日常记录（23）代码熟悉

'赋值过程

module datt ();
    reg [7:0] mem;
    initial begin
        $monitor("ans is %b", mem);
    end

    initial begin
        mem=0;
        #10 mem=1;
        #10 mem='1;
        #10 $finish;
    end

    bit[7:0] mem2[3];
    initial begin
        mem2[0]='x;
        mem2[1]='1;
        mem2[2]=2;
        foreach(mem2[i])
            $display("mem2 %b", mem2[i]);
    end
endmodule

输出

mem2 00000000
mem2 11111111
mem2 00000010
ans is 00000000
ans is 00000001
ans is 11111111
$finish called from file "datt.v", line 11.
$finish at simulation time                   30

　　

foreach、初始化赋值{}、动态数组、队列

使用{}进行初始化赋值时候，'可以用在进行缩写的时候，而常量可以不用单引号进行说明。

module tcc ();
    int a[10]='{10{16'hfafa}};
    int b[]={1,3,4};
    initial begin
        a[0]=3;
        a[1]=5;
        b=a;
        b[0]=1;
        foreach(a[i])
            $display("a %b",a[i]);

        foreach(b[i])
            $display("b %b",b[i]);
    end

    int c[$]='{5{11}};
    int d[$]='{1,2,3,4,56};
    int e[5]={1,2,3,4,5};
    initial begin
        c.insert(2,0);
        c.insert(6,1);
        // out of bound will be wrong in run time. insert in the tail is use the finall index+1
        for(int i=0;i<c.size();i++)
            $display("the queue value is %b",c[i]);
    end
    initial begin
        for(int i=0;i<d.size();i++)
            $display("the queue value d is %b",d[i]);
    end
endmodule

输出

a 00000000000000000000000000000011
a 00000000000000000000000000000101
a 00000000000000001111101011111010
a 00000000000000001111101011111010
a 00000000000000001111101011111010
a 00000000000000001111101011111010
a 00000000000000001111101011111010
a 00000000000000001111101011111010
a 00000000000000001111101011111010
a 00000000000000001111101011111010
b 00000000000000000000000000000001
b 00000000000000000000000000000101
b 00000000000000001111101011111010
b 00000000000000001111101011111010
b 00000000000000001111101011111010
b 00000000000000001111101011111010
b 00000000000000001111101011111010
b 00000000000000001111101011111010
b 00000000000000001111101011111010
b 00000000000000001111101011111010
the queue value is 00000000000000000000000000001011
the queue value is 00000000000000000000000000001011
the queue value is 00000000000000000000000000000000
the queue value is 00000000000000000000000000001011
the queue value is 00000000000000000000000000001011
the queue value is 00000000000000000000000000001011
the queue value is 00000000000000000000000000000001
the queue value d is 00000000000000000000000000000001
the queue value d is 00000000000000000000000000000010
the queue value d is 00000000000000000000000000000011
the queue value d is 00000000000000000000000000000100
the queue value d is 00000000000000000000000000111000

　　

关联数组、itoa函数

sv的语法允许在initial中定义变量，但是似乎只能在开头定义。其它地方定义会报错。在Verilog语法中，则无关，一定在initial和always外面。

module tdd ();
initial begin

    bit [63:0] assoc1[bit[63:0]], idx=1;
    int assoc2[string];
    string idx2_str;
    int idx2=123;

    repeat (64) begin
        assoc1[idx]=idx;
        idx=idx<<1;
    end

    foreach(assoc1[i])
    $display("the assoc1 is %b", assoc1[i]);


    repeat (64) begin
        idx2_str.itoa(idx2);
        assoc2[idx2_str]=idx2;
        ++idx2;
    end
    foreach(assoc2[i])
    $display("%s, the assoc2 is %b",i, assoc2[i]);

end

reg xx;
endmodule

输出

  1 the assoc1 is 0000000000000000000000000000000000000000000000000000000000000001
  2 the assoc1 is 0000000000000000000000000000000000000000000000000000000000000010
  3 the assoc1 is 0000000000000000000000000000000000000000000000000000000000000100
  4 the assoc1 is 0000000000000000000000000000000000000000000000000000000000001000
  5 the assoc1 is 0000000000000000000000000000000000000000000000000000000000010000
  6 the assoc1 is 0000000000000000000000000000000000000000000000000000000000100000
  7 the assoc1 is 0000000000000000000000000000000000000000000000000000000001000000
  8 the assoc1 is 0000000000000000000000000000000000000000000000000000000010000000
  9 the assoc1 is 0000000000000000000000000000000000000000000000000000000100000000
 10 the assoc1 is 0000000000000000000000000000000000000000000000000000001000000000
 11 the assoc1 is 0000000000000000000000000000000000000000000000000000010000000000
 12 the assoc1 is 0000000000000000000000000000000000000000000000000000100000000000
 13 the assoc1 is 0000000000000000000000000000000000000000000000000001000000000000
 14 the assoc1 is 0000000000000000000000000000000000000000000000000010000000000000
 15 the assoc1 is 0000000000000000000000000000000000000000000000000100000000000000
 16 the assoc1 is 0000000000000000000000000000000000000000000000001000000000000000
 17 the assoc1 is 0000000000000000000000000000000000000000000000010000000000000000
 18 the assoc1 is 0000000000000000000000000000000000000000000000100000000000000000
 19 the assoc1 is 0000000000000000000000000000000000000000000001000000000000000000
 20 the assoc1 is 0000000000000000000000000000000000000000000010000000000000000000
 21 the assoc1 is 0000000000000000000000000000000000000000000100000000000000000000
 22 the assoc1 is 0000000000000000000000000000000000000000001000000000000000000000
 23 the assoc1 is 0000000000000000000000000000000000000000010000000000000000000000
 24 the assoc1 is 0000000000000000000000000000000000000000100000000000000000000000
 25 the assoc1 is 0000000000000000000000000000000000000001000000000000000000000000
 26 the assoc1 is 0000000000000000000000000000000000000010000000000000000000000000
 27 the assoc1 is 0000000000000000000000000000000000000100000000000000000000000000
 28 the assoc1 is 0000000000000000000000000000000000001000000000000000000000000000
 29 the assoc1 is 0000000000000000000000000000000000010000000000000000000000000000
 30 the assoc1 is 0000000000000000000000000000000000100000000000000000000000000000
 31 the assoc1 is 0000000000000000000000000000000001000000000000000000000000000000
 32 the assoc1 is 0000000000000000000000000000000010000000000000000000000000000000
 33 the assoc1 is 0000000000000000000000000000000100000000000000000000000000000000
 34 the assoc1 is 0000000000000000000000000000001000000000000000000000000000000000
 35 the assoc1 is 0000000000000000000000000000010000000000000000000000000000000000
 36 the assoc1 is 0000000000000000000000000000100000000000000000000000000000000000
 37 the assoc1 is 0000000000000000000000000001000000000000000000000000000000000000
 38 the assoc1 is 0000000000000000000000000010000000000000000000000000000000000000
 39 the assoc1 is 0000000000000000000000000100000000000000000000000000000000000000
 40 the assoc1 is 0000000000000000000000001000000000000000000000000000000000000000
 41 the assoc1 is 0000000000000000000000010000000000000000000000000000000000000000
 42 the assoc1 is 0000000000000000000000100000000000000000000000000000000000000000
 43 the assoc1 is 0000000000000000000001000000000000000000000000000000000000000000
 44 the assoc1 is 0000000000000000000010000000000000000000000000000000000000000000
 45 the assoc1 is 0000000000000000000100000000000000000000000000000000000000000000
 46 the assoc1 is 0000000000000000001000000000000000000000000000000000000000000000
 47 the assoc1 is 0000000000000000010000000000000000000000000000000000000000000000
 48 the assoc1 is 0000000000000000100000000000000000000000000000000000000000000000
 49 the assoc1 is 0000000000000001000000000000000000000000000000000000000000000000
 50 the assoc1 is 0000000000000010000000000000000000000000000000000000000000000000
 51 the assoc1 is 0000000000000100000000000000000000000000000000000000000000000000
 52 the assoc1 is 0000000000001000000000000000000000000000000000000000000000000000
 53 the assoc1 is 0000000000010000000000000000000000000000000000000000000000000000
 54 the assoc1 is 0000000000100000000000000000000000000000000000000000000000000000
 55 the assoc1 is 0000000001000000000000000000000000000000000000000000000000000000
 56 the assoc1 is 0000000010000000000000000000000000000000000000000000000000000000
 57 the assoc1 is 0000000100000000000000000000000000000000000000000000000000000000
 58 the assoc1 is 0000001000000000000000000000000000000000000000000000000000000000
 59 the assoc1 is 0000010000000000000000000000000000000000000000000000000000000000
 60 the assoc1 is 0000100000000000000000000000000000000000000000000000000000000000
 61 the assoc1 is 0001000000000000000000000000000000000000000000000000000000000000
 62 the assoc1 is 0010000000000000000000000000000000000000000000000000000000000000
 63 the assoc1 is 0100000000000000000000000000000000000000000000000000000000000000
 64 the assoc1 is 1000000000000000000000000000000000000000000000000000000000000000
 65 123, the assoc2 is 00000000000000000000000001111011
 66 124, the assoc2 is 00000000000000000000000001111100
 67 125, the assoc2 is 00000000000000000000000001111101
 68 126, the assoc2 is 00000000000000000000000001111110
 69 127, the assoc2 is 00000000000000000000000001111111
 70 128, the assoc2 is 00000000000000000000000010000000
 71 129, the assoc2 is 00000000000000000000000010000001
 72 130, the assoc2 is 00000000000000000000000010000010
 73 131, the assoc2 is 00000000000000000000000010000011
 74 132, the assoc2 is 00000000000000000000000010000100
 75 133, the assoc2 is 00000000000000000000000010000101
 76 134, the assoc2 is 00000000000000000000000010000110
 77 135, the assoc2 is 00000000000000000000000010000111
 78 136, the assoc2 is 00000000000000000000000010001000
 79 137, the assoc2 is 00000000000000000000000010001001
 80 138, the assoc2 is 00000000000000000000000010001010
 81 139, the assoc2 is 00000000000000000000000010001011
 82 140, the assoc2 is 00000000000000000000000010001100
 83 141, the assoc2 is 00000000000000000000000010001101
 84 142, the assoc2 is 00000000000000000000000010001110
 85 143, the assoc2 is 00000000000000000000000010001111
 86 144, the assoc2 is 00000000000000000000000010010000
 87 145, the assoc2 is 00000000000000000000000010010001
 88 146, the assoc2 is 00000000000000000000000010010010
 89 147, the assoc2 is 00000000000000000000000010010011
 90 148, the assoc2 is 00000000000000000000000010010100
 91 149, the assoc2 is 00000000000000000000000010010101
 92 150, the assoc2 is 00000000000000000000000010010110
 93 151, the assoc2 is 00000000000000000000000010010111
 94 152, the assoc2 is 00000000000000000000000010011000
 95 153, the assoc2 is 00000000000000000000000010011001
 96 154, the assoc2 is 00000000000000000000000010011010
 97 155, the assoc2 is 00000000000000000000000010011011
 98 156, the assoc2 is 00000000000000000000000010011100
 99 157, the assoc2 is 00000000000000000000000010011101
100 158, the assoc2 is 00000000000000000000000010011110
101 159, the assoc2 is 00000000000000000000000010011111
102 160, the assoc2 is 00000000000000000000000010100000
103 161, the assoc2 is 00000000000000000000000010100001
104 162, the assoc2 is 00000000000000000000000010100010
105 163, the assoc2 is 00000000000000000000000010100011
106 164, the assoc2 is 00000000000000000000000010100100
107 165, the assoc2 is 00000000000000000000000010100101
108 166, the assoc2 is 00000000000000000000000010100110
109 167, the assoc2 is 00000000000000000000000010100111
110 168, the assoc2 is 00000000000000000000000010101000
111 169, the assoc2 is 00000000000000000000000010101001
112 170, the assoc2 is 00000000000000000000000010101010
113 171, the assoc2 is 00000000000000000000000010101011
114 172, the assoc2 is 00000000000000000000000010101100
115 173, the assoc2 is 00000000000000000000000010101101
116 174, the assoc2 is 00000000000000000000000010101110
117 175, the assoc2 is 00000000000000000000000010101111
118 176, the assoc2 is 00000000000000000000000010110000
119 177, the assoc2 is 00000000000000000000000010110001
120 178, the assoc2 is 00000000000000000000000010110010
121 179, the assoc2 is 00000000000000000000000010110011
122 180, the assoc2 is 00000000000000000000000010110100
123 181, the assoc2 is 00000000000000000000000010110101
124 182, the assoc2 is 00000000000000000000000010110110
125 183, the assoc2 is 00000000000000000000000010110111
126 184, the assoc2 is 00000000000000000000000010111000
127 185, the assoc2 is 00000000000000000000000010111001
128 186, the assoc2 is 00000000000000000000000010111010
129            V C S   S i m u l a t i o n   R e p o r t 
130 Time: 0
131 CPU Time:      0.120 seconds;       Data structure size:   0.0Mb
View Code

 

合并数组、x的逻辑判断

module tee ();
reg [7:0] mem[7]='{7{4'b0011}};
bit [7:0] mem2[2][3]='{'{3{15}}, '{3,4,5}};

initial begin
    foreach(mem[i])
    begin
        $display("reg mem %b", mem[i]);
    end
end

initial begin
    for(int i=0;i<2;i++)
        for(int j=0;j<3;j++)
            $display("reg mem2 %b", mem2[i][j]);
    mem[0]=1;
    mem[1]=2;
    $display("the sum value is %d",mem.sum() with(item<3));
    $display("the sum value is %d",mem.sum with((item<3) *1));
    $display("logic value %b", 4'b0100>4'bxxzz);
end
endmodule

输出

 1 reg mem 00000011
 2 reg mem 00000011
 3 reg mem 00000011
 4 reg mem 00000011
 5 reg mem 00000011
 6 reg mem 00000011
 7 reg mem 00000011
 8 reg mem2 00001111
 9 reg mem2 00001111
10 reg mem2 00001111
11 reg mem2 00000011
12 reg mem2 00000100
13 reg mem2 00000101
14 the sum value is 0
15 the sum value is          2
16 logic value x
View Code

 

结构体、流操作符、合并结构

另外union为联合体、enum为枚举。定义时候用typedef比较好，以_s、_u、_e为类型后缀，表示结构体、联合体、枚举等。

结构体可综合，在如像素等内容上可用。

module tff ();
int adx[];
initial begin
    adx = new[5];
end

initial begin
    typedef struct{
        logic valid;
    logic [7:0] tags;
    logic [31:0] data;
    } data_word;
    data_word st1='{1'b1, 2'b10, 3'b111};
    //data_word st1={1'b1, 2'b10, 3'b111};
    
    data_word a1;
    a1.valid=1;
    a1.tags=7'b1100_0011;
    a1.data=8'hfa;
    $display("a1 is %b, %b, %b", a1.valid, a1.tags, a1.data);
    a1={>>{st1}};
    $display("after a1 is %b, %b, %b", a1.valid, a1.tags, a1.data);
end

initial begin
    typedef struct packed{
        logic valid;
    logic [7:0] tags;
    logic [31:0] data;
    } data_word2_s;
    data_word2_s st={1'b1, 2'b10, 3'b111};
    data_word2_s a2;
    a2.valid=1;
    a2.tags=7'b100_0011;
    a2.data=8'hfa;
    $display("a2 is %b, %b, %b", a2.valid, a2.tags, a2.data);
    a2={>>{st}};
    $display("after a2 is %b, %b, %b", a2.valid, a2.tags, a2.data);
end

endmodule

输出

合并结构在输出的时候，通过数据流，则最终数据挤在了最后的单元上。

非合并结构，即普通结构体，赋值常量需要加'，否则通不过编译。

Add a ' before concatenation operator to convert it to a valid assignment pattern.

a1 is 1, 01000011, 00000000000000000000000011111010
after a1 is 1, 00000010, 00000000000000000000000000000111
a2 is 1, 01000011, 00000000000000000000000011111010
after a2 is 0, 00000000, 00000000000000000000000000110111

　　

枚举、实数的指数、inside的逻辑或、等号通配、cast强制转换、n'的强制转换、property、unique

inside的逻辑或应该和随机约束相区分，二者是不同的概念。又如assign语句在行为级和数据流级一样是不同的概念，又如行为级中的<=有时候是非阻塞赋值，有时候又是逻辑判断，是不同的概念。

inside：https://blog.csdn.net/qq_22742971/article/details/115466654

property和unique在case语句中使用时候，前者必须有一个表达式有效，后者表示匹配的表达式必须只有一个。否则编译过程产生警告。

module tgg ();
    initial begin
        real a=3.1;
        typedef enum{
            R,G,B
        } color_e;
        color_e e1=R;
        int c;
        $display("the a is %.4f", a);
        $display("the squire of a is %4.f",a**2);

        $display("the squire of a is %.4f",a**2);
        $display("the inside method %b",2 inside{3,4});
        $display("the inside method %b",2 inside{3,2,4});
        $display("the compare ans is %b ", 4'b1011==?4'bxz11);
        $display("the compare ans is %b ", 4'b0011!=?4'b1x11);

        $display("typeof is %s", e1);
        e1++;
        $display("typeof is %s %d", e1, e1);
        c=e1;
        $cast(e1, c);
        $display("typeof is %s %d", e1, e1);
        $display("other cast method : %h",int'("a"));
        $display("other cast method : %h",8'(int'("a")));
    end

    int irq;
    always_comb
        priority case (10'd8)
            0: irq = 4'b0001;
            1: irq = 4'b0010;
            0: irq = 4'b0100;
            3: irq = 4'b1000;
        endcase

    always_comb
        unique case (10'd8)
            0: irq = 4'b0001;
            1: irq = 4'b0010;
            0: irq = 4'b0100;
            3: irq = 4'b1000;
        endcase

endmodule

 

输出：

the a is 3.1000
the squire of a is   10
the squire of a is 9.6100
the inside method 0
the inside method 1
the compare ans is 1 
the compare ans is 1 
typeof is R
typeof is G           1
typeof is G           1
other cast method : 00000061
other cast method : 61

Warning-[RT-NCMPRCS] No condition matches in statement
aaa.sv, 30
  No condition matches in 'priority case' statement. 'default' specification 
  is missing, inside tgg, at time 0s.


Warning-[RT-NCMUCS] No condition matches in statement
aaa.sv, 38
  No condition matches in 'unique case' statement. 'default' specification is 
  missing, inside tgg, at time 0s.

　　

always_ff、always_comb、always_latch

来源：https://www.cnblogs.com/zeushuang/p/7966679.html

第一个是触发器（时序逻辑），第二个是组合逻辑，第三个是允许latch的组合逻辑。据说会警告，但是我没有。

module thh ();
int a=1,b=2,out;
always_comb
    if(a > b)
        out = 1;
    else
        out = 0;

int c=1,d=2,out2;
always_latch
   if(c > d)
        out2 = 1;

reg clk;
reg en;
reg in, out3;
always_ff @(posedge clk)
    if(en)
        out3 <= in;
endmodule

　　

posted @ 2021-12-28 12:57  大浪淘沙、  阅读(89)  评论(0)    收藏  举报