--- /dev/null
+"""Computation Unit (aka "ALU Manager").
+
+Manages a Pipeline or FSM, ensuring that the start and end time are 100%
+monitored. At no time may the ALU proceed without this module notifying
+the Dependency Matrices. At no time is a result production "abandoned".
+This module blocks (indicates busy) starting from when it first receives
+an opcode until it receives notification that
+its result(s) have been successfully stored in the regfile(s)
+
+Documented at http://libre-soc.org/3d_gpu/architecture/compunit
+"""
+
+from nmigen.compat.sim import run_simulation, Settle
+from nmigen.cli import rtlil
+from nmigen import Module
+
+from openpower.decoder.power_enums import MicrOp
+
+from soc.experiment.compalu_multi import MultiCompUnit
+from soc.experiment.alu_hier import ALU, DummyALU
+from soc.fu.alu.alu_input_record import CompALUOpSubset
+
+
+def op_sim(dut, a, b, op, inv_a=0, imm=0, imm_ok=0, zero_a=0):
+ yield dut.issue_i.eq(0)
+ yield
+ yield dut.src_i[0].eq(a)
+ yield dut.src_i[1].eq(b)
+ yield dut.oper_i.insn_type.eq(op)
+ yield dut.oper_i.invert_in.eq(inv_a)
+ yield dut.oper_i.imm_data.data.eq(imm)
+ yield dut.oper_i.imm_data.ok.eq(imm_ok)
+ yield dut.oper_i.zero_a.eq(zero_a)
+ yield dut.issue_i.eq(1)
+ yield
+ yield dut.issue_i.eq(0)
+ yield
+ if not imm_ok or not zero_a:
+ yield dut.rd.go_i.eq(0b11)
+ while True:
+ yield
+ rd_rel_o = yield dut.rd.rel_o
+ print ("rd_rel", rd_rel_o)
+ if rd_rel_o:
+ break
+ yield dut.rd.go_i.eq(0)
+ if len(dut.src_i) == 3:
+ yield dut.rd.go_i.eq(0b100)
+ while True:
+ yield
+ rd_rel_o = yield dut.rd.rel_o
+ print ("rd_rel", rd_rel_o)
+ if rd_rel_o:
+ break
+ yield dut.rd.go_i.eq(0)
+
+ req_rel_o = yield dut.wr.rel_o
+ result = yield dut.o_data
+ print ("req_rel", req_rel_o, result)
+ while True:
+ req_rel_o = yield dut.wr.rel_o
+ result = yield dut.o_data
+ print ("req_rel", req_rel_o, result)
+ if req_rel_o:
+ break
+ yield
+ yield dut.wr.go_i[0].eq(1)
+ yield Settle()
+ result = yield dut.o_data
+ yield
+ print ("result", result)
+ yield dut.wr.go_i[0].eq(0)
+ yield
+ return result
+
+
+def scoreboard_sim_dummy(dut):
+ result = yield from op_sim(dut, 5, 2, MicrOp.OP_NOP, inv_a=0,
+ imm=8, imm_ok=1)
+ assert result == 5, result
+
+ result = yield from op_sim(dut, 9, 2, MicrOp.OP_NOP, inv_a=0,
+ imm=8, imm_ok=1)
+ assert result == 9, result
+
+
+def scoreboard_sim(dut):
+ result = yield from op_sim(dut, 5, 2, MicrOp.OP_ADD, inv_a=0,
+ imm=8, imm_ok=1)
+ assert result == 13
+
+ result = yield from op_sim(dut, 5, 2, MicrOp.OP_ADD)
+ assert result == 7
+
+ result = yield from op_sim(dut, 5, 2, MicrOp.OP_ADD, inv_a=1)
+ assert result == 65532
+
+ result = yield from op_sim(dut, 5, 2, MicrOp.OP_ADD, zero_a=1,
+ imm=8, imm_ok=1)
+ assert result == 8
+
+ result = yield from op_sim(dut, 5, 2, MicrOp.OP_ADD, zero_a=1)
+ assert result == 2
+
+ # test combinatorial zero-delay operation
+ # In the test ALU, any operation other than ADD, MUL or SHR
+ # is zero-delay, and do a subtraction.
+ result = yield from op_sim(dut, 5, 2, MicrOp.OP_NOP)
+ assert result == 3
+
+
+def test_compunit():
+
+ m = Module()
+ alu = ALU(16)
+ dut = MultiCompUnit(16, alu, CompALUOpSubset)
+ m.submodules.cu = dut
+
+ vl = rtlil.convert(dut, ports=dut.ports())
+ with open("test_compunit1.il", "w") as f:
+ f.write(vl)
+
+ run_simulation(m, scoreboard_sim(dut), vcd_name='test_compunit1.vcd')
+
+
+class CompUnitParallelTest:
+ def __init__(self, dut):
+ self.dut = dut
+
+ # Operation cycle should not take longer than this:
+ self.MAX_BUSY_WAIT = 50
+
+ # Minimum duration in which issue_i will be kept inactive,
+ # during which busy_o must remain low.
+ self.MIN_BUSY_LOW = 5
+
+ # Number of cycles to stall until the assertion of go.
+ # One value, for each port. Can be zero, for no delay.
+ self.RD_GO_DELAY = [0, 3]
+
+ # store common data for the input operation of the processes
+ # input operation:
+ self.op = 0
+ self.inv_a = self.zero_a = 0
+ self.imm = self.imm_ok = 0
+ self.imm_control = (0, 0)
+ self.rdmaskn = (0, 0)
+ # input data:
+ self.operands = (0, 0)
+
+ # Indicates completion of the sub-processes
+ self.rd_complete = [False, False]
+
+ def driver(self):
+ print("Begin parallel test.")
+ yield from self.operation(5, 2, MicrOp.OP_ADD)
+
+ def operation(self, a, b, op, inv_a=0, imm=0, imm_ok=0, zero_a=0,
+ rdmaskn=(0, 0)):
+ # store data for the operation
+ self.operands = (a, b)
+ self.op = op
+ self.inv_a = inv_a
+ self.imm = imm
+ self.imm_ok = imm_ok
+ self.zero_a = zero_a
+ self.imm_control = (zero_a, imm_ok)
+ self.rdmaskn = rdmaskn
+
+ # Initialize completion flags
+ self.rd_complete = [False, False]
+
+ # trigger operation cycle
+ yield from self.issue()
+
+ # check that the sub-processes completed, before the busy_o cycle ended
+ for completion in self.rd_complete:
+ assert completion
+
+ def issue(self):
+ # issue_i starts inactive
+ yield self.dut.issue_i.eq(0)
+
+ for n in range(self.MIN_BUSY_LOW):
+ yield
+ # busy_o must remain inactive. It cannot rise on its own.
+ busy_o = yield self.dut.busy_o
+ assert not busy_o
+
+ # activate issue_i to begin the operation cycle
+ yield self.dut.issue_i.eq(1)
+
+ # at the same time, present the operation
+ yield self.dut.oper_i.insn_type.eq(self.op)
+ yield self.dut.oper_i.invert_in.eq(self.inv_a)
+ yield self.dut.oper_i.imm_data.imm.eq(self.imm)
+ yield self.dut.oper_i.imm_data.imm_ok.eq(self.imm_ok)
+ yield self.dut.oper_i.zero_a.eq(self.zero_a)
+ rdmaskn = self.rdmaskn[0] | (self.rdmaskn[1] << 1)
+ yield self.dut.rdmaskn.eq(rdmaskn)
+
+ # give one cycle for the CompUnit to latch the data
+ yield
+
+ # busy_o must keep being low in this cycle, because issue_i was
+ # low on the previous cycle.
+ # It cannot rise on its own.
+ # Also, busy_o and issue_i must never be active at the same time, ever.
+ busy_o = yield self.dut.busy_o
+ assert not busy_o
+
+ # Lower issue_i
+ yield self.dut.issue_i.eq(0)
+
+ # deactivate inputs along with issue_i, so we can be sure the data
+ # was latched at the correct cycle
+ # note: rdmaskn must be held, while busy_o is active
+ # TODO: deactivate rdmaskn when the busy_o cycle ends
+ yield self.dut.oper_i.insn_type.eq(0)
+ yield self.dut.oper_i.invert_in.eq(0)
+ yield self.dut.oper_i.imm_data.imm.eq(0)
+ yield self.dut.oper_i.imm_data.imm_ok.eq(0)
+ yield self.dut.oper_i.zero_a.eq(0)
+ yield
+
+ # wait for busy_o to lower
+ # timeout after self.MAX_BUSY_WAIT cycles
+ for n in range(self.MAX_BUSY_WAIT):
+ # sample busy_o in the current cycle
+ busy_o = yield self.dut.busy_o
+ if not busy_o:
+ # operation cycle ends when busy_o becomes inactive
+ break
+ yield
+
+ # if busy_o is still active, a timeout has occurred
+ # TODO: Uncomment this, once the test is complete:
+ # assert not busy_o
+
+ if busy_o:
+ print("If you are reading this, "
+ "it's because the above test failed, as expected,\n"
+ "with a timeout. It must pass, once the test is complete.")
+ return
+
+ print("If you are reading this, "
+ "it's because the above test unexpectedly passed.")
+
+ def rd(self, rd_idx):
+ # wait for issue_i to rise
+ while True:
+ issue_i = yield self.dut.issue_i
+ if issue_i:
+ break
+ # issue_i has not risen yet, so rd must keep low
+ rel = yield self.dut.rd.rel_o[rd_idx]
+ assert not rel
+ yield
+
+ # we do not want rd to rise on an immediate operand
+ # if it is immediate, exit the process
+ # likewise, if the read mask is active
+ # TODO: don't exit the process, monitor rd instead to ensure it
+ # doesn't rise on its own
+ if self.rdmaskn[rd_idx] or self.imm_control[rd_idx]:
+ self.rd_complete[rd_idx] = True
+ return
+
+ # issue_i has risen. rel must rise on the next cycle
+ rel = yield self.dut.rd.rel_o[rd_idx]
+ assert not rel
+
+ # stall for additional cycles. Check that rel doesn't fall on its own
+ for n in range(self.RD_GO_DELAY[rd_idx]):
+ yield
+ rel = yield self.dut.rd.rel_o[rd_idx]
+ assert rel
+
+ # Before asserting "go", make sure "rel" has risen.
+ # The use of Settle allows "go" to be set combinatorially,
+ # rising on the same cycle as "rel".
+ yield Settle()
+ rel = yield self.dut.rd.rel_o[rd_idx]
+ assert rel
+
+ # assert go for one cycle, passing along the operand value
+ yield self.dut.rd.go_i[rd_idx].eq(1)
+ yield self.dut.src_i[rd_idx].eq(self.operands[rd_idx])
+ # check that the operand was sent to the alu
+ # TODO: Properly check the alu protocol
+ yield Settle()
+ alu_input = yield self.dut.get_in(rd_idx)
+ assert alu_input == self.operands[rd_idx]
+ yield
+
+ # rel must keep high, since go was inactive in the last cycle
+ rel = yield self.dut.rd.rel_o[rd_idx]
+ assert rel
+
+ # finish the go one-clock pulse
+ yield self.dut.rd.go_i[rd_idx].eq(0)
+ yield self.dut.src_i[rd_idx].eq(0)
+ yield
+
+ # rel must have gone low in response to go being high
+ # on the previous cycle
+ rel = yield self.dut.rd.rel_o[rd_idx]
+ assert not rel
+
+ self.rd_complete[rd_idx] = True
+
+ # TODO: check that rel doesn't rise again until the end of the
+ # busy_o cycle
+
+ def wr(self, wr_idx):
+ # monitor self.dut.wr.req[rd_idx] and sets dut.wr.go[idx] for one cycle
+ yield
+ # TODO: also when dut.wr.go is set, check the output against the
+ # self.expected_o and assert. use dut.get_out(wr_idx) to do so.
+
+ def run_simulation(self, vcd_name):
+ run_simulation(self.dut, [self.driver(),
+ self.rd(0), # one read port (a)
+ self.rd(1), # one read port (b)
+ self.wr(0), # one write port (o)
+ ],
+ vcd_name=vcd_name)
+
+
+def test_compunit_regspec3():
+
+ inspec = [('INT', 'a', '0:15'),
+ ('INT', 'b', '0:15'),
+ ('INT', 'c', '0:15')]
+ outspec = [('INT', 'o', '0:15'),
+ ]
+
+ regspec = (inspec, outspec)
+
+ m = Module()
+ alu = DummyALU(16)
+ dut = MultiCompUnit(regspec, alu, CompALUOpSubset)
+ m.submodules.cu = dut
+
+ run_simulation(m, scoreboard_sim_dummy(dut),
+ vcd_name='test_compunit_regspec3.vcd')
+
+
+def test_compunit_regspec1():
+
+ inspec = [('INT', 'a', '0:15'),
+ ('INT', 'b', '0:15')]
+ outspec = [('INT', 'o', '0:15'),
+ ]
+
+ regspec = (inspec, outspec)
+
+ m = Module()
+ alu = ALU(16)
+ dut = MultiCompUnit(regspec, alu, CompALUOpSubset)
+ m.submodules.cu = dut
+
+ vl = rtlil.convert(dut, ports=dut.ports())
+ with open("test_compunit_regspec1.il", "w") as f:
+ f.write(vl)
+
+ run_simulation(m, scoreboard_sim(dut),
+ vcd_name='test_compunit_regspec1.vcd')
+
+ test = CompUnitParallelTest(dut)
+ test.run_simulation("test_compunit_parallel.vcd")
+
+
+if __name__ == '__main__':
+ test_compunit()
+ test_compunit_regspec1()
+ test_compunit_regspec3()
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