聊聊Systemverilog中的function in constraints 有些情况下,constraint不能简单用一行来表达,而是需要复杂的计算,如果都写到constraint block内部就比较复杂,而且很乱,这时候可以调用functions来约束随机变量。在constraint内调用function就称为”function in constraints”。它的格式如下: constraintconstraint_name {rand_var=...
在SystemVerilog中,用randc关键字声明的变量是循环随机(random-cyclic)变量,在其声明范围内循环随机,直到所有的值都随机过。 例如: 声明一个2bit randc变量; 代码语言:javascript 复制 randc bit[1:0]y; 每次随机此变量时都会随机可能的范围(这种情况下为0、1、2、3),在随机到所有值之前不会重复任何值。 在...
Static Constraints in SystemVerilog static constraints example syntax disable static constraints turn off static and non static constraint example
SystemVerilog Random Constraints 使用Constraint-driven(约束驱动)可以让用户自动生成测试激励进行功能验证。 随机测试比传统的定向测试方法更有效。通过指定约束,可以轻松进行难以触及的corner cases(极端情况)的验证。 在Verilog中,我们使用$random方法生成随机整数值,它返回32位随机值。 为了帮助基于类的对象进行随机化,S...
Functions in constraints example In the below example, The function is called inside the constraint. class packet; rand bit [3:0] start_addr; rand bit [3:0] end_addr; constraint start_addr_c { start_addr == s_addr(end_addr); } ...
takes precedence, while in the case of b, both constraints can be resolved by the number 20. The difference between a soft constraint failing, and a constraint failing is that in the case of a soft constraint, the alternate constraint takes precedence and the generation continues with no error...
The normal constraints are called hard constraints because it is mandatory for the solver to always satisfy them. If the solver fails to find a solution, then the randomization will fail. However, a constraint declared as soft gives the solver some flex
WhenrunningtheVivadoIDEinNon-ProjectMode,youcanreadintheconstraintsdirectly betweenanystepsoftheflow.ThepropertiesUSED_IN_SYNTHESISand USED_IN_IMPLEMENTATIONdonotmatterinthismode. ThefollowingcompilationTclscriptshowshowtoreadtwoXDCfilesfordifferentstepsof theflow: read_verilog[globsrc/*.v] read_xdcwave_gen_...
To retain the parameter value in the SystemVerilog environment use a Simulink.Parameter. In that parameter, the default value is 2100 and the valid range is [0, 4936]. (The pulse must be entirely within the frame of 5000 samples.) In the generated UVM code, two constraints are placed on...
(2003). Behavioral consistency of C and verilog programs using bounded model checking. In Proc. of DAC 2003 (pp. 368–371). Collavizza, H., & Rueher, M. (2006). Exploration of the capabilities of constraint programming for software verification. In Proc. of TACAS 2006 (pp. 182–196)...