程序声明
- initial：仿真开始初始化，仅执行1次
- final：仿真结束执行
- always：SV中新引入always_comb, always_latch, always_ff
- task：任务
- function：函数
选择声明
unique、priority
可加在 if … else … if前，表示一定意义，条件分支不全，匹配不到会报错
- unique：条件分支不能有重复
- priority：条件分支有优先级，按照顺序执行
module unique_priority ();byte a = 0;// unique
always @ (*)
begin unique if ((a==0) || (a==1)) begin$display("Unique if : 0 or 1"); end else if (a == 2) begin$display("Unique if : 2"); end else if (a == 4) begin$display("Unique if : 4"); end
end
// priority
always @ (*)
beginpriority if (a[2:1]==0) begin$display("Priority if : 0 or 1"); end else if (a[2] == 0) begin$display("Priority if : 2 or 3"); end else begin$display("Priority if : 4 to 7"); end
end
// unique case
always @ (*)
beginunique case(a) 0,1: $display("Unique Case 0 or 1");2 : $display("Unique Case 2");4 : $display("Unique Case 4");endcase
end
// priority case
always @ (*)
beginpriority casez(a) 3'b00?: $display("Priority Casez 0 or 1");3'b0??: $display("Priority Casez 2 or 3");endcase
end
// unique case inside
always @ (*)
beginunique case(a) inside[0 : 3]: $display("Unique Case inside 0 to 3");2 : $display("Unique Case inside 2");4 : $display("Unique Case inside 4");endcase
endinitial beginrepeat (7) begin#1 a ++;end#1 $finish;
endendmodule
Unique if : 0 or 1Unique Case 0 or 1Priority Casez 0 or 1Unique Case inside 0 to 3Unique if : 2Unique Case 2Priority Casez 2 or 3Warning: More than one conditions match in 'unique case' statement."unique_priority.sv", line 47,. Line 48 & 49 are overlapping at time 2.Unique Case inside 0 to 3Priority if : 2 or 3Warning: No condition matches in 'unique if' statement."unique_priority.sv", line 8, at time 3.Warning: No condition matches in 'unique case' statement."unique_priority.sv", line 30, at time 3.Priority Casez 2 or 3Unique Case inside 0 to 3Unique if : 4Unique Case 4Warning: No condition matches in 'priority case' statement."unique_priority.sv", line 39, at time 4.Unique Case inside 4Priority if : 4 to 7Warning: No condition matches in 'unique if' statement."unique_priority.sv", line 8, at time 5.Warning: No condition matches in 'unique case' statement."unique_priority.sv", line 30, at time 5.Warning: No condition matches in 'priority case' statement."unique_priority.sv", line 39, at time 5.Warning: No condition matches in 'unique case' statement."unique_priority.sv", line 47, at time 5.Warning: No condition matches in 'unique if' statement."unique_priority.sv", line 8, at time 6.Warning: No condition matches in 'unique case' statement."unique_priority.sv", line 30, at time 6.Warning: No condition matches in 'priority case' statement."unique_priority.sv", line 39, at time 6.Warning: No condition matches in 'unique case' statement."unique_priority.sv", line 47, at time 6.Priority if : 4 to 7Warning: No condition matches in 'unique if' statement."unique_priority.sv", line 8, at time 7.Warning: No condition matches in 'unique case' statement."unique_priority.sv", line 30, at time 7.Warning: No condition matches in 'priority case' statement."unique_priority.sv", line 39, at time 7.Warning: No condition matches in 'unique case' statement."unique_priority.sv", line 47, at time 7.
循环
- do while
- for
- foreach
跳转
- break
- continue
- return
序列（sequence）
待补充