mirror of
https://github.com/akuker/RASCSI.git
synced 2024-11-22 01:31:25 +00:00
99 lines
3.0 KiB
C++
99 lines
3.0 KiB
C++
//---------------------------------------------------------------------------
|
||
//
|
||
// X68000 EMULATOR "XM6"
|
||
//
|
||
// Copyright (C) 2001-2006 ＰＩ．(ytanaka@ipc-tokai.or.jp)
|
||
// Copyright (C) 2014-2020 GIMONS
|
||
// Copyright (C) 2022 Uwe Seimet
|
||
//
|
||
//---------------------------------------------------------------------------
|
||
|
||
#include "bus.h"
|
||
|
||
using namespace std;
|
||
using namespace scsi_defs;
|
||
|
||
//---------------------------------------------------------------------------
|
||
//
|
||
// Get the number of bytes for a command
|
||
//
|
||
//---------------------------------------------------------------------------
|
||
int BUS::GetCommandByteCount(uint8_t opcode)
|
||
{
|
||
const auto& mapping = command_mapping.find(static_cast<scsi_command>(opcode));
|
||
|
||
return mapping != command_mapping.end() ? mapping->second.first : 0;
|
||
}
|
||
|
||
//---------------------------------------------------------------------------
|
||
//
|
||
// 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" }
|
||
};
|