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Verilog2001 Grammar
Top level symbols:
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library_textsource_textgenvar_function_callcommentcomment_textmemory_identifiertext_macro_identifierwhite_space
1 Source text
1.1 Library source text
library_text ::=
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library library_identifier file_path_spec ( ( , file_path_spec )* )? ( -incdir file_path_spec ( , file_path_spec )* )? ;
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file_path_spec ::=
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1.2 Configuration source text
design_statement ::=
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default_clause ::=
| default |
inst_clause ::=
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instance inst_name
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inst_name ::=
liblist_clause ::=
cell_clause ::=
use_clause ::=
1.3 Module and primitive source text
source_text ::=
description ::=
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( attribute_instance )* module_keyword module_identifier ( module_parameter_port_list )? ( list_of_ports )? ; ( module_item )* endmodule
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( attribute_instance )* module_keyword module_identifier ( module_parameter_port_list )? ( list_of_port_declarations )? ; ( non_port_module_item )* endmodule
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module_keyword ::=
| module | macromodule |
1.4 Module parameters and ports
list_of_ports ::=
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( )
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port ::=
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port_expression ::=
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port_reference ::=
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port_declaration ::=
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1.5 Module items
module_item ::=
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2 Declarations
2.1 Declaration types
2.1.1 Module parameter declarations
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2.1.2 Port declarations
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2.1.3 Type declarations
time_declaration ::=
real_declaration ::=
reg_declaration ::=
net_declaration ::=
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trireg ( charge_strength )? ( vectored | scalared )? ( signed )? range ( delay3 )? list_of_net_identifiers ;
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trireg ( drive_strength )? ( vectored | scalared )? ( signed )? range ( delay3 )? list_of_net_decl_assignments ;
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net_type ( drive_strength )? ( vectored | scalared )? ( signed )? range ( delay3 )? list_of_net_decl_assignments ;
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2.2 Declaration data types
2.2.1 Net and variable types
net_type ::=
| supply0 | supply1 | tri | triand | trior | tri0 | tri1 | wire | wand | wor |
| integer | time |
real_type ::=
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variable_type ::=
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2.2.2 Strengths
drive_strength ::=
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strength0 ::=
| supply0 | strong0 | pull0 | weak0 |
strength1 ::=
| supply1 | strong1 | pull1 | weak1 |
charge_strength ::=
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( small )
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( medium )
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( large )
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2.2.3 Delays
delay3 ::=
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delay2 ::=
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delay_value ::=
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2.3 Declaration lists
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event_identifier ( dimension ( dimension )* )? ( , event_identifier ( dimension ( dimension )* )? )*
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2.4 Declaration assignments
param_assignment ::=
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PATHPULSE$ specify_input_terminal_descriptor $ specify_output_terminal_descriptor = ( reject_limit_value ( , error_limit_value )? ) ;
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| limit_value |
| limit_value |
limit_value ::=
2.5 Declaration ranges
dimension ::=
range ::=
2.6 Function declarations
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function ( automatic )? ( signed )? ( range_or_type )? function_identifier ; function_item_declaration ( function_item_declaration )* function_statement endfunction
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function ( automatic )? ( signed )? ( range_or_type )? function_identifier ( function_port_list ) ; block_item_declaration ( block_item_declaration )* function_statement endfunction
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range_or_type ::=
| range | integer | real | realtime | time |
2.7 Task declarations
task_declaration ::=
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task ( automatic )? task_identifier ( task_port_list ) ; ( block_item_declaration )* statement endtask
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task_port_list ::=
task_port_item ::=
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task_port_type ::=
| time | real | realtime | integer |
2.8 Block item declarations
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3 Primitive instances
3.1 Primitive instantiation and instances
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n_input_gatetype ( drive_strength )? ( delay2 )? n_input_gate_instance ( , n_input_gate_instance )* ;
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n_output_gatetype ( drive_strength )? ( delay2 )? n_output_gate_instance ( , n_output_gate_instance )* ;
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3.2 Primitive strengths
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pullup_strength ::=
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3.3 Primitive terminals
enable_terminal ::=
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| expression |
| expression |
input_terminal ::=
| expression |
inout_terminal ::=
| net_lvalue |
output_terminal ::=
| net_lvalue |
3.4 Primitive gate and switch types
cmos_switchtype ::=
| cmos | rcmos |
enable_gatetype ::=
| bufif0 | bufif1 | notif0 | notif1 |
mos_switchtype ::=
| nmos | pmos | rnmos | rpmos |
n_input_gatetype ::=
| and | nand | or | nor | xor | xnor |
| buf | not |
| tranif0 | tranif1 | rtranif1 | rtranif0 |
pass_switchtype ::=
| tran | rtran |
4 Module and generated instantiation
4.1 Module instantiation
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| expression |
module_instance ::=
name_of_instance ::=
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4.2 Generated instantiation
| generate_item | ; |
generate_item ::=
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genvar_case_item ::=
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for ( genvar_assignment ; constant_expression ; genvar_assignment ) begin : generate_block_identifier ( generate_item )* end
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generate_block ::=
5 UDP declaration and instantiation
5.1 UDP declaration
udp_declaration ::=
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( attribute_instance )* primitive udp_identifier ( udp_port_list ) ; udp_port_declaration ( udp_port_declaration )* udp_body endprimitive
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( attribute_instance )* primitive udp_identifier ( udp_declaration_port_list ) ; udp_body endprimitive
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5.2 UDP ports
udp_port_list ::=
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5.3 UDP body
udp_body ::=
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sequential_body ::=
init_val ::=
| 1'b0 | 1'b1 | 1'bx | 1'bX | 1'B0 | 1'B1 | 1'Bx | 1'BX | 1 | 0 |
sequential_entry ::=
seq_input_list ::=
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level_input_list ::=
edge_input_list ::=
edge_indicator ::=
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current_state ::=
| level_symbol |
next_state ::=
| output_symbol | - |
output_symbol ::=
| 0 | 1 | x | X |
level_symbol ::=
| 0 | 1 | x | X | ? | b | B |
edge_symbol ::=
| r | R | f | F | p | P | n | N | * |
5.4 UDP instantiation
udp_instance ::=
6 Behavioral statements
6.1 Continuous assignment statements
net_assignment ::=
6.2 Procedural blocks and assignments
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initial statement
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always_construct ::=
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always statement
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assign variable_assignment
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deassign variable_lvalue
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force variable_assignment
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force net_assignment
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release variable_lvalue
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release net_lvalue
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6.3 Parallel and sequential blocks
par_block ::=
seq_block ::=
6.4 Statements
statement ::=
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6.5 Timing control statements
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delay_control ::=
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event_control ::=
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@ *
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@ ( * )
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event_trigger ::=
event_expression ::=
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posedge expression
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negedge expression
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wait_statement ::=
6.6 Conditional statements
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if ( expression ) statement_or_null ( else if ( expression ) statement_or_null )* ( else statement_or_null )?
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if ( expression ) function_statement_or_null ( else if ( expression ) function_statement_or_null )* ( else function_statement_or_null )?
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6.7 Case statements
case_statement ::=
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case_item ::=
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6.8 Looping statements
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forever function_statement
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loop_statement ::=
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forever statement
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6.9 Task enable statements
task_enable ::=
7 Specify section
7.1 Specify block declaration
specify_block ::=
specify_item ::=
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7.2 Specify path declarations
path_declaration ::=
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7.3 Specify block terminals
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input_identifier ::=
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7.4 Specify path delays
path_delay_value ::=
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| expression |
edge_identifier ::=
| posedge | negedge |
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ifnone simple_path_declaration
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| + | - |
7.5 System timing checks
7.5.1 System timing check commands
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$setuphold ( reference_event , data_event , timing_check_limit , timing_check_limit ( , ( notify_reg )? ( , ( stamptime_condition )? ( , ( checktime_condition )? ( , ( delayed_reference )? ( , ( delayed_data )? )? )? )? )? )? ) ;
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$recrem ( reference_event , data_event , timing_check_limit , timing_check_limit ( , ( notify_reg )? ( , ( stamptime_condition )? ( , ( checktime_condition )? ( , ( delayed_reference )? ( , ( delayed_data )? )? )? )? )? )? ) ;
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$timeskew ( reference_event , data_event , timing_check_limit ( , ( notify_reg )? ( , ( event_based_flag )? ( , ( remain_active_flag )? )? )? )? ) ;
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$fullskew ( reference_event , data_event , timing_check_limit , timing_check_limit ( , ( notify_reg )? ( , ( event_based_flag )? ( , ( remain_active_flag )? )? )? )? ) ;
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$nochange ( reference_event , data_event , start_edge_offset , end_edge_offset ( , ( notify_reg )? )? ) ;
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7.5.2 System timing check command arguments
data_event ::=
delayed_data ::=
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end_edge_offset ::=
event_based_flag ::=
notify_reg ::=
reference_event ::=
threshold ::=
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7.5.3 System timing check event definitions
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posedge
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negedge
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zero_or_one ::=
| 0 | 1 |
z_or_x ::=
| x | X | z | Z |
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scalar_constant ::=
| 1'b0 | 1'b1 | 1'B0 | 1'B1 | 'b0 | 'b1 | 'B0 | 'B1 | 1 | 0 |
8 Expressions
8.1 Concatenations
concatenation ::=
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8.2 Function calls
function_call ::=
8.3 Expressions
base_expression ::=
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expression1 ::=
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expression2 ::=
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expression3 ::=
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expression ::=
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range_expression ::=
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8.4 Primaries
constant_primary ::=
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primary ::=
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8.5 Expression left-side values
net_lvalue ::=
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variable_lvalue ::=
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8.6 Operators
unary_operator ::=
| + | - | ! | ~ | & | ~& | | | ~| | ^ | ~^ | ^~ |
binary_operator ::=
| + | - | * | / | % | == | != | === | !== | && | || | ** | < | <= | > | >= | & | | | ^ | ^~ | ~^ | >> | << | >>> | <<< |
| ! | ~ | & | ~& | | | ~| | ^ | ~^ | ^~ |
| == | != | && | || | & | | | ^ | ^~ | ~^ |
8.7 Numbers
number ::=
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exp ::=
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decimal_number ::=
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binary_number ::=
octal_number ::=
hex_number ::=
sign ::=
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size ::=
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' ( s | S )? D
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' ( s | S )? B
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' ( s | S )? O
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' ( s | S )? h
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' ( s | S )? H
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| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
decimal_digit ::=
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
binary_digit ::=
| x_digit | z_digit | 0 | 1 |
octal_digit ::=
| x_digit | z_digit | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
hex_digit ::=
| x_digit | z_digit | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | a | b | c | d | e | f | A | B | C | D | E | F |
x_digit ::=
| x | X |
z_digit ::=
| z | Z | ? |
8.8 Strings
string ::=
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" ( _any_ASCII_Character_except_new_line_ )* "
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9 General
9.1 Attributes
attr_spec ::=
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attr_name ::=
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9.2 Comments
comment ::=
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one_line_comment ::=
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// _comment_text_ \n
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block_comment ::=
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/* _comment_text_ */
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comment_text ::=
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( _any_ASCII_character_ )*
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9.3 Identifiers
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block_identifier ::=
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cell_identifier ::=
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\ ( _any_ASCII_character_except_white_space_ )* _white_space_
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event_identifier ::=
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| identifier |
| identifier |
| identifier f |
| identifier |
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identifier ::=
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| identifier |
| identifier |
| identifier |
| identifier |
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net_identifier ::=
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| identifier |
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port_identifier ::=
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real_identifier ::=
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[a-zA-Z_] ( [a-zA-Z0-9_$] )*
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$[a-zA-Z0-9_$] ( [a-zA-Z0-9_$] )*
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$[a-zA-Z0-9_$] ( [a-zA-Z0-9_$] )*
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task_identifier ::=
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| identifier |
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udp_identifier ::=
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| identifier |
9.4 Identifier branches
9.5 White space
white_space ::=
| _space_ | _tab_ | _newline_ | _eof_ |
Notes:
a) Embedded spaces are illegal.
b) The period in escaped_hierarchical_identifier and escaped_hierarchical_branch shall be preceded by white_space, but shall not be followed by white_space.
c) The period (.) in simple_hierarchical_identifier and simple_hierarchical_branch shall not be preceded or followed by white_space.
d) A simple_identifier shall start with an alpha or underscore (_) character, shall have at least one character, and shall not have any spaces.
e) The $ character in a system_function_identifier or system_task_identifier shall not be followed by white_space. A system_function_identifier or system_task_identifier shall not be escaped.
f) Hierarchy disallowed!
