RASCSI/cpp/bus.cpp
Uwe Seimet c41373d9bd
Use lambdas for dispatcher, code cleanup, test updates (#958)
* Using lambdas instead of member function pointers simplifies the command dispatching and reduces the code volume

* Removed duplicate error handling

* Fix for issue #956

* Unit test updates

* Resolved SonarQube issues
2022-11-02 15:36:19 +01:00

105 lines
3.2 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

//---------------------------------------------------------------------------
//
// X68000 EMULATOR "XM6"
//
// Copyright (C) 2001-2006 (ytanaka@ipc-tokai.or.jp)
// Copyright (C) 2014-2020 GIMONS
// Copyright (C) 2022 Uwe Seimet
//
//---------------------------------------------------------------------------
#include "bus.h"
using namespace std;
//---------------------------------------------------------------------------
//
// Get the number of bytes for a command
// TODO Add the byte count to the enum value/command name mapping and remove the comparisons
//
//---------------------------------------------------------------------------
int BUS::GetCommandByteCount(uint8_t opcode)
{
if (opcode == 0x88 || opcode == 0x8A || opcode == 0x8F || opcode == 0x91 || opcode == 0x9E || opcode == 0x9F) {
return 16;
} else if (opcode == 0xA0) {
return 12;
} else if (opcode >= 0x20 && opcode <= 0x7D) {
return 10;
} else {
return 6;
}
}
//---------------------------------------------------------------------------
//
// Phase Acquisition
//
//---------------------------------------------------------------------------
BUS::phase_t BUS::GetPhase()
{
// Selection Phase
if (GetSEL()) {
return phase_t::selection;
}
// Bus busy phase
if (!GetBSY()) {
return phase_t::busfree;
}
// Get target phase from bus signal line
int mci = GetMSG() ? 0b100 : 0b000;
mci |= GetCD() ? 0b010 : 0b000;
mci |= GetIO() ? 0b001 : 0b000;
return GetPhase(mci);
}
//---------------------------------------------------------------------------
//
// Determine Phase String phase enum
//
//---------------------------------------------------------------------------
const char* BUS::GetPhaseStrRaw(phase_t current_phase) {
const auto& it = phase_str_mapping.find(current_phase);
return it != phase_str_mapping.end() ? it->second : "INVALID";
}
//---------------------------------------------------------------------------
//
// Phase Table
// Reference Table 8: https://www.staff.uni-mainz.de/tacke/scsi/SCSI2-06.html
// This determines the phase based upon the Msg, C/D and I/O signals.
//
//---------------------------------------------------------------------------
const array<BUS::phase_t, 8> BUS::phase_table = {
// | MSG|C/D|I/O |
phase_t::dataout, // | 0 | 0 | 0 |
phase_t::datain, // | 0 | 0 | 1 |
phase_t::command, // | 0 | 1 | 0 |
phase_t::status, // | 0 | 1 | 1 |
phase_t::reserved, // | 1 | 0 | 0 |
phase_t::reserved, // | 1 | 0 | 1 |
phase_t::msgout, // | 1 | 1 | 0 |
phase_t::msgin // | 1 | 1 | 1 |
};
//---------------------------------------------------------------------------
//
// Phase string to phase mapping
//
//---------------------------------------------------------------------------
const unordered_map<BUS::phase_t, const char*> BUS::phase_str_mapping = {
{ phase_t::busfree, "busfree" },
{ phase_t::arbitration, "arbitration" },
{ phase_t::selection, "selection" },
{ phase_t::reselection, "reselection" },
{ phase_t::command, "command" },
{ phase_t::datain, "datain" },
{ phase_t::dataout, "dataout" },
{ phase_t::status, "status" },
{ phase_t::msgin, "msgin" },
{ phase_t::msgout, "msgout" },
{ phase_t::reserved, "reserved" }
};