Module Basic Ovm Session7 Sequences and Tests Jaynsley

8/18/2019 Module Basic Ovm Session7 Sequences and Tests Jaynsley

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www.verificationacademy.com

Basic OVMSequences and Tests

John AynsleyCTO, Doulos


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Layered Sequential Stimulus

Drive transactions into DUT

Constrained random

sequence of transactions

Nested, layered or

virtual sequences


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Sequence of Transactions

cl ass r ead_modi f y_wr i t e ext ends ovm_sequence#( my_t r ansact i on) ;

`ovm_obj ect _ut i l s( r ead_modi f y_wr i t e)f unct i on new ( st r i ng name = " " ) ;

super . new( name) ;endf unct i on: new

t ask body;my_t r ansact i on t x;i nt a;i nt d;

tx = my_transaction: : t ype_i d: : cr eat e( "t x") ;st ar t _i t em( tx) ;


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cl ass r ead_modi f y_wr i t e ext ends ovm_sequence#( my_t r ansact i on) ;

`ovm_obj ect _ut i l s( r ead_modi f y_wr i t e)f unct i on new ( st r i ng name = " " ) ;

super . new( name) ;endf unct i on: new

t ask body;my_t r ansact i on t x;i nt a;i nt d;

t x = my_t r ansact i on: : t ype_i d: : creat e( " t x") ;st ar t _i t em( t x) ;assert( tx.randomize() with { cmd == 0; } ) ;f i ni sh_i t em( t x) ;

Read


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. . .a = tx.addr;

d = tx.data;

++d;

Modify


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. . .a = t x. addr ;d = t x. dat a;++d;

t x = my_t r ansact i on: : t ype_i d: : creat e( " t x" ) ;st ar t _i t em( t x) ;assert( tx.randomize() with {

cmd == 1; addr == a; data == d; } ) ;

f i ni sh_i t em( t x) ;endt ask: body

endcl ass: r ead_modi f y_wr i t e

Write


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Sequence of Sequences

cl ass seq_of _commands ext ends ovm_sequence#( my_t r ansact i on) ;

`ovm_obj ect _ut i l s( seq_of _commands)rand int n;


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`ovm_obj ect _ut i l s( seq_of _commands)r and i nt n;constraint how_many { n inside {[2:4]}; }


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`ovm_obj ect _ut i l s( seq_of _commands)r and i nt n;const r ai nt how_many { n i nsi de {[ 2: 4] }; }. . .

t ask body;repeat(n)

begi n

endendt ask: body


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`ovm_obj ect _ut i l s( seq_of _commands)r and i nt n;const r ai nt how_many { n i nsi de {[ 2: 4] }; }. . .

t ask body;r epeat ( n)begi n

r ead_modi f y_wr i t e seq;seq = read_modify_write: : t ype_i d: : cr eat e( "seq") ;

st ar t _i t em( seq ) ;f i ni sh_i t em( seq ) ;

endendt ask: body


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A Sequence Library

package my_seq_l i br ary;i mpor t ovm_pkg: : *;

cl ass read_modify_write ext ends ovm_sequence#( my_t r ansact i on) ;

. . .

cl ass seq_of_commands ext ends ovm_sequence#( my_t r ansact i on) ;

. . .

endpackage


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Starting a Sequence

cl ass t est 1 ext ends ovm_test;

`ovm_component _ut i l s( t est 1)

my_env my_env_h;

. . .

t ask run;r ead_modi f y_wr i t e seq;seq = read_modify_write: : t ype_i d: : cr eat e( "seq") ;


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Starting a Sequence

cl ass t est 1 ext ends ovm_t est ;


my_env my_env_h;

. . .

t ask run;r ead_modi f y_wr i t e seq;seq = r ead_modi f y_wr i t e: : t ype_i d: : cr eat e( "seq") ;seq.start( . . .


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Starting a Sequence

cl ass t est 1 ext ends ovm_t est ;


my_env my_env_h;

. . .

t ask run;r ead_modi f y_wr i t e seq;seq = r ead_modi f y_wr i t e: : t ype_i d: : cr eat e( "seq") ;seq. star t ( my_env_h.my_agent_h.my_sequencer_h ) ;


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Starting a Sequence

cl ass test2 ext ends ovm_t est ;


my_env my_env_h;

. . .

t ask run;seq_of _commands seq;seq = seq_of_commands: : t ype_i d: : cr eat e( "seq") ;


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Randomizing a Sequence



my_env my_env_h;

. . .

t ask run;seq_of _commands seq;seq = seq_of_commands: : t ype_i d: : cr eat e( "seq") ;

assert( seq.randomize( ) ) ;

seq. st ar t ( my_env_h. my_agent _h. my_sequencer_h ) ;


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Constraining a Sequence



my_env my_env_h;

. . .

t ask run;seq_of _commands seq;seq = seq_of _commands: : t ype_i d: : cr eat e( "seq" ) ;seq. how_many. constraint_mode(0) ;

asser t ( seq. r andomi ze( ) with {seq. n > 10 && seq. n < 20; } ) ;seq. st ar t ( my_env_h. my_agent _h. my_sequencer_h ) ;


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Selecting a Test

modul e t op;. . .

i ni t i albegi n: bl k

. . .run_test(" test3") ;

end

endmodul e: t op


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Selecting a Test

modul e t op;. . .

i ni t i albegi n: bl k

. . .run_test( ) ;

end

endmodul e: t op

vsim +OVM_TESTNAME=test3Command line:


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Summary

Tests define differences


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[email protected]

www.verificationacademy.com

Basic OVMSequences and Tests

John AynsleyCTO, Doulos

Module Basic Ovm Session7 Sequences and Tests Jaynsley

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