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SCI: Continue disasm until no jumps go past the current opcode

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This should ensure disasm will disassemble an entire function, and
not stop at an intermediate ret opcode.
This commit is contained in:
Willem Jan Palenstijn 2011-03-12 23:43:29 +01:00
parent fa10ee66e4
commit 6fe95780d3
3 changed files with 38 additions and 7 deletions
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15
engines/sci/console.cpp
View File

@ -2601,7 +2601,6 @@ bool Console::cmdDisassemble(int argc, const char **argv) {
DebugPrintf("Valid options are:\n");
DebugPrintf(" bwt : Print byte/word tag\n");
DebugPrintf(" bc : Print bytecode\n");
DebugPrintf(" rX : Continue after X ret opcodes before stopping decompilation\n");
return true;
}
@ -2640,17 +2639,19 @@ bool Console::cmdDisassemble(int argc, const char **argv) {
printBWTag = true;
else if (!scumm_stricmp(argv[i], "bc"))
printBytecode = true;
else if (argv[i][0] == 'r')
ignoreXret = atoi(argv[i] + 1);
}
reg_t farthestTarget = addr;
do {
reg_t prevAddr = addr;
addr = disassemble(_engine->_gamestate, addr, printBWTag, printBytecode);
if (addr.isNull() && ignoreXret) {
addr = prevAddr + 1; // skip past the ret
ignoreXret--;
reg_t jumpTarget;
if (isJumpOpcode(_engine->_gamestate, addr, jumpTarget)) {
if (jumpTarget > farthestTarget)
farthestTarget = jumpTarget;
}
addr = disassemble(_engine->_gamestate, addr, printBWTag, printBytecode);
if (addr.isNull() && prevAddr < farthestTarget)
addr = prevAddr + 1; // skip past the ret
} while (addr.offset > 0);
return true;

1
engines/sci/console.h
View File

@ -37,6 +37,7 @@ class SciEngine;
struct List;
reg_t disassemble(EngineState *s, reg_t pos, bool printBWTag, bool printBytecode);
bool isJumpOpcode(EngineState *s, reg_t pos, reg_t& jumpOffset);
class Console : public GUI::Debugger {
public:

29
engines/sci/engine/scriptdebug.cpp
View File

@ -281,6 +281,35 @@ reg_t disassemble(EngineState *s, reg_t pos, bool printBWTag, bool printBytecode
return retval;
}
bool isJumpOpcode(EngineState *s, reg_t pos, reg_t& jumpTarget)
{
SegmentObj *mobj = s->_segMan->getSegment(pos.segment, SEG_TYPE_SCRIPT);
if (!mobj)
return false;
Script *script_entity = (Script *)mobj;
const byte *scr = script_entity->getBuf();
int scr_size = script_entity->getBufSize();
if (pos.offset >= scr_size)
return false;
int16 opparams[4];
byte opsize;
int bytecount = readPMachineInstruction(scr + pos.offset, opsize, opparams);
const byte opcode = opsize >> 1;
switch (opcode) {
case op_bt:
case op_bnt:
case op_jmp:
jumpTarget = pos + bytecount + opparams[0];
return true;
default:
return false;
}
}
void SciEngine::scriptDebug() {
EngineState *s = _gamestate;