69 lines
2.3 KiB
Python
69 lines
2.3 KiB
Python
import cocotb
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from cocotb.handle import Immediate
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from cocotb.clock import Clock
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from cocotb.triggers import Timer, RisingEdge
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from collections import defaultdict
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CLK_PERIOD = 5
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memory = defaultdict(int)
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def write_dword(addr: int, data: int):
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memory[addr + 0] = (data >> 0) & 0xff
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memory[addr + 1] = (data >> 8) & 0xff
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memory[addr + 2] = (data >> 16) & 0xff
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memory[addr + 3] = (data >> 24) & 0xff
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async def handle_memory(dut):
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while True:
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await RisingEdge(dut.clk)
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addr = int(dut.AB.value)
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we = bool(dut.WE.value)
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dut.DI.value = memory[addr]
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if we:
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memory[addr] = int(dut.DO.value)
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@cocotb.test
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async def test_absolute(dut):
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cocotb.start_soon(Clock(dut.clk, CLK_PERIOD, unit="ns").start())
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cocotb.start_soon(handle_memory(dut))
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write_dword(0xfffffff4, 0x12345678)
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dut.RDY.value = Immediate(1)
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dut.reset.value = Immediate(1)
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for _ in range(10):
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await RisingEdge(dut.clk)
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dut.reset.value = 0
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expected_cpu_outputs = [
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(0x00000100, True, (int(dut.PC.value) >> 24) & 0xff), # High addr
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(0x000001ff, True, (int(dut.PC.value) >> 16) & 0xff), # Mid high addr
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(0x000001fe, True, (int(dut.PC.value) >> 8) & 0xff), # Mid low addr
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(0x000001fd, True, (int(dut.PC.value) >> 0) & 0xff), # Low addr
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(0x000001fc, True, int(dut.P.value)), # Status
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(0xfffffff4, False, int(dut.regfile.value)), # read vector byte 0
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(0xfffffff5, False, int(dut.regfile.value)), # read vector byte 1
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(0xfffffff6, False, int(dut.regfile.value)), # read vector byte 2
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(0xfffffff7, False, int(dut.regfile.value)), # read vector byte 3
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(0x12345678, False, int(dut.regfile.value)), # Load PC with vector
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(0x12345678, False, int(dut.regfile.value)), # Read first instruction
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]
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for expected_output in expected_cpu_outputs:
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await RisingEdge(dut.clk)
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expected_addr, expected_we, expected_do = expected_output
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dut_addr = int(dut.AB.value)
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dut_we = bool(dut.WE.value)
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dut_do = int(dut.DO.value)
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assert dut_addr == expected_addr
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assert dut_we == expected_we
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assert dut_do == expected_do
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