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|
/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2019-2020 whitequark <whitequark@whitequark.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
// This file is included by the designs generated with `write_cxxrtl`. It is not used in Yosys itself.
#ifndef CXXRTL_H
#define CXXRTL_H
#include <cstddef>
#include <cstdint>
#include <cassert>
#include <limits>
#include <type_traits>
#include <tuple>
#include <vector>
#include <map>
#include <algorithm>
#include <memory>
#include <sstream>
// The cxxrtl support library implements compile time specialized arbitrary width arithmetics, as well as provides
// composite lvalues made out of bit slices and concatenations of lvalues. This allows the `write_cxxrtl` pass
// to perform a straightforward translation of RTLIL structures to readable C++, relying on the C++ compiler
// to unwrap the abstraction and generate efficient code.
namespace cxxrtl {
// All arbitrary-width values in cxxrtl are backed by arrays of unsigned integers called chunks. The chunk size
// is the same regardless of the value width to simplify manipulating values via FFI interfaces, e.g. driving
// and introspecting the simulation in Python.
//
// It is practical to use chunk sizes between 32 bits and platform register size because when arithmetics on
// narrower integer types is legalized by the C++ compiler, it inserts code to clear the high bits of the register.
// However, (a) most of our operations do not change those bits in the first place because of invariants that are
// invisible to the compiler, (b) we often operate on non-power-of-2 values and have to clear the high bits anyway.
// Therefore, using relatively wide chunks and clearing the high bits explicitly and only when we know they may be
// clobbered results in simpler generated code.
template<typename T>
struct chunk_traits {
static_assert(std::is_integral<T>::value && std::is_unsigned<T>::value,
"chunk type must be an unsigned integral type");
using type = T;
static constexpr size_t bits = std::numeric_limits<T>::digits;
static constexpr T mask = std::numeric_limits<T>::max();
};
template<class T>
struct expr_base;
template<size_t Bits>
struct value : public expr_base<value<Bits>> {
static constexpr size_t bits = Bits;
using chunk = chunk_traits<uint32_t>;
static constexpr chunk::type msb_mask = (Bits % chunk::bits == 0) ? chunk::mask
: chunk::mask >> (chunk::bits - (Bits % chunk::bits));
static constexpr size_t chunks = (Bits + chunk::bits - 1) / chunk::bits;
chunk::type data[chunks] = {};
value() = default;
template<typename... Init>
explicit constexpr value(Init ...init) : data{init...} {}
value(const value<Bits> &) = default;
value(value<Bits> &&) = default;
value<Bits> &operator=(const value<Bits> &) = default;
// A (no-op) helper that forces the cast to value<>.
const value<Bits> &val() const {
return *this;
}
std::string str() const {
std::stringstream ss;
ss << *this;
return ss.str();
}
// Operations with compile-time parameters.
//
// These operations are used to implement slicing, concatenation, and blitting.
// The trunc, zext and sext operations add or remove most significant bits (i.e. on the left);
// the rtrunc and rzext operations add or remove least significant bits (i.e. on the right).
template<size_t NewBits>
value<NewBits> trunc() const {
static_assert(NewBits <= Bits, "trunc() may not increase width");
value<NewBits> result;
for (size_t n = 0; n < result.chunks; n++)
result.data[n] = data[n];
result.data[result.chunks - 1] &= result.msb_mask;
return result;
}
template<size_t NewBits>
value<NewBits> zext() const {
static_assert(NewBits >= Bits, "zext() may not decrease width");
value<NewBits> result;
for (size_t n = 0; n < chunks; n++)
result.data[n] = data[n];
return result;
}
template<size_t NewBits>
value<NewBits> sext() const {
static_assert(NewBits >= Bits, "sext() may not decrease width");
value<NewBits> result;
for (size_t n = 0; n < chunks; n++)
result.data[n] = data[n];
if (is_neg()) {
result.data[chunks - 1] |= ~msb_mask;
for (size_t n = chunks; n < result.chunks; n++)
result.data[n] = chunk::mask;
result.data[result.chunks - 1] &= result.msb_mask;
}
return result;
}
template<size_t NewBits>
value<NewBits> rtrunc() const {
static_assert(NewBits <= Bits, "rtrunc() may not increase width");
value<NewBits> result;
constexpr size_t shift_chunks = (Bits - NewBits) / chunk::bits;
constexpr size_t shift_bits = (Bits - NewBits) % chunk::bits;
chunk::type carry = 0;
if (shift_chunks + result.chunks < chunks) {
carry = (shift_bits == 0) ? 0
: data[shift_chunks + result.chunks] << (chunk::bits - shift_bits);
}
for (size_t n = result.chunks; n > 0; n--) {
result.data[n - 1] = carry | (data[shift_chunks + n - 1] >> shift_bits);
carry = (shift_bits == 0) ? 0
: data[shift_chunks + n - 1] << (chunk::bits - shift_bits);
}
return result;
}
template<size_t NewBits>
value<NewBits> rzext() const {
static_assert(NewBits >= Bits, "rzext() may not decrease width");
value<NewBits> result;
constexpr size_t shift_chunks = (NewBits - Bits) / chunk::bits;
constexpr size_t shift_bits = (NewBits - Bits) % chunk::bits;
chunk::type carry = 0;
for (size_t n = 0; n < chunks; n++) {
result.data[shift_chunks + n] = (data[n] << shift_bits) | carry;
carry = (shift_bits == 0) ? 0
: data[n] >> (chunk::bits - shift_bits);
}
if (carry != 0)
result.data[result.chunks - 1] = carry;
return result;
}
// Bit blit operation, i.e. a partial read-modify-write.
template<size_t Stop, size_t Start>
value<Bits> blit(const value<Stop - Start + 1> &source) const {
static_assert(Stop >= Start, "blit() may not reverse bit order");
constexpr chunk::type start_mask = ~(chunk::mask << (Start % chunk::bits));
constexpr chunk::type stop_mask = (Stop % chunk::bits + 1 == chunk::bits) ? 0
: (chunk::mask << (Stop % chunk::bits + 1));
value<Bits> masked = *this;
if (Start / chunk::bits == Stop / chunk::bits) {
masked.data[Start / chunk::bits] &= stop_mask | start_mask;
} else {
masked.data[Start / chunk::bits] &= start_mask;
for (size_t n = Start / chunk::bits + 1; n < Stop / chunk::bits; n++)
masked.data[n] = 0;
masked.data[Stop / chunk::bits] &= stop_mask;
}
value<Bits> shifted = source
.template rzext<Stop + 1>()
.template zext<Bits>();
return masked.bit_or(shifted);
}
// Helpers for selecting extending or truncating operation depending on whether the result is wider or narrower
// than the operand. In C++17 these can be replaced with `if constexpr`.
template<size_t NewBits, typename = void>
struct zext_cast {
value<NewBits> operator()(const value<Bits> &val) {
return val.template zext<NewBits>();
}
};
template<size_t NewBits>
struct zext_cast<NewBits, typename std::enable_if<(NewBits < Bits)>::type> {
value<NewBits> operator()(const value<Bits> &val) {
return val.template trunc<NewBits>();
}
};
template<size_t NewBits, typename = void>
struct sext_cast {
value<NewBits> operator()(const value<Bits> &val) {
return val.template sext<NewBits>();
}
};
template<size_t NewBits>
struct sext_cast<NewBits, typename std::enable_if<(NewBits < Bits)>::type> {
value<NewBits> operator()(const value<Bits> &val) {
return val.template trunc<NewBits>();
}
};
template<size_t NewBits>
value<NewBits> zcast() const {
return zext_cast<NewBits>()(*this);
}
template<size_t NewBits>
value<NewBits> scast() const {
return sext_cast<NewBits>()(*this);
}
// Operations with run-time parameters (offsets, amounts, etc).
//
// These operations are used for computations.
bool bit(size_t offset) const {
return data[offset / chunk::bits] & (1 << (offset % chunk::bits));
}
void set_bit(size_t offset, bool value = true) {
size_t offset_chunks = offset / chunk::bits;
size_t offset_bits = offset % chunk::bits;
data[offset_chunks] &= ~(1 << offset_bits);
data[offset_chunks] |= value ? 1 << offset_bits : 0;
}
bool is_zero() const {
for (size_t n = 0; n < chunks; n++)
if (data[n] != 0)
return false;
return true;
}
explicit operator bool() const {
return !is_zero();
}
bool is_neg() const {
return data[chunks - 1] & (1 << ((Bits - 1) % chunk::bits));
}
bool operator ==(const value<Bits> &other) const {
for (size_t n = 0; n < chunks; n++)
if (data[n] != other.data[n])
return false;
return true;
}
bool operator !=(const value<Bits> &other) const {
return !(*this == other);
}
value<Bits> bit_not() const {
value<Bits> result;
for (size_t n = 0; n < chunks; n++)
result.data[n] = ~data[n];
result.data[chunks - 1] &= msb_mask;
return result;
}
value<Bits> bit_and(const value<Bits> &other) const {
value<Bits> result;
for (size_t n = 0; n < chunks; n++)
result.data[n] = data[n] & other.data[n];
return result;
}
value<Bits> bit_or(const value<Bits> &other) const {
value<Bits> result;
for (size_t n = 0; n < chunks; n++)
result.data[n] = data[n] | other.data[n];
return result;
}
value<Bits> bit_xor(const value<Bits> &other) const {
value<Bits> result;
for (size_t n = 0; n < chunks; n++)
result.data[n] = data[n] ^ other.data[n];
return result;
}
value<Bits> update(const value<Bits> &val, const value<Bits> &mask) const {
return bit_and(mask.bit_not()).bit_or(val.bit_and(mask));
}
template<size_t AmountBits>
value<Bits> shl(const value<AmountBits> &amount) const {
// Ensure our early return is correct by prohibiting values larger than 4 Gbit.
static_assert(Bits <= chunk::mask, "shl() of unreasonably large values is not supported");
// Detect shifts definitely large than Bits early.
for (size_t n = 1; n < amount.chunks; n++)
if (amount.data[n] != 0)
return {};
// Past this point we can use the least significant chunk as the shift size.
size_t shift_chunks = amount.data[0] / chunk::bits;
size_t shift_bits = amount.data[0] % chunk::bits;
if (shift_chunks >= chunks)
return {};
value<Bits> result;
chunk::type carry = 0;
for (size_t n = 0; n < chunks - shift_chunks; n++) {
result.data[shift_chunks + n] = (data[n] << shift_bits) | carry;
carry = (shift_bits == 0) ? 0
: data[n] >> (chunk::bits - shift_bits);
}
return result;
}
template<size_t AmountBits, bool Signed = false>
value<Bits> shr(const value<AmountBits> &amount) const {
// Ensure our early return is correct by prohibiting values larger than 4 Gbit.
static_assert(Bits <= chunk::mask, "shr() of unreasonably large values is not supported");
// Detect shifts definitely large than Bits early.
for (size_t n = 1; n < amount.chunks; n++)
if (amount.data[n] != 0)
return {};
// Past this point we can use the least significant chunk as the shift size.
size_t shift_chunks = amount.data[0] / chunk::bits;
size_t shift_bits = amount.data[0] % chunk::bits;
if (shift_chunks >= chunks)
return {};
value<Bits> result;
chunk::type carry = 0;
for (size_t n = 0; n < chunks - shift_chunks; n++) {
result.data[chunks - shift_chunks - 1 - n] = carry | (data[chunks - 1 - n] >> shift_bits);
carry = (shift_bits == 0) ? 0
: data[chunks - 1 - n] << (chunk::bits - shift_bits);
}
if (Signed && is_neg()) {
for (size_t n = chunks - shift_chunks; n < chunks; n++)
result.data[n] = chunk::mask;
if (shift_bits != 0)
result.data[chunks - shift_chunks] |= chunk::mask << (chunk::bits - shift_bits);
}
return result;
}
template<size_t AmountBits>
value<Bits> sshr(const value<AmountBits> &amount) const {
return shr<AmountBits, /*Signed=*/true>(amount);
}
size_t ctpop() const {
size_t count = 0;
for (size_t n = 0; n < chunks; n++) {
// This loop implements the population count idiom as recognized by LLVM and GCC.
for (chunk::type x = data[n]; x != 0; count++)
x = x & (x - 1);
}
return count;
}
size_t ctlz() const {
size_t count = 0;
for (size_t n = 0; n < chunks; n++) {
chunk::type x = data[chunks - 1 - n];
if (x == 0) {
count += (n == 0 ? Bits % chunk::bits : chunk::bits);
} else {
// This loop implements the find first set idiom as recognized by LLVM.
for (; x != 0; count++)
x >>= 1;
}
}
return count;
}
template<bool Invert, bool CarryIn>
std::pair<value<Bits>, bool /*CarryOut*/> alu(const value<Bits> &other) const {
value<Bits> result;
bool carry = CarryIn;
for (size_t n = 0; n < result.chunks; n++) {
result.data[n] = data[n] + (Invert ? ~other.data[n] : other.data[n]) + carry;
carry = (result.data[n] < data[n]) ||
(result.data[n] == data[n] && carry);
}
result.data[result.chunks - 1] &= result.msb_mask;
return {result, carry};
}
value<Bits> add(const value<Bits> &other) const {
return alu</*Invert=*/false, /*CarryIn=*/false>(other).first;
}
value<Bits> sub(const value<Bits> &other) const {
return alu</*Invert=*/true, /*CarryIn=*/true>(other).first;
}
value<Bits> neg() const {
return value<Bits> { 0u }.sub(*this);
}
bool ucmp(const value<Bits> &other) const {
bool carry;
std::tie(std::ignore, carry) = alu</*Invert=*/true, /*CarryIn=*/true>(other);
return !carry; // a.ucmp(b) ≡ a u< b
}
bool scmp(const value<Bits> &other) const {
value<Bits> result;
bool carry;
std::tie(result, carry) = alu</*Invert=*/true, /*CarryIn=*/true>(other);
bool overflow = (is_neg() == !other.is_neg()) && (is_neg() != result.is_neg());
return result.is_neg() ^ overflow; // a.scmp(b) ≡ a s< b
}
};
// Expression template for a slice, usable as lvalue or rvalue, and composable with other expression templates here.
template<class T, size_t Stop, size_t Start>
struct slice_expr : public expr_base<slice_expr<T, Stop, Start>> {
static_assert(Stop >= Start, "slice_expr() may not reverse bit order");
static_assert(Start < T::bits && Stop < T::bits, "slice_expr() must be within bounds");
static constexpr size_t bits = Stop - Start + 1;
T &expr;
slice_expr(T &expr) : expr(expr) {}
slice_expr(const slice_expr<T, Stop, Start> &) = delete;
operator value<bits>() const {
return static_cast<const value<T::bits> &>(expr)
.template rtrunc<T::bits - Start>()
.template trunc<bits>();
}
slice_expr<T, Stop, Start> &operator=(const value<bits> &rhs) {
// Generic partial assignment implemented using a read-modify-write operation on the sliced expression.
expr = static_cast<const value<T::bits> &>(expr)
.template blit<Stop, Start>(rhs);
return *this;
}
// A helper that forces the cast to value<>, which allows deduction to work.
value<bits> val() const {
return static_cast<const value<bits> &>(*this);
}
};
// Expression template for a concatenation, usable as lvalue or rvalue, and composable with other expression templates here.
template<class T, class U>
struct concat_expr : public expr_base<concat_expr<T, U>> {
static constexpr size_t bits = T::bits + U::bits;
T &ms_expr;
U &ls_expr;
concat_expr(T &ms_expr, U &ls_expr) : ms_expr(ms_expr), ls_expr(ls_expr) {}
concat_expr(const concat_expr<T, U> &) = delete;
operator value<bits>() const {
value<bits> ms_shifted = static_cast<const value<T::bits> &>(ms_expr)
.template rzext<bits>();
value<bits> ls_extended = static_cast<const value<U::bits> &>(ls_expr)
.template zext<bits>();
return ms_shifted.bit_or(ls_extended);
}
concat_expr<T, U> &operator=(const value<bits> &rhs) {
ms_expr = rhs.template rtrunc<T::bits>();
ls_expr = rhs.template trunc<U::bits>();
return *this;
}
// A helper that forces the cast to value<>, which allows deduction to work.
value<bits> val() const {
return static_cast<const value<bits> &>(*this);
}
};
// Base class for expression templates, providing helper methods for operations that are valid on both rvalues and lvalues.
//
// Note that expression objects (slices and concatenations) constructed in this way should NEVER be captured because
// they refer to temporaries that will, in general, only live until the end of the statement. For example, both of
// these snippets perform use-after-free:
//
// const auto &a = val.slice<7,0>().slice<1>();
// value<1> b = a;
//
// auto &&c = val.slice<7,0>().slice<1>();
// c = value<1>{1u};
//
// An easy way to write code using slices and concatenations safely is to follow two simple rules:
// * Never explicitly name any type except `value<W>` or `const value<W> &`.
// * Never use a `const auto &` or `auto &&` in any such expression.
// Then, any code that compiles will be well-defined.
template<class T>
struct expr_base {
template<size_t Stop, size_t Start = Stop>
slice_expr<const T, Stop, Start> slice() const {
return {*static_cast<const T *>(this)};
}
template<size_t Stop, size_t Start = Stop>
slice_expr<T, Stop, Start> slice() {
return {*static_cast<T *>(this)};
}
template<class U>
concat_expr<const T, typename std::remove_reference<const U>::type> concat(const U &other) const {
return {*static_cast<const T *>(this), other};
}
template<class U>
concat_expr<T, typename std::remove_reference<U>::type> concat(U &&other) {
return {*static_cast<T *>(this), other};
}
};
template<size_t Bits>
std::ostream &operator<<(std::ostream &os, const value<Bits> &val) {
auto old_flags = os.flags(std::ios::right);
auto old_width = os.width(0);
auto old_fill = os.fill('0');
os << val.bits << '\'' << std::hex;
for (size_t n = val.chunks - 1; n != (size_t)-1; n--) {
if (n == val.chunks - 1 && Bits % value<Bits>::chunk::bits != 0)
os.width((Bits % value<Bits>::chunk::bits + 3) / 4);
else
os.width((value<Bits>::chunk::bits + 3) / 4);
os << val.data[n];
}
os.fill(old_fill);
os.width(old_width);
os.flags(old_flags);
return os;
}
template<size_t Bits>
struct wire {
static constexpr size_t bits = Bits;
value<Bits> curr;
value<Bits> next;
wire() = default;
constexpr wire(const value<Bits> &init) : curr(init), next(init) {}
template<typename... Init>
explicit constexpr wire(Init ...init) : curr{init...}, next{init...} {}
wire(const wire<Bits> &) = delete;
wire(wire<Bits> &&) = default;
wire<Bits> &operator=(const wire<Bits> &) = delete;
bool commit() {
if (curr != next) {
curr = next;
return true;
}
return false;
}
};
template<size_t Bits>
std::ostream &operator<<(std::ostream &os, const wire<Bits> &val) {
os << val.curr;
return os;
}
template<size_t Width>
struct memory {
std::vector<value<Width>> data;
size_t depth() const {
return data.size();
}
memory() = delete;
explicit memory(size_t depth) : data(depth) {}
memory(const memory<Width> &) = delete;
memory<Width> &operator=(const memory<Width> &) = delete;
// The only way to get the compiler to put the initializer in .rodata and do not copy it on stack is to stuff it
// into a plain array. You'd think an std::initializer_list would work here, but it doesn't, because you can't
// construct an initializer_list in a constexpr (or something) and so if you try to do that the whole thing is
// first copied on the stack (probably overflowing it) and then again into `data`.
template<size_t Size>
struct init {
size_t offset;
value<Width> data[Size];
};
template<size_t... InitSize>
explicit memory(size_t depth, const init<InitSize> &...init) : data(depth) {
data.resize(depth);
// This utterly reprehensible construct is the most reasonable way to apply a function to every element
// of a parameter pack, if the elements all have different types and so cannot be cast to an initializer list.
auto _ = {std::move(std::begin(init.data), std::end(init.data), data.begin() + init.offset)...};
}
// An operator for direct memory reads. May be used at any time during the simulation.
const value<Width> &operator [](size_t index) const {
assert(index < data.size());
return data[index];
}
// An operator for direct memory writes. May only be used before the simulation is started. If used
// after the simulation is started, the design may malfunction.
value<Width> &operator [](size_t index) {
assert(index < data.size());
return data[index];
}
// A simple way to make a writable memory would be to use an array of wires instead of an array of values.
// However, there are two significant downsides to this approach: first, it has large overhead (2× space
// overhead, and O(depth) time overhead during commit); second, it does not simplify handling write port
// priorities. Although in principle write ports could be ordered or conditionally enabled in generated
// code based on their priorities and selected addresses, the feedback arc set problem is computationally
// expensive, and the heuristic based algorithms are not easily modified to guarantee (rather than prefer)
// a particular write port evaluation order.
//
// The approach used here instead is to queue writes into a buffer during the eval phase, then perform
// the writes during the commit phase in the priority order. This approach has low overhead, with both space
// and time proportional to the amount of write ports. Because virtually every memory in a practical design
// has at most two write ports, linear search is used on every write, being the fastest and simplest approach.
struct write {
size_t index;
value<Width> val;
value<Width> mask;
int priority;
};
std::vector<write> write_queue;
void update(size_t index, const value<Width> &val, const value<Width> &mask, int priority = 0) {
assert(index < data.size());
write_queue.emplace_back(write { index, val, mask, priority });
}
bool commit() {
bool changed = false;
std::sort(write_queue.begin(), write_queue.end(),
[](const write &a, const write &b) { return a.priority < b.priority; });
for (const write &entry : write_queue) {
value<Width> elem = data[entry.index];
elem = elem.update(entry.val, entry.mask);
changed |= (data[entry.index] != elem);
data[entry.index] = elem;
}
write_queue.clear();
return changed;
}
};
struct metadata {
const enum {
MISSING = 0,
UINT = 1,
SINT = 2,
STRING = 3,
DOUBLE = 4,
} value_type;
// In debug mode, using the wrong .as_*() function will assert.
// In release mode, using the wrong .as_*() function will safely return a default value.
union {
const unsigned uint_value = 0;
const signed sint_value;
};
const std::string string_value = "";
const double double_value = 0.0;
metadata() : value_type(MISSING) {}
metadata(unsigned value) : value_type(UINT), uint_value(value) {}
metadata(signed value) : value_type(SINT), sint_value(value) {}
metadata(const std::string &value) : value_type(STRING), string_value(value) {}
metadata(const char *value) : value_type(STRING), string_value(value) {}
metadata(double value) : value_type(DOUBLE), double_value(value) {}
metadata(const metadata &) = default;
metadata &operator=(const metadata &) = delete;
unsigned as_uint() const {
assert(value_type == UINT);
return uint_value;
}
signed as_sint() const {
assert(value_type == SINT);
return sint_value;
}
const std::string &as_string() const {
assert(value_type == STRING);
return string_value;
}
double as_double() const {
assert(value_type == DOUBLE);
return double_value;
}
};
typedef std::map<std::string, metadata> metadata_map;
struct module {
module() {}
virtual ~module() {}
module(const module &) = delete;
module &operator=(const module &) = delete;
virtual void eval() = 0;
virtual bool commit() = 0;
size_t step() {
size_t deltas = 0;
do {
eval();
deltas++;
} while (commit());
return deltas;
}
};
} // namespace cxxrtl
// Definitions of internal Yosys cells. Other than the functions in this namespace, cxxrtl is fully generic
// and indepenent of Yosys implementation details.
//
// The `write_cxxrtl` pass translates internal cells (cells with names that start with `$`) to calls of these
// functions. All of Yosys arithmetic and logical cells perform sign or zero extension on their operands,
// whereas basic operations on arbitrary width values require operands to be of the same width. These functions
// bridge the gap by performing the necessary casts. They are named similar to `cell_A[B]`, where A and B are `u`
// if the corresponding operand is unsigned, and `s` if it is signed.
namespace cxxrtl_yosys {
using namespace cxxrtl;
// std::max isn't constexpr until C++14 for no particular reason (it's an oversight), so we define our own.
template<class T>
constexpr T max(const T &a, const T &b) {
return a > b ? a : b;
}
// Logic operations
template<size_t BitsY, size_t BitsA>
value<BitsY> not_u(const value<BitsA> &a) {
return a.template zcast<BitsY>().bit_not();
}
template<size_t BitsY, size_t BitsA>
value<BitsY> not_s(const value<BitsA> &a) {
return a.template scast<BitsY>().bit_not();
}
template<size_t BitsY, size_t BitsA>
value<BitsY> logic_not_u(const value<BitsA> &a) {
return value<BitsY> { a ? 0u : 1u };
}
template<size_t BitsY, size_t BitsA>
value<BitsY> logic_not_s(const value<BitsA> &a) {
return value<BitsY> { a ? 0u : 1u };
}
template<size_t BitsY, size_t BitsA>
value<BitsY> reduce_and_u(const value<BitsA> &a) {
return value<BitsY> { a.bit_not().is_zero() ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA>
value<BitsY> reduce_and_s(const value<BitsA> &a) {
return value<BitsY> { a.bit_not().is_zero() ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA>
value<BitsY> reduce_or_u(const value<BitsA> &a) {
return value<BitsY> { a ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA>
value<BitsY> reduce_or_s(const value<BitsA> &a) {
return value<BitsY> { a ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA>
value<BitsY> reduce_xor_u(const value<BitsA> &a) {
return value<BitsY> { (a.ctpop() % 2) ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA>
value<BitsY> reduce_xor_s(const value<BitsA> &a) {
return value<BitsY> { (a.ctpop() % 2) ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA>
value<BitsY> reduce_xnor_u(const value<BitsA> &a) {
return value<BitsY> { (a.ctpop() % 2) ? 0u : 1u };
}
template<size_t BitsY, size_t BitsA>
value<BitsY> reduce_xnor_s(const value<BitsA> &a) {
return value<BitsY> { (a.ctpop() % 2) ? 0u : 1u };
}
template<size_t BitsY, size_t BitsA>
value<BitsY> reduce_bool_u(const value<BitsA> &a) {
return value<BitsY> { a ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA>
value<BitsY> reduce_bool_s(const value<BitsA> &a) {
return value<BitsY> { a ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> and_uu(const value<BitsA> &a, const value<BitsB> &b) {
return a.template zcast<BitsY>().bit_and(b.template zcast<BitsY>());
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> and_ss(const value<BitsA> &a, const value<BitsB> &b) {
return a.template scast<BitsY>().bit_and(b.template scast<BitsY>());
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> or_uu(const value<BitsA> &a, const value<BitsB> &b) {
return a.template zcast<BitsY>().bit_or(b.template zcast<BitsY>());
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> or_ss(const value<BitsA> &a, const value<BitsB> &b) {
return a.template scast<BitsY>().bit_or(b.template scast<BitsY>());
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> xor_uu(const value<BitsA> &a, const value<BitsB> &b) {
return a.template zcast<BitsY>().bit_xor(b.template zcast<BitsY>());
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> xor_ss(const value<BitsA> &a, const value<BitsB> &b) {
return a.template scast<BitsY>().bit_xor(b.template scast<BitsY>());
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> xnor_uu(const value<BitsA> &a, const value<BitsB> &b) {
return a.template zcast<BitsY>().bit_xor(b.template zcast<BitsY>()).bit_not();
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> xnor_ss(const value<BitsA> &a, const value<BitsB> &b) {
return a.template scast<BitsY>().bit_xor(b.template scast<BitsY>()).bit_not();
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> logic_and_uu(const value<BitsA> &a, const value<BitsB> &b) {
return value<BitsY> { (bool(a) & bool(b)) ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> logic_and_ss(const value<BitsA> &a, const value<BitsB> &b) {
return value<BitsY> { (bool(a) & bool(b)) ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> logic_or_uu(const value<BitsA> &a, const value<BitsB> &b) {
return value<BitsY> { (bool(a) | bool(b)) ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> logic_or_ss(const value<BitsA> &a, const value<BitsB> &b) {
return value<BitsY> { (bool(a) | bool(b)) ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> shl_uu(const value<BitsA> &a, const value<BitsB> &b) {
return a.template zcast<BitsY>().template shl(b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> shl_su(const value<BitsA> &a, const value<BitsB> &b) {
return a.template scast<BitsY>().template shl(b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> sshl_uu(const value<BitsA> &a, const value<BitsB> &b) {
return a.template zcast<BitsY>().template shl(b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> sshl_su(const value<BitsA> &a, const value<BitsB> &b) {
return a.template scast<BitsY>().template shl(b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> shr_uu(const value<BitsA> &a, const value<BitsB> &b) {
return a.template shr(b).template zcast<BitsY>();
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> shr_su(const value<BitsA> &a, const value<BitsB> &b) {
return a.template shr(b).template scast<BitsY>();
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> sshr_uu(const value<BitsA> &a, const value<BitsB> &b) {
return a.template shr(b).template zcast<BitsY>();
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> sshr_su(const value<BitsA> &a, const value<BitsB> &b) {
return a.template shr(b).template scast<BitsY>();
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> shift_uu(const value<BitsA> &a, const value<BitsB> &b) {
return shr_uu<BitsY>(a, b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> shift_su(const value<BitsA> &a, const value<BitsB> &b) {
return shr_su<BitsY>(a, b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> shift_us(const value<BitsA> &a, const value<BitsB> &b) {
return b.is_neg() ? shl_uu<BitsY>(a, b.template sext<BitsB + 1>().neg()) : shr_uu<BitsY>(a, b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> shift_ss(const value<BitsA> &a, const value<BitsB> &b) {
return b.is_neg() ? shl_su<BitsY>(a, b.template sext<BitsB + 1>().neg()) : shr_su<BitsY>(a, b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> shiftx_uu(const value<BitsA> &a, const value<BitsB> &b) {
return shift_uu<BitsY>(a, b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> shiftx_su(const value<BitsA> &a, const value<BitsB> &b) {
return shift_su<BitsY>(a, b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> shiftx_us(const value<BitsA> &a, const value<BitsB> &b) {
return shift_us<BitsY>(a, b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> shiftx_ss(const value<BitsA> &a, const value<BitsB> &b) {
return shift_ss<BitsY>(a, b);
}
// Comparison operations
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> eq_uu(const value<BitsA> &a, const value<BitsB> &b) {
constexpr size_t BitsExt = max(BitsA, BitsB);
return value<BitsY>{ a.template zext<BitsExt>() == b.template zext<BitsExt>() ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> eq_ss(const value<BitsA> &a, const value<BitsB> &b) {
constexpr size_t BitsExt = max(BitsA, BitsB);
return value<BitsY>{ a.template sext<BitsExt>() == b.template sext<BitsExt>() ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> ne_uu(const value<BitsA> &a, const value<BitsB> &b) {
constexpr size_t BitsExt = max(BitsA, BitsB);
return value<BitsY>{ a.template zext<BitsExt>() != b.template zext<BitsExt>() ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> ne_ss(const value<BitsA> &a, const value<BitsB> &b) {
constexpr size_t BitsExt = max(BitsA, BitsB);
return value<BitsY>{ a.template sext<BitsExt>() != b.template sext<BitsExt>() ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> eqx_uu(const value<BitsA> &a, const value<BitsB> &b) {
return eq_uu<BitsY>(a, b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> eqx_ss(const value<BitsA> &a, const value<BitsB> &b) {
return eq_ss<BitsY>(a, b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> nex_uu(const value<BitsA> &a, const value<BitsB> &b) {
return ne_uu<BitsY>(a, b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> nex_ss(const value<BitsA> &a, const value<BitsB> &b) {
return ne_ss<BitsY>(a, b);
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> gt_uu(const value<BitsA> &a, const value<BitsB> &b) {
constexpr size_t BitsExt = max(BitsA, BitsB);
return value<BitsY> { b.template zext<BitsExt>().ucmp(a.template zext<BitsExt>()) ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> gt_ss(const value<BitsA> &a, const value<BitsB> &b) {
constexpr size_t BitsExt = max(BitsA, BitsB);
return value<BitsY> { b.template sext<BitsExt>().scmp(a.template sext<BitsExt>()) ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> ge_uu(const value<BitsA> &a, const value<BitsB> &b) {
constexpr size_t BitsExt = max(BitsA, BitsB);
return value<BitsY> { !a.template zext<BitsExt>().ucmp(b.template zext<BitsExt>()) ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> ge_ss(const value<BitsA> &a, const value<BitsB> &b) {
constexpr size_t BitsExt = max(BitsA, BitsB);
return value<BitsY> { !a.template sext<BitsExt>().scmp(b.template sext<BitsExt>()) ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> lt_uu(const value<BitsA> &a, const value<BitsB> &b) {
constexpr size_t BitsExt = max(BitsA, BitsB);
return value<BitsY> { a.template zext<BitsExt>().ucmp(b.template zext<BitsExt>()) ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> lt_ss(const value<BitsA> &a, const value<BitsB> &b) {
constexpr size_t BitsExt = max(BitsA, BitsB);
return value<BitsY> { a.template sext<BitsExt>().scmp(b.template sext<BitsExt>()) ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> le_uu(const value<BitsA> &a, const value<BitsB> &b) {
constexpr size_t BitsExt = max(BitsA, BitsB);
return value<BitsY> { !b.template zext<BitsExt>().ucmp(a.template zext<BitsExt>()) ? 1u : 0u };
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> le_ss(const value<BitsA> &a, const value<BitsB> &b) {
constexpr size_t BitsExt = max(BitsA, BitsB);
return value<BitsY> { !b.template sext<BitsExt>().scmp(a.template sext<BitsExt>()) ? 1u : 0u };
}
// Arithmetic operations
template<size_t BitsY, size_t BitsA>
value<BitsY> pos_u(const value<BitsA> &a) {
return a.template zcast<BitsY>();
}
template<size_t BitsY, size_t BitsA>
value<BitsY> pos_s(const value<BitsA> &a) {
return a.template scast<BitsY>();
}
template<size_t BitsY, size_t BitsA>
value<BitsY> neg_u(const value<BitsA> &a) {
return a.template zcast<BitsY>().neg();
}
template<size_t BitsY, size_t BitsA>
value<BitsY> neg_s(const value<BitsA> &a) {
return a.template scast<BitsY>().neg();
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> add_uu(const value<BitsA> &a, const value<BitsB> &b) {
return a.template zcast<BitsY>().add(b.template zcast<BitsY>());
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> add_ss(const value<BitsA> &a, const value<BitsB> &b) {
return a.template scast<BitsY>().add(b.template scast<BitsY>());
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> sub_uu(const value<BitsA> &a, const value<BitsB> &b) {
return a.template zcast<BitsY>().sub(b.template zcast<BitsY>());
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> sub_ss(const value<BitsA> &a, const value<BitsB> &b) {
return a.template scast<BitsY>().sub(b.template scast<BitsY>());
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> mul_uu(const value<BitsA> &a, const value<BitsB> &b) {
value<BitsY> product;
value<BitsY> multiplicand = a.template zcast<BitsY>();
const value<BitsB> &multiplier = b;
uint32_t multiplicand_shift = 0;
for (size_t step = 0; step < BitsB; step++) {
if (multiplier.bit(step)) {
multiplicand = multiplicand.shl(value<32> { multiplicand_shift });
product = product.add(multiplicand);
multiplicand_shift = 0;
}
multiplicand_shift++;
}
return product;
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> mul_ss(const value<BitsA> &a, const value<BitsB> &b) {
value<BitsB + 1> ub = b.template sext<BitsB + 1>();
if (ub.is_neg()) ub = ub.neg();
value<BitsY> y = mul_uu<BitsY>(a.template scast<BitsY>(), ub);
return b.is_neg() ? y.neg() : y;
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
std::pair<value<BitsY>, value<BitsY>> divmod_uu(const value<BitsA> &a, const value<BitsB> &b) {
constexpr size_t Bits = max(BitsY, max(BitsA, BitsB));
value<Bits> quotient;
value<Bits> dividend = a.template zext<Bits>();
value<Bits> divisor = b.template zext<Bits>();
if (dividend.ucmp(divisor))
return {/*quotient=*/value<BitsY> { 0u }, /*remainder=*/dividend.template trunc<BitsY>()};
uint32_t divisor_shift = dividend.ctlz() - divisor.ctlz();
divisor = divisor.shl(value<32> { divisor_shift });
for (size_t step = 0; step <= divisor_shift; step++) {
quotient = quotient.shl(value<1> { 1u });
if (!dividend.ucmp(divisor)) {
dividend = dividend.sub(divisor);
quotient.set_bit(0, true);
}
divisor = divisor.shr(value<1> { 1u });
}
return {quotient.template trunc<BitsY>(), /*remainder=*/dividend.template trunc<BitsY>()};
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
std::pair<value<BitsY>, value<BitsY>> divmod_ss(const value<BitsA> &a, const value<BitsB> &b) {
value<BitsA + 1> ua = a.template sext<BitsA + 1>();
value<BitsB + 1> ub = b.template sext<BitsB + 1>();
if (ua.is_neg()) ua = ua.neg();
if (ub.is_neg()) ub = ub.neg();
value<BitsY> y, r;
std::tie(y, r) = divmod_uu<BitsY>(ua, ub);
if (a.is_neg() != b.is_neg()) y = y.neg();
if (a.is_neg()) r = r.neg();
return {y, r};
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> div_uu(const value<BitsA> &a, const value<BitsB> &b) {
return divmod_uu<BitsY>(a, b).first;
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> div_ss(const value<BitsA> &a, const value<BitsB> &b) {
return divmod_ss<BitsY>(a, b).first;
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> mod_uu(const value<BitsA> &a, const value<BitsB> &b) {
return divmod_uu<BitsY>(a, b).second;
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
value<BitsY> mod_ss(const value<BitsA> &a, const value<BitsB> &b) {
return divmod_ss<BitsY>(a, b).second;
}
// Memory helper
struct memory_index {
bool valid;
size_t index;
template<size_t BitsAddr>
memory_index(const value<BitsAddr> &addr, size_t offset, size_t depth) {
static_assert(value<BitsAddr>::chunks <= 1, "memory address is too wide");
size_t offset_index = addr.data[0];
valid = (offset_index >= offset && offset_index < offset + depth);
index = offset_index - offset;
}
};
} // namespace cxxrtl_yosys
#endif
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