While this was a pain to get working, that pain only went to prove the
value of using proper "types" (even if only an enum) for different
expression types: just finding all the places to edit was a chore, and
easy to make mistakes (forgetting bits here and there).
Strangely enough, this exposed a pile of *type* aliasing bugs (next
commit).
Both pr_type_size and pr_type_name. I want to macroize the enum, but
need to sort out the clutter of headers first, just need to decide on
naming. This at least sorts out the missed values for now.
v6 vs v6p are more or less as before, with ruamoko added in. qfcc will
now try (and fail, due to the opcode table opnames being wrong) to
create ruamoko progs when given the ruamoko target option.
At this stage, I doubt emit.c will need to know the details of the
target (v6, v6p, ruamoko) since the instruction formats are identical,
just different meanings for the opcode itself.
This allows v6, v6p (older QF VM) or ruamoko (new QF VM) to be targeted.
Currently defaults to v6p to allow QF to continue building without too
much hassle.
While qfcc dealing sensibly with mixed target VMs in the object files
has always been an outstanding issue, with the new instruction set it
has become a priority. Most importantly, this should allow QF to
continue building while I work on qfcc targeting the new IS.
It does little good for documentation to refer to fields that don't
exist (because a certain someone forgot to change the docs when changing
the field names, I wonder who :P).
In some cases, gcc-11 does a good enough job translating normal looking
C expressions so use just those, but other times need to dig around for
an appropriate intrinsic.
Also, now need to disable psapi warnings when compiling for anything
less than avx.
The bug (alignment issues with AVX on windows) seems to have in gcc from
the 4.x days, and is still present in 11.2: it does not ensure stack
parameters that need 32 byte alignment are aligned. Telling gcc to use
the sysv abi (safe on a static function) lets gcc do what it does for
linux (usually pass the parameters in registers, which it seems to have
done).
And partial implementations in qfcc (most places will generate an
internal error (not implemented) or segfault, but some low-hanging fruit
has already been implemented).
As I expect to be tweaking things for a while, it's part of the build
process. This will make it a lot easier to adjust mnemonics and argument
formats (tweaking the old table was a pain when conventions changed).
It's not quite done as it still needs arg widths and types.
While working on the new opcode table, I decided a lot of the names were
not to my liking. Part of the problem was the earlier clash with the
v6p opcode names, but that has been resolved via the v6p tag.
Use the new "1" versions of loadvec3 to get a 1 in w to avoid
divide-by-zero errors, and use the correct type for longs (forgot to
change i to l on the vector types).
Always setting w to 0 made it impossible to use the resulting 4d vectors
in division-based operations as they would result in divide-by-zero and
thus an unavoidable exception (CPUs don't like integer div-by-zero).
I'll probably add similar for float and double, but they're not as
critical as they'll just give inf or nan. This also increases my doubts
about the value of keeping 3d vector operations.
It turned out I had no way of using a pointer or field as the value to
load, so all 4 modes are duplicated with loads from where operand b
points, but the loaded value interpreted the same way. Also, fixed an
error in the calculation of op-b offsets.
Statements can be bounds checked in the one place (jump calculation),
but memory accesses cannot as they can be used in lea instructions which
should never cause an exception (unless one of lea's operands is OOB).
* / % %% + -
As a bonus, includes partial tests for a few extra operators. Several
things are broken at this stage, but uncommitted code is already
working.
Float bit-ops as well.
Also, add q*v4 and v4*q instructions. There are currently 48 free
opcodes, and I might remove the scale instructions, but they could be
useful as expanding a single float to a vector would take 3 instructions
(copy to temp, swizzle-expand temp, multiply, vs just scale).
The swizzle instruction is very powerful in that in can do any of the
256 permutations of xyzw, optionally negate any combination of the
resulting components, and zero any combination of the result components
(even all). This means the one instruction can take care of any actual
swizzles, conjugation for complex and quaternion values, zeroing vectors
(not that it's the only way), and probably other weird things.
The python file was used to generate the jump table and actual swizzle
code.
It turns out gcc optimizes the obvious code nicely. It doesn't do so
well for cmul, but I decided to use obvious code anyway (the instruction
counts were the same, so maybe it doesn't get better for a single pair
of operands).
They even found a bug in the addressing mode functions :) (I'd forgotten
that I wanted signed offsets from the pointer and thus forgot to cast
st->b to short in order to get the sign extension)
This allows the VM to select the right execution loop and qfcc currently
still produces only the old IS (it doesn't know how to deal with the new
IS yet)
When it's finalized (most of the conversion operations will go, probably
the float bit ops, maybe (very undecided) the 3-component vector ops,
and likely the CALLN ops), this will be the actual instruction set for
Ruamoko.
Main features:
- Significant reduction in redundant instructions: no more multiple
opcodes to move the one operand size.
- load, store, push, and pop share unified addressing mode encoding
(with the exception of mode 0 for load as that is redundant with mode
0 for store, thus load mode 0 gives quick access to entity.field).
- Full support for both 32 and 64 bit signed integer, unsigned integer,
and floating point values.
- SIMD for 1, 2, (currently) 3, and 4 components. Transfers support up
to 128-bit wide operations (need two operations to transfer a full
4-component double/long vector), but all math operations support both
128-bit (32-bit components) and 256-bit (64-bit components) vectors.
- "Interpreted" operations for the various vector sizes: complex dot
and multiplication, 3d vector dot and cross product, quaternion dot
and multiplication, along with qv and vq shortcuts.
- 4-component swizzles for both sizes (not yet implemented, but the
instructions are allocated), with the option to zero or negate (thus
conjugates for complex and quaternion values) individual components.
- "Based offsets": all relevant instructions include base register
indices for all three operands allowing for direct access to any of
four areas (eg, current entity, current stack frame, Objective-QC
self, ...) instructions to set a register and push/pop the four
registers to/from the stack.
Remaining work:
- Implement swizzle operations and a few other stragglers.
= Make a decision about conversion operations (if any instructions
remain, they'll be just single-component (at 14 meaningful pairs,
that's a lot of instructions to waste on SIMD versions).
- Decide whether to keep CALL1-CALL8: probably little point in
supporting two different calling conventions, and it would free up
another eight instructions.
- Unit tests for the instructions.
- Teach qfcc to generate code for the new instruction set (hah, biggest
job, I'm sure, though hopefully not as crazy as the rewrite eleven
years ago).
