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Add flooring modulo operator 

The $div and $mod cells use truncating division semantics (rounding
towards 0), as defined by e.g. Verilog. Another rounding mode, flooring
(rounding towards negative infinity), can be used in e.g. VHDL. The
new $modfloor cell provides this flooring modulo (also known as "remainder"
in several languages, but this name is ambiguous).

This commit also fixes the handling of $mod in opt_expr, which was
previously optimized as if it was $modfloor.
This commit is contained in:
Xiretza 2020-04-08 19:30:47 +02:00
parent 0d99522b3c
commit 17163cf43a
No known key found for this signature in database
GPG Key ID: 17B78226F7139993
23 changed files with 280 additions and 37 deletions
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14
backends/btor/btor.cc
View File

@ -266,20 +266,26 @@ struct BtorWorker
goto okay;
}
if (cell->type.in(ID($div), ID($mod)))
if (cell->type.in(ID($div), ID($mod), ID($modfloor)))
{
bool a_signed = cell->hasParam(ID::A_SIGNED) ? cell->getParam(ID::A_SIGNED).as_bool() : false;
bool b_signed = cell->hasParam(ID::B_SIGNED) ? cell->getParam(ID::B_SIGNED).as_bool() : false;
string btor_op;
if (cell->type == ID($div)) btor_op = "div";
// "rem" = truncating modulo
if (cell->type == ID($mod)) btor_op = "rem";
// "mod" = flooring modulo
if (cell->type == ID($modfloor)) {
// "umod" doesn't exist because it's the same as "urem"
btor_op = a_signed || b_signed ? "mod" : "rem";
}
log_assert(!btor_op.empty());
int width = GetSize(cell->getPort(ID::Y));
width = std::max(width, GetSize(cell->getPort(ID::A)));
width = std::max(width, GetSize(cell->getPort(ID::B)));
bool a_signed = cell->hasParam(ID::A_SIGNED) ? cell->getParam(ID::A_SIGNED).as_bool() : false;
bool b_signed = cell->hasParam(ID::B_SIGNED) ? cell->getParam(ID::B_SIGNED).as_bool() : false;
int nid_a = get_sig_nid(cell->getPort(ID::A), width, a_signed);
int nid_b = get_sig_nid(cell->getPort(ID::B), width, b_signed);

2
backends/btor/test_cells.sh
View File

@ -6,7 +6,7 @@ rm -rf test_cells.tmp
mkdir -p test_cells.tmp
cd test_cells.tmp
../../../yosys -p 'test_cell -n 5 -w test all /$alu /$fa /$lcu /$lut /$sop /$macc /$mul /$div /$mod'
../../../yosys -p 'test_cell -n 5 -w test all /$alu /$fa /$lcu /$lut /$sop /$macc /$mul /$div /$mod /$modfloor'
for fn in test_*.il; do
../../../yosys -p "

1
backends/firrtl/firrtl.cc
View File

@ -585,6 +585,7 @@ struct FirrtlWorker
firrtl_is_signed = a_signed | b_signed;
firrtl_width = a_width;
} else if (cell->type == ID($mod)) {
// "rem" = truncating modulo
primop = "rem";
firrtl_width = min(a_width, b_width);
} else if (cell->type.in(ID($and), ID($_AND_))) {

10
backends/smt2/smt2.cc
View File

@ -590,7 +590,17 @@ struct Smt2Worker
if (cell->type == ID($sub)) return export_bvop(cell, "(bvsub A B)");
if (cell->type == ID($mul)) return export_bvop(cell, "(bvmul A B)");
if (cell->type == ID($div)) return export_bvop(cell, "(bvUdiv A B)", 'd');
// "rem" = truncating modulo
if (cell->type == ID($mod)) return export_bvop(cell, "(bvUrem A B)", 'd');
// "mod" = flooring modulo
if (cell->type == ID($modfloor)) {
// bvumod doesn't exist because it's the same as bvurem
if (cell->getParam(ID::A_SIGNED).as_bool()) {
return export_bvop(cell, "(bvsmod A B)", 'd');
} else {
return export_bvop(cell, "(bvurem A B)", 'd');
}
}
if (cell->type.in(ID($reduce_and), ID($reduce_or), ID($reduce_bool)) &&
2*GetSize(cell->getPort(ID::A).chunks()) < GetSize(cell->getPort(ID::A))) {

5
backends/smv/smv.cc
View File

@ -358,7 +358,8 @@ struct SmvWorker
continue;
}
if (cell->type.in(ID($div), ID($mod)))
// SMV has a "mod" operator, but its semantics don't seem to be well-defined - to be safe, don't generate it at all
if (cell->type.in(ID($div)/*, ID($mod), ID($modfloor)*/))
{
int width_y = GetSize(cell->getPort(ID::Y));
int width = max(width_y, GetSize(cell->getPort(ID::A)));
@ -366,7 +367,7 @@ struct SmvWorker
string expr_a, expr_b, op;
if (cell->type == ID($div)) op = "/";
if (cell->type == ID($mod)) op = "mod";
//if (cell->type == ID($mod)) op = "mod";
if (cell->getParam(ID::A_SIGNED).as_bool())
{

4
backends/smv/test_cells.sh
View File

@ -7,8 +7,8 @@ mkdir -p test_cells.tmp
cd test_cells.tmp
# don't test $mul to reduce runtime
# don't test $div and $mod to reduce runtime and avoid "div by zero" message
../../../yosys -p 'test_cell -n 5 -w test all /$alu /$fa /$lcu /$lut /$macc /$mul /$div /$mod'
# don't test $div/$mod/$modfloor to reduce runtime and avoid "div by zero" message
../../../yosys -p 'test_cell -n 5 -w test all /$alu /$fa /$lcu /$lut /$macc /$mul /$div /$mod /$modfloor'
cat > template.txt << "EOT"
%module main

34
backends/verilog/verilog_backend.cc
View File

@ -740,6 +740,40 @@ bool dump_cell_expr(std::ostream &f, std::string indent, RTLIL::Cell *cell)
#undef HANDLE_UNIOP
#undef HANDLE_BINOP
if (cell->type == ID($modfloor))
{
// wire truncated = $signed(A) % $signed(B);
// assign Y = (A[-1] == B[-1]) || truncated == 0 ? truncated : $signed(B) + $signed(truncated);
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 temp_id = next_auto_id();
f << stringf("%s" "wire [%d:0] %s = ", indent.c_str(), GetSize(cell->getPort(ID::A))-1, temp_id.c_str());
dump_cell_expr_port(f, cell, "A", true);
f << stringf(" %% ");
dump_attributes(f, "", cell->attributes, ' ');
dump_cell_expr_port(f, cell, "B", true);
f << stringf(";\n");
f << stringf("%s" "assign ", indent.c_str());
dump_sigspec(f, cell->getPort(ID::Y));
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(") || %s == 0 ? %s : ", temp_id.c_str(), temp_id.c_str());
dump_cell_expr_port(f, cell, "B", true);
f << stringf(" + $signed(%s);\n", temp_id.c_str());
return true;
} else {
// same as truncating modulo
dump_cell_expr_binop(f, indent, cell, "%");
return true;
}
}
if (cell->type == ID($shift))
{
f << stringf("%s" "assign ", indent.c_str());

25
kernel/calc.cc
View File

@ -489,6 +489,7 @@ RTLIL::Const RTLIL::const_mul(const RTLIL::Const &arg1, const RTLIL::Const &arg2
return big2const(y, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
}
// truncating division
RTLIL::Const RTLIL::const_div(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
{
int undef_bit_pos = -1;
@ -502,6 +503,7 @@ RTLIL::Const RTLIL::const_div(const RTLIL::Const &arg1, const RTLIL::Const &arg2
return big2const(result_neg ? -(a / b) : (a / b), result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
}
// truncating modulo
RTLIL::Const RTLIL::const_mod(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
{
int undef_bit_pos = -1;
@ -515,6 +517,29 @@ RTLIL::Const RTLIL::const_mod(const RTLIL::Const &arg1, const RTLIL::Const &arg2
return big2const(result_neg ? -(a % b) : (a % b), result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
}
RTLIL::Const RTLIL::const_modfloor(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
{
int undef_bit_pos = -1;
BigInteger a = const2big(arg1, signed1, undef_bit_pos);
BigInteger b = const2big(arg2, signed2, undef_bit_pos);
if (b.isZero())
return RTLIL::Const(RTLIL::State::Sx, result_len);
BigInteger::Sign a_sign = a.getSign();
BigInteger::Sign b_sign = b.getSign();
a = a_sign == BigInteger::negative ? -a : a;
b = b_sign == BigInteger::negative ? -b : b;
BigInteger truncated = a_sign == BigInteger::negative ? -(a % b) : (a % b);
BigInteger modulo;
if (truncated == 0 || (a_sign == b_sign)) {
modulo = truncated;
} else {
modulo = b_sign == BigInteger::negative ? truncated - b : truncated + b;
}
return big2const(modulo, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
}
RTLIL::Const RTLIL::const_pow(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
{
int undef_bit_pos = -1;

2
kernel/celledges.cc
View File

@ -187,7 +187,7 @@ bool YOSYS_NAMESPACE_PREFIX AbstractCellEdgesDatabase::add_edges_from_cell(RTLIL
return true;
}
// FIXME: $mul $div $mod $slice $concat
// FIXME: $mul $div $mod $modfloor $slice $concat
// FIXME: $lut $sop $alu $lcu $macc $fa
return false;

3
kernel/celltypes.h
View File

@ -114,7 +114,7 @@ struct CellTypes
ID($and), ID($or), ID($xor), ID($xnor),
ID($shl), ID($shr), ID($sshl), ID($sshr), ID($shift), ID($shiftx),
ID($lt), ID($le), ID($eq), ID($ne), ID($eqx), ID($nex), ID($ge), ID($gt),
ID($add), ID($sub), ID($mul), ID($div), ID($mod), ID($pow),
ID($add), ID($sub), ID($mul), ID($div), ID($mod), ID($modfloor), ID($pow),
ID($logic_and), ID($logic_or), ID($concat), ID($macc)
};
@ -304,6 +304,7 @@ struct CellTypes
HANDLE_CELL_TYPE(mul)
HANDLE_CELL_TYPE(div)
HANDLE_CELL_TYPE(mod)
HANDLE_CELL_TYPE(modfloor)
HANDLE_CELL_TYPE(pow)
HANDLE_CELL_TYPE(pos)
HANDLE_CELL_TYPE(neg)

3
kernel/rtlil.cc
View File

@ -948,7 +948,7 @@ namespace {
return;
}
if (cell->type.in(ID($add), ID($sub), ID($mul), ID($div), ID($mod), ID($pow))) {
if (cell->type.in(ID($add), ID($sub), ID($mul), ID($div), ID($mod), ID($modfloor), ID($pow))) {
param_bool(ID::A_SIGNED);
param_bool(ID::B_SIGNED);
port(ID::A, param(ID::A_WIDTH));
@ -1949,6 +1949,7 @@ DEF_METHOD(Sub, max(sig_a.size(), sig_b.size()), ID($sub))
DEF_METHOD(Mul, max(sig_a.size(), sig_b.size()), ID($mul))
DEF_METHOD(Div, max(sig_a.size(), sig_b.size()), ID($div))
DEF_METHOD(Mod, max(sig_a.size(), sig_b.size()), ID($mod))
DEF_METHOD(ModFloor, max(sig_a.size(), sig_b.size()), ID($modfloor))
DEF_METHOD(LogicAnd, 1, ID($logic_and))
DEF_METHOD(LogicOr, 1, ID($logic_or))
#undef DEF_METHOD

3
kernel/rtlil.h
View File

@ -466,6 +466,7 @@ namespace RTLIL
RTLIL::Const const_sub (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
RTLIL::Const const_mul (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
RTLIL::Const const_div (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
RTLIL::Const const_modfloor (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
RTLIL::Const const_mod (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
RTLIL::Const const_pow (const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len);
@ -1204,6 +1205,7 @@ public:
RTLIL::Cell* addMul (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
RTLIL::Cell* addDiv (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
RTLIL::Cell* addMod (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
RTLIL::Cell* addModFloor (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
RTLIL::Cell* addPow (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, const RTLIL::SigSpec &sig_y, bool a_signed = false, bool b_signed = false, const std::string &src = "");
RTLIL::Cell* addLogicNot (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_y, bool is_signed = false, const std::string &src = "");
@ -1303,6 +1305,7 @@ public:
RTLIL::SigSpec Mul (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, bool is_signed = false, const std::string &src = "");
RTLIL::SigSpec Div (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, bool is_signed = false, const std::string &src = "");
RTLIL::SigSpec Mod (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, bool is_signed = false, const std::string &src = "");
RTLIL::SigSpec ModFloor (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, bool is_signed = false, const std::string &src = "");
RTLIL::SigSpec Pow (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, const RTLIL::SigSpec &sig_b, bool a_signed = false, bool b_signed = false, const std::string &src = "");
RTLIL::SigSpec LogicNot (RTLIL::IdString name, const RTLIL::SigSpec &sig_a, bool is_signed = false, const std::string &src = "");

31
kernel/satgen.h
View File

@ -279,7 +279,7 @@ struct SatGen
bool arith_undef_handled = false;
bool is_arith_compare = cell->type.in(ID($lt), ID($le), ID($ge), ID($gt));
if (model_undef && (cell->type.in(ID($add), ID($sub), ID($mul), ID($div), ID($mod)) || is_arith_compare))
if (model_undef && (cell->type.in(ID($add), ID($sub), ID($mul), ID($div), ID($mod), ID($modfloor)) || is_arith_compare))
{
std::vector<int> undef_a = importUndefSigSpec(cell->getPort(ID::A), timestep);
std::vector<int> undef_b = importUndefSigSpec(cell->getPort(ID::B), timestep);
@ -293,7 +293,7 @@ struct SatGen
int undef_any_b = ez->expression(ezSAT::OpOr, undef_b);
int undef_y_bit = ez->OR(undef_any_a, undef_any_b);
if (cell->type.in(ID($div), ID($mod))) {
if (cell->type.in(ID($div), ID($mod), ID($modfloor))) {
std::vector<int> b = importSigSpec(cell->getPort(ID::B), timestep);
undef_y_bit = ez->OR(undef_y_bit, ez->NOT(ez->expression(ezSAT::OpOr, b)));
}
@ -935,7 +935,7 @@ struct SatGen
return true;
}
if (cell->type.in(ID($div), ID($mod)))
if (cell->type.in(ID($div), ID($mod), ID($modfloor)))
{
std::vector<int> a = importDefSigSpec(cell->getPort(ID::A), timestep);
std::vector<int> b = importDefSigSpec(cell->getPort(ID::B), timestep);
@ -970,16 +970,28 @@ struct SatGen
}
std::vector<int> y_tmp = ignore_div_by_zero ? yy : ez->vec_var(y.size());
// modulo calculation
std::vector<int> modulo_trunc;
int floored_eq_trunc;
if (cell->parameters[ID::A_SIGNED].as_bool() && cell->parameters[ID::B_SIGNED].as_bool()) {
modulo_trunc = ez->vec_ite(a.back(), ez->vec_neg(chain_buf), chain_buf);
// floor == trunc when sgn(a) == sgn(b) or trunc == 0
floored_eq_trunc = ez->OR(ez->IFF(a.back(), b.back()), ez->NOT(ez->expression(ezSAT::OpOr, modulo_trunc)));
} else {
modulo_trunc = chain_buf;
floored_eq_trunc = ez->CONST_TRUE;
}
if (cell->type == ID($div)) {
if (cell->parameters[ID::A_SIGNED].as_bool() && cell->parameters[ID::B_SIGNED].as_bool())
ez->assume(ez->vec_eq(y_tmp, ez->vec_ite(ez->XOR(a.back(), b.back()), ez->vec_neg(y_u), y_u)));
else
ez->assume(ez->vec_eq(y_tmp, y_u));
} else {
if (cell->parameters[ID::A_SIGNED].as_bool() && cell->parameters[ID::B_SIGNED].as_bool())
ez->assume(ez->vec_eq(y_tmp, ez->vec_ite(a.back(), ez->vec_neg(chain_buf), chain_buf)));
else
ez->assume(ez->vec_eq(y_tmp, chain_buf));
} else if (cell->type == ID($mod)) {
ez->assume(ez->vec_eq(y_tmp, modulo_trunc));
} else if (cell->type == ID($modfloor)) {
ez->assume(ez->vec_eq(y_tmp, ez->vec_ite(floored_eq_trunc, modulo_trunc, ez->vec_add(modulo_trunc, b))));
}
if (ignore_div_by_zero) {
@ -996,7 +1008,8 @@ struct SatGen
div_zero_result.insert(div_zero_result.end(), cell->getPort(ID::A).size(), ez->CONST_TRUE);
div_zero_result.insert(div_zero_result.end(), y.size() - div_zero_result.size(), ez->CONST_FALSE);
}
} else {
} else if (cell->type.in(ID($mod), ID($modfloor))) {
// a mod 0 = a
int copy_a_bits = min(cell->getPort(ID::A).size(), cell->getPort(ID::B).size());
div_zero_result.insert(div_zero_result.end(), a.begin(), a.begin() + copy_a_bits);
if (cell->parameters[ID::A_SIGNED].as_bool() && cell->parameters[ID::B_SIGNED].as_bool())

2
manual/PRESENTATION_Prog.tex
View File

@ -307,7 +307,7 @@ cell name from the internal cell library:
\begin{lstlisting}[xleftmargin=1cm, basicstyle=\ttfamily\fontsize{6pt}{7pt}\selectfont]
$not $pos $neg $and $or $xor $xnor $reduce_and $reduce_or $reduce_xor $reduce_xnor
$reduce_bool $shl $shr $sshl $sshr $lt $le $eq $ne $eqx $nex $ge $gt $add $sub $mul $div $mod
$pow $logic_not $logic_and $logic_or $mux $pmux $slice $concat $lut $assert $sr $dff
$modfloor $pow $logic_not $logic_and $logic_or $mux $pmux $slice $concat $lut $assert $sr $dff
$dffsr $adff $dlatch $dlatchsr $memrd $memwr $mem $fsm $_NOT_ $_AND_ $_OR_ $_XOR_ $_MUX_ $_SR_NN_
$_SR_NP_ $_SR_PN_ $_SR_PP_ $_DFF_N_ $_DFF_P_ $_DFF_NN0_ $_DFF_NN1_ $_DFF_NP0_ $_DFF_NP1_ $_DFF_PN0_
$_DFF_PN1_ $_DFF_PP0_ $_DFF_PP1_ $_DFFSR_NNN_ $_DFFSR_NNP_ $_DFFSR_NPN_ $_DFFSR_NPP_ $_DFFSR_PNN_

2
passes/cmds/stat.cc
View File

@ -109,7 +109,7 @@ struct statdata_t
ID($lut), ID($and), ID($or), ID($xor), ID($xnor),
ID($shl), ID($shr), ID($sshl), ID($sshr), ID($shift), ID($shiftx),
ID($lt), ID($le), ID($eq), ID($ne), ID($eqx), ID($nex), ID($ge), ID($gt),
ID($add), ID($sub), ID($mul), ID($div), ID($mod), ID($pow), ID($alu))) {
ID($add), ID($sub), ID($mul), ID($div), ID($mod), ID($modfloor), ID($pow), ID($alu))) {
int width_a = cell->hasPort(ID::A) ? GetSize(cell->getPort(ID::A)) : 0;
int width_b = cell->hasPort(ID::B) ? GetSize(cell->getPort(ID::B)) : 0;
int width_y = cell->hasPort(ID::Y) ? GetSize(cell->getPort(ID::Y)) : 0;

1
passes/memory/memory_share.cc
View File

@ -715,6 +715,7 @@ struct MemoryShareWorker
cone_ct.cell_types.erase(ID($mul));
cone_ct.cell_types.erase(ID($mod));
cone_ct.cell_types.erase(ID($div));
cone_ct.cell_types.erase(ID($modfloor));
cone_ct.cell_types.erase(ID($pow));
cone_ct.cell_types.erase(ID($shl));
cone_ct.cell_types.erase(ID($shr));

33
passes/opt/opt_expr.cc
View File

@ -864,7 +864,7 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
skip_fine_alu:
if (cell->type.in(ID($reduce_xor), ID($reduce_xnor), ID($shift), ID($shiftx), ID($shl), ID($shr), ID($sshl), ID($sshr),
ID($lt), ID($le), ID($ge), ID($gt), ID($neg), ID($add), ID($sub), ID($mul), ID($div), ID($mod), ID($pow)))
ID($lt), ID($le), ID($ge), ID($gt), ID($neg), ID($add), ID($sub), ID($mul), ID($div), ID($mod), ID($modfloor), ID($pow)))
{
RTLIL::SigSpec sig_a = assign_map(cell->getPort(ID::A));
RTLIL::SigSpec sig_b = cell->hasPort(ID::B) ? assign_map(cell->getPort(ID::B)) : RTLIL::SigSpec();
@ -883,7 +883,7 @@ skip_fine_alu:
if (0) {
found_the_x_bit:
cover_list("opt.opt_expr.xbit", "$reduce_xor", "$reduce_xnor", "$shl", "$shr", "$sshl", "$sshr", "$shift", "$shiftx",
"$lt", "$le", "$ge", "$gt", "$neg", "$add", "$sub", "$mul", "$div", "$mod", "$pow", cell->type.str());
"$lt", "$le", "$ge", "$gt", "$neg", "$add", "$sub", "$mul", "$div", "$mod", "$modfloor", "$pow", cell->type.str());
if (cell->type.in(ID($reduce_xor), ID($reduce_xnor), ID($lt), ID($le), ID($ge), ID($gt)))
replace_cell(assign_map, module, cell, "x-bit in input", ID::Y, RTLIL::State::Sx);
else
@ -1469,6 +1469,7 @@ skip_identity:
FOLD_2ARG_CELL(mul)
FOLD_2ARG_CELL(div)
FOLD_2ARG_CELL(mod)
FOLD_2ARG_CELL(modfloor)
FOLD_2ARG_CELL(pow)
FOLD_1ARG_CELL(pos)
@ -1583,9 +1584,11 @@ skip_identity:
}
}
if (!keepdc && cell->type.in(ID($div), ID($mod)))
if (!keepdc && cell->type.in(ID($div), ID($mod), ID($modfloor)))
{
bool a_signed = cell->parameters[ID::A_SIGNED].as_bool();
bool b_signed = cell->parameters[ID::B_SIGNED].as_bool();
SigSpec sig_a = assign_map(cell->getPort(ID::A));
SigSpec sig_b = assign_map(cell->getPort(ID::B));
SigSpec sig_y = assign_map(cell->getPort(ID::Y));
@ -1628,11 +1631,13 @@ skip_identity:
cell->setPort(ID::B, new_b);
cell->check();
}
else
else if (cell->type.in(ID($mod), ID($modfloor)))
{
cover("opt.opt_expr.mod_mask");
log_debug("Replacing modulo-by-%d cell `%s' in module `%s' with bitmask.\n",
bool is_truncating = cell->type == ID($mod);
log_debug("Replacing %s-modulo-by-%d cell `%s' in module `%s' with bitmask.\n",
is_truncating ? "truncating" : "flooring",
b_val, cell->name.c_str(), module->name.c_str());
std::vector<RTLIL::SigBit> new_b = RTLIL::SigSpec(State::S1, i);
@ -1643,6 +1648,24 @@ skip_identity:
cell->type = ID($and);
cell->parameters[ID::B_WIDTH] = GetSize(new_b);
cell->setPort(ID::B, new_b);
// truncating modulo has the same masked bits as flooring modulo, but
// the sign bits are those of A (except when R=0)
if (is_truncating && a_signed) {
Wire *flooring = module->addWire(NEW_ID, sig_y.size());
cell->setPort(ID::Y, flooring);
SigSpec truncating = SigSpec(flooring).extract(0, i);
Wire *rem_nonzero = module->addWire(NEW_ID);
module->addReduceOr(NEW_ID, truncating, rem_nonzero);
SigSpec a_sign = sig_a[sig_a.size()-1];
Wire *extend_bit = module->addWire(NEW_ID);
module->addAnd(NEW_ID, a_sign, rem_nonzero, extend_bit);
truncating.append(extend_bit);
module->addPos(NEW_ID, truncating, sig_y, true);
}
cell->check();
}

4
passes/opt/opt_share.cc
View File

@ -103,7 +103,7 @@ bool cell_supported(RTLIL::Cell *cell)
if (sig_bi.is_fully_const() && sig_ci.is_fully_const() && sig_bi == sig_ci)
return true;
} else if (cell->type.in(LOGICAL_OPS, SHIFT_OPS, BITWISE_OPS, RELATIONAL_OPS, ID($add), ID($sub), ID($mul), ID($div), ID($mod), ID($concat))) {
} else if (cell->type.in(LOGICAL_OPS, SHIFT_OPS, BITWISE_OPS, RELATIONAL_OPS, ID($add), ID($sub), ID($mul), ID($div), ID($mod), ID($modfloor), ID($concat))) {
return true;
}
@ -130,7 +130,7 @@ bool mergeable(RTLIL::Cell *a, RTLIL::Cell *b)
RTLIL::IdString decode_port_semantics(RTLIL::Cell *cell, RTLIL::IdString port_name)
{
if (cell->type.in(ID($lt), ID($le), ID($ge), ID($gt), ID($div), ID($mod), ID($concat), SHIFT_OPS) && port_name == ID::B)
if (cell->type.in(ID($lt), ID($le), ID($ge), ID($gt), ID($div), ID($mod), ID($modfloor), ID($concat), SHIFT_OPS) && port_name == ID::B)
return port_name;
return "";

4
passes/opt/share.cc
View File

@ -376,7 +376,7 @@ struct ShareWorker
continue;
}
if (cell->type.in(ID($mul), ID($div), ID($mod))) {
if (cell->type.in(ID($mul), ID($div), ID($mod), ID($modfloor))) {
if (config.opt_aggressive || cell->parameters.at(ID::Y_WIDTH).as_int() >= 4)
shareable_cells.insert(cell);
continue;
@ -1133,6 +1133,7 @@ struct ShareWorker
cone_ct.cell_types.erase(ID($mul));
cone_ct.cell_types.erase(ID($mod));
cone_ct.cell_types.erase(ID($div));
cone_ct.cell_types.erase(ID($modfloor));
cone_ct.cell_types.erase(ID($pow));
cone_ct.cell_types.erase(ID($shl));
cone_ct.cell_types.erase(ID($shr));
@ -1512,6 +1513,7 @@ struct SharePass : public Pass {
config.generic_bin_ops.insert(ID($sub));
config.generic_bin_ops.insert(ID($div));
config.generic_bin_ops.insert(ID($mod));
config.generic_bin_ops.insert(ID($modfloor));
// config.generic_bin_ops.insert(ID($pow));
config.generic_uni_ops.insert(ID($logic_not));

4
passes/opt/wreduce.cc
View File

@ -37,7 +37,7 @@ struct WreduceConfig
ID($and), ID($or), ID($xor), ID($xnor),
ID($shl), ID($shr), ID($sshl), ID($sshr), ID($shift), ID($shiftx),
ID($lt), ID($le), ID($eq), ID($ne), ID($eqx), ID($nex), ID($ge), ID($gt),
ID($add), ID($sub), ID($mul), // ID($div), ID($mod), ID($pow),
ID($add), ID($sub), ID($mul), // ID($div), ID($mod), ID($modfloor), ID($pow),
ID($mux), ID($pmux),
ID($dff), ID($adff)
});
@ -545,7 +545,7 @@ struct WreducePass : public Pass {
}
}
if (c->type.in(ID($div), ID($mod), ID($pow)))
if (c->type.in(ID($div), ID($mod), ID($modfloor), ID($pow)))
{
SigSpec A = c->getPort(ID::A);
int original_a_width = GetSize(A);

3
passes/tests/test_cell.cc
View File

@ -264,7 +264,7 @@ static void create_gold_module(RTLIL::Design *design, RTLIL::IdString cell_type,
cell->setPort(ID::Y, wire);
}
if (muxdiv && cell_type.in(ID($div), ID($mod))) {
if (muxdiv && cell_type.in(ID($div), ID($mod), ID($modfloor))) {
auto b_not_zero = module->ReduceBool(NEW_ID, cell->getPort(ID::B));
auto div_out = module->addWire(NEW_ID, GetSize(cell->getPort(ID::Y)));
module->addMux(NEW_ID, RTLIL::SigSpec(0, GetSize(div_out)), div_out, b_not_zero, cell->getPort(ID::Y));
@ -839,6 +839,7 @@ struct TestCellPass : public Pass {
cell_types[ID($mul)] = "ABSY";
cell_types[ID($div)] = "ABSY";
cell_types[ID($mod)] = "ABSY";
cell_types[ID($modfloor)] = "ABSY";
// cell_types[ID($pow)] = "ABsY";
cell_types[ID($logic_not)] = "ASY";

48
techlibs/common/simlib.v
View File

@ -1021,6 +1021,14 @@ endmodule
// --------------------------------------------------------
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
//-
//- $mod (A, B, Y)
//-
//- Modulo/remainder of division with truncated result (rounded towards 0).
//-
//- Invariant: $div(A, B) * B + $mod(A, B) == A
//-
module \$mod (A, B, Y);
parameter A_SIGNED = 0;
@ -1043,6 +1051,46 @@ endgenerate
endmodule
// --------------------------------------------------------
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
//-
//- $modfloor (A, B, Y)
//-
//- Modulo/remainder of division with floored result (rounded towards negative infinity).
//-
//- Invariant: $divfloor(A, B) * B + $modfloor(A, B) == A
//-
module \$modfloor (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 (A_SIGNED && B_SIGNED) begin:BLOCK1
localparam WIDTH = B_WIDTH >= Y_WIDTH ? B_WIDTH : Y_WIDTH;
wire [WIDTH-1:0] B_buf, Y_trunc;
assign B_buf = $signed(B);
assign Y_trunc = $signed(A) % $signed(B);
// flooring mod is the same as truncating mod for positive division results (A and B have
// the same sign), as well as when there's no remainder.
// For all other cases, they behave as `floor - trunc = B`
assign Y = (A[A_WIDTH-1] == B[B_WIDTH-1]) || Y_trunc == 0 ? Y_trunc : $signed(B_buf) + $signed(Y_trunc);
end else begin:BLOCK2
// no difference between truncating and flooring for unsigned
assign Y = A % B;
end
endgenerate
endmodule
// --------------------------------------------------------
`ifndef SIMLIB_NOPOW

79
techlibs/common/techmap.v
View File

@ -364,7 +364,8 @@ module \$__div_mod_u (A, B, Y, R);
end endgenerate
endmodule
module \$__div_mod (A, B, Y, R);
// truncating signed division/modulo
module \$__div_mod_trunc (A, B, Y, R);
parameter A_SIGNED = 0;
parameter B_SIGNED = 0;
parameter A_WIDTH = 1;
@ -420,7 +421,7 @@ module _90_div (A, B, Y);
(* force_downto *)
output [Y_WIDTH-1:0] Y;
\$__div_mod #(
\$__div_mod_trunc #(
.A_SIGNED(A_SIGNED),
.B_SIGNED(B_SIGNED),
.A_WIDTH(A_WIDTH),
@ -448,7 +449,79 @@ module _90_mod (A, B, Y);
(* force_downto *)
output [Y_WIDTH-1:0] Y;
\$__div_mod #(
\$__div_mod_trunc #(
.A_SIGNED(A_SIGNED),
.B_SIGNED(B_SIGNED),
.A_WIDTH(A_WIDTH),
.B_WIDTH(B_WIDTH),
.Y_WIDTH(Y_WIDTH)
) div_mod (
.A(A),
.B(B),
.R(Y)
);
endmodule
// flooring signed division/modulo
module \$__div_mod_floor (A, B, Y, R);
parameter A_SIGNED = 0;
parameter B_SIGNED = 0;
parameter A_WIDTH = 1;
parameter B_WIDTH = 1;
parameter Y_WIDTH = 1;
localparam WIDTH =
A_WIDTH >= B_WIDTH && A_WIDTH >= Y_WIDTH ? A_WIDTH :
B_WIDTH >= A_WIDTH && B_WIDTH >= Y_WIDTH ? B_WIDTH : Y_WIDTH;
input [A_WIDTH-1:0] A;
input [B_WIDTH-1:0] B;
output [Y_WIDTH-1:0] Y, R;
wire [WIDTH-1:0] A_buf, B_buf;
\$pos #(.A_SIGNED(A_SIGNED), .A_WIDTH(A_WIDTH), .Y_WIDTH(WIDTH)) A_conv (.A(A), .Y(A_buf));
\$pos #(.A_SIGNED(B_SIGNED), .A_WIDTH(B_WIDTH), .Y_WIDTH(WIDTH)) B_conv (.A(B), .Y(B_buf));
wire [WIDTH-1:0] A_buf_u, B_buf_u, Y_u, R_u, R_s;
assign A_buf_u = A_SIGNED && A_buf[WIDTH-1] ? -A_buf : A_buf;
assign B_buf_u = B_SIGNED && B_buf[WIDTH-1] ? -B_buf : B_buf;
\$__div_mod_u #(
.WIDTH(WIDTH)
) div_mod_u (
.A(A_buf_u),
.B(B_buf_u),
.Y(Y_u),
.R(R_u)
);
// For negative results, if there was a remainder, subtract one to turn
// the round towards 0 into a round towards -inf
assign Y = A_SIGNED && B_SIGNED && (A_buf[WIDTH-1] != B_buf[WIDTH-1]) ? (R_u == 0 ? -Y_u : -Y_u-1) : Y_u;
// truncating modulo
assign R_s = A_SIGNED && B_SIGNED && A_buf[WIDTH-1] ? -R_u : R_u;
// Flooring modulo differs from truncating modulo only if it is nonzero and
// A and B have different signs - then `floor - trunc = B`
assign R = (R_s != 0) && A_SIGNED && B_SIGNED && (A_buf[WIDTH-1] != B_buf[WIDTH-1]) ? $signed(B_buf) + $signed(R_s) : R_s;
endmodule
(* techmap_celltype = "$modfloor" *)
module _90_modfloor (A, B, Y);
parameter A_SIGNED = 0;
parameter B_SIGNED = 0;
parameter A_WIDTH = 1;
parameter B_WIDTH = 1;
parameter Y_WIDTH = 1;
(* force_downto *)
input [A_WIDTH-1:0] A;
(* force_downto *)
input [B_WIDTH-1:0] B;
(* force_downto *)
output [Y_WIDTH-1:0] Y;
\$__div_mod_floor #(
.A_SIGNED(A_SIGNED),
.B_SIGNED(B_SIGNED),
.A_WIDTH(A_WIDTH),