And rename prd_exit to prd_terminate (the idea is the host will
terminate the VM). This makes it possible for the debugger to pause the
VM before any code, even a builtin function, is executed. Breaks the
debugger source window, but only because it's not updating on file
change (I think).
I decided I want events for VM enter/exit but enter needs to somehow
pass the function which will be executed (even if a builtin). A generic
void * param seemed the best idea, which meant the error string could be
passed via the param instead of a "global" string in the progs struct.
While there was a breakpoint hook, it was for only breakpoints and more
was needed. Now there's a generic hook that is called for tracing,
breakpoints, watch points, runtime errors and VM errors, with the
"event" type passed as the first parameter and a data pointer in the
second.
The memset instructions now match the move* instructions other than the
first operand (always int). Probably breaks much, but fixed in next few
commits.
If a temp string is found in the return slot, PR_FreeTempStrings won't
delete the string. However, PR_PopFrame was blindly stomping on the
possibly surviving temp string with the push strings, which would cause
a leak.
This "pushes" a temp string onto the callee's stack frame after removing
it from the caller's stack frame. This is so builtins can pass
auto-freed memory to called progs code. No checking is done, but mayhem
is likely to ensue if a string is pushed that was allocated in an
earlier frame.
The progs execution code will call a breakpoint handler just before
executing an instruction with the flag set. This means there's no need
for the breakpoint handler to mess with execution state or even the
instruction in order to continue past the breakpoint.
The flag being set in a progs file is invalid.
It is now set to 0 when progs are loaded and every time
PR_ExecuteProgram() returns. This takes care of the default case, but
when setting parameters, pr_argc needs to be set correctly in case a
vararg function is called.
PR_SaveParams() is required for implementing the +initialize diversion
used by Objective-QuakeC because builtins do not have local def spaces
(of course, a normal stack calling convention would help). However, it
is entirely possible for a call to +initialize to trigger another call
to +initialize, thus the need for stacking parameter stashes. As a
bonus, this implementation cleans up some fields in progs_t.
The engine now requires non-v6 progs to store the log2 alignment for the
param struct in .param_alignment.
PR_EnterFunction is clearer and possibly more efficient.
Only as scalars, I still need to think about what to do for vectors and
quaternions due to param size issues. Also, doubles are not yet
guaranteed to be correctly aligned.
The offset to compensate for st++ was missing.
Obviously, the code has never been tested. Found while looking at the
jump code and thinking about using 32-bit addresses for the jump tables.
It was pointed out by Blub\w (gmqcc) that OP_MUL_FV and friends were buggy
when the operands overlapped (eg, x = x.x * x) as the result would become
'x.x*x.x x.y*x.x*x.x x.z*x.x*x.x' (note the x.x squared for y and z). On
testing, sure enough the bug was present (and is a nice demonstration that
QF's VM does NOT have strict-aliasing bugs). As a very nice benefit: the
code produced by the fixes is actually faster than the broken version :).
The ruamoko code used for testing:
void (string fmt, ...) printf = #0;
vector foo (vector x)
{
x = x * x.x;
return x;
}
vector bar (vector x)
{
x = x.x * x;
return x;
}
int main ()
{
vector x = '2 3 4';
vector y = foo (x);
vector z = bar (x);
printf ("x=%v y=%v z=%v 2*x=%v\n", x, y, z, 2*x);
return 0;
}
Normally, the order doesn't matter, but when tracing code, it becomes very
difficult to tell where the trace ends and the dump begins. Printing the
message first puts the message between the trace and the dump: much easier
:)
another builtin by name, and returns it.
Soon I'll change all our new builtins to by allocated dynamically, as
well as changing the number checkfunction uses, and happily break
everything that uses them :D
