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273 lines
9.2 KiB
Python

from amaranth import *
from amaranth.utils import log2_int
from power_fv import pfv
from power_fv.insn.const import *
from . import InsnSpec
from .utils import iea, byte_reversed
__all__ = ["LoadStoreSpec"]
class LoadStoreSpec(InsnSpec, Elaboratable):
def __init__(self, insn, *, dword_aligned=False):
self.pfv = pfv.Interface()
self.insn = insn
self.dword_aligned = dword_aligned
def elaborate(self, platform):
m = Module()
m.d.comb += [
self.pfv.stb .eq(1),
self.pfv.insn.eq(Cat(Const(0, 32), self.insn.as_value())),
self.pfv.nia .eq(iea(self.pfv.cia + 4, self.pfv.msr.r_data.sf)),
self.pfv.msr.r_mask.sf.eq(1),
]
# EA (effective address) = ea_base + ea_offset
ea = Signal(64)
ea_base = Signal(64)
ea_offset = Signal(64)
# ea_base : (RA|0) or (RA)
m.d.comb += self.pfv.ra.index.eq(self.insn.RA)
if isinstance(self.insn, (
LBZ, LBZX, LHZ, LHZX, LHA, LHAX, LWZ, LWZX,
STB, STBX, STH, STHX, STW, STWX,
LWBRX, STHBRX, STWBRX
)):
m.d.comb += [
self.pfv.ra.r_stb.eq(self.insn.RA != 0),
ea_base.eq(Mux(self.insn.RA != 0, self.pfv.ra.r_data, 0)),
]
elif isinstance(self.insn, (
LBZU, LBZUX, LHZU, LHZUX, LHAU, LHAUX, LWZU, LWZUX,
STBU, STBUX, STHU, STHUX, STWU, STWUX
)):
m.d.comb += [
self.pfv.ra.r_stb.eq(1),
ea_base.eq(self.pfv.ra.r_data),
]
else:
assert False
# ea_offset : EXTS(D) or (RB)
if isinstance(self.insn, (
LBZ, LBZU, LHZ, LHZU, LHA, LHAU, LWZ, LWZU,
STB, STBU, STH, STHU, STW, STWU,
)):
m.d.comb += ea_offset.eq(self.insn.D.as_signed())
elif isinstance(self.insn, (
LBZX, LBZUX, LHZX, LHZUX, LHAX, LHAUX, LWZX, LWZUX,
STBX, STBUX, STHX, STHUX, STWX, STWUX,
LWBRX, STHBRX, STWBRX,
)):
m.d.comb += [
self.pfv.rb.index.eq(self.insn.RB),
self.pfv.rb.r_stb.eq(1),
ea_offset.eq(self.pfv.rb.r_data)
]
else:
assert False
m.d.comb += ea.eq(iea(ea_base + ea_offset, self.pfv.msr.r_data.sf))
# If `dword_aligned` is set, `pfv.mem.addr` points to the dword containing EA.
# If `dword_aligned` is unset, `pfv.mem.addr` is equal to EA.
byte_offset = Signal(3)
half_offset = Signal(2)
word_offset = Signal(1)
m.d.comb += self.pfv.mem.addr[3:].eq(ea[3:])
if self.dword_aligned:
m.d.comb += [
self.pfv.mem.addr[:3].eq(0),
byte_offset.eq(ea[:3]),
]
else:
m.d.comb += [
self.pfv.mem.addr[:3].eq(ea[:3]),
byte_offset.eq(0),
]
m.d.comb += [
half_offset.eq(byte_offset[1:]),
word_offset.eq(byte_offset[2:]),
]
msr_le = self.pfv.msr.r_data.le
m.d.comb += self.pfv.msr.r_mask.le.eq(1)
# Load: read from memory, then write the result to RT.
if isinstance(self.insn, (
LBZ, LBZX, LBZU, LBZUX,
LHZ, LHZX, LHZU, LHZUX,
LHA, LHAX, LHAU, LHAUX,
LWZ, LWZX, LWZU, LWZUX,
LWBRX,
)):
load_byte = Signal( 8)
load_half = Signal(16)
load_word = Signal(32)
load_result = Signal(64)
m.d.comb += [
load_byte.eq(self.pfv.mem.r_data.word_select(byte_offset, width= 8)),
load_half.eq(self.pfv.mem.r_data.word_select(half_offset, width=16)),
load_word.eq(self.pfv.mem.r_data.word_select(word_offset, width=32)),
]
if isinstance(self.insn, (LBZ, LBZX, LBZU, LBZUX)):
m.d.comb += [
self.pfv.mem.r_mask.word_select(byte_offset, width=1).eq(0x1),
load_result.eq(load_byte.as_unsigned()),
]
elif isinstance(self.insn, (LHZ, LHZX, LHZU, LHZUX)):
m.d.comb += [
self.pfv.mem.r_mask.word_select(half_offset, width=2).eq(0x3),
load_result.eq(byte_reversed(load_half, ~msr_le).as_unsigned()),
]
elif isinstance(self.insn, (LHA, LHAX, LHAU, LHAUX)):
m.d.comb += [
self.pfv.mem.r_mask.word_select(half_offset, width=2).eq(0x3),
load_result.eq(byte_reversed(load_half, ~msr_le).as_signed())
]
elif isinstance(self.insn, (LWZ, LWZX, LWZU, LWZUX)):
m.d.comb += [
self.pfv.mem.r_mask.word_select(word_offset, width=4).eq(0xf),
load_result.eq(byte_reversed(load_word, ~msr_le).as_unsigned()),
]
elif isinstance(self.insn, LWBRX):
m.d.comb += [
self.pfv.mem.r_mask.word_select(word_offset, width=4).eq(0xf),
load_result.eq(byte_reversed(load_word, msr_le).as_unsigned()),
]
else:
assert False
m.d.comb += [
self.pfv.rt.index .eq(self.insn.RT),
self.pfv.rt.w_stb .eq(1),
self.pfv.rt.w_data.eq(load_result),
]
# Store: read from RS, then write the result to memory.
elif isinstance(self.insn, (
STB, STBX, STBU, STBUX,
STH, STHX, STHU, STHUX,
STW, STWX, STWU, STWUX,
STHBRX, STWBRX,
)):
store_byte = Signal(64)
store_half = Signal(64)
store_word = Signal(64)
m.d.comb += [
self.pfv.rs.index.eq(self.insn.RS),
self.pfv.rs.r_stb.eq(1),
store_byte.eq(Repl(self.pfv.rs.r_data[: 8], count=8)),
store_half.eq(Repl(self.pfv.rs.r_data[:16], count=4)),
store_word.eq(Repl(self.pfv.rs.r_data[:32], count=2)),
]
if isinstance(self.insn, (STB, STBX, STBU, STBUX)):
m.d.comb += [
self.pfv.mem.w_mask.word_select(byte_offset, width=1).eq(0x1),
self.pfv.mem.w_data.eq(store_byte),
]
elif isinstance(self.insn, (STH, STHX, STHU, STHUX)):
m.d.comb += [
self.pfv.mem.w_mask.word_select(half_offset, width=2).eq(0x3),
self.pfv.mem.w_data.eq(byte_reversed(store_half, ~msr_le)),
]
elif isinstance(self.insn, (STW, STWX, STWU, STWUX)):
m.d.comb += [
self.pfv.mem.w_mask.word_select(word_offset, width=4).eq(0xf),
self.pfv.mem.w_data.eq(byte_reversed(store_word, ~msr_le)),
]
elif isinstance(self.insn, STHBRX):
m.d.comb += [
self.pfv.mem.w_mask.word_select(half_offset, width=2).eq(0x3),
self.pfv.mem.w_data.eq(byte_reversed(store_half, msr_le)),
]
elif isinstance(self.insn, STWBRX):
m.d.comb += [
self.pfv.mem.w_mask.word_select(word_offset, width=4).eq(0xf),
self.pfv.mem.w_data.eq(byte_reversed(store_word, msr_le)),
]
else:
assert False
else:
assert False
# Load/store with update: write EA to RA.
if isinstance(self.insn, (
LBZU, LBZUX, LHZU, LHZUX, LHAU, LHAUX, LWZU, LWZUX,
STBU, STBUX, STHU, STHUX, STWU, STWUX,
)):
m.d.comb += [
self.pfv.ra.w_stb .eq(1),
self.pfv.ra.w_data.eq(ea),
]
# Interrupt causes
intr = Record([
("misaligned", 1),
("update_zero", 1),
("update_rt", 1),
])
if isinstance(self.insn, (
LBZ, LBZX, LBZU, LBZUX,
STB, STBX, STBU, STBUX,
)):
m.d.comb += intr.misaligned.eq(0)
elif isinstance(self.insn, (
LHZ, LHZX, LHZU, LHZUX, LHA, LHAX, LHAU, LHAUX,
STH, STHX, STHU, STHUX,
STHBRX,
)):
m.d.comb += intr.misaligned.eq(byte_offset[0])
elif isinstance(self.insn, (
LWZ, LWZX, LWZU, LWZUX,
STW, STWX, STWU, STWUX,
LWBRX, STWBRX,
)):
m.d.comb += intr.misaligned.eq(byte_offset[:1].any())
else:
assert False
if isinstance(self.insn, (
LBZU, LBZUX, LHZU, LHZUX, LHAU, LHAUX, LWZU, LWZUX,
STBU, STBUX, STHU, STHUX, STWU, STWUX,
)):
m.d.comb += intr.update_zero.eq(self.insn.RA == 0)
else:
m.d.comb += intr.update_zero.eq(0)
if isinstance(self.insn, (
LBZU, LBZUX, LHZU, LHZUX, LHAU, LHAUX, LWZU, LWZUX,
)):
m.d.comb += intr.update_rt.eq(self.insn.RA == self.insn.RT)
else:
m.d.comb += intr.update_rt.eq(0)
m.d.comb += self.pfv.intr.eq(intr.any())
return m