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// Copyright (C) 2003 Dolphin Project.
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, version 2.0.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License 2.0 for more details.
// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/
// Official SVN repository and contact information can be found at
// http://code.google.com/p/dolphin-emu/
#include "DSPAnalyzer.h"
#include "DSPInterpreter.h"
#include "DSPTables.h"
#include "DSPMemoryMap.h"
namespace DSPAnalyzer {
// Holds data about all instructions in RAM.
u8 code_flags[ISPACE];
// Good candidates for idle skipping is mail wait loops. If we're time slicing
// between the main CPU and the DSP, if the DSP runs into one of these, it might
// as well give up its time slice immediately, after executing once.
// Max signature length is 6. A 0 in a signature is ignored.
#define NUM_IDLE_SIGS 5
#define MAX_IDLE_SIG_SIZE 6
// 0xFFFF means ignore.
const u16 idle_skip_sigs[NUM_IDLE_SIGS][MAX_IDLE_SIG_SIZE + 1] =
{
// From AX:
{ 0x26fc, // LRS $30, @DMBH
0x02c0, 0x8000, // ANDCF $30, #0x8000
0x029d, 0xFFFF, // JLZ 0x027a
0, 0 }, // RET
{ 0x27fc, // LRS $31, @DMBH
0x03c0, 0x8000, // ANDCF $31, #0x8000
0x029d, 0xFFFF, // JLZ 0x027a
0, 0 }, // RET
{ 0x26fe, // LRS $30, @CMBH
0x02c0, 0x8000, // ANDCF $30, #0x8000
0x029c, 0xFFFF, // JLNZ 0x0280
0, 0 }, // RET
{ 0x27fe, // LRS $31, @CMBH
0x03c0, 0x8000, // ANDCF $31, #0x8000
0x029c, 0xFFFF, // JLNZ 0x0280
0, 0 }, // RET
// From Zelda:
{ 0x00de, 0xFFFE, // LR $AC0.M, @CMBH
0x02c0, 0x8000, // ANDCF $AC0.M, #0x8000
0x029c, 0xFFFF, // JLNZ 0x05cf
0 }
};
void Reset()
{
memset(code_flags, 0, sizeof(code_flags));
}
void AnalyzeRange(int start_addr, int end_addr)
{
// First we run an extremely simplified version of a disassembler to find
// where all instructions start.
// This may not be 100% accurate in case of jump tables!
// It could get desynced, which would be bad. We'll see if that's an issue.
for (int addr = start_addr; addr < end_addr;)
{
UDSPInstruction inst = dsp_imem_read(addr);
const DSPOPCTemplate *opcode = GetOpTemplate(inst);
if (!opcode)
{
addr++;
continue;
}
code_flags[addr] |= CODE_START_OF_INST;
addr += opcode->size;
// Look for loops.
if ((inst.hex & 0xffe0) == 0x0060 || (inst.hex & 0xff00) == 0x1100) {
// BLOOP, BLOOPI
u16 loop_end = dsp_imem_read(addr + 1);
code_flags[loop_end] |= CODE_LOOP_END;
} else if ((inst.hex & 0xffe0) == 0x0040 || (inst.hex & 0xff00) == 0x1000) {
// LOOP, LOOPI
code_flags[addr + 1] |= CODE_LOOP_END;
}
}
// Next, we'll scan for potential idle skips.
for (int s = 0; s < NUM_IDLE_SIGS; s++)
{
for (int addr = start_addr; addr < end_addr; addr++)
{
bool found = false;
for (int i = 0; i < MAX_IDLE_SIG_SIZE + 1; i++)
{
if (idle_skip_sigs[s][i] == 0)
found = true;
if (idle_skip_sigs[s][i] == 0xFFFF)
continue;
if (idle_skip_sigs[s][i] != dsp_imem_read(addr + i))
break;
}
if (found)
{
NOTICE_LOG(DSPLLE, "Idle skip location found at %02x", addr);
code_flags[addr] |= CODE_IDLE_SKIP;
// TODO: actually use this flag somewhere.
}
}
}
NOTICE_LOG(DSPLLE, "Finished analysis.");
}
void Analyze()
{
Reset();
AnalyzeRange(0x0000, 0x1000); // IRAM
AnalyzeRange(0x8000, 0x9000); // IROM
}
} // namespace
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