def bench():
opcode = Signal(alu_opcode_t.alu_add)
operand_0 = Signal(data_bus(0))
operand_1 = Signal(data_bus(0))
result = Signal(data_bus(0))
alu = ALU(opcode, operand_0, operand_1, result)
@instance
def stimulus():
for i in range(100):
for operator, compute_result in (
(alu_opcode_t.alu_add, lambda a, b: a + b),
(alu_opcode_t.alu_sub, lambda a, b: a - b),
):
a = random.randrange(-2 ** 30, 2 ** 30)
b = random.randrange(-2 ** 30, 2 ** 30)
expect = compute_result(a, b)
opcode.next = operator
operand_0.next = data_bus(a)
operand_1.next = data_bus(b)
yield delay(10)
assert result.signed() == expect
return alu, stimulus
def bench(number_of_registers = 32, ram_from_file = False):
def ClockDriver(clock, period = 100):
@always(delay(period / 2))
def drive_clock():
clock.next = not clock
return drive_clock
clock = Signal(False)
clock_driver = ClockDriver(clock)
abus = Signal(data_bus(0))
dbus = Signal(data_bus(0))
data_in = Signal(data_bus(0))
write_enabled = Signal(False)
ram = Ram(
clock,
dbus, data_in,
abus,
write_enabled,
from_file = ram_from_file,
)
processor = Processor(clock, dbus, abus)
return clock_driver, ram, processor
def logic():
opcode.next = opcode_t.add
operand_0.next = data_bus(1)
operand_1.next = data_bus(1)
update_select_a.next = 0
update_value_a.next = 0
update_select_b.next = 0
update_value_b.next = 0
write_enabled.next = False
select_a.next = 0
select_b.next = 0
def bench(number_of_registers = 32):
update_select_a = Signal(intbv(min = 0, max = number_of_registers))
update_value_a = Signal(data_bus(0))
update_select_b = Signal(intbv(min = 0, max = number_of_registers))
update_value_b = Signal(data_bus(0))
write_enabled = Signal(False)
select_a = Signal(intbv(min = 0, max = number_of_registers))
result_a = Signal(data_bus(0))
select_b = Signal(intbv(min = 0, max = number_of_registers))
result_b = Signal(data_bus(0))
clock = Signal(False)
register_bank = RegisterBank(
update_select_a, update_value_a,
update_select_b, update_value_b,
write_enabled,
select_a, result_a,
select_b, result_b,
clock,
number_of_registers,
)
@instance
def stimulus():
for i in range(number_of_registers):
for v in range(100):
update_select_a.next = i
update_value_a.next = v
update_select_b.next = i
update_value_b.next = v
write_enabled.next = True
clock.next = True
yield delay(10)
clock.next = False
yield delay(10)
write_enabled.next = False
select_a.next = i
select_b.next = i
clock.next = True
yield delay(10)
clock.next = False
yield delay(10)
assert result.signed() == v
return register_bank, stimulus
def stimulus():
for i in range(100):
for operator, compute_result in (
(alu_opcode_t.alu_add, lambda a, b: a + b),
(alu_opcode_t.alu_sub, lambda a, b: a - b),
):
a = random.randrange(-2 ** 30, 2 ** 30)
b = random.randrange(-2 ** 30, 2 ** 30)
expect = compute_result(a, b)
opcode.next = operator
operand_0.next = data_bus(a)
operand_1.next = data_bus(b)
yield delay(10)
assert result.signed() == expect
def bench(number_of_ram=128):
address = Signal(intbv(min = 0, max = number_of_ram))
data_in = Signal(data_bus(0))
data_out = Signal(data_bus(0))
write_enabled = Signal(False)
clock = Signal(False)
ram = Ram(
clock,
data_out, data_in,
address,
write_enabled,
number_of_ram,
)
@instance
def stimulus():
for i in range(number_of_ram):
for v in range(100):
write_enabled.next = True
address.next = i
data_in.next = v
clock.next = True
yield delay(10)
clock.next = False
yield delay(10)
write_enabled.next = False
address.next = i
clock.next = True
yield delay(10)
clock.next = False
yield delay(10)
result = data_out.next
assert result.signed() == v
return ram, stimulus
def Processor(clock, dbus, abus):
number_of_registers = 32
alu_opcode = Signal(alu_opcode_t.alu_add)
operand_0 = Signal(data_bus(0))
operand_1 = Signal(data_bus(0))
result = Signal(data_bus(0))
alu = ALU(alu_opcode, operand_0, operand_1, result)
update_select_a = Signal(intbv(min = 0, max = number_of_registers))
update_value_a = Signal(data_bus(0))
update_select_b = Signal(intbv(min = 0, max = number_of_registers))
update_value_b = Signal(data_bus(0))
write_enabled = Signal(False)
select_a = Signal(intbv(min = 0, max = number_of_registers))
value_a = Signal(data_bus(0))
select_b = Signal(intbv(min = 0, max = number_of_registers))
value_b = Signal(data_bus(0))
register_bank = RegisterBank(
update_select_a, update_value_a,
update_select_b, update_value_b,
write_enabled,
select_a, value_a,
select_b, value_b,
clock,
)
opcode = Signal(data_bus(0))
control_unit = ControlUnit(
clock,
opcode,
alu_opcode, operand_0, operand_1, result,
update_select_a, update_value_a,
update_select_b, update_value_b,
write_enabled,
select_a, value_a,
select_b, value_b,
dbus, abus,
)
return alu, register_bank, control_unit
def RegisterBank(
update_select_a, update_value_a,
update_select_b, update_value_b,
write_enabled,
select_a, value_a,
select_b, value_b,
clock,
number_of_registers = 32):
'''
Comment
'''
registers = [Signal(data_bus(0)) for i in range(number_of_registers)]
@always_comb
def read_logic():
'''
Handles reads to the register bank.
'''
if select_a == ZERO_REGISTER:
value_a.next = 0
else:
value_a.next = registers[select_a]
if select_b == ZERO_REGISTER:
value_b.next = 0
else:
value_b.next = registers[select_b]
@always(clock.posedge)
def logic():
'''
Updates the values stored in the register bank.
'''
if write_enabled:
if update_select_a != ZERO_REGISTER:
registers[update_select_a].next = update_value_a
if update_select_b != ZERO_REGISTER:
registers[update_select_b].next = update_value_b
return logic, read_logic
def Processor(clock):
number_of_registers = 32
opcode = Signal(opcode_t.add)
operand_0 = Signal(data_bus(0))
operand_1 = Signal(data_bus(0))
result = Signal(data_bus(0))
alu = ALU(opcode, operand_0, operand_1, result)
update_select_a = Signal(intbv(min = 0, max = number_of_registers))
update_value_a = Signal(data_bus(0))
update_select_b = Signal(intbv(min = 0, max = number_of_registers))
update_value_b = Signal(data_bus(0))
write_enabled = Signal(False)
select_a = Signal(intbv(min = 0, max = number_of_registers))
value_a = Signal(data_bus(0))
select_b = Signal(intbv(min = 0, max = number_of_registers))
value_b = Signal(data_bus(0))
register_bank = RegisterBank(
update_select_a, update_value_a,
update_select_b, update_value_b,
write_enabled,
select_a, value_a,
select_b, value_b,
clock,
)
@always(clock.posedge)
def logic():
opcode.next = opcode_t.add
operand_0.next = data_bus(1)
operand_1.next = data_bus(1)
update_select_a.next = 0
update_value_a.next = 0
update_select_b.next = 0
update_value_b.next = 0
write_enabled.next = False
select_a.next = 0
select_b.next = 0
return alu, register_bank, logic
def RegisterBank(
update_select_a, update_value_a,
update_select_b, update_value_b,
write_enabled,
select_a, value_a,
select_b, value_b,
clock,
number_of_registers = 32):
'''
Comment
'''
registers = [Signal(data_bus(0)) for i in range(number_of_registers)]
@always_comb
def read_logic():
value_a.next = registers[select_a]
value_b.next = registers[select_b]
@always_comb
def read_logic():
value_a.next = registers[select_a]
value_b.next = registers[select_b]
@always(clock.posedge)
def logic():
'''
Updates the values stored in the register bank. Also handles reads.
'''
if write_enabled:
registers[update_select_a] = update_value_a
registers[update_select_b] = update_value_b
return logic, read_logic
assert result.signed() == v
return ram, stimulus
def test_bench():
sim = Simulation(traceSignals(bench))
sim.run()
if __name__ == '__main__':
from myhdl import toVHDL
number_of_ram=128
addressess = Signal(intbv(min = 0, max = number_of_ram))
data_in = Signal(data_bus(0))
data_out = Signal(data_bus(0))
write_enabled = Signal(False)
clock = Signal(False)
toVHDL(
Ram,
data_in, data_out,
addressess,
write_enabled,
clock,
number_of_ram,
)
write_enabled,
from_file = ram_from_file,
)
processor = Processor(clock, dbus, abus)
return clock_driver, ram, processor
def test_bench(ram_from_file):
sim = Simulation(traceSignals(bench, ram_from_file = ram_from_file))
sim.run()
if __name__ == '__main__':
import sys
if sys.argv[1] == 'convert':
from myhdl import toVHDL
clock = Signal(False)
abus = Signal(data_bus(0))
dbus = Signal(data_bus(0))
toVHDL(
Processor,
clock,
dbus,
abus,
)
else:
test_bench(open(sys.argv[1]))
assert result.signed() == v
return register_bank, stimulus
def test_bench():
sim = Simulation(traceSignals(bench))
sim.run()
if __name__ == '__main__':
from myhdl import toVHDL
number_of_registers = 32
update_select_a = Signal(intbv(min = 0, max = number_of_registers))
update_value_a = Signal(data_bus(0))
update_select_b = Signal(intbv(min = 0, max = number_of_registers))
update_value_b = Signal(data_bus(0))
write_enabled = Signal(False)
select_a = Signal(intbv(min = 0, max = number_of_registers))
result_a = Signal(data_bus(0))
select_b = Signal(intbv(min = 0, max = number_of_registers))
result_b = Signal(data_bus(0))
clock = Signal(False)
toVHDL(
RegisterBank,
update_select_a, update_value_a,
update_select_b, update_value_b,
(alu_opcode_t.alu_add, lambda a, b: a + b),
(alu_opcode_t.alu_sub, lambda a, b: a - b),
):
a = random.randrange(-2 ** 30, 2 ** 30)
b = random.randrange(-2 ** 30, 2 ** 30)
expect = compute_result(a, b)
opcode.next = operator
operand_0.next = data_bus(a)
operand_1.next = data_bus(b)
yield delay(10)
assert result.signed() == expect
return alu, stimulus
def test_bench():
sim = Simulation(traceSignals(bench))
sim.run()
if __name__ == '__main__':
from myhdl import toVHDL
opcode = Signal(alu_opcode_t.alu_add)
operand_0 = Signal(data_bus(0))
operand_1 = Signal(data_bus(0))
result = Signal(data_bus(0))
toVHDL(ALU, opcode, operand_0, operand_1, result)
def ControlUnit(
clock,
instruction,
alu_opcode, operand_0, operand_1, result,
update_select_a, update_value_a,
update_select_b, update_value_b,
write_enabled,
select_a, value_a,
select_b, value_b,
dbus, abus,
):
'''
Pipeline stages:
0 - decode instruction
1 - load operands
2 - compute
3 - store result
'''
# todo: find a more appropriate name for this variable
depth = 4
p_opcode = [Signal(opcode_t.op_nop) for i in range(depth)]
p_conditional = [Signal(conditional_t.al) for i in range(depth)]
p_alu_opcode = [Signal(alu_opcode_t.alu_sub) for i in range(depth)]
p_is_alu_opcode = [Signal(False) for i in range(depth)]
p_modify_status = [Signal(False) for i in range(depth)]
p_argument_0 = [Signal(intbv()[5:]) for i in range(depth)]
p_argument_1 = [Signal(intbv()[19:]) for i in range(depth)]
p_argument_2 = [Signal(intbv()[5:]) for i in range(depth)]
p_argument_3 = [Signal(intbv()[9:]) for i in range(depth)]
p_result = [Signal(data_bus(0)) for i in range(depth)]
p_is_valid = [Signal(True) for i in range(depth)]
d_instruction = Signal(data_bus(0))
d_opcode = Signal(opcode_t.op_nop)
d_conditional = Signal(conditional_t.al)
d_modify_status = Signal(False)
d_is_alu_opcode = Signal(False)
d_alu_opcode = Signal(alu_opcode_t.alu_add)
d_argument_0 = Signal(intbv()[5:])
d_argument_1 = Signal(intbv()[19:])
d_argument_2 = Signal(intbv()[5:])
d_argument_3 = Signal(intbv()[9:])
instruction_register = Signal(intbv()[32:])
instruction_decoder = InstructionDecoder(
d_instruction,
d_opcode,
d_conditional,
d_modify_status,
d_is_alu_opcode, d_alu_opcode,
d_argument_0, d_argument_1, d_argument_2, d_argument_3)
@always(clock.posedge)
def logic():
'''
push pipeline register values
'''
for i in range(depth - 1):
p_opcode[i + 1].next = p_opcode[i]
p_alu_opcode[i + 1].next = p_alu_opcode[i]
p_is_alu_opcode[i + 1].next = p_is_alu_opcode[i]
p_modify_status[i + 1].next = p_modify_status[i]
p_argument_0[i + 1].next = p_argument_0[i]
p_argument_1[i + 1].next = p_argument_1[i]
p_argument_2[i + 1].next = p_argument_2[i]
p_argument_3[i + 1].next = p_argument_3[i]
p_result[i + 1].next = p_result[i]
p_is_valid[i + 1].next = p_is_valid[i]
'''
increment instruction register
'''
instruction_register.next = instruction_register + 1
'''
0th stage - fetch instruction
'''
abus.next = instruction_register
'''
1st stage - decode instruction
'''
d_instruction.next = dbus
'''
2nd stage - load operands
'''
# note the index is 1 b/c of signal semantics!
'''
- remember decoding result
'''
p_opcode[1].next = d_opcode
p_alu_opcode[1].next = d_alu_opcode
p_is_alu_opcode[1].next = d_is_alu_opcode
p_modify_status[1].next = d_modify_status
p_argument_0[1].next = d_argument_0
p_argument_1[1].next = d_argument_1
p_argument_2[1].next = d_argument_2
p_argument_3[1].next = d_argument_3
'''
- load operands
'''
select_a.next = d_argument_0
select_b.next = d_argument_1
'''
3rd stage - execute
'''
alu_opcode.next = p_alu_opcode[2]
operand_0.next = value_a
operand_1.next = value_b
p_result[3].next = result
'''
- handle branches
'''
if p_opcode[2] == opcode_t.op_br:
for i in range(1, 3):
p_is_valid[i].next = False
# todo: this is a quick and dirty absolute jump
instruction_register.next = p_argument_0[2]
'''
4th stage - store result
'''
write_enabled.next = False
if not p_is_valid[3]:
return
if p_is_alu_opcode[3]:
update_select_a.next = p_argument_2[3]
update_value_a.next = p_result[3]
write_enabled.next = True
elif p_opcode[3] == opcode_t.op_li:
update_select_a.next = p_argument_0[3]
update_value_a.next = p_argument_1[3]
write_enabled.next = True
return instruction_decoder, logic
