::check() in kernel/rtlil.cc
+ - Add to techlibs/common/simlib.v
+ - Add to techlibs/common/stdcells.v
Things to do after finalizing the cell interface:
cell_type_translation["$shl"] = "sll";
cell_type_translation["$sshr"] = "sra";
cell_type_translation["$sshl"] = "sll";
+ cell_type_translation["$shift"] = "srl";
+ cell_type_translation["$shiftx"] = "srl";
cell_type_translation["$lt"] = "ult";
cell_type_translation["$le"] = "ulte";
cell_type_translation["$gt"] = "ugt";
}
line_ref[cell->name]=line_num;
}
- else if(cell->type == "$shr" || cell->type == "$shl" || cell->type == "$sshr" || cell->type == "$sshl")
+ else if(cell->type == "$shr" || cell->type == "$shl" || cell->type == "$sshr" || cell->type == "$sshl" || cell->type == "$shift" || cell->type == "$shiftx")
{
log("writing binary cell - %s\n", cstr(cell->type));
int output_width = cell->parameters.at(RTLIL::IdString("\\Y_WIDTH")).as_int();
children[0]->children[1]->clone() : children[0]->children[0]->clone());
fake_ast->children[0]->delete_children();
RTLIL::SigSpec shift_val = fake_ast->children[1]->genRTLIL();
- if (id2ast->range_right != 0)
- shift_val = current_module->Sub(NEW_ID, shift_val, id2ast->range_right);
- if (id2ast->range_swapped)
- shift_val = current_module->Sub(NEW_ID, RTLIL::SigSpec(source_width - width), shift_val);
- RTLIL::SigSpec sig = binop2rtlil(fake_ast, "$shr", width, fake_ast->children[0]->genRTLIL(), shift_val);
+ if (id2ast->range_right != 0) {
+ shift_val = current_module->Sub(NEW_ID, shift_val, id2ast->range_right, fake_ast->children[1]->is_signed);
+ fake_ast->children[1]->is_signed = true;
+ }
+ if (id2ast->range_swapped) {
+ shift_val = current_module->Sub(NEW_ID, RTLIL::SigSpec(source_width - width), shift_val, fake_ast->children[1]->is_signed);
+ fake_ast->children[1]->is_signed = true;
+ }
+ if (SIZE(shift_val) >= 32)
+ fake_ast->children[1]->is_signed = true;
+ RTLIL::SigSpec sig = binop2rtlil(fake_ast, "$shiftx", width, fake_ast->children[0]->genRTLIL(), shift_val);
delete left_at_zero_ast;
delete right_at_zero_ast;
delete fake_ast;
return result;
}
-static RTLIL::Const const_shift(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool sign_ext, int direction, int result_len)
+static RTLIL::Const const_shift_worker(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool sign_ext, int direction, int result_len)
{
int undef_bit_pos = -1;
BigInteger offset = const2big(arg2, false, undef_bit_pos) * direction;
{
RTLIL::Const arg1_ext = arg1;
extend_u0(arg1_ext, result_len, signed1);
- return const_shift(arg1_ext, arg2, false, -1, result_len);
+ return const_shift_worker(arg1_ext, arg2, false, -1, result_len);
}
RTLIL::Const RTLIL::const_shr(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool, int result_len)
{
RTLIL::Const arg1_ext = arg1;
extend_u0(arg1_ext, result_len, signed1);
- return const_shift(arg1_ext, arg2, false, +1, result_len);
+ return const_shift_worker(arg1_ext, arg2, false, +1, result_len);
}
RTLIL::Const RTLIL::const_sshl(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
{
if (!signed1)
return const_shl(arg1, arg2, signed1, signed2, result_len);
- return const_shift(arg1, arg2, true, -1, result_len);
+ return const_shift_worker(arg1, arg2, true, -1, result_len);
}
RTLIL::Const RTLIL::const_sshr(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
{
if (!signed1)
return const_shr(arg1, arg2, signed1, signed2, result_len);
- return const_shift(arg1, arg2, true, +1, result_len);
+ return const_shift_worker(arg1, arg2, true, +1, result_len);
+}
+
+static RTLIL::Const const_shift_shiftx(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool, bool signed2, int result_len, RTLIL::State other_bits)
+{
+ int undef_bit_pos = -1;
+ BigInteger offset = const2big(arg2, signed2, undef_bit_pos);
+
+ if (result_len < 0)
+ result_len = arg1.bits.size();
+
+ RTLIL::Const result(RTLIL::State::Sx, result_len);
+ if (undef_bit_pos >= 0)
+ return result;
+
+ for (int i = 0; i < result_len; i++) {
+ BigInteger pos = BigInteger(i) + offset;
+ if (pos < 0 || pos >= arg1.bits.size())
+ result.bits[i] = other_bits;
+ else
+ result.bits[i] = arg1.bits[pos.toInt()];
+ }
+
+ return result;
+}
+
+RTLIL::Const RTLIL::const_shift(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
+{
+ return const_shift_shiftx(arg1, arg2, signed1, signed2, result_len, RTLIL::State::S0);
+}
+
+RTLIL::Const RTLIL::const_shiftx(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
+{
+ return const_shift_shiftx(arg1, arg2, signed1, signed2, result_len, RTLIL::State::Sx);
}
RTLIL::Const RTLIL::const_lt(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
cell_types.insert("$shr");
cell_types.insert("$sshl");
cell_types.insert("$sshr");
+ cell_types.insert("$shift");
+ cell_types.insert("$shiftx");
cell_types.insert("$lt");
cell_types.insert("$le");
cell_types.insert("$eq");
if (type == "$sshl" && !signed1)
type = "$shl";
- if (type != "$sshr" && type != "$sshl" && type != "$shr" && type != "$shl" &&
+ if (type != "$sshr" && type != "$sshl" && type != "$shr" && type != "$shl" && type != "$shift" && type != "$shiftx" &&
type != "$pos" && type != "$neg" && type != "$not" && type != "$bu0") {
if (!signed1 || !signed2)
signed1 = false, signed2 = false;
HANDLE_CELL_TYPE(shr)
HANDLE_CELL_TYPE(sshl)
HANDLE_CELL_TYPE(sshr)
+ HANDLE_CELL_TYPE(shift)
+ HANDLE_CELL_TYPE(shiftx)
HANDLE_CELL_TYPE(lt)
HANDLE_CELL_TYPE(le)
HANDLE_CELL_TYPE(eq)
return;
}
- if (cell->type == "$shl" || cell->type == "$shr" || cell->type == "$sshl" || cell->type == "$sshr") {
+ if (cell->type == "$shl" || cell->type == "$shr" || cell->type == "$sshl" || cell->type == "$sshr" ||
+ cell->type == "$shift" || cell->type == "$shiftx") {
param_bool("\\A_SIGNED");
param_bool("\\B_SIGNED");
port("\\A", param("\\A_WIDTH"));
DEF_METHOD(Shr, sig_a.size(), "$shr")
DEF_METHOD(Sshl, sig_a.size(), "$sshl")
DEF_METHOD(Sshr, sig_a.size(), "$sshr")
+DEF_METHOD(Shift, sig_a.size(), "$shift")
+DEF_METHOD(Shiftx, sig_a.size(), "$shiftx")
DEF_METHOD(Lt, 1, "$lt")
DEF_METHOD(Le, 1, "$le")
DEF_METHOD(Eq, 1, "$eq")
RTLIL::Const const_shr (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
RTLIL::Const const_sshl (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
RTLIL::Const const_sshr (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
+ RTLIL::Const const_shift (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
+ RTLIL::Const const_shiftx (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
RTLIL::Const const_lt (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
RTLIL::Const const_le (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
RTLIL::Cell* addReduceXnor (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_y, bool is_signed = false);
RTLIL::Cell* addReduceBool (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_y, bool is_signed = false);
- RTLIL::Cell* addShl (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, RTLIL::SigSpec sig_y, bool is_signed = false);
- RTLIL::Cell* addShr (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, RTLIL::SigSpec sig_y, bool is_signed = false);
- RTLIL::Cell* addSshl (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, RTLIL::SigSpec sig_y, bool is_signed = false);
- RTLIL::Cell* addSshr (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, RTLIL::SigSpec sig_y, bool is_signed = false);
+ RTLIL::Cell* addShl (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, RTLIL::SigSpec sig_y, bool is_signed = false);
+ RTLIL::Cell* addShr (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, RTLIL::SigSpec sig_y, bool is_signed = false);
+ RTLIL::Cell* addSshl (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, RTLIL::SigSpec sig_y, bool is_signed = false);
+ RTLIL::Cell* addSshr (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, RTLIL::SigSpec sig_y, bool is_signed = false);
+ RTLIL::Cell* addShift (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, RTLIL::SigSpec sig_y, bool is_signed = false);
+ RTLIL::Cell* addShiftx (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, RTLIL::SigSpec sig_y, bool is_signed = false);
RTLIL::Cell* addLt (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, RTLIL::SigSpec sig_y, bool is_signed = false);
RTLIL::Cell* addLe (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, RTLIL::SigSpec sig_y, bool is_signed = false);
RTLIL::SigSpec ReduceXnor (RTLIL::IdString name, RTLIL::SigSpec sig_a, bool is_signed = false);
RTLIL::SigSpec ReduceBool (RTLIL::IdString name, RTLIL::SigSpec sig_a, bool is_signed = false);
- RTLIL::SigSpec Shl (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, bool is_signed = false);
- RTLIL::SigSpec Shr (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, bool is_signed = false);
- RTLIL::SigSpec Sshl (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, bool is_signed = false);
- RTLIL::SigSpec Sshr (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, bool is_signed = false);
+ RTLIL::SigSpec Shl (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, bool is_signed = false);
+ RTLIL::SigSpec Shr (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, bool is_signed = false);
+ RTLIL::SigSpec Sshl (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, bool is_signed = false);
+ RTLIL::SigSpec Sshr (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, bool is_signed = false);
+ RTLIL::SigSpec Shift (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, bool is_signed = false);
+ RTLIL::SigSpec Shiftx (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, bool is_signed = false);
RTLIL::SigSpec Lt (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, bool is_signed = false);
RTLIL::SigSpec Le (RTLIL::IdString name, RTLIL::SigSpec sig_a, RTLIL::SigSpec sig_b, bool is_signed = false);
return true;
}
- if (cell->type == "$shl" || cell->type == "$shr" || cell->type == "$sshl" || cell->type == "$sshr")
+ if (cell->type == "$shl" || cell->type == "$shr" || cell->type == "$sshl" || cell->type == "$sshr" || cell->type == "$shift" || cell->type == "$shiftx")
{
std::vector<int> a = importDefSigSpec(cell->get("\\A"), timestep);
std::vector<int> b = importDefSigSpec(cell->get("\\B"), timestep);
char shift_left = cell->type == "$shl" || cell->type == "$sshl";
bool sign_extend = cell->type == "$sshr" && cell->parameters["\\A_SIGNED"].as_bool();
+ bool shift_shiftx = cell->type == "$shift" || cell->type == "$shiftx";
while (y.size() < a.size())
y.push_back(ez->literal());
std::vector<int> tmp = a;
for (size_t i = 0; i < b.size(); i++)
{
+ bool shift_left_this = shift_left;
+ if (shift_shiftx && i == b.size()-1 && cell->parameters["\\B_SIGNED"].as_bool())
+ shift_left_this = true;
+
std::vector<int> tmp_shifted(tmp.size());
for (size_t j = 0; j < tmp.size(); j++) {
- int idx = j + (1 << (i > 30 ? 30 : i)) * (shift_left ? -1 : +1);
+ int idx = j + (1 << (i > 30 ? 30 : i)) * (shift_left_this ? -1 : +1);
tmp_shifted.at(j) = (0 <= idx && idx < int(tmp.size())) ? tmp.at(idx) : sign_extend ? tmp.back() : ez->FALSE;
}
tmp = ez->vec_ite(b.at(i), tmp_shifted, tmp);
tmp = undef_a;
for (size_t i = 0; i < b.size(); i++)
{
+ bool shift_left_this = shift_left;
+ if (shift_shiftx && i == b.size()-1 && cell->parameters["\\B_SIGNED"].as_bool())
+ shift_left_this = true;
+
std::vector<int> tmp_shifted(tmp.size());
for (size_t j = 0; j < tmp.size(); j++) {
- int idx = j + (1 << (i > 30 ? 30 : i)) * (shift_left ? -1 : +1);
- tmp_shifted.at(j) = (0 <= idx && idx < int(tmp.size())) ? tmp.at(idx) : sign_extend ? tmp.back() : ez->FALSE;
+ int idx = j + (1 << (i > 30 ? 30 : i)) * (shift_left_this ? -1 : +1);
+ tmp_shifted.at(j) = (0 <= idx && idx < int(tmp.size())) ? tmp.at(idx) :
+ sign_extend ? tmp.back() : cell->type == "$shiftx" ? ez->TRUE : ez->FALSE;
}
tmp = ez->vec_ite(b.at(i), tmp_shifted, tmp);
}
cone_ct.cell_types.erase("$shr");
cone_ct.cell_types.erase("$sshl");
cone_ct.cell_types.erase("$sshr");
+ cone_ct.cell_types.erase("$shift");
+ cone_ct.cell_types.erase("$shiftx");
modwalker.setup(design, module, &cone_ct);
goto next_cell;
}
- if (cell->type == "$reduce_xor" || cell->type == "$reduce_xnor" ||
+ if (cell->type == "$reduce_xor" || cell->type == "$reduce_xnor" || cell->type == "$shift" || cell->type == "$shiftx" ||
cell->type == "$shl" || cell->type == "$shr" || cell->type == "$sshl" || cell->type == "$sshr" ||
cell->type == "$lt" || cell->type == "$le" || cell->type == "$ge" || cell->type == "$gt" ||
cell->type == "$neg" || cell->type == "$add" || cell->type == "$sub" ||
RTLIL::SigSpec sig_a = assign_map(cell->get("\\A"));
RTLIL::SigSpec sig_b = cell->has("\\B") ? assign_map(cell->get("\\B")) : RTLIL::SigSpec();
- if (cell->type == "$shl" || cell->type == "$shr" || cell->type == "$sshl" || cell->type == "$sshr")
+ if (cell->type == "$shl" || cell->type == "$shr" || cell->type == "$sshl" || cell->type == "$sshr" || cell->type == "$shift" || cell->type == "$shiftx")
sig_a = RTLIL::SigSpec();
for (auto &bit : sig_a.to_sigbit_vector())
if (0) {
found_the_x_bit:
- cover_list("opt.opt_const.xbit", "$reduce_xor", "$reduce_xnor", "$shl", "$shr", "$sshl", "$sshr", "$lt", "$le", "$ge", "$gt",
- "$neg", "$add", "$sub", "$mul", "$div", "$mod", "$pow", cell->type);
+ cover_list("opt.opt_const.xbit", "$reduce_xor", "$reduce_xnor", "$shl", "$shr", "$sshl", "$sshr", "$shift", "$shiftx",
+ "$lt", "$le", "$ge", "$gt", "$neg", "$add", "$sub", "$mul", "$div", "$mod", "$pow", cell->type);
if (cell->type == "$reduce_xor" || cell->type == "$reduce_xnor" ||
cell->type == "$lt" || cell->type == "$le" || cell->type == "$ge" || cell->type == "$gt")
replace_cell(assign_map, module, cell, "x-bit in input", "\\Y", RTLIL::State::Sx);
identity_wrt_a = true;
}
- if (cell->type == "$shl" || cell->type == "$shr" || cell->type == "$sshl" || cell->type == "$sshr")
+ if (cell->type == "$shl" || cell->type == "$shr" || cell->type == "$sshl" || cell->type == "$sshr" || cell->type == "$shift" || cell->type == "$shiftx")
{
RTLIL::SigSpec b = assign_map(cell->get("\\B"));
if (identity_wrt_a || identity_wrt_b)
{
if (identity_wrt_a)
- cover_list("opt.opt_const.identwrt.a", "$add", "$sub", "$or", "$xor", "$shl", "$shr", "$sshl", "$sshr", "$mul", "$div", cell->type);
+ cover_list("opt.opt_const.identwrt.a", "$add", "$sub", "$or", "$xor", "$shl", "$shr", "$sshl", "$sshr", "$shift", "$shiftx", "$mul", "$div", cell->type);
if (identity_wrt_b)
- cover_list("opt.opt_const.identwrt.b", "$add", "$sub", "$or", "$xor", "$shl", "$shr", "$sshl", "$sshr", "$mul", "$div", cell->type);
+ cover_list("opt.opt_const.identwrt.b", "$add", "$sub", "$or", "$xor", "$shl", "$shr", "$sshl", "$sshr", "$shift", "$shiftx", "$mul", "$div", cell->type);
log("Replacing %s cell `%s' in module `%s' with identity for port %c.\n",
cell->type.c_str(), cell->name.c_str(), module->name.c_str(), identity_wrt_a ? 'A' : 'B');
FOLD_2ARG_CELL(shr)
FOLD_2ARG_CELL(sshl)
FOLD_2ARG_CELL(sshr)
+ FOLD_2ARG_CELL(shift)
+ FOLD_2ARG_CELL(shiftx)
FOLD_2ARG_CELL(lt)
FOLD_2ARG_CELL(le)
// --------------------------------------------------------
+module \$shift (A, B, Y);
+
+parameter A_SIGNED = 0;
+parameter B_SIGNED = 0;
+parameter A_WIDTH = 0;
+parameter B_WIDTH = 0;
+parameter Y_WIDTH = 0;
+
+input [A_WIDTH-1:0] A;
+input [B_WIDTH-1:0] B;
+output [Y_WIDTH-1:0] Y;
+
+generate
+ if (B_SIGNED) begin:BLOCK1
+ assign Y = $signed(B) < 0 ? A << -B : A >> B;
+ end else begin:BLOCK2
+ assign Y = A >> B;
+ end
+endgenerate
+
+endmodule
+
+// --------------------------------------------------------
+
+module \$shiftx (A, B, Y);
+
+parameter A_SIGNED = 0;
+parameter B_SIGNED = 0;
+parameter A_WIDTH = 0;
+parameter B_WIDTH = 0;
+parameter Y_WIDTH = 0;
+
+input [A_WIDTH-1:0] A;
+input [B_WIDTH-1:0] B;
+output [Y_WIDTH-1:0] Y;
+
+generate
+ if (B_SIGNED) begin:BLOCK1
+ assign Y = A[$signed(B) +: Y_WIDTH];
+ end else begin:BLOCK2
+ assign Y = A[B +: Y_WIDTH];
+ end
+endgenerate
+
+endmodule
+
+// --------------------------------------------------------
+
module \$lt (A, B, Y);
parameter A_SIGNED = 0;
// --------------------------------------------------------
-module \$__shift (X, A, Y);
+module \$__shift (XL, XR, A, Y);
parameter WIDTH = 1;
parameter SHIFT = 0;
-input X;
+input XL, XR;
input [WIDTH-1:0] A;
output [WIDTH-1:0] Y;
generate
for (i = 0; i < WIDTH; i = i + 1) begin:V
if (i+SHIFT < 0) begin
- assign Y[i] = 0;
+ assign Y[i] = XR;
end else
if (i+SHIFT < WIDTH) begin
assign Y[i] = A[i+SHIFT];
end else begin
- assign Y[i] = X;
+ assign Y[i] = XL;
end
end
endgenerate
.WIDTH(WIDTH),
.SHIFT(0 - (2 ** (i > 30 ? 30 : i)))
) sh (
- .X(0),
+ .XL(1'b0),
+ .XR(1'b0),
.A(unshifted),
.Y(shifted)
);
.WIDTH(WIDTH),
.SHIFT(2 ** (i > 30 ? 30 : i))
) sh (
- .X(0),
+ .XL(1'b0),
+ .XR(1'b0),
.A(unshifted),
.Y(shifted)
);
.WIDTH(WIDTH),
.SHIFT(0 - (2 ** (i > 30 ? 30 : i)))
) sh (
- .X(0),
+ .XL(1'b0),
+ .XR(1'b0),
.A(unshifted),
.Y(shifted)
);
.WIDTH(WIDTH),
.SHIFT(2 ** (i > 30 ? 30 : i))
) sh (
- .X(A_SIGNED && A[A_WIDTH-1]),
+ .XL(A_SIGNED && A[A_WIDTH-1]),
+ .XR(1'b0),
.A(unshifted),
.Y(shifted)
);
// --------------------------------------------------------
+module \$shift (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;
+
+generate
+ if (B_SIGNED) begin:BLOCK1
+ assign Y = $signed(B) < 0 ? A << -B : A >> B;
+ end else begin:BLOCK2
+ assign Y = A >> B;
+ end
+endgenerate
+
+endmodule
+
+// --------------------------------------------------------
+
+module \$shiftx (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;
+
+\$shift #(
+ .A_SIGNED(A_SIGNED),
+ .B_SIGNED(B_SIGNED),
+ .A_WIDTH(A_WIDTH),
+ .B_WIDTH(B_WIDTH),
+ .Y_WIDTH(Y_WIDTH),
+) sh (
+ .A(A),
+ .B(B),
+ .Y(Y)
+);
+
+endmodule
+
+// --------------------------------------------------------
+
module \$__fulladd (A, B, C, X, Y);
// {X, Y} = A + B + C