verilator/test_regress/t/t_timing_class.v

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Timing support (#3363) Adds timing support to Verilator. It makes it possible to use delays, event controls within processes (not just at the start), wait statements, and forks. Building a design with those constructs requires a compiler that supports C++20 coroutines (GCC 10, Clang 5). The basic idea is to have processes and tasks with delays/event controls implemented as C++20 coroutines. This allows us to suspend and resume them at any time. There are five main runtime classes responsible for managing suspended coroutines: * `VlCoroutineHandle`, a wrapper over C++20's `std::coroutine_handle` with move semantics and automatic cleanup. * `VlDelayScheduler`, for coroutines suspended by delays. It resumes them at a proper simulation time. * `VlTriggerScheduler`, for coroutines suspended by event controls. It resumes them if its corresponding trigger was set. * `VlForkSync`, used for syncing `fork..join` and `fork..join_any` blocks. * `VlCoroutine`, the return type of all verilated coroutines. It allows for suspending a stack of coroutines (normally, C++ coroutines are stackless). There is a new visitor in `V3Timing.cpp` which: * scales delays according to the timescale, * simplifies intra-assignment timing controls and net delays into regular timing controls and assignments, * simplifies wait statements into loops with event controls, * marks processes and tasks with timing controls in them as suspendable, * creates delay, trigger scheduler, and fork sync variables, * transforms timing controls and fork joins into C++ awaits There are new functions in `V3SchedTiming.cpp` (used by `V3Sched.cpp`) that integrate static scheduling with timing. This involves providing external domains for variables, so that the necessary combinational logic gets triggered after coroutine resumption, as well as statements that need to be injected into the design eval function to perform this resumption at the correct time. There is also a function that transforms forked processes into separate functions. See the comments in `verilated_timing.h`, `verilated_timing.cpp`, `V3Timing.cpp`, and `V3SchedTiming.cpp`, as well as the internals documentation for more details. Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>
2022-08-22 12:26:32 +00:00
// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed under the Creative Commons Public Domain, for
// any use, without warranty, 2022 by Antmicro Ltd.
// SPDX-License-Identifier: CC0-1.0
`ifdef TEST_VERBOSE
`define WRITE_VERBOSE(args) $write args
`else
`define WRITE_VERBOSE(args)
`endif
module t;
// =============================================
// EVENTS
class EventClass;
event e;
int trig_count;
Timing support (#3363) Adds timing support to Verilator. It makes it possible to use delays, event controls within processes (not just at the start), wait statements, and forks. Building a design with those constructs requires a compiler that supports C++20 coroutines (GCC 10, Clang 5). The basic idea is to have processes and tasks with delays/event controls implemented as C++20 coroutines. This allows us to suspend and resume them at any time. There are five main runtime classes responsible for managing suspended coroutines: * `VlCoroutineHandle`, a wrapper over C++20's `std::coroutine_handle` with move semantics and automatic cleanup. * `VlDelayScheduler`, for coroutines suspended by delays. It resumes them at a proper simulation time. * `VlTriggerScheduler`, for coroutines suspended by event controls. It resumes them if its corresponding trigger was set. * `VlForkSync`, used for syncing `fork..join` and `fork..join_any` blocks. * `VlCoroutine`, the return type of all verilated coroutines. It allows for suspending a stack of coroutines (normally, C++ coroutines are stackless). There is a new visitor in `V3Timing.cpp` which: * scales delays according to the timescale, * simplifies intra-assignment timing controls and net delays into regular timing controls and assignments, * simplifies wait statements into loops with event controls, * marks processes and tasks with timing controls in them as suspendable, * creates delay, trigger scheduler, and fork sync variables, * transforms timing controls and fork joins into C++ awaits There are new functions in `V3SchedTiming.cpp` (used by `V3Sched.cpp`) that integrate static scheduling with timing. This involves providing external domains for variables, so that the necessary combinational logic gets triggered after coroutine resumption, as well as statements that need to be injected into the design eval function to perform this resumption at the correct time. There is also a function that transforms forked processes into separate functions. See the comments in `verilated_timing.h`, `verilated_timing.cpp`, `V3Timing.cpp`, and `V3SchedTiming.cpp`, as well as the internals documentation for more details. Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>
2022-08-22 12:26:32 +00:00
function new;
trig_count = 0;
endfunction
task inc_trig_count;
trig_count++;
endtask;
task sleep;
@e inc_trig_count;
`WRITE_VERBOSE(("Event in class triggered at time %0t!\n", $time));
endtask
task wake;
->e;
endtask
endclass
class WaitClass;
int a;
int b;
logic ok;
function new;
a = 0;
b = 0;
ok = 0;
endfunction
task await;
wait(a == 4 && b > 16) if (a != 4 || b <= 16) $stop;
ok = 1;
`WRITE_VERBOSE(("Condition in object met at time %0t!\n", $time));
endtask
endclass
class LocalWaitClass;
logic ok;
function new;
ok = 0;
endfunction
task await;
int a = 0;
int b = 100;
fork
wait(a == 42 || b != 100) if (a != 42 && b == 100) $stop;
#10 a = 42;
join
ok = 1;
`WRITE_VERBOSE(("Condition with local variables met at time %0t!\n", $time));
endtask
Timing support (#3363) Adds timing support to Verilator. It makes it possible to use delays, event controls within processes (not just at the start), wait statements, and forks. Building a design with those constructs requires a compiler that supports C++20 coroutines (GCC 10, Clang 5). The basic idea is to have processes and tasks with delays/event controls implemented as C++20 coroutines. This allows us to suspend and resume them at any time. There are five main runtime classes responsible for managing suspended coroutines: * `VlCoroutineHandle`, a wrapper over C++20's `std::coroutine_handle` with move semantics and automatic cleanup. * `VlDelayScheduler`, for coroutines suspended by delays. It resumes them at a proper simulation time. * `VlTriggerScheduler`, for coroutines suspended by event controls. It resumes them if its corresponding trigger was set. * `VlForkSync`, used for syncing `fork..join` and `fork..join_any` blocks. * `VlCoroutine`, the return type of all verilated coroutines. It allows for suspending a stack of coroutines (normally, C++ coroutines are stackless). There is a new visitor in `V3Timing.cpp` which: * scales delays according to the timescale, * simplifies intra-assignment timing controls and net delays into regular timing controls and assignments, * simplifies wait statements into loops with event controls, * marks processes and tasks with timing controls in them as suspendable, * creates delay, trigger scheduler, and fork sync variables, * transforms timing controls and fork joins into C++ awaits There are new functions in `V3SchedTiming.cpp` (used by `V3Sched.cpp`) that integrate static scheduling with timing. This involves providing external domains for variables, so that the necessary combinational logic gets triggered after coroutine resumption, as well as statements that need to be injected into the design eval function to perform this resumption at the correct time. There is also a function that transforms forked processes into separate functions. See the comments in `verilated_timing.h`, `verilated_timing.cpp`, `V3Timing.cpp`, and `V3SchedTiming.cpp`, as well as the internals documentation for more details. Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>
2022-08-22 12:26:32 +00:00
endclass
EventClass ec = new;
WaitClass wc = new;
LocalWaitClass lc = new;
Timing support (#3363) Adds timing support to Verilator. It makes it possible to use delays, event controls within processes (not just at the start), wait statements, and forks. Building a design with those constructs requires a compiler that supports C++20 coroutines (GCC 10, Clang 5). The basic idea is to have processes and tasks with delays/event controls implemented as C++20 coroutines. This allows us to suspend and resume them at any time. There are five main runtime classes responsible for managing suspended coroutines: * `VlCoroutineHandle`, a wrapper over C++20's `std::coroutine_handle` with move semantics and automatic cleanup. * `VlDelayScheduler`, for coroutines suspended by delays. It resumes them at a proper simulation time. * `VlTriggerScheduler`, for coroutines suspended by event controls. It resumes them if its corresponding trigger was set. * `VlForkSync`, used for syncing `fork..join` and `fork..join_any` blocks. * `VlCoroutine`, the return type of all verilated coroutines. It allows for suspending a stack of coroutines (normally, C++ coroutines are stackless). There is a new visitor in `V3Timing.cpp` which: * scales delays according to the timescale, * simplifies intra-assignment timing controls and net delays into regular timing controls and assignments, * simplifies wait statements into loops with event controls, * marks processes and tasks with timing controls in them as suspendable, * creates delay, trigger scheduler, and fork sync variables, * transforms timing controls and fork joins into C++ awaits There are new functions in `V3SchedTiming.cpp` (used by `V3Sched.cpp`) that integrate static scheduling with timing. This involves providing external domains for variables, so that the necessary combinational logic gets triggered after coroutine resumption, as well as statements that need to be injected into the design eval function to perform this resumption at the correct time. There is also a function that transforms forked processes into separate functions. See the comments in `verilated_timing.h`, `verilated_timing.cpp`, `V3Timing.cpp`, and `V3SchedTiming.cpp`, as well as the internals documentation for more details. Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>
2022-08-22 12:26:32 +00:00
initial begin
@ec.e;
ec.sleep;
if (wc.ok) $stop;
wc.await;
if (lc.ok) $stop;
lc.await;
Timing support (#3363) Adds timing support to Verilator. It makes it possible to use delays, event controls within processes (not just at the start), wait statements, and forks. Building a design with those constructs requires a compiler that supports C++20 coroutines (GCC 10, Clang 5). The basic idea is to have processes and tasks with delays/event controls implemented as C++20 coroutines. This allows us to suspend and resume them at any time. There are five main runtime classes responsible for managing suspended coroutines: * `VlCoroutineHandle`, a wrapper over C++20's `std::coroutine_handle` with move semantics and automatic cleanup. * `VlDelayScheduler`, for coroutines suspended by delays. It resumes them at a proper simulation time. * `VlTriggerScheduler`, for coroutines suspended by event controls. It resumes them if its corresponding trigger was set. * `VlForkSync`, used for syncing `fork..join` and `fork..join_any` blocks. * `VlCoroutine`, the return type of all verilated coroutines. It allows for suspending a stack of coroutines (normally, C++ coroutines are stackless). There is a new visitor in `V3Timing.cpp` which: * scales delays according to the timescale, * simplifies intra-assignment timing controls and net delays into regular timing controls and assignments, * simplifies wait statements into loops with event controls, * marks processes and tasks with timing controls in them as suspendable, * creates delay, trigger scheduler, and fork sync variables, * transforms timing controls and fork joins into C++ awaits There are new functions in `V3SchedTiming.cpp` (used by `V3Sched.cpp`) that integrate static scheduling with timing. This involves providing external domains for variables, so that the necessary combinational logic gets triggered after coroutine resumption, as well as statements that need to be injected into the design eval function to perform this resumption at the correct time. There is also a function that transforms forked processes into separate functions. See the comments in `verilated_timing.h`, `verilated_timing.cpp`, `V3Timing.cpp`, and `V3SchedTiming.cpp`, as well as the internals documentation for more details. Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>
2022-08-22 12:26:32 +00:00
end
initial #20 ec.wake;
initial #40 ->ec.e;
initial begin
wc.a = #50 4;
wc.b = #10 32;
end
Timing support (#3363) Adds timing support to Verilator. It makes it possible to use delays, event controls within processes (not just at the start), wait statements, and forks. Building a design with those constructs requires a compiler that supports C++20 coroutines (GCC 10, Clang 5). The basic idea is to have processes and tasks with delays/event controls implemented as C++20 coroutines. This allows us to suspend and resume them at any time. There are five main runtime classes responsible for managing suspended coroutines: * `VlCoroutineHandle`, a wrapper over C++20's `std::coroutine_handle` with move semantics and automatic cleanup. * `VlDelayScheduler`, for coroutines suspended by delays. It resumes them at a proper simulation time. * `VlTriggerScheduler`, for coroutines suspended by event controls. It resumes them if its corresponding trigger was set. * `VlForkSync`, used for syncing `fork..join` and `fork..join_any` blocks. * `VlCoroutine`, the return type of all verilated coroutines. It allows for suspending a stack of coroutines (normally, C++ coroutines are stackless). There is a new visitor in `V3Timing.cpp` which: * scales delays according to the timescale, * simplifies intra-assignment timing controls and net delays into regular timing controls and assignments, * simplifies wait statements into loops with event controls, * marks processes and tasks with timing controls in them as suspendable, * creates delay, trigger scheduler, and fork sync variables, * transforms timing controls and fork joins into C++ awaits There are new functions in `V3SchedTiming.cpp` (used by `V3Sched.cpp`) that integrate static scheduling with timing. This involves providing external domains for variables, so that the necessary combinational logic gets triggered after coroutine resumption, as well as statements that need to be injected into the design eval function to perform this resumption at the correct time. There is also a function that transforms forked processes into separate functions. See the comments in `verilated_timing.h`, `verilated_timing.cpp`, `V3Timing.cpp`, and `V3SchedTiming.cpp`, as well as the internals documentation for more details. Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>
2022-08-22 12:26:32 +00:00
always @ec.e begin
ec.inc_trig_count;
Timing support (#3363) Adds timing support to Verilator. It makes it possible to use delays, event controls within processes (not just at the start), wait statements, and forks. Building a design with those constructs requires a compiler that supports C++20 coroutines (GCC 10, Clang 5). The basic idea is to have processes and tasks with delays/event controls implemented as C++20 coroutines. This allows us to suspend and resume them at any time. There are five main runtime classes responsible for managing suspended coroutines: * `VlCoroutineHandle`, a wrapper over C++20's `std::coroutine_handle` with move semantics and automatic cleanup. * `VlDelayScheduler`, for coroutines suspended by delays. It resumes them at a proper simulation time. * `VlTriggerScheduler`, for coroutines suspended by event controls. It resumes them if its corresponding trigger was set. * `VlForkSync`, used for syncing `fork..join` and `fork..join_any` blocks. * `VlCoroutine`, the return type of all verilated coroutines. It allows for suspending a stack of coroutines (normally, C++ coroutines are stackless). There is a new visitor in `V3Timing.cpp` which: * scales delays according to the timescale, * simplifies intra-assignment timing controls and net delays into regular timing controls and assignments, * simplifies wait statements into loops with event controls, * marks processes and tasks with timing controls in them as suspendable, * creates delay, trigger scheduler, and fork sync variables, * transforms timing controls and fork joins into C++ awaits There are new functions in `V3SchedTiming.cpp` (used by `V3Sched.cpp`) that integrate static scheduling with timing. This involves providing external domains for variables, so that the necessary combinational logic gets triggered after coroutine resumption, as well as statements that need to be injected into the design eval function to perform this resumption at the correct time. There is also a function that transforms forked processes into separate functions. See the comments in `verilated_timing.h`, `verilated_timing.cpp`, `V3Timing.cpp`, and `V3SchedTiming.cpp`, as well as the internals documentation for more details. Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>
2022-08-22 12:26:32 +00:00
`WRITE_VERBOSE(("Event in class triggered at time %0t!\n", $time));
end
initial begin
#80
if (ec.trig_count != 3) $stop;
if (!wc.ok) $stop;
if (!lc.ok) $stop;
end
Timing support (#3363) Adds timing support to Verilator. It makes it possible to use delays, event controls within processes (not just at the start), wait statements, and forks. Building a design with those constructs requires a compiler that supports C++20 coroutines (GCC 10, Clang 5). The basic idea is to have processes and tasks with delays/event controls implemented as C++20 coroutines. This allows us to suspend and resume them at any time. There are five main runtime classes responsible for managing suspended coroutines: * `VlCoroutineHandle`, a wrapper over C++20's `std::coroutine_handle` with move semantics and automatic cleanup. * `VlDelayScheduler`, for coroutines suspended by delays. It resumes them at a proper simulation time. * `VlTriggerScheduler`, for coroutines suspended by event controls. It resumes them if its corresponding trigger was set. * `VlForkSync`, used for syncing `fork..join` and `fork..join_any` blocks. * `VlCoroutine`, the return type of all verilated coroutines. It allows for suspending a stack of coroutines (normally, C++ coroutines are stackless). There is a new visitor in `V3Timing.cpp` which: * scales delays according to the timescale, * simplifies intra-assignment timing controls and net delays into regular timing controls and assignments, * simplifies wait statements into loops with event controls, * marks processes and tasks with timing controls in them as suspendable, * creates delay, trigger scheduler, and fork sync variables, * transforms timing controls and fork joins into C++ awaits There are new functions in `V3SchedTiming.cpp` (used by `V3Sched.cpp`) that integrate static scheduling with timing. This involves providing external domains for variables, so that the necessary combinational logic gets triggered after coroutine resumption, as well as statements that need to be injected into the design eval function to perform this resumption at the correct time. There is also a function that transforms forked processes into separate functions. See the comments in `verilated_timing.h`, `verilated_timing.cpp`, `V3Timing.cpp`, and `V3SchedTiming.cpp`, as well as the internals documentation for more details. Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>
2022-08-22 12:26:32 +00:00
// =============================================
// DELAYS
virtual class DelayClass;
pure virtual task do_delay;
pure virtual task do_sth_else;
endclass
`ifdef TEST_VERBOSE
`define DELAY_CLASS(dt) \
class Delay``dt extends DelayClass; \
virtual task do_delay; \
$write("Starting a #%0d delay\n", dt); \
#dt \
$write("Ended a #%0d delay\n", dt); \
endtask \
virtual task do_sth_else; \
$write("Task with no delay (in Delay%0d)\n", dt); \
endtask \
endclass
`else
`define DELAY_CLASS(dt) \
class Delay``dt extends DelayClass; \
virtual task do_delay; \
#dt; \
endtask \
virtual task do_sth_else; \
endtask \
endclass
`endif
`DELAY_CLASS(10);
`DELAY_CLASS(20);
`DELAY_CLASS(40);
class NoDelay extends DelayClass;
virtual task do_delay;
`WRITE_VERBOSE(("Task with no delay\n"));
endtask
virtual task do_sth_else;
`WRITE_VERBOSE(("Task with no delay (in NoDelay)\n"));
endtask
endclass
class AssignDelayClass;
logic x;
logic y;
task do_assign;
y = #10 x;
`WRITE_VERBOSE(("Did assignment with delay\n"));
Timing support (#3363) Adds timing support to Verilator. It makes it possible to use delays, event controls within processes (not just at the start), wait statements, and forks. Building a design with those constructs requires a compiler that supports C++20 coroutines (GCC 10, Clang 5). The basic idea is to have processes and tasks with delays/event controls implemented as C++20 coroutines. This allows us to suspend and resume them at any time. There are five main runtime classes responsible for managing suspended coroutines: * `VlCoroutineHandle`, a wrapper over C++20's `std::coroutine_handle` with move semantics and automatic cleanup. * `VlDelayScheduler`, for coroutines suspended by delays. It resumes them at a proper simulation time. * `VlTriggerScheduler`, for coroutines suspended by event controls. It resumes them if its corresponding trigger was set. * `VlForkSync`, used for syncing `fork..join` and `fork..join_any` blocks. * `VlCoroutine`, the return type of all verilated coroutines. It allows for suspending a stack of coroutines (normally, C++ coroutines are stackless). There is a new visitor in `V3Timing.cpp` which: * scales delays according to the timescale, * simplifies intra-assignment timing controls and net delays into regular timing controls and assignments, * simplifies wait statements into loops with event controls, * marks processes and tasks with timing controls in them as suspendable, * creates delay, trigger scheduler, and fork sync variables, * transforms timing controls and fork joins into C++ awaits There are new functions in `V3SchedTiming.cpp` (used by `V3Sched.cpp`) that integrate static scheduling with timing. This involves providing external domains for variables, so that the necessary combinational logic gets triggered after coroutine resumption, as well as statements that need to be injected into the design eval function to perform this resumption at the correct time. There is also a function that transforms forked processes into separate functions. See the comments in `verilated_timing.h`, `verilated_timing.cpp`, `V3Timing.cpp`, and `V3SchedTiming.cpp`, as well as the internals documentation for more details. Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>
2022-08-22 12:26:32 +00:00
endtask
endclass
initial begin
DelayClass dc;
Delay10 d10 = new;
Delay20 d20 = new;
Delay40 d40 = new;
NoDelay dNo = new;
AssignDelayClass dAsgn = new;
`WRITE_VERBOSE(("I'm at time %0t\n", $time));
dc = d10;
dc.do_delay;
dc.do_sth_else;
`WRITE_VERBOSE(("I'm at time %0t\n", $time));
if ($time != 10) $stop;
dc = d20;
dc.do_delay;
dc.do_sth_else;
`WRITE_VERBOSE(("I'm at time %0t\n", $time));
if ($time != 30) $stop;
dc = d40;
dc.do_delay;
dc.do_sth_else;
`WRITE_VERBOSE(("I'm at time %0t\n", $time));
if ($time != 70) $stop;
dc = dNo;
dc.do_delay;
dc.do_sth_else;
`WRITE_VERBOSE(("I'm at time %0t\n", $time));
dAsgn.x = 1;
dAsgn.y = 0;
fork #5 dAsgn.x = 0; join_none
dAsgn.do_assign;
if ($time != 80) $stop;
if (dAsgn.y != 1) $stop;
// Test if the object is deleted before do_assign finishes:
fork dAsgn.do_assign; join_none
#5 dAsgn = null;
#15 $write("*-* All Finished *-*\n");
Timing support (#3363) Adds timing support to Verilator. It makes it possible to use delays, event controls within processes (not just at the start), wait statements, and forks. Building a design with those constructs requires a compiler that supports C++20 coroutines (GCC 10, Clang 5). The basic idea is to have processes and tasks with delays/event controls implemented as C++20 coroutines. This allows us to suspend and resume them at any time. There are five main runtime classes responsible for managing suspended coroutines: * `VlCoroutineHandle`, a wrapper over C++20's `std::coroutine_handle` with move semantics and automatic cleanup. * `VlDelayScheduler`, for coroutines suspended by delays. It resumes them at a proper simulation time. * `VlTriggerScheduler`, for coroutines suspended by event controls. It resumes them if its corresponding trigger was set. * `VlForkSync`, used for syncing `fork..join` and `fork..join_any` blocks. * `VlCoroutine`, the return type of all verilated coroutines. It allows for suspending a stack of coroutines (normally, C++ coroutines are stackless). There is a new visitor in `V3Timing.cpp` which: * scales delays according to the timescale, * simplifies intra-assignment timing controls and net delays into regular timing controls and assignments, * simplifies wait statements into loops with event controls, * marks processes and tasks with timing controls in them as suspendable, * creates delay, trigger scheduler, and fork sync variables, * transforms timing controls and fork joins into C++ awaits There are new functions in `V3SchedTiming.cpp` (used by `V3Sched.cpp`) that integrate static scheduling with timing. This involves providing external domains for variables, so that the necessary combinational logic gets triggered after coroutine resumption, as well as statements that need to be injected into the design eval function to perform this resumption at the correct time. There is also a function that transforms forked processes into separate functions. See the comments in `verilated_timing.h`, `verilated_timing.cpp`, `V3Timing.cpp`, and `V3SchedTiming.cpp`, as well as the internals documentation for more details. Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>
2022-08-22 12:26:32 +00:00
$finish;
end
// =============================================
// FORKS
class ForkDelayClass;
task do_delay; #40; endtask
endclass
class ForkClass;
int done = 0;
task do_fork();
ForkDelayClass d;
fork
begin
#10 done++;
`WRITE_VERBOSE(("Forked process %0d ending at time %0t\n", done, $time));
end
begin
#20 done++;
`WRITE_VERBOSE(("Forked process %0d ending at time %0t\n", done, $time));
d = new;
end
begin
#30 d.do_delay;
done++;
`WRITE_VERBOSE(("Forked process %0d ending at time %0t\n", done, $time));
end
join
done++;
`WRITE_VERBOSE(("All forked processes ended at time %0t\n", $time));
endtask
endclass
initial begin
ForkClass fc = new;
fc.do_fork;
if (fc.done != 4 || $time != 70) $stop;
end
initial #101 $stop; // timeout
Timing support (#3363) Adds timing support to Verilator. It makes it possible to use delays, event controls within processes (not just at the start), wait statements, and forks. Building a design with those constructs requires a compiler that supports C++20 coroutines (GCC 10, Clang 5). The basic idea is to have processes and tasks with delays/event controls implemented as C++20 coroutines. This allows us to suspend and resume them at any time. There are five main runtime classes responsible for managing suspended coroutines: * `VlCoroutineHandle`, a wrapper over C++20's `std::coroutine_handle` with move semantics and automatic cleanup. * `VlDelayScheduler`, for coroutines suspended by delays. It resumes them at a proper simulation time. * `VlTriggerScheduler`, for coroutines suspended by event controls. It resumes them if its corresponding trigger was set. * `VlForkSync`, used for syncing `fork..join` and `fork..join_any` blocks. * `VlCoroutine`, the return type of all verilated coroutines. It allows for suspending a stack of coroutines (normally, C++ coroutines are stackless). There is a new visitor in `V3Timing.cpp` which: * scales delays according to the timescale, * simplifies intra-assignment timing controls and net delays into regular timing controls and assignments, * simplifies wait statements into loops with event controls, * marks processes and tasks with timing controls in them as suspendable, * creates delay, trigger scheduler, and fork sync variables, * transforms timing controls and fork joins into C++ awaits There are new functions in `V3SchedTiming.cpp` (used by `V3Sched.cpp`) that integrate static scheduling with timing. This involves providing external domains for variables, so that the necessary combinational logic gets triggered after coroutine resumption, as well as statements that need to be injected into the design eval function to perform this resumption at the correct time. There is also a function that transforms forked processes into separate functions. See the comments in `verilated_timing.h`, `verilated_timing.cpp`, `V3Timing.cpp`, and `V3SchedTiming.cpp`, as well as the internals documentation for more details. Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>
2022-08-22 12:26:32 +00:00
endmodule