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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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; either version 2
* of the License, or (at your option) any later version.
* 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 for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#include <pspkernel.h>
#include <pspdebug.h>
#include <stdarg.h>
#include <stdio.h>
#define FORBIDDEN_SYMBOL_ALLOW_ALL
#include "common/scummsys.h"
int psp_debug_indent = 0;
bool firstWriteToFile = true;
void PspDebugTrace(bool alsoToScreen, const char *format, ...) {
va_list opt;
char buffer[2048];
int bufsz;
FILE *fd = 0;
va_start(opt, format);
bufsz = vsnprintf(buffer, (size_t) sizeof(buffer), format, opt);
va_end(opt);
if (firstWriteToFile) {
fd = fopen("SCUMMTRACE.TXT", "wb"); // erase the file the first time we write
firstWriteToFile = false;
} else {
fd = fopen("SCUMMTRACE.TXT", "ab");
}
if (fd == 0)
return;
fwrite(buffer, 1, bufsz, fd);
fclose(fd);
if (alsoToScreen)
fprintf(stderr, buffer);
}
// Assembly functions to get the Return Address register and the Stack pointer register
#define GET_RET(retAddr) \
asm volatile ("move %0,$ra\n\t" \
: "=&r" (retAddr) : )
#define GET_SP(stackPtr) \
asm volatile ("move %0,$sp\n\t" \
: "=&r" (stackPtr) : )
// Function to retrieve a backtrace for the MIPS processor
// This is not trivial since the MIPS doesn't use a frame pointer.
// Takes the number of levels wanted above the calling function (included) and an array of void *
//
void mipsBacktrace(uint32 levels, void **addresses) {
// get the current return address
register byte *retAddr;
register byte *stackPointer;
GET_RET(retAddr);
GET_SP(stackPointer);
char string[100];
if (!levels)
return;
memset(addresses, 0, sizeof(void *) * levels);
uint32 curLevel = 0;
const uint32 SP_SUBTRACT = 0x27bd8000; // The instruction to subtract from the SP looks like this
const uint32 SP_SUB_HIGH_MASK = 0xffff8000; // The mask to check for the subtract SP instruction
const uint32 SP_SUB_LOW_MASK = 0x0000ffff; // The mask that gives us how much was subtracted
// make sure we go out of the stack of this current level
// we already have the return address for this level from the register
if (curLevel < levels) {
void *thisFunc = (void *)mipsBacktrace;
for (uint32 *seekPtr = (uint32 *)thisFunc; ; seekPtr++) {
if ((*seekPtr & SP_SUB_HIGH_MASK) == SP_SUBTRACT) {
// we found the $sp subtraction at the beginning of the function
int16 subAmount = (int16)((*seekPtr) & SP_SUB_LOW_MASK);
//sprintf(string, "found local $sp sub at %p. Data[%x]. Sub amount %d\n", seekPtr, *seekPtr, subAmount);
//fputs(string, stderr);
stackPointer -= subAmount;
byte *testRetAddr = (byte *)*((uint32 *)(stackPointer - 4));
if (testRetAddr != retAddr) {
sprintf(string, "mismatch in testretAddr.\n");
fputs(string, stderr);
}
break;
}
}
}
// keep scanning while more levels are requested
while (curLevel < levels) {
// now scan backwards from the return address to find the size of the stack
for(uint32 *seekPtr = (uint32 *)retAddr; ; seekPtr--) {
if (((*seekPtr) & SP_SUB_HIGH_MASK) == SP_SUBTRACT) {
// we found the $sp subtraction at the beginning of the function
int16 subAmount = (int16)((*seekPtr) & SP_SUB_LOW_MASK);
//sprintf(string, "found $sp sub at %p. Data[%x]. Sub amount %d\n", seekPtr, *seekPtr, subAmount);
//fputs(string, stderr);
stackPointer -= subAmount;
retAddr = (byte *)*((uint32 *)(stackPointer - 4));
if (retAddr < (byte *)0x8900000 || retAddr > (byte *)0xC900000) {
sprintf(string, "invalid retAddr %p\n", retAddr);
fputs(string, stderr);
return;
}
//sprintf(string, "retAddr[%p]\n", retAddr);
//fputs(string, stderr);
addresses[curLevel++] = retAddr;
break;
}
}
}
}
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