Files
wasmtime/lib/cretonne/meta/isa/intel/recipes.py
2017-06-30 12:21:36 -07:00

217 lines
6.8 KiB
Python

"""
Intel Encoding recipes.
"""
from __future__ import absolute_import
from cdsl.isa import EncRecipe
from cdsl.predicates import IsSignedInt, IsEqual
from base.formats import UnaryImm, Binary, BinaryImm, Store, Load
from base.formats import MultiAry, Call, IndirectCall
from .registers import GPR, ABCD
try:
from typing import Tuple, Dict # noqa
from cdsl.instructions import InstructionFormat # noqa
from cdsl.isa import ConstraintSeq, BranchRange, PredNode # noqa
except ImportError:
pass
# Opcode representation.
#
# Cretonne requires each recipe to have a single encoding size in bytes, and
# Intel opcodes are variable length, so we use separate recipes for different
# styles of opcodes and prefixes. The opcode format is indicated by the recipe
# name prefix:
OPCODE_PREFIX = {
# Prefix bytes Name mmpp
(): ('Op1', 0b0000),
(0x66,): ('Mp1', 0b0001),
(0xf3,): ('Mp1', 0b0010),
(0xf2,): ('Mp1', 0b0011),
(0x0f,): ('Op2', 0b0100),
(0x66, 0x0f): ('Mp2', 0b0101),
(0xf3, 0x0f): ('Mp2', 0b0110),
(0xf2, 0x0f): ('Mp2', 0b0111),
(0x0f, 0x38): ('Op3', 0b1000),
(0x66, 0x0f, 0x38): ('Mp3', 0b1001),
(0xf3, 0x0f, 0x38): ('Mp3', 0b1010),
(0xf2, 0x0f, 0x38): ('Mp3', 0b1011),
(0x0f, 0x3a): ('Op3', 0b1100),
(0x66, 0x0f, 0x3a): ('Mp3', 0b1101),
(0xf3, 0x0f, 0x3a): ('Mp3', 0b1110),
(0xf2, 0x0f, 0x3a): ('Mp3', 0b1111)
}
# VEX/XOP and EVEX prefixes are not yet supported.
#
# The encoding bits are:
#
# 0-7: The opcode byte <op>.
# 8-9: pp, mandatory prefix:
# 00 none (Op*)
# 01 66 (Mp*)
# 10 F3 (Mp*)
# 11 F2 (Mp*)
# 10-11: mm, opcode map:
# 00 <op> (Op1/Mp1)
# 01 0F <op> (Op2/Mp2)
# 10 0F 38 <op> (Op3/Mp3)
# 11 0F 3A <op> (Op3/Mp3)
# 12-14 rrr, opcode bits for the ModR/M byte for certain opcodes.
# 15: REX.W bit (or VEX.W/E)
#
# There is some redundancy between bits 8-11 and the recipe names, but we have
# enough bits, and the pp+mm format is ready for supporting VEX prefixes.
def decode_ops(ops, rrr=0, w=0):
# type: (Tuple[int, ...], int, int) -> Tuple[str, int]
"""
Given a sequence of opcode bytes, compute the recipe name prefix and
encoding bits.
"""
assert rrr <= 0b111
assert w <= 1
name, mmpp = OPCODE_PREFIX[ops[:-1]]
op = ops[-1]
assert op <= 256
return (name, op | (mmpp << 8) | (rrr << 12) | (w << 15))
class TailRecipe:
"""
Generate encoding recipes on demand.
Intel encodings are somewhat orthogonal with the opcode representation on
one side and the ModR/M, SIB and immediate fields on the other side.
A `TailRecipe` represents the part of an encoding that follow the opcode.
It is used to generate full encoding recipes on demand when combined with
an opcode.
The arguments are the same as for an `EncRecipe`, except for `size` which
does not include the size of the opcode.
"""
def __init__(
self,
name, # type: str
format, # type: InstructionFormat
size, # type: int
ins, # type: ConstraintSeq
outs, # type: ConstraintSeq
branch_range=None, # type: BranchRange
instp=None, # type: PredNode
isap=None # type: PredNode
):
# type: (...) -> None
self.name = name
self.format = format
self.size = size
self.ins = ins
self.outs = outs
self.branch_range = branch_range
self.instp = instp
self.isap = isap
# Cached recipes, keyed by name prefix.
self.recipes = dict() # type: Dict[str, EncRecipe]
def __call__(self, *ops, **kwargs):
# type: (*int, **int) -> Tuple[EncRecipe, int]
"""
Create an encoding recipe and encoding bits for the opcode bytes in
`ops`.
"""
rrr = kwargs.get('rrr', 0)
w = kwargs.get('w', 0)
name, bits = decode_ops(ops, rrr, w)
if name not in self.recipes:
self.recipes[name] = EncRecipe(
name + self.name,
self.format,
len(ops) + self.size,
ins=self.ins,
outs=self.outs,
branch_range=self.branch_range,
instp=self.instp,
isap=self.isap)
return (self.recipes[name], bits)
# XX /r
rr = TailRecipe('rr', Binary, size=1, ins=(GPR, GPR), outs=0)
# XX /n with one arg in %rcx, for shifts.
rc = TailRecipe('rc', Binary, size=1, ins=(GPR, GPR.rcx), outs=0)
# XX /n ib with 8-bit immediate sign-extended.
rib = TailRecipe(
'rib', BinaryImm, size=2, ins=GPR, outs=0,
instp=IsSignedInt(BinaryImm.imm, 8))
# XX /n id with 32-bit immediate sign-extended.
rid = TailRecipe(
'rid', BinaryImm, size=5, ins=GPR, outs=0,
instp=IsSignedInt(BinaryImm.imm, 32))
# XX+rd id unary with 32-bit immediate.
uid = TailRecipe(
'uid', UnaryImm, size=4, ins=(), outs=GPR,
instp=IsSignedInt(UnaryImm.imm, 32))
#
# Store recipes.
#
# XX /r register-indirect store with no offset.
st = TailRecipe(
'st', Store, size=1, ins=(GPR, GPR), outs=(),
instp=IsEqual(Store.offset, 0))
# XX /r register-indirect store with no offset.
# Only ABCD allowed for stored value. This is for byte stores.
st_abcd = TailRecipe(
'st_abcd', Store, size=1, ins=(ABCD, GPR), outs=(),
instp=IsEqual(Store.offset, 0))
# XX /r register-indirect store with 8-bit offset.
stDisp8 = TailRecipe(
'stDisp8', Store, size=2, ins=(GPR, GPR), outs=(),
instp=IsSignedInt(Store.offset, 8))
stDisp8_abcd = TailRecipe(
'stDisp8_abcd', Store, size=2, ins=(ABCD, GPR), outs=(),
instp=IsSignedInt(Store.offset, 8))
# XX /r register-indirect store with 32-bit offset.
stDisp32 = TailRecipe('stDisp32', Store, size=5, ins=(GPR, GPR), outs=())
stDisp32_abcd = TailRecipe(
'stDisp32_abcd', Store, size=5, ins=(ABCD, GPR), outs=())
#
# Load recipes
#
# XX /r load with no offset.
ld = TailRecipe(
'ld', Load, size=1, ins=(GPR), outs=(GPR),
instp=IsEqual(Load.offset, 0))
# XX /r load with 8-bit offset.
ldDisp8 = TailRecipe(
'ldDisp8', Load, size=2, ins=(GPR), outs=(GPR),
instp=IsSignedInt(Load.offset, 8))
# XX /r load with 32-bit offset.
ldDisp32 = TailRecipe(
'ldDisp32', Load, size=5, ins=(GPR), outs=(GPR),
instp=IsSignedInt(Load.offset, 32))
#
# Call/return
#
call_id = TailRecipe('call_id', Call, size=4, ins=(), outs=())
call_r = TailRecipe('call_r', IndirectCall, size=1, ins=GPR, outs=())
ret = TailRecipe('ret', MultiAry, size=0, ins=(), outs=())