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| author | Yotam Barnoy | 2010-11-18 07:52:04 +0000 |
|---|---|---|
| committer | Yotam Barnoy | 2010-11-18 07:52:04 +0000 |
| commit | 5c8b4dbee7deaebd89f3f7a18bb51172859e6998 (patch) | |
| tree | 68b957b385a325190c959b5c9b0a2c104529dc8a | |
| parent | b77ef177ed6ccfb685ca88e7de568f9ff287d0d2 (diff) | |
| download | scummvm-rg350-5c8b4dbee7deaebd89f3f7a18bb51172859e6998.tar.gz scummvm-rg350-5c8b4dbee7deaebd89f3f7a18bb51172859e6998.tar.bz2 scummvm-rg350-5c8b4dbee7deaebd89f3f7a18bb51172859e6998.zip | |
PSP: added backtracing function for debugging
Currently not used by anything.
svn-id: r54312
| -rw-r--r-- | backends/platform/psp/trace.cpp | 81 | ||||
| -rw-r--r-- | backends/platform/psp/trace.h | 1 |
2 files changed, 82 insertions, 0 deletions
diff --git a/backends/platform/psp/trace.cpp b/backends/platform/psp/trace.cpp index 7bac6534da..74c2f64300 100644 --- a/backends/platform/psp/trace.cpp +++ b/backends/platform/psp/trace.cpp @@ -28,6 +28,8 @@ #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; @@ -58,3 +60,82 @@ void PspDebugTrace(bool alsoToScreen, const char *format, ...) { 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; + } + } + } +} + diff --git a/backends/platform/psp/trace.h b/backends/platform/psp/trace.h index 625aa60772..39b335b16c 100644 --- a/backends/platform/psp/trace.h +++ b/backends/platform/psp/trace.h @@ -55,6 +55,7 @@ __PSP_PRINT__(format, ## __VA_ARGS__); } void PspDebugTrace(bool alsoToScreen, const char *format, ...); +void mipsBacktrace(uint32 levels, void **addresses); extern int psp_debug_indent; |