This is the bulk of the work for recording the resource pointer with
with builtin data. I don't know how much of a difference it makes for
most things, but it's probably pretty big for qwaq-curses due to the
very high number of calls to the curses builtins.
Closes#26
These add legacy support for basic float bitops (& | ^ ~). Avoiding the
instructions would require tot only the source to be converted, but also
the servers (as they do access those fields), and this seemed to be too
much.
I had forgotten that unsigned division was different from signed
division (rather silly of me). However, with some testing and analysis,
unsigned true modulo is not needed as it's not possible to have
negative inputs and thus it's the same as remainder.
This loads the current return pointer into the specified register. No
offset is used (should make that an error, but for now any offset is
simply ignored). This is part of the fix for getting obj_msg_sendv to
work with return values.
With the return buffer in progs_t, it could not be addressed by the
progs on 64-bit machines (this was intentional, actually), but in order
to get obj_msg_sendv working properly, I needed a way to "bounce" the
return address of a calling function to the called function. The
cleanest solution I could think of was to add a mode to the with
instruction allowing the return pointer to be loaded into a register and
then calling the function with a 0 offset for the return value but using
the relevant register (next few commits). Testing promptly segfaulted
due to the 64-bit offset not fitting into a 32-bit value.
The plan is to use the types to extract the number of parameters for a
selector when it is necessary to know the count. However, it'll probably
become useful for something else alter (these things seem to always do
so).
It's a bit disconcerting seeing a builtin in the top 10 when builtins
are counted by call while progs functions are counted by instruction.
Also, show the total profile after the function top-10 list.
It's currently only 4 (or even 3 for v6) words, but this fixes false
positives when checking for null pointers in Ruamoko progs due to
pr_return pointing to the return buffer and thus outside the progs
memory map resulting in an impossible to exceed value.
It turns out the return pointer still needs to be saved even when a
builtin sets up a chain call to progs, but rather than the pointer being
simply restored, it needs to be saved in the call stack exactly as if
the function was called directly by progs. This fixes the invalid self
issue quite thoroughly: parameter state seems to be correct across all
calls now.
I should set up an automated test now that I know and understand the
situation.
When calling a builtin, normally the return pointer needs to be
restored, but if the builtin changes the call depth (usually by
effecting "return foo()" as in support for objects, but possibly
setjmp/longjmp when they are implemented), then the return pointer must
not be restored. This gets vkgen past object allocation, but it dies
when trying to send messages to super. This appears to be a compiler
bug.
Since the operand types sort out the difference between asr and shr, no
need to give them different opnames. Means qfcc doesn't need to worry
about which one it's searching for.
Yet another redundant addressing mode (since ptr + 0 can be used), so
replace it with a variable-indexed array (same as in v6p). Was forced
into noticing the problem when trying to compile Machine.r.
I abandoned the reason for doing it (adding a pile of vector types), but
I liked the cleanup. All the implementations are hand-written still, but
at least the boilerplate stuff is automated.
Of course, only in Ruamoko progs, but it works quite nicely.
global_string is now passed the absolute address of the referenced
operand. With a little groveling through the progs stack, it should be
possible to resolve pointers to locals in functions further up the
stack.
This fixes Ruamoko's return format string. It looks like it's producing
the correct address (but doesn't show all the information it should),
but the rest of the debug code needs work locals.
It turned out I need locals count and params_start for debugging, so use
the progs version instead to bail early from PR_EnterFunction and
PR_LeaveFunction (which I had forgotten anyway, oops).
They now include base register index and effective address of the
operands (though it may be wrong for instructions that don't use a base
register for that operand).
This cleans up dprograms_t, making it easier to read and see what chunks
are in it (I was surprised to see only 6, the explicit pairs made it
seem to have more).
Intel hardware requires 32-byte alignment for lvec4 and dvec4.
Unfortunately, it turns out that my attempts to align progs data in qfcc
went awry do to the order block sizes are calculated when writing the
progs.
This makes return consistent with load, store, etc, though its
addressing mode is encoded in bits 5 and 6 of c rather than the opcode.
It turns out I had no tests for any of return's addressing modes other
than basic def references, so no tests needed changing.
The parameter defs are allocated from the parameter space using a
minimum alignment of 4, and varargs functions get a va_list struct in
place of the ...
An "args" expression is unconditionally injected into the call arguments
list at the place where ... is in the list, with arguments passed
through ... coming after the ...
Arguments get through to functions now, but there's problems with taking
the address of local variables: currently done using constant pointer
defs, which can't work for the base register addressing used in Ruamoko
progs.
With the update to test-bi's printf (and a hack to qfcc for lea),
triangle.r actually works, printing the expected results (but -1 instead
of 1 for equality, though that too is actually expected). qfcc will take
a bit longer because it seems there are some design issues in address
expressions (ambiguity, and a few other things) that have pretty much
always been there.
PR_SetupParams is new and sets up the parameter pointers so older code
that expects only up to 8 parameter will work with both v6p and Ruamoko
progs without having to check what progs are running. PR_SetupParams is
useful even when Ruamoko progs are expected as it reserves the required
space (respecting alignment) on the stack and returns a pointer to the
top (bottom? confusing) of the stack. PR_PushFrame and PR_PopFrame
need to be used around PR_SetupParams, regardless of using temp strings,
to avoid a stack leak (need to do an audit).
This is part of the work for #26 (Record resource pointer with builtin
function data). Currently, the data pointer gets as far as the
per-instance VM function table (I don't feel like tackling the job of
converting all the builtin functions tonight). All the builtin modules
that register a resources data block pass that block on to
PR_RegisterBuiltins.
The builtin and progs function data is overlaid so the extra data
doesn't cause too much memory to be used (it's actually 8 bytes smaller
now). The plan is to pre-compute the offsets based on the parameter
size and alignment data.
As even the simplest v6p functions that take parameters but have no
local or temporary variables still have locals for the local copy of the
parameters, this is a both a good check for for the Ruamoko ISA as its
functions never have locals (everything's on the progs data stack), and
an optimization for v6p functions that have no params or locals (simple
getters (very rare?), most .ctor, etc).
And fix an incorrect definition for RETURN_QUAT.
Prefixed MAX_STACK_DEPTH and LOCALSTACK_SIZE (and LOCALSTACK_SIZE got an
extra _).
The rest is just edits to documentation comments.
ldconst isn't implemented yet but the plan is to load various constants
(eg, 0, 1, 2, pi, e, ...).
Stack adjust is useful for adding an offset to the stack pointer without
having to worry about finding it (and it checks for alignment).
nop is just that :)
Due to how OP_RETURN works, a destination is required for any function
returning data, but the caller may not have allocated any space for the
value. Thus the VM maintains a buffer into which the data can be put and
ignored. It also makes a good place for return values when the engine
calls Ruamoko code as trusting progs code with return sizes seems like a
recipe for disaster, especially if the return location is on the C
stack.
It turned out that address mode B was redundant as C with 0 offset
(immediate) was the same (except for the underlying C code of course,
but adding st->b is very cheap). This allowed B to be used for
entity.field for all transfer operations. Thus instructions 0-3 are now
free as load E became load B, and other than the specifics of format
codes for statement printing, transfers+lea are unified.
This makes the v6p instruction table consistent with the ruamoko
instruction table, and clears up some of the ugliness with the load,
store, and assign instructions (. .= and = are now spelled out). I think
I'd still prefer an enum code (faster) but at least this is more
readable.
And provide a table for such for qfcc and the like. With this, using
pr_double_t (for example) in C will cause the double value to always be
8-byte aligned and thus structures shared between gcc and qfcc will be
consistent (with a little fuss to take care of the warts).
And other related fields so integer is now int (and uinteger is uint). I
really don't know why I went with integer in the first place, but this
will make using macros easier for dealing with types.
They are both gone, and pr_pointer_t is now pr_ptr_t (pointer may be a
little clearer than ptr, but ptr is consistent with things like intptr,
and keeps the type name short).
This required delaying the setting of the return pointer by call until
after the current pointer had been saved, and thus passing the desired
pointer into PR_CallFunction (which does have some advantages for C
functions calling progs functions, but some dangers too (should ensure a
128 byte (32 word) buffer when calling untrusted code (which is any,
really)).
This fixes the issue of the data stack not being restored properly
because the returning function needs to return a value from its local
variables (stored on the stack) and accessing stack data below the stack
pointer is a bad idea (sure, no interrupts yet, but who knows...).
Call's operand c is used to specify where the return value of the
function is to be stored. This gets both the correct function being
called, and the value being returned correctly. Test still fails due to
the stack restoration issue.
It currently fails for two reasons:
- call's mode selection is incorrect (never updated from when there was
only the one call instruction and the mode was encoded in operand c)
- return should automatically restore the stack pointer to the value it
had on entry to the function, thus allowing local values stored on
the stack to be safely returned.
I don't know why they were ever signed (oversight at id and just
propagated?). Anyway, this resulted in "unsigned" spreading a bit, but
all to reasonable places.
This has been a long-held wishlist item, really, and I thought I might
as well take the opportunity to add the instructions. The double
versions of STATE require both the nextthink field and time global to be
double (but they're not resolved properly yet: marked with
"FIXME double time" comments).
Also, the frame number for double time state is integer rather than
float.
In the end, I decided any/all/none should be separate from the other
horizontal ops, if I even do them (can be implemented by first
converting to bool, then using the appropriate horizontal operation (& |
etc).
ANY/ALL/NONE have been temporarily removed until I implement the HOPS
(horizontal operations) sub-instructions, which will all both 32-bit and
64-bit operands and several other operations (eg, horizontal add).
All the fancy addressing modes for the conditional branch instructions
have been permanently removed: I decided the gain was too little for the
cost (24 instructions vs 6). JUMP and CALL retain their addressing
modes, though.
Other instructions have been shuffled around a little to fill most of
the holes in the upper block of 256 instructions: just a single small
7-instruction hole.
Rearrangements in the actual engine are mostly just to keep the code
organized. The only real changes were the various IF statements and
dealing with the resulting changes in their addressing.
When creating the tests for lea, I noticed that B was yet another simple
assign, so I decided it was best to drop it and move E into its place
(freeing up another instruction).
Most useful for 64-bit values as only one instruction is needed to move
the data around rather than two, but could be slightly faster for 32-bit
as the addressing is simpler (needs profiling).
The compare/ne operator returns "random" -ve, 0, +ve values (really,
just the numerical difference between the chars of the strings), but all
the rest return -1 for true and 0 for false, as with the rest of the
comparison operators.
