verilog语法笔记

浅浅的花香味﹌ 2023-02-15 12:43 1阅读 0赞

具体语法信息可以参考synopsys的帮助文档：

[http://www.svnchina.com/svn2/shareyou/reference.pdf][http_www.svnchina.com_svn2_shareyou_reference.pdf]

当verilog赋值左右不对等时，数据默认都是放在低位的，而没有指定的高位默认置为0。

比如：

wr\_op\_list<=1'b1;  
write\_buffer\[63:63-7-8\] <= \{8'h99\};   //对应\[63:63-7\]则为0

同样：当把一个48位数据给到32位数据时会如何：

reg\[31:0\] a;

reg\[47:0\]b;

always @

a<=b:

![20201021114119630.png][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70][]

结论：**b最终会优化为31bit**

\---------------------------------

reg \[7:0\]  SR1V = 'b0;

这种语法只对应与仿真，以及上电后的初始默认值，软件复位时必需明确指定每个寄存器变量的初始值否则状态可能会

保留上一次的数值。

//条件编译：

\`define

\`ifdef、\`else、\`elsif和\`endif

//system verilog 数组赋值

![20200908193913406.png][]

参考：[https://blog.csdn.net/moon9999/article/details/106149862][https_blog.csdn.net_moon9999_article_details_106149862]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 2][]

![20201010135355644.png][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 3][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 4][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 5][]

[http_www.svnchina.com_svn2_shareyou_reference.pdf]: http://www.svnchina.com/svn2/shareyou/reference.pdf
[20201021114119630.png]: https://img-blog.csdnimg.cn/20201021114119630.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/2020102111410630.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc=,size_16,color_FFFFFF,t_70
[20200908193913406.png]: https://img-blog.csdnimg.cn/20200908193913406.png
[https_blog.csdn.net_moon9999_article_details_106149862]: https://blog.csdn.net/moon9999/article/details/106149862
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200909103908153.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20200909111738351.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc=,size_16,color_FFFFFF,t_70
[20201010135355644.png]: https://img-blog.csdnimg.cn/20201010135355644.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 3]: https://img-blog.csdnimg.cn/20201010135652557.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 4]: https://img-blog.csdnimg.cn/20201010142906413.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc_size_16_color_FFFFFF_t_70 5]: https://img-blog.csdnimg.cn/20201010143125288.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTEzMjk5Njc=,size_16,color_FFFFFF,t_70