This is just the basic 'imul' the M instruction set also has mulh/mulhu which
yield the high bits of a multiplication, and there are div/rem instructions to
be implemented.
These instructions are gated by the use_m predicate, but ISA predicates are not
completely implemented yet.
Three predicates affect each extension:
- supports_m determines whether the target CPU supports the instruction set.
- enable_m determines if the instructions should be used, assuming they're
available.
- use_m is the predicate used to actually use the instructions.
Define data types for the level 1 and level 2 hash tables. These data types are
generic over the offset integer type so they can be twice as compact for
typically small ISAs.
Use these new types when generating encoding hash tables.
Emit both level 1 and level 2 hash tables.
Define generic functions that perform lookups in the encoding tables.
Implement the TargetIsa::encode() method for RISC-V using these building
blocks.
Rustfmt is still so immature that developers can't have different versions
installed, or there will be minute differences in formatting causing the tests
to fail.
Only run rustfmt as part of the test-all script if the expected version is
available.
Compute the u16 representation of encoding lists and emit a big table
concatenating all of them. Use the UniqueSeqTable to share some table space
between CPU modes.
We need to generate hash tables keyed by types, so the Python scripts need to
know the index used to represent types in Rust code.
To enforce this, add a new gen_types.py script which generates constant
definitions for the ir/types module.
Also generate constants for common SIMD vector sizes.
Amend build script to generate an encodings-<isa>.rs file for each target ISA.
Emit a function that can evaluate instruction predicates.
Describe the 3-level tables used for representing insrruction encoding tables.
Add Python classes representing the tables.
The generated code is incomplete and not used anywhere yet.
When generating Rust code for an instruction predicate, call the corresponding
function in the predicates module, using a qualified name.
We don't have methods corresponding to the predicates.
This collects all of the leaf predicates that go into a compound predicate.
Current leaf predicates are:
- Settings for ISA predicates, and
- FieldPredicates for instruction predicates.
Add new instruction predicates to support the 'I' encoding recipe: IsSignedInt,
IsUnsignedInt used to test that an immediate operand is in the allowed range.
Each InstructionFormat instance gets data members corresponding to its immediate
operands, so the can be referred to as BinaryImm.imm, for example.
This will be used to construct instruction predicates.
Usually an instruction firmat has only a single immediate operand called 'imm',
or 'cond' if it is one of the condigtion codes. Add a 'default_member' field to
ImmediateKind to keep track of this default member name in the InstructionData
struct.
We have multiple pre-computed constant hash tables that all use the same
quadratic probing algorithm.
Add a constant_hash Rust module to match the meta/constant_hash.py module.
Move the simple_hash() function into constant_hash. Its Python equivalent is in
the constant_hash.py module.
