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overhaul GXFIFO packed-command handling to more closely resemble a reasonable hardware behaviour. this is unlikely to have fixed anything, since previous revisions had somehow smashed their way through most of the bugs; however, the previous revision did have a tiny potential bug which might have been fixed by this (array out of bounds access). the code is so pretty now, I think it must be right, but there's a chance that I have created a new bug.

This commit is contained in:
zeromus 2014-03-30 21:32:53 +00:00
parent 2873d83de4
commit a51fb22a40
1 changed files with 68 additions and 95 deletions
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163
desmume/src/gfx3d.cpp
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@ -98,135 +98,108 @@ static const u8 gfx3d_commandTypes[] = {
class GXF_Hardware
{
public:
GXF_Hardware()
{
reset();
}
void reset() {
countdown = 0;
commandCursor = 4;
for(int i=0;i<4;i++) {
commandsPending[i].command = 0;
commandsPending[i].countdown = 0;
}
size = 0;
void reset()
{
shiftCommand = 0;
paramCounter = 0;
}
void receive(u32 val)
{
if (size > 0)
NEXTCOMMAND:
u8 currCommand = shiftCommand & 0xFF;
u8 currCommandType = gfx3d_commandTypes[currCommand];
if(currCommandType == GFX_INVALID_COMMAND)
{
GFX_FIFOsend(front().command, val);
front().countdown--;
if (front().countdown == 0)
{
size--;
if (size == 0) return;
dequeue();
while (gfx3d_commandTypes[front().command] == GFX_NOARG_COMMAND)
{
GFX_FIFOsend(front().command, 0);
size--;
if (size == 0) break;
dequeue();
}
}
//if current command is invalid, receive a packed command
shiftCommand = val;
}
else if(currCommandType == GFX_UNDEFINED_COMMAND)
{
//not completely sure what to do with these. lets just pretend they didnt happen: skip the command
shiftCommand >>= 8;
}
else
{
if (val == 0) return; // nop
const u8 commands[] = { val&0xFF, (val>>8)&0xFF, (val>>16)&0xFF, (val>>24)&0xFF };
const u8 commandTypes[] = { gfx3d_commandTypes[commands[0]], gfx3d_commandTypes[commands[1]], gfx3d_commandTypes[commands[2]], gfx3d_commandTypes[commands[3]] };
commandCursor = 0;
size = 0;
// A "command without parameters" is one of the four following commands:
// - PushMatrix
// - LoadIdentity
// - End
// - Commands undefined within the region between 0x10 and 0xFF
for (u8 i = 0; i < 4; i++)
//if we are currently in a 0-param command, send it, and immediately apply this param to the next command
if(currCommandType == GFX_NOARG_COMMAND)
{
if (commandTypes[i] == GFX_INVALID_COMMAND)
{
//printf("gfx3D: invalid command (%02X)\n", commands[i]);
continue;
}
if (commandTypes[i] == GFX_UNDEFINED_COMMAND)
{
//printf("gfx3D: undefined command (%02X)\n", commands[i]);
continue;
}
commandsPending[size].command = commands[i];
commandsPending[size].countdown = commandTypes[i];
//printf("%i: CMD %02X size %i\n", i, commands[i], commandsPending[size].countdown);
if ((commandsPending[size].countdown == 0) && (size == 0)) // cmd 0x11, 0x15, 0x41 - no params
{
GFX_FIFOsend(commands[i], 0);
while ((i < 4) && commands[i+1] != 0 && gfx3d_commandTypes[commands[i+1]] == GFX_NOARG_COMMAND)
GFX_FIFOsend(commands[++i], 0);
}
else
size++;
GFX_FIFOsend(currCommand, 0);
shiftCommand >>= 8;
goto NEXTCOMMAND;
}
//otherwise, this is a parameter for the existing command (or a dummy value for a 0-param command)
GFX_FIFOsend(currCommand, val);
paramCounter++;
//if the current command's parameters are completed, shift down to the next command
if(paramCounter >= currCommandType)
{
paramCounter = 0;
shiftCommand >>= 8;
}
//note that we don't go to NEXTCOMMAND here.
//this means that if a 0-param command follows a N-param command, it won't get submitted until a dummy value is sent to strobe this process again
}
}
struct CommandItem {
u8 command, countdown;
} commandsPending[4];
u32 commandCursor;
u8 countdown;
private:
void dequeue() { commandCursor++; }
CommandItem& front() { return commandsPending[commandCursor]; }
u32 size;
u32 shiftCommand;
u32 paramCounter;
public:
void savestate(EMUFILE *f)
{
//TODO - next time we invalidate savestates, simplify this format.
write32le(1,f); //version
write32le(size,f);
write32le(commandCursor,f);
for(u32 i=0;i<4;i++) write8le(commandsPending[i].command,f);
for(u32 i=0;i<4;i++) write8le(commandsPending[i].countdown,f);
write8le(countdown,f);
write32le(2,f); //version
write32le(shiftCommand,f);
write32le(paramCounter,f);
}
bool loadstate(EMUFILE *f)
{
u32 version;
if(read32le(&version,f) != 1) return false;
if(version > 1) return false;
u8 junk8;
u32 junk32;
if (version == 0)
{
read32le(&size,f);
commandCursor = 4-size;
for(u32 i=commandCursor;i<4;i++) read8le(&commandsPending[i-commandCursor].command,f);
read32le(&size,f);
size = 4-commandCursor;
for(u32 i=commandCursor;i<4;i++) read8le(&commandsPending[i-commandCursor].countdown,f);
//untested
read32le(&junk32,f);
int commandCursor = 4-junk32;
for(u32 i=commandCursor;i<4;i++) read8le(&junk8,f);
read32le(&junk32,f);
for(u32 i=commandCursor;i<4;i++) read8le(&junk8,f);
read8le(&junk8,f);
}
else
if (version == 1)
else if (version == 1)
{
read32le(&size,f);
read32le(&commandCursor,f);
for(u32 i=0;i<4;i++) read8le(&commandsPending[i].command,f);
for(u32 i=0;i<4;i++) read8le(&commandsPending[i].countdown,f);
//untested
read32le(&junk32,f);
read32le(&junk32,f);
for(u32 i=0;i<4;i++) read8le(&junk8,f);
for(u32 i=0;i<4;i++) read8le(&junk8,f);
read8le(&junk8,f);
}
else if(version == 2)
{
read32le(&shiftCommand,f);
read32le(&paramCounter,f);
}
read8le(&countdown,f);
return true;
}