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// license:BSD-3-Clause
// copyright-holders:Aaron Giles,Vas Crabb
/***************************************************************************
delegate.cpp
Templates and classes to enable delegates for callbacks.
***************************************************************************/
#include "delegate.h"
#include <cstdio>
//**************************************************************************
// MACROS
//**************************************************************************
#if defined(LOG_DELEGATES)
#define LOG(...) printf(__VA_ARGS__)
#else
#define LOG(...) do { if (false) printf(__VA_ARGS__); } while (false)
#endif
// some architectures use function descriptor pointers
// usually this is a global pointer value along with the branch target
// other platforms using this convention include:
// * AIX, Classic MacOS and WinNT on 32-bit POWER/PowerPC
// * pretty much anything on Itanium
#if (defined(__ppc64__) || (defined(__PPC64__))) && !defined(__APPLE__)
#define MAME_DELEGATE_VT_DESCRIPTOR 1
#endif
#ifndef MAME_DELEGATE_VT_DESCRIPTOR
#define MAME_DELEGATE_VT_DESCRIPTOR 0
#endif
namespace util::detail {
//**************************************************************************
// GLOBAL VARIABLES
//**************************************************************************
const delegate_mfp_compatible::raw_mfp_data delegate_mfp_compatible::s_null_mfp = { { 0 } };
//**************************************************************************
// INTERNAL DELEGATE HELPERS
//**************************************************************************
//-------------------------------------------------
// delegate_convert_raw - given an object and an raw function, adjust the object base
// and return the actual final code pointer
//-------------------------------------------------//
delegate_generic_function delegate_mfp_itanium::convert_to_generic(delegate_generic_class *&object) const
{
#if MAME_DELEGATE_ITANIUM_ARM
// apply the "this" delta to the object first - remember to shift right one bit position
object = reinterpret_cast<delegate_generic_class *>(reinterpret_cast<std::uint8_t *>(object) + (m_this_delta >> 1));
if (!(m_this_delta & 1))
{
// if the low bit of the 'this' delta is clear, the pointer is a conventional function pointer
LOG("Calculated Addr = %p\n", reinterpret_cast<void const *>(m_function));
return reinterpret_cast<delegate_generic_function>(m_function);
}
else
{
// otherwise, it is the byte index into the vtable where the actual function lives
std::uint8_t const *const vtable_ptr = *reinterpret_cast<std::uint8_t const *const *>(object) + m_function;
#if MAME_DELEGATE_VT_DESCRIPTOR
delegate_generic_function const result = reinterpret_cast<delegate_generic_function>(uintptr_t(vtable_ptr));
#else // MAME_DELEGATE_VT_DESCRIPTOR
delegate_generic_function const result = *reinterpret_cast<delegate_generic_function const *>(vtable_ptr);
#endif // MAME_DELEGATE_VT_DESCRIPTOR
LOG("Calculated Addr = %p (VTAB)\n", reinterpret_cast<void const *>(uintptr_t(result)));
return result;
}
#else // MAME_DELEGATE_ITANIUM_ARM
// apply the "this" delta to the object first
object = reinterpret_cast<delegate_generic_class *>(reinterpret_cast<std::uint8_t *>(object) + m_this_delta);
if (!(m_function & 1))
{
// if the low bit of the pointer is clear, then it is a conventional function pointer
LOG("Calculated Addr = %p\n", reinterpret_cast<void const *>(m_function));
return reinterpret_cast<delegate_generic_function>(m_function);
}
else
{
// otherwise, it is the byte index into the vtable where the actual function lives
std::uint8_t const *const vtable_ptr = *reinterpret_cast<std::uint8_t const *const *>(object) + m_function - 1;
#if MAME_DELEGATE_VT_DESCRIPTOR
delegate_generic_function const result = reinterpret_cast<delegate_generic_function>(uintptr_t(vtable_ptr));
#else // MAME_DELEGATE_VT_DESCRIPTOR
delegate_generic_function const result = *reinterpret_cast<delegate_generic_function const *>(vtable_ptr);
#endif // MAME_DELEGATE_VT_DESCRIPTOR
LOG("Calculated Addr = %p (VTAB)\n", reinterpret_cast<void const *>(uintptr_t(result)));
return result;
}
#endif // MAME_DELEGATE_ITANIUM_ARM
}
} // namespace util::detail
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