“随着综合工具的进步,已经不需要讨论if-else 和case的区别了,两者可以等同 ” “Verilog 2001标准(IEEE 1364-2001)第132页: The case item expressions shall be evaluated and compared in the exact order in which they are given. 指出了case是串行有优先级。又: Apart from syntax, the case statement di...
Apart from syntax, the case statement differs from the multiway if-else-if construct in two important ways: a) The conditional expressions in the if-else-if construct are more general than comparing one expression with several others, as in the case statement. b) The case statement provides ...
The code snippet below shows the general syntax for the case statement in verilog. case(<variable>)<value1> :begin// This branch executes when <variable> = <value1>end<value2> :begin// This branch executes when <variable> = <value2>enddefault:begin// This branch executes in all other ...
When the number of the nesting grows, it becomes difficult to understand the if else statement. The verilog case statement, comes handy in such cases. We will first look at the usage of the case statement and then learn about its syntax and variations. ...
Syntax A Verilogcasestatement starts with thecasekeyword and ends with theendcasekeyword. The expression within parantheses will be evaluated exactly once and is compared with the list of alternatives in the order they are written and the statements for which the alternative matches the given expres...
4. Conditional、 Case statement 5. Looping statements 6. Procedural timing controls 7. Block statements 8. Structured procedures 1. initial: 2. always: 3. task: 4. Function: 1. Behavioral model overview Verilog包含控制仿真和操作数据变量的过程性语句:initial 和 always 。
b_out = c;elseb_out = ~c;end// case statementalways@(*)begincase(a)0: b_out = c;1: b_out = ~c;default: b_out = c;endcaseend WARNING: For and while loops can not be mapped to hardware! They are non-synthesizable control statements ...
4to1_bh(D,S,En,Y);input[3:0]D,[1:0]S;inputEn;outputregY;always@(D,S,En)//2001, 2005 syntax;或@(D or S or En)beginif(En==1)Y=0;//En=1时,输出为0else//En=0时,选择器工作case(S)2’d0:Y=D[0];2’d1:Y=D[1];2’d2:Y=D[2];2’d3:Y=D[3];endcaseend...
This code is proper in syntax and could be synthesized too. But in this way, I couldn't insert the default part of case statement in the loop. What I wanna express is like below case(ctrl) 0 : out <= 0; 1 : out <= 1; 2 : out <= 2; 3 : out <= 3; 4 : out <=...
else and not just if or use case statement if you don't want priority. second: I think you should not add begin at start. As far as I remember the begin...end is for constructs, functions,tasks etc. unlike vhdl but please check that. For example your first module hasn't got ...