MentorSystemCverification

1、copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 1 advanced functional verification using systemc presented by: raghu ardeishar technical marketing engineer design verification and test modelmodelsim sim copyright 2001-2003, model tec

2、hnology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 2 ntechnology overview nbasic systemc nscv (systemc verification library) nsystemc support in modelsim ndemo agenda copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc supp

3、ort in modelsim 3 what is systemc? nhigh level hardware verification language models designs at high level of abstraction (algorithmic) ndesigns modeled in untimed manner for fast execution nideal for proof of concept sc_module(adder) .; is a systemc macro for class adder: public sc_module .; copyri

4、ght 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 7 ndefine set of methods (functions) method signatures only not implementation of methods channels implement interfaces different implementation for same interface possible nderived from syst

5、emc base class sc_interface nbuilt-in interface examples: sc_signal_in_if, sc_fifo_in_if, etc. interfaces class simple_rw_if: public sc_interface public: void read(unsigned addr, char*data); void write(unsigned addr, char*data); ; copyright 2001-2003, model technology copyright 1999-2004, mentor gra

6、phics corporation systemc support in modelsim 8 nused by modules to communicate with surroundings naccess channels through interfaces what a port can do (read, write, etc.) is restricted to the methods defined in the associated interface(s) ports can only be used with channels that implement the ass

7、ociated interfaces nderived from systemc base class sc_port usage: sc_port port_name; ports sc_in a; is a short-hand for sc_portsc_signal_in_if a; a is an input port of type int that can access methods defined in sc_signal_in_if. sc_module(adder) sc_in a; sc_in b; sc_out c; / processes, etc. sc_ctor

8、(adder) / body of constructor / process declaration, sensitivities, etc. ; copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 9 nused to store example: sc_fifo fifo_a; nports are bound to channels through interfaces channels copyright 2

9、001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 10 interfaces, ports, channels port a interface a_if method_c() method_d() method_c() implementation method_d() implementation port b interface b_if method_e() method_f() method_e() implementation

10、 method_f() implementation module portinterfacechannel channel channel_a channel channel_b a-method_c() legal a-method_f() illegal copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 11 nfunctions to describe module functionality concurr

11、ently nnot hierarchical nconstructor used to register member functions as systemc processes (sc_method, sc_thread) ninvoked based on static sc_in b; sc_out c; void compute() c=a+b; sc_ctor(adder) sc_method(compute); sensitive a b; ; copyright 2001-2003, model technology copyright 1999-2004, mentor g

12、raphics corporation systemc support in modelsim 12 nalways execute function body from start to end no suspension (no wait() ) inside sc_method nsupport static sensitivity execute when signals on sensitivity list change example: sensitive a b; nsupport dynamic sensitivity with next_trigger() executio

13、n continues to the end next_trigger(e1 | e2); next_trigger(e1 next_trigger(100, sc_ns); next_trigger(100, sc_ns, e1); copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 13 nmay suspend execution with wait() statements are executed until

14、 wait() is encountered at wait() , process execution is suspended until an event it is sensitive to occurs continue to execute from where it was suspended nsupport static sensitivity execute when signals on sensitivity list change example: sensitive a b; nsupport dynamic sensitivity with wait() thre

15、ad processes (sc_thread) wait(e1); wait(e1 | e2); wait(e1 wait(100, sc_ns); wait(100, sc_ns, e1); sc_module(adder) sc_in a; sc_in b; sc_out c; void compute() while(1) wait(100, sc_ps); c=a+b; sc_ctor(adder) sc_thread(compute); sensitive a b; ; copyright 2001-2003, model technology copyright 1999-200

16、4, mentor graphics corporation systemc support in modelsim 14 nbasic synchronization objects of class sc_event used to synchronize nto trigger an explicit event, use event_name.notify(args) example: sc_event e1; e1.notify(); causes e1 to be made immediately ready to run events copyright 2001-2003, m

17、odel technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 15 nimmediate notification causes processes which are sensitive to the event to be made immediately ready to run example: e1.notify(); / current delta cycle ndelayed notification causes processes which are s

18、ensitive to the event to be made immediately ready to run in the next evaluation phase (a delta cycle later) example: e1.notify(sc_zero_time); / next delta cycle ntimed notification causes processes which are sensitive to the event to be made immediately ready to run at a specified time in the futur

19、e example: e1.notify(10, sc_ns); / 10ns delay events copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 16 nturn off process imitialization use dont_initialize() after its sc_method or sc_thread declaration inside the constructor ngener

20、ate clock signals e.g: sc_clock clk (clk, 10, sc_ns, 0.2, 5, sc_ns, false); default period = 1ns, duty cycle = 50%, initial value = true nstart simulation osci uses sc_start(10, sc_ps); use run command in modelsim nstop simulation example: sc_stop(); simulation control copyright 2001-2003, model tec

21、hnology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 17 nsupported formats: vcd (value change dump) wif (waveform interchange format) isdb (integrated signal data base) nstep 1: create trace file syntax: sc_trace_file * = sc_create_trace_file(); nstep 2: specify signa

22、ls to save syntax: sc_trace(, , ); nstep 3: close file vcd: sc_close_vcd_trace_file(); wif: sc_close_wif_trace_file(); isdb: sc_close_isdb_trace_file(); waveform export sc_trace_file *tf = sc_create_vcd_trace_file(myvcd); sc_trace(tf, clock, clock); sc_trace(tf, reset, reset); sc_close_vcd_trace_fil

23、e(tf); copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 18 ntechnology overview nbasic systemc ntestbench automation nscv (systemc verification library) nsystemc support in modelsim ndemo agenda copyright 2001-2003, model technology c

24、opyright 1999-2004, mentor graphics corporation systemc support in modelsim 19 nscaffolding around the design nall the stuff you need to build and verify a design software programming-centric view of the intent nspecified in the verification plan ncan cost as much or more than the design itself neff

25、iciency, reuse, etc are important tba is all about infrastructure verification engineers copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 20 building infrastructures ncollections of verification components ncomponents that participate

26、 in the simulation, but are not part of the design nbuild reusable modular components to the extent possible copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 21 building a testbench basics intent is captured in test and scoreboard cop

27、yright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 22 ngenerate more efficient verification reduce time per test nobject-oriented programming objects, abstraction, encapsulation, inheritance, etc. reusable test components nautomated stimul

28、us generation constrained sequence, control and data randomization. ntest bench infrastructure sampling of stable test values nclean interface between systemc and hdl systemc testbench automation copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support i

29、n modelsim 23 classes nencapsulate model behaviour properties hold data values methods implement processing nreusable test components extensible provide an object-oriented inheritance paradigm class ether_packet public: sc_uint preamble; sc_uint sfd; sc_uint dest; sc_uint src; sc_uint len; ; copyrig

30、ht 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 24 stimulus generation methodologies directed randomconstrained-random nverifies specific scenarios nother scenarios left untested nlabor expensive nimpossible to cover the verification space

31、nbroader coverage neasy to write tests nnot deep sequences required to penetrate nnot efficient redundant tests nbroad and deep neasy to write ntests are more productive nlet the tool find unforeseen corner cases ndirected tests is a highly constrained random test copyright 2001-2003, model technolo

32、gy copyright 1999-2004, mentor graphics corporation systemc support in modelsim 25 constrained random saves time signoff quality time functionality verified constrained random testing directed testing time savings copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation

33、 systemc support in modelsim 26 systemc testbench automation using systemc verification library (scv) nc+ class library stimulus generators, monitors, checkers, transactors. nmodeling scv_smart_ptr num2 (“num2”); num1-next(); - randomizes num1 cout get_name() *num1 *num1 endl ; copyright 2001-2003,

34、model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 30 introspection for simple types nfor simple types eg, int, float as shown below you inherit from scv_constraint_base to randomize data. class men_constr public: scv_smart_ptr scv_smart_ptr scv_constraint_

35、ctor(men_constr) scv_constraint(num1() = 1 : public scv_constraint_base use scv_constraint_ctor macro and bind each element with scv_constraint macro. int num1; float num2; ; copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 31 simple

36、types #include systemc.h #include scv.h class men_constr : public scv_constraint_base public: scv_smart_ptr num1; scv_smart_ptr num2; scv_constraint_ctor(men_constr) scv_constraint(num1() = 1 ; sc_module(mytop) sc_signal inn; men_constr a; void randomis(); sc_ctor(mytop) :inn(inn),a(a) sc_thread(ran

37、domis); sensitive inn; ; void mytop: randomis() for (int i=0; i 10; i+) a.next(); cout *a.num1 *a.num2 endl; sc_module_export(mytop); copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 32 introspection for user defined types nfor user d

38、efined types eg, structs, classes a template needs to be provided based on the scv_extensions class. class my_pkt public: int num1; float num2; ; struct my_pkt int num1; float num2; ; or name of the class or struct elements in the class copyright 2001-2003, model technology copyright 1999-2004, ment

39、or graphics corporation systemc support in modelsim 33 introspection for user defined types nfor user defined types eg, structs, classes a template needs to be provided based on the scv_extensions class. class public: template scv_extensions scv_extensions scv_extensions scv_extensions_ctor(my_pkt)

40、scv_field(num1); scv_field(num2); : public scv_extensions_base use scv_extensions_ctor macro and wrap each element with scv_field macro. my_pkt int num1; float num2; ; copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 34 user defined d

41、ata types nbut wait. nsome operators need to be overloaded before you proceed class my_pkt public: int num1; float num2; ; bool operator = (const my_pkt ; ostream os p.num2 endl; return os; copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in mode

42、lsim 35 randomization nscv_smart_ptr can have its data randomized nthe seed is set by default. to change use the method: scv_random:set_global_seed(unsigned long long) nuse the call to the next() method to randomize data nbut before you randomize it would be a good idea to constrain the elements in

43、your class/struct to get a directed random stimulus copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 36 constraints nconstraints allow you to control the parameters to bound the generation of data ninherit from scv_constraint_base nus

44、e scv_constraint_ctor constructor nuse scv_constraint macro to bind elements of class/struct. class men_constr : public scv_constraint_base public: scv_smart_ptr pkt; scv_constraint_ctor(men_constr) scv_constraint(pkt-num1() = 1 ; / num1 is bound between 1 and 99,num2 between 100 and 200 / the sum o

45、f num1 and num2 cannot exceed 200 copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 37 full example #include systemc.h #include scv.h class my_pkt public: int num1; int num2; bool operator = (const my_pkt ; ; ostream os p.num1 endl; os

46、 p.num2 endl; os end endl; return os; template class scv_extensions : public scv_extensions_base public: scv_extensions num1; scv_extensions num2; scv_extensions_ctor(my_pkt) scv_field(num1); scv_field(num2); ; class men_constr : public scv_constraint_base public: scv_smart_ptr pkt; scv_constraint_c

47、tor(men_constr) scv_constraint(pkt-num1() = 1 ; sc_module(mytop_mypkt) sc_signal inn; men_constr a; void randomis(); sc_ctor(mytop_mypkt) :inn(inn),a(a) sc_thread(randomis); sensitive inn; ; void mytop_mypkt: randomis() for (int i=0; i 10; i+) a.next(); cout *a.pkt endl; sc_module_export(mytop_mypkt

48、); copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 38 introspection for enum types enum color red = 0, green = 2 , blue = 4, orange = 6, black = 8, pewter = 16 ; use scv_enum_ctor macro and wrap each element with scv_enum macro. temp

49、late class scv_extensions : public scv_enum_base public: (red); (green); (blue); (orange); (black); (pewter); ; scv_enum_ctor(color) scv_enum scv_enum scv_enum scv_enum scv_enum scv_enum copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsi

50、m 39 introspection for enum types nfor enum types scv_enum_base needs to be provided before the scv_extensions class. struct / struct implies a class with public elements template scv_extensions scv_extensions scv_extensions scv_extensions_ctor(data_t) scv_field(col); scv_field(num); : public scv_ex

51、tensions_base use scv_extensions_ctor macro and wrap each element with scv_field macro. data_t color col; int num; ; copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 40 example of ethernet packet class ether_packet public: sc_uint pre

52、amble; sc_uint sfd; sc_uint dest; sc_uint src; sc_uint len; ; enum packet_type send_mp3, send_noise ; enum ifg_gaps normal_ifg, short_ifg, long_ifg, random_ifg; copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 41 scv extensions of eth

53、ernet packet enum packet_type send_mp3, send_noise; template class scv_extensions : public scv_enum_base public: scv_enum_ctor(packet_type) scv_enum(send_mp3); scv_enum(send_noise); ; template class scv_extensions : public scv_enum_base public: scv_enum_ctor(ifg_gaps) scv_enum(normal_ifg); scv_enum(

54、short_ifg); scv_enum(long_ifg); scv_enum(random_ifg); ; enum ifg_gaps normal_ifg, short_ifg, long_ifg, random_ifg; is extended to is extended to copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 42 scv extensions of ethernet packet tem

55、plate class scv_extensions : public scv_extensions_base public: scv_extensionssc_uint preamble; scv_extensionssc_uint sfd; scv_extensionssc_uint dest; scv_extensionssc_uint src; scv_extensionssc_uint len; scv_extensions_ctor(ether_packet) /must be in order scv_field(preamble); scv_field(sfd); scv_fi

56、eld(dest); scv_field(src); scv_field(len); ; class ether_packet public: sc_uint preamble; sc_uint sfd; sc_uint dest; sc_uint src; sc_uint len; ; is extended to copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 43 weighted randomization

57、 ncontrol the distribution of values by creating a “bag” nrelative number of items in the “bag” will determine what you pick from it / define the data types enum color red = 0, green = 2 , blue = 4; color_dist.add(red,1); struct data_t color col; int num; ; scv_smart_ptr a; / create a bag to put the

58、 colors scv_bag color_dist; / put the colors in the bag color_dist.add(red,1); color_dist.add(green,1); color_dist.add(blue,100); a-col.set_mode(color_dist); a-next(); the bag color_dist has 1 red, 1 green and 100 blue. so the probability of getting the blue is accordingly that much higher associate

59、 bag(color_dist)with element(col) in struct(“a”) copyright 2001-2003, model technology copyright 1999-2004, mentor graphics corporation systemc support in modelsim 44 example with enum #include #include enum color red = 0, green = 2 , blue = 4 ; struct data_t color col; int num; bool operator = (con

60、st data_t ; / not a complete = operator ; template class scv_extensions : public scv_enum_base public: scv_enum_ctor(color) scv_enum(red); scv_enum(green); scv_enum(blue); ; template class scv_extensions : public scv_extensions_base public: scv_extensions col; scv_extensions num; scv_extensions_ctor