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// Copyright 2020 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef HWREG_ASM_H_
#define HWREG_ASM_H_
#include <string>
#include <string_view>
#include <type_traits>
#include <hwreg/bitfields.h>
namespace hwreg {
// A `RegisterBase` "PrinterState" parameter that permits the generation of
// assembly constants from the fields of derived, register classes (see below).
// We define an alias for clarity in contexts in which enabling "print"ing
// would not seem relevant to these ends.
// TODO( Use at your own risk.
using EnableAsmGeneration = EnablePrinter;
// This can be used in fluid style to define macros directly for constants,
// or to define macros derived from an hwreg::RegisterBase subclass, e.g.:
// ```
// int main(int argc, char**) {
// return hwreg::AsmHeader()
// .Register<FooReg>("FOO_")
// .Macro("FOO_BAR_VAL", FooReg::kBarVal)
// .Main(argc, argv);
// }
// ```
// See //zircon/system/ulib/hwreg/hwreg_asm_header.gni to easily plug such a
// header generator program into the build.
class AsmHeader {
// Emit a fixed macro definition.
AsmHeader& Macro(std::string_view name, std::string_view value);
// Same but for integer values.
AsmHeader& Macro(std::string_view name, uint64_t value);
// Emit a macro for each field in the register, plus a macro for the mask
// of reserved-zero bits and a macro for the mask of unknown bits.
// T is required to inherit from a `RegisterBase` with `EnableAsmGeneration`.
template <typename T>
AsmHeader& Register(std::string_view prefix) {
[this, prefix](const char* name, auto value, auto bit_high_incl, auto bit_low) {
if (name) {
FieldMacro(prefix, name, bit_high_incl, bit_low);
RegisterMacros(prefix, T{}.rsvdz_mask(), ~T{}.fields_mask());
return *this;
// Format the contents of a header file with the accumulated definitions.
// The header should be the #include "name" for the header, which is
// translated into its guard symbol.
std::string Output(std::string_view include_name);
// Write out the accumulated definitions to the file, not touching it if
// it hasn't changed. Returns 0 on success or an errno code for failure
// to write the file.
int Output(const char* filename, std::string_view include_name);
// Parse two command line arguments for filename and include_name and
// write the file. Returns exit status and prints errors to stderr.
int Main(int argc, char** argv);
std::string body_;
void FieldMacro(std::string_view prefix, const char* name, uint32_t bit_high_incl,
uint32_t bit_low);
void RegisterMacros(std::string_view prefix, uint64_t rsvdz, uint64_t unkn);
} // namespace hwreg
#endif // HWREG_ASM_H_