forked from dolphin-emu/dolphin
0a576c7508
git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@4234 8ced0084-cf51-0410-be5f-012b33b47a6e
133 lines
3.7 KiB
C++
133 lines
3.7 KiB
C++
// Copyright (C) 2003 Dolphin Project.
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, version 2.0.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License 2.0 for more details.
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// A copy of the GPL 2.0 should have been included with the program.
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// If not, see http://www.gnu.org/licenses/
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// Official SVN repository and contact information can be found at
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// http://code.google.com/p/dolphin-emu/
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#include "DSPAnalyzer.h"
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#include "DSPInterpreter.h"
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#include "DSPTables.h"
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#include "DSPMemoryMap.h"
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namespace DSPAnalyzer {
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// Holds data about all instructions in RAM.
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u8 code_flags[ISPACE];
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// Good candidates for idle skipping is mail wait loops. If we're time slicing
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// between the main CPU and the DSP, if the DSP runs into one of these, it might
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// as well give up its time slice immediately, after executing once.
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// Max signature length is 6. A 0 in a signature is ignored.
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#define NUM_IDLE_SIGS 5
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#define MAX_IDLE_SIG_SIZE 6
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// 0xFFFF means ignore.
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const u16 idle_skip_sigs[NUM_IDLE_SIGS][MAX_IDLE_SIG_SIZE + 1] =
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{
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// From AX:
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{ 0x26fc, // LRS $30, @DMBH
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0x02c0, 0x8000, // ANDCF $30, #0x8000
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0x029d, 0xFFFF, // JLZ 0x027a
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0, 0 }, // RET
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{ 0x27fc, // LRS $31, @DMBH
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0x03c0, 0x8000, // ANDCF $31, #0x8000
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0x029d, 0xFFFF, // JLZ 0x027a
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0, 0 }, // RET
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{ 0x26fe, // LRS $30, @CMBH
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0x02c0, 0x8000, // ANDCF $30, #0x8000
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0x029c, 0xFFFF, // JLNZ 0x0280
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0, 0 }, // RET
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{ 0x27fe, // LRS $31, @CMBH
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0x03c0, 0x8000, // ANDCF $31, #0x8000
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0x029c, 0xFFFF, // JLNZ 0x0280
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0, 0 }, // RET
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// From Zelda:
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{ 0x00de, 0xFFFE, // LR $AC0.M, @CMBH
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0x02c0, 0x8000, // ANDCF $AC0.M, #0x8000
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0x029c, 0xFFFF, // JLNZ 0x05cf
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0 }
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};
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void Reset()
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{
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memset(code_flags, 0, sizeof(code_flags));
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}
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void AnalyzeRange(int start_addr, int end_addr)
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{
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// First we run an extremely simplified version of a disassembler to find
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// where all instructions start.
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// This may not be 100% accurate in case of jump tables!
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// It could get desynced, which would be bad. We'll see if that's an issue.
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for (int addr = start_addr; addr < end_addr;)
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{
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UDSPInstruction inst = dsp_imem_read(addr);
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const DSPOPCTemplate *opcode = GetOpTemplate(inst);
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if (!opcode)
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{
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addr++;
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continue;
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}
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code_flags[addr] |= CODE_START_OF_INST;
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addr += opcode->size;
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// Look for loops.
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if ((inst.hex & 0xffe0) == 0x0060 || (inst.hex & 0xff00) == 0x1100) {
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// BLOOP, BLOOPI
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u16 loop_end = dsp_imem_read(addr + 1);
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code_flags[loop_end] |= CODE_LOOP_END;
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} else if ((inst.hex & 0xffe0) == 0x0040 || (inst.hex & 0xff00) == 0x1000) {
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// LOOP, LOOPI
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code_flags[addr + 1] |= CODE_LOOP_END;
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}
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}
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// Next, we'll scan for potential idle skips.
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for (int s = 0; s < NUM_IDLE_SIGS; s++)
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{
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for (int addr = start_addr; addr < end_addr; addr++)
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{
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bool found = false;
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for (int i = 0; i < MAX_IDLE_SIG_SIZE + 1; i++)
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{
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if (idle_skip_sigs[s][i] == 0)
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found = true;
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if (idle_skip_sigs[s][i] == 0xFFFF)
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continue;
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if (idle_skip_sigs[s][i] != dsp_imem_read(addr + i))
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break;
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}
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if (found)
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{
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NOTICE_LOG(DSPLLE, "Idle skip location found at %02x", addr);
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code_flags[addr] |= CODE_IDLE_SKIP;
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// TODO: actually use this flag somewhere.
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}
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}
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}
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NOTICE_LOG(DSPLLE, "Finished analysis.");
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}
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void Analyze()
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{
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Reset();
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AnalyzeRange(0x0000, 0x1000); // IRAM
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AnalyzeRange(0x8000, 0x9000); // IROM
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}
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} // namespace
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