diff options
author | jjsuperpower <jjs29356@gmail.com> | 2022-09-05 20:10:16 -0500 |
---|---|---|
committer | jjsuperpower <jjs29356@gmail.com> | 2022-09-05 20:10:16 -0500 |
commit | cb06c203a8e9f57d0ff61bf55007946b4eb542ef (patch) | |
tree | 9167a1f99edebdc4c9c31850f800435a70a77f6c /hdl | |
parent | 63626f2f6fc7e8912a349f120e37998cd1a05554 (diff) |
honestly i don't know what I did
Diffstat (limited to 'hdl')
-rw-r--r-- | hdl/core/reg.py | 304 | ||||
-rw-r--r-- | hdl/utils.py | 6 |
2 files changed, 307 insertions, 3 deletions
diff --git a/hdl/core/reg.py b/hdl/core/reg.py new file mode 100644 index 0000000..b6aa3c5 --- /dev/null +++ b/hdl/core/reg.py @@ -0,0 +1,304 @@ +from amaranth import * +from amaranth.sim import Settle + +from hdl.lib.in_out_buff import InOutBuff +from hdl.utils import cmd, step, sim + +class Reg(Elaboratable): + def __init__(self, **kargs): # sim is only for modularity, does nothing for this + + ################ INPUTS ################ + self.wr_en = Signal(1) + self.stall = Signal(1) # stall instruction pointer increment + + self.rd = Signal(32) + self.rd_addr = Signal(4) + self.rs1_addr = Signal(4) + self.rs2_addr = Signal(4) + + self.alu_flgs = Signal(5) # flags from alu + + # these signals should be used one hot only + self.int_sig = Signal(1) # unconditional interrupt + self.iret = Signal(1) # return from interrupt + self.call = Signal(1) # call subroutine, save return address + self.jump = Signal(1) # jump, do not save return address + + + ################ OUTPUTS ################ + + self.rs1 = Signal(32) # read data 1 + self.rs2 = Signal(32) # read data 2 + + self.int_en = Signal(1) #interupt enable output signal to control unit + self.user_mode = Signal(1) # user mode output signal to control unit + + + ################ INTERNAL SIGNALS ################ + self._wr_alu_flg = Signal(1) + self._inc_ip = Signal(1) + + self.zx = Signal(32) #0 + self.ax = Signal(32) #1 + self.bx = Signal(32) #2 + self.bx = Signal(32) #3 + self.cx = Signal(32) #4 + self.dx = Signal(32) #5 + self.ex = Signal(32) #6 + self.fx = Signal(32) #7 + self.gx = Signal(32) #8 + self.hx = Signal(32) #9 + self.ip = Signal(32) #10 + self.sp = Signal(32) #11 + self.flg = Signal(32) #12 + self.cs0 = Signal(32) #13 + self.cs1 = Signal(32) #14 + self.cs2 = Signal(32) #15 + self.pda = Signal(32) #16 + + # for sake of modularity, make bit locations easily configurable + setattr(self.flg, 'c', self.flg[0]) + setattr(self.flg, 'ov', self.flg[1]) + setattr(self.flg, 'z', self.flg[2]) + setattr(self.flg, 'n', self.flg[3]) + setattr(self.flg, 'od', self.flg[4]) + setattr(self.flg, 'int', self.flg[16]) + setattr(self.flg, 'user_mode', self.flg[17]) + setattr(self.flg, 'page_en', self.flg[18]) + + + reg_list = [self.zx, self.ax, self.bx, self.cx, self.dx, self.ex, self.fx, self.gx, self.hx, self.ip, self.sp, self.flg, self.cs0, self.cs1, self.cs2, self.pda] + for idx, reg in enumerate(reg_list): + setattr(reg, 'idx', idx) # set idx attribute to each register + + self.reg_arr = Array(reg_list) + + ports_in = [self.wr_en, self.alu_flgs, self.int_sig, self.iret, self.call, self.jump, self.rd_addr, self.rd, self.rs1_addr, self.rs2_addr] + ports_out = [self.int_en, self.user_mode, self.rs1, self.rs2, self.ip] + self.ports = {'in': ports_in, 'out': ports_out} + + + def elaborate(self, platform=None): + m = Module() + + # output signals to control unit + m.d.comb += self.int_en.eq(self.flg.int) + m.d.comb += self.user_mode.eq(self.flg.user_mode & ~self.int_sig) + + # defualt value of internal signals + m.d.comb += self._wr_alu_flg.eq(1) + m.d.comb += self._inc_ip.eq(1) + + with m.If(self.int_sig): + m.d.comb += self._inc_ip.eq(0) + m.d.sync += self.ip.eq(self.rd) + m.d.sync += self.cs0.eq(self.ip) + m.d.sync += self.cs1.eq(self.sp) + m.d.sync += self.cs2.eq(self.flg) + m.d.sync += self.flg.user_mode.eq(0) # set to system mode or iret cannot be used + m.d.sync += self.flg.int.eq(0) # clear int flag, essential because another interrupt can be triggered without this + + with m.Elif(self.iret): + m.d.comb += self._inc_ip.eq(0) + m.d.sync += self.ip.eq(self.cs0) + m.d.sync += self.sp.eq(self.cs1) + m.d.sync += self.flg.eq(self.cs2) + + with m.Elif(self.call): + m.d.comb += self._inc_ip.eq(0) + m.d.sync += self.ip.eq(self.rd) + m.d.sync += self.cs0.eq(self.ip) + + with m.Elif(self.jump): + m.d.comb += self._inc_ip.eq(0) + m.d.sync += self.ip.eq(self.cs0) + + with m.Elif(self.wr_en): + with m.Switch(self.rd_addr): + with m.Case(self.zx.idx): # do not write to zero register + pass + + with m.Case(self.ip.idx): #do not directly write to ip register + pass + + with m.Case(self.flg.idx): + # mask top half of register to prevent writing to flags in user mode + with m.If(~self.flg.user_mode): + m.d.sync += self.flg.eq(self.rd) # system mode, full control + with m.Else(): + m.d.sync += self.flg.eq(Cat(self.rd[:16], self.flg[16:])) # usermode can only effect lower 16 bits + + # don't update flags from alu + m.d.comb += self._wr_alu_flg.eq(0) + + with m.Case(): + m.d.sync += self.reg_arr[self.rd_addr].eq(self.rd) + + with m.If(self._wr_alu_flg): # alu flags are written only if write enabled and not writing to flags register + m.d.sync += self.flg.eq(Cat(self.alu_flgs, self.flg[len(self.alu_flgs):])) + + + with m.If(self._inc_ip & ~self.stall): # increment ip if not directly writing to ip register + m.d.sync += self.ip.eq(self.ip + 4) + + + ### Combination signal outputs ### + with m.Switch(self.rs1_addr): + with m.Case(self.flg.idx): + m.d.comb += self.rs1.eq(self.flg & Cat(Const(0xFFFF, 16), Repl(~self.flg.user_mode, 16))) + with m.Case(): + m.d.comb += self.rs1.eq(self.reg_arr[self.rs1_addr]) + + with m.Switch(self.rs2_addr): + with m.Case(self.flg.idx): + m.d.comb += self.rs2.eq(self.flg & Cat(Const(0xFFFF, 16), Repl(~self.flg.user_mode, 16))) + with m.Case(): + m.d.comb += self.rs2.eq(self.reg_arr[self.rs2_addr]) + + return m + + +#--------------------------------- TEST BENCH BELOW ---------------------------------# + +def _init(dut): + for i in range(16): + yield dut.reg_arr[i].eq(i) + yield Settle() + + +# test combinational output +def test_reg_comb_output(): + dut = Reg() + def proc(): + yield from _init(dut) + for i in range(16): + yield dut.rs1_addr.eq(i) + yield Settle() + assert (yield dut.rs1) == i, f'ERROR reading {dut.reg_arr[i].name} != {i}' + for i in range(16): + yield dut.rs2_addr.eq(i) + yield Settle() + assert (yield dut.rs2) == i, f'ERROR reading {dut.reg_arr[i].name} != {i}' + sim(dut, proc) + +# test writeback with writeback disabled +def test_reg_writeback_dsb(): + dut = Reg() + def proc(): + yield from _init(dut) + for i in range(16): + yield dut.rd_addr.eq(i) + yield dut.rd.eq(i + 1) + yield from step() + if (i != dut.ip.idx) and (i != dut.flg.idx): # flag gets update by the alu + assert (yield dut.reg_arr[i]) == i, f'ERROR writing to {dut.reg_arr[i].name} != {i}' + sim(dut, proc) + +# test writeback with writeback enabled +def test_reg_writeback_en(): + dut = Reg() + def proc(): + for i in range(16): + yield from _init(dut) + yield dut.wr_en.eq(1) + yield dut.rd_addr.eq(i) + yield dut.rd.eq(i - 1) + yield from step() + if (i != dut.zx.idx) and (i != dut.ip.idx): + assert (yield dut.reg_arr[i]) == i-1, f'ERROR writing to {dut.reg_arr[i].name} != {i-1}' + elif i == dut.zx.idx: + assert (yield dut.zx) == 0, f'ERROR {dut.zx.name} != 0' + elif i == dut.ip.idx: + # ip should be incremented and not written to + assert (yield dut.reg_arr[i]) == i+1, f'ERROR {dut.ip.name} != {i + 1} should not be able to be directly written to' + sim(dut, proc) + +# check to make sure alu is writing values +def test_reg_flg_write_aluflg(): + dut = Reg() + def proc(): + yield dut.flg.eq(0) + yield dut.alu_flgs.eq(Repl(1, dut.alu_flgs.width)) + yield dut.wr_en.eq(1) + yield dut.flg.user_mode.eq(0) + yield dut.rd_addr.eq(dut.zx.idx) # can be anything except flg register + yield dut.rd.eq(0xFFFF0000) # this does not matter + yield from step() + assert (yield dut.flg) == (yield dut.alu_flgs), f'ERROR: alu is not writing to flg register' + sim(dut, proc) + +def test_reg_flg_overwrite(): + dut = Reg() + def proc(): + yield dut.flg.eq(0) + yield dut.alu_flgs.eq(Repl(1, dut.alu_flgs.width)) + yield dut.wr_en.eq(1) + yield dut.flg.user_mode.eq(0) + yield dut.flg[15].eq(1) + yield dut.flg[31].eq(1) + yield dut.rd_addr.eq(dut.flg.idx) + yield dut.rd.eq(0xFFFF0000) + yield from step() + assert (yield dut.flg) == (0xFFFF0000), f'ERROR: alu status should not be to flag' + sim(dut, proc) + +# test flag register security +def test_reg_flg_read_usermode(): + dut = Reg() + def proc(): + yield dut.flg.eq(0) + yield dut.flg.user_mode.eq(1) + yield dut.flg[15].eq(1) + yield dut.flg[31].eq(1) + yield dut.rs1_addr.eq(dut.flg.idx) + yield Settle() + assert (yield dut.rs1) == 0x00008000, f'ERROR: able to read upper 16 bits of flg reg in user mode' + sim(dut, proc) + +# test flag register security +def test_reg_flg_write_usermode(): + dut = Reg() + def proc(): + yield dut.flg.eq(0) + yield dut.wr_en.eq(1) + yield dut.flg.user_mode.eq(1) + yield dut.flg[15].eq(1) + yield dut.flg[31].eq(1) + yield dut.rd_addr.eq(dut.flg.idx) + yield dut.rd.eq(0xABCD5789) + yield from step() + assert (yield dut.flg) == (0x80020000 | 0x5789), f'ERROR: able to write to upper 16 bits of flg reg in user mode' + sim(dut, proc) + +def test_reg_flg_read_systemmode(): + dut = Reg() + def proc(): + yield dut.flg.eq(0) + yield dut.flg.user_mode.eq(0) + yield dut.flg[15].eq(1) + yield dut.flg[31].eq(1) + yield dut.rs1_addr.eq(dut.flg.idx) + yield Settle() + assert (yield dut.rs1) == 0x80008000, f'ERROR: able to read all bits of flg reg in system mode' + sim(dut, proc) + +# make sure not to write alu flags when directly writing to flg register +def test_reg_flg_write_systemmode(): + dut = Reg() + def proc(): + yield dut.flg.eq(0) + yield dut.wr_en.eq(1) + yield dut.flg.user_mode.eq(0) + yield dut.flg[15].eq(1) + yield dut.flg[31].eq(1) + yield dut.rd_addr.eq(dut.flg.idx) + yield dut.rd.eq(0xABCD5789) + yield from step() + assert (yield dut.flg) == (0xABCD5789), f'ERROR: unamble to write to all bits in supervisor mode' + sim(dut, proc) + + + +if __name__ == '__main__': + reg = InOutBuff(Reg()) + cmd(reg)
\ No newline at end of file diff --git a/hdl/utils.py b/hdl/utils.py index 80dc3ee..b496356 100644 --- a/hdl/utils.py +++ b/hdl/utils.py @@ -26,12 +26,12 @@ def cmd(hdl): if sys.argv[1] == "v": out = verilog.convert(hdl, ports=hdl.ports['in'] + hdl.ports['out']) - with open(os.path.join(VERILOG_DIR, sys.argv[0].replace('.py', '.v')), 'w') as f: + with open(os.path.join(VERILOG_DIR, os.path.basename(sys.argv[0]).replace('.py', '.v')), 'w') as f: f.write(out) elif sys.argv[1] == "cc": out = cxxrtl.convert(hdl, ports=hdl.ports['in'] + hdl.ports['out']) - with open(os.path.join(CXXRTL_DIR, sys.argv[0].replace('.py', '.cc')), 'w') as f: + with open(os.path.join(CXXRTL_DIR, os.path.basename(sys.argv[0]).replace('.py', '.cc')), 'w') as f: f.write(out) @@ -41,7 +41,7 @@ def sim(dut:Elaboratable, proc: Callable): sim.add_clock(1e-6) sim.add_sync_process(proc) - with sim.write_vcd(os.path.join(VCD_DIR, stack()[1].function + '.vcd')): + with sim.write_vcd(os.path.join(VCD_DIR, stack()[1].function + '.vcd')): # get name of caller function sim.run() def step(cycles=1): |