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4 changed files with 17 additions and 251 deletions
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98
lib/DelayLine.bsv
View File

@ -1,98 +0,0 @@
package DelayLine;
import List::*;
// A DelayLine mirrors writes back as reads after a number of delay
// cycles. Delay lines are pipelined and multiple values can be "in
// flight" at once.
//
// Reads block until a value is available, but the DelayLine doesn't
// stall if there are no readers - the value is available for reading
// after the set delay, and is lost if not read by anything.
//
// For callers that need to check for a value without tripping over an
// implicit condition, ready() can poll the delay line's output
// without blocking.
interface DelayLine#(type value);
method Action _write (value v);
method value _read();
(* always_ready *)
method Bool ready();
endinterface
// mkDelayLine constructs a DelayLine with delay_cycles of latency
// between writes and reads. delay_cycles may be zero, with the result
// being Wire/RWire like scheduling semantics.
module mkDelayLine(Integer delay_cycles, DelayLine#(a) ifc)
provisos (Bits#(a, a_sz));
// In most cases a DelayLine is a pipeline of registers through
// which values flow, and so it inherits the scheduling properties
// of registers: all reads from the delay line happen before any
// writes take effect.
//
// The exception is when the caller asks for zero cycles of delay:
// in that case, a write must be visible to reads within the same
// cycle, and thus the write to the delay line must execute before
// any reads.
//
// So, handle a delay of 0 cycles specially and implement it as an
// RWire, which has write-before-read behavior. Otherwise, build a
// pipeline of registers with read-before-write behavior.
//
// You might wonder why even bother allowing a DelayLine with zero
// delay. It's because doing so is handy in parameterized
// modules. Say for example you're wrapping a blackbox module that
// has optional input and output registers. Depending on the
// parameters, the in->out delay could be 0 cycles (pure
// combinatorial circuit), 1 cycle (input or output register) or 2
// cycles (input and output register). It's very handy to be able
// to plop down a DelayLine regardless of the requested
// configuration, and have it gracefully go all the way to zero
// latency.
if (delay_cycles == 0) begin
RWire#(a) w <- mkRWire();
method Action _write(a value);
w.wset(value);
endmethod
method a _read() if (w.wget matches tagged Valid .val);
return val;
endmethod
method Bool ready();
return isValid(w.wget);
endmethod
end
else begin
RWire#(a) inputVal <- mkRWire;
// Note that in rules and modules, for loops get unrolled
// statically at compile time. We're not specifying a circuit
// that runs a loop in hardware here, this is shorthand for
// "splat out N registers and wire them together in a line".
List#(Reg#(Maybe#(a))) delay = Nil;
for (Integer i = 0; i < delay_cycles; i = i+1) begin
let r <- mkReg(Invalid);
delay = cons(r, delay);
end
(* no_implicit_conditions, fire_when_enabled *)
rule pump_line;
delay[0] <= inputVal.wget();
for (Integer i = 0; i < delay_cycles-1; i = i+1)
delay[i+1] <= delay[i];
endrule
method Action _write(a value);
inputVal.wset(value);
endmethod
method a _read() if (delay[delay_cycles-1] matches tagged Valid .val);
return val;
endmethod
method Bool ready();
return isValid(delay[delay_cycles-1]);
endmethod
end
endmodule
endpackage

85
lib/DelayLine_Test.bsv
View File

@ -1,85 +0,0 @@
package DelayLine_Test;
import Assert::*;
import StmtFSM::*;
import Testing::*;
import Printf::*;
import List::*;
import DelayLine::*;
module mkTB();
let cycles <- mkCycleCounter();
function Stmt testDelayLine(DelayLine#(Int#(8)) delay, Bit#(32) wantDelay);
seq
action
delay <= 42;
cycles.reset();
$display(" write cycle: %0d", cycles.all);
endaction
repeat (wantDelay-1)
action
if (delay.ready) begin
$display("delay line ready after %0d cycles, want %0d (on cycle %0d)", cycles, wantDelay, cycles.all);
$finish;
end
endaction
// Check the value coming off the delay line and the timing
// separately, since the delay line read can be blocked by
// implicit conditions.
par
dynamicAssert(delay == 42, "delay output was wrong value");
action
dynamicAssert(delay.ready == True, "delay line not ready when expected");
if (cycles != wantDelay) begin
$display("delay line became ready after %0d cycles, want %0d (on cycle %0d)", cycles, wantDelay, cycles.all);
$finish;
end
$display(" read cycle: %0d", cycles.all);
endaction
endpar
dynamicAssert(delay.ready == False, "delay line still ready after value yield");
endseq;
endfunction
let delay0 <- mkDelayLine(0);
let delay1 <- mkDelayLine(1);
let delay2 <- mkDelayLine(2);
let delay3 <- mkDelayLine(3);
let delay4 <- mkDelayLine(4);
let test0 = seq
dynamicAssert(delay0.ready == False, "delay line ready before put");
par
action
delay0 <= 42;
$display(" write cycle: %0d", cycles.all);
endaction
action
dynamicAssert(delay0.ready == True, "delay line not ready on same cycle");
$display(" read cycle: %0d", cycles.all);
endaction
dynamicAssert(delay0 == 42, "delay line has wrong value");
endpar
dynamicAssert(delay0.ready == False, "delay line ready without write");
endseq;
runTest(100,
mkTest("DelayLine", seq
mkTest("DelayLine/0", test0);
mkTest("DelayLine/1", testDelayLine(delay1, 1));
mkTest("DelayLine/2", testDelayLine(delay2, 2));
mkTest("DelayLine/3", testDelayLine(delay3, 3));
mkTest("DelayLine/4", testDelayLine(delay4, 4));
endseq));
endmodule
endpackage

63
lib/Testing.bsv
View File

@ -2,65 +2,22 @@ package Testing;
import Assert::*;
import StmtFSM::*;
import Cntrs::*;
// A CycleCounter keeps a count of total elapsed cycles in a
// simulation, as well as cycles since the last reset.
interface CycleCounter;
// _read returns the number of cycles since the last time reset()
// was called.
method Bit#(32) _read();
// reset resets the cycle counter. The counter will read 1 on the
// cycle following the call to reset.
method Action reset();
module mkTestCycleLimit#(Integer max_cycles)();
Reg#(UInt#(64)) c <- mkReg(fromInteger(max_cycles));
// all returns the number of cycles elapsed since simulation start,
// for use in $display and the like.
method Bit#(32) all();
endinterface
module mkCycleCounter(CycleCounter);
let total <- mkCount(0);
let cnt <- mkCount(0);
(* no_implicit_conditions, fire_when_enabled *)
rule count_up;
cnt.incr(1);
total.incr(1);
rule count;
dynamicAssert(c > 0, "FAIL: test timed out");
c <= c-1;
endrule
method _read = cnt._read;
method Action reset();
cnt.update(0);
endmethod
method all = total._read;
endmodule
// mkTest runs the given test, printing status text before and after
// the run. Tests can be nested.
function Stmt mkTest(String name, Stmt test);
seq
$display("RUN %s", name);
test;
$display("OK %s", name);
endseq;
endfunction
// runTest runs the given test with a timeout.
module runTest(Integer cycle_limit, Stmt test, Empty ifc);
Bit#(32) max = fromInteger(cycle_limit);
let cnt <- mkCount(0);
(* no_implicit_conditions, fire_when_enabled *)
rule cycle_deadline;
dynamicAssert(cnt < max, "Test timed out");
cnt.incr(1);
endrule
module mkTest#(String name, RStmt#(Bit#(0)) test)();
mkAutoFSM(seq
$display("Running test with %0d cycle timeout", max);
test;
endseq);
$display("RUN ", name);
test;
$display("OK ", name);
endseq);
endmodule
endpackage

22
tasks.py
View File

@ -92,18 +92,13 @@ def build(c, target="."):
c.run(f"bsc -aggressive-conditions -check-assert -u -verilog -info-dir {out_info} -vdir {out_verilog} -bdir {out_bsc} -p {target.parent}:lib:%/Libraries -show-module-use -show-compiles {target}")
module_name = Path(f"mk{target.stem}")
verilog_main_file = out_verilog / module_name.with_suffix(".v")
if verilog_main_file.is_file():
verilog_files.append(verilog_main_file)
use_file = out_verilog / module_name.with_suffix(".use")
if use_file.is_file():
with open(out_verilog / module_name.with_suffix(".use")) as f:
verilog_files.extend(find_verilog_modules(c, f.read().splitlines()))
verilog_files.append(out_verilog / module_name.with_suffix(".v"))
with open(out_verilog / module_name.with_suffix(".use")) as f:
verilog_files.extend(find_verilog_modules(c, f.read().splitlines()))
if verilog_files:
print("\nVerilog files for synthesis:")
for v in verilog_files:
print(" "+str(v))
print("\nVerilog files for synthesis:")
for v in verilog_files:
print(" "+str(v))
return verilog_files
@ -115,9 +110,6 @@ def synth(c, target):
module_name = Path(f"mk{target.stem}")
verilog_files = build(c, target)
if not verilog_files:
print("\nWARNING: bluespec compile didn't output any verilog files, did you (* synthesize *) something?")
return
phase("Logic synthesis")
yosys_script = out_yosys / "script.ys"
@ -167,7 +159,7 @@ def synth(c, target):
print(f"Wrote bitstream to {bitstream}")
@task
def test(c, target):
def test(c, target="."):
for target in expand_test_target(target):
out_info, out_sim, out_bsc = ensure_build_dirs(target, "info", "sim", "bsc")
c.run(f"bsc -show-schedule -aggressive-conditions -check-assert -u -sim -info-dir {out_info} -simdir {out_sim} -bdir {out_bsc} -g mkTB -p {target.parent}:lib:%/Libraries {target}")