impure function <name> (<arguments>) return <return_type> is -- variable declaration begin -- Function end function <name>; At first, it may be difficult to see the use for impure functions. However, one common use is when we require a function which generates random values to use in ...
-- A function that returns the current simulation time, Tc (see Section 12.6.4): impure function NOW return DELAY_LENGTH; -- Predefined numeric subtypes: subtype NATURAL is INTEGER range 0 to INTEGER'HIGH; subtype POSITIVE is INTEGER range 1 to INTEGER'HIGH; -- Predefined array types: type...
Impure functions/procedures166–68 In-line comments22–23 Inadvertent latch interference68117 Inferences70–77 Initializing arrays38 Instantiations70–77154156–57161 Institute of Electrical and Electronics Engineers see IEEE Integer data types35–36 Intellectual property (IP)143–44 ISim tool109110139 J Jitt...
impure function init_ram return ram is file v_file : text open read_mode is "data.txt"; variable v_1LINE : line; variable v_value : bit_vector(3 downto 0); variable v_ram : ram; begin readline(v_file, v_1LINE); --for i in ram'range loop -- To fill the whole RAM for ...
impure function get_data return std_logic; end protected sh_data; end shared_function; package body shared_function is type sh_data is protected body variable data : std_logic; procedure reset is begin data := '0'; end reset; procedure set(signal new_data : std_logic) is...
absaccess after alias all and architecture array assert attribute begin block buffer bus case component configuraTIon constant disconnect downto else elsif end enTIty exit file for funcTIon generate generic group guarded if impure in inerTIal inout is label library linkage literal loop map mod nand new...
A pure function must not contain a reference to an explicitly declared file object. A pure function must not be the parent of an impure function. The rules of the preceding three paragraphs apply to all pure function subprograms. For pure functions that are not foreign subprograms, violations ...
为避免错误地修改全局信号,不推荐用非内的参数来传递信息 在含有敏感信号表的进程中调用过程时,过程内部禁用wait语句 函数: 可以被看作是一个能和运算符一起参加运算的广义表达式,其功能可以通过 一组顺序语句来实现 pure|impure function () return is begin ; end function ;注:函数只允许形式参数为常量和信号...
CE中。不能带出PROCESS,FUNCTION,PROCEDUCE,传送出去,而信号可以。1.3VHDL设计的基本语句VHDL常用语句可以分为两大类并行语句和顺序语句,在数字系统的设计中,这些语句用来描述系统的内部硬件结构和动作行为,以及信号之间的基本逻辑关系。顺序语句必须放在进程中,因此可以把顺序语句称作为进程中的语句。顺序语句的执行方式...
10、architecture array assert attributebegin block buffer bus case component configuration constantdisconnect downto else elsif end entity exit file for functiongenerate generic group guarded if impure in inertial inoutis label library linkage literal loop map mod nand new next nornot null of on open...