通信软件设计05SDL语言.ppt

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * FSM是形式化的方式 EFSM的形式化 我们使用的半形式化方式 * * * * 迁移过程-分支 5、分支 分支操作是一个动作，通过计算条件表达式选择不同迁移过程 ① 图形语法 decision area ::= decision symbol contains question is followed by graphical decision body decision symbol ::= 迁移过程-分支 question ::= expression | informal text | any graphical decision body ::= { graphical answer part+ [graphical else part] } set graphical answer part ::= flow line symbol is associated with graphical answer is followed by transition area graphical answer ::= [answer] | ( [answer] ) graphical else part ::= flow line symbol is associated with else is followed by transition area answer ::= range condition | informal text flow line symbol ::= 分支 process calling 2/5 wait_for_num T1 busyTone VIA uG wait_for_onHook num (toNum) reset (T1) getUserPid (toNum, otherPid) otherPid = NULL True msg (Sorry, wrong number) wait_for_onHook False wait_for_connRepl onHook reset (T1) A1 迁移过程-定时器 6、定时器 在状态机图中，监视激励信号是否在定时器规定时间间隔内到达。若无激励到达，则触发超时事件，作为激励输入。 定时器操作包括：设置和复位 执行一个定时器操作即执行一个任务 超时作为一个触发事件，引起状态的迁移过程 迁移过程-定时器 ① 文本语法 timer definition ::= timer timer definiton item { , timer definition item }* ; timer definition item ::= timer name [sort list][:=Duration constant expression] sort list ::= ( sort { , sort }* ) ② 图形语法 设置定时器、复位定时器 超时事件 迁移过程-定时器 set area ::= task symbol contains timer set timer set ::= set ( [time expression , ]timer access ) time expression ::= now + Duration constant expression timer access ::= timer name [ ( expression { , expression}* ) ] reset area ::= task symbol contains timer reset timer reset ::= reset ( timer access ) 迁移过程-汇接 7、汇接 两种方式：连接符、合并 ① 连接符 入连接域和出连接域 对每个出连接域，必须有且仅有一个同名入连接域与之对应 多个出连接域可汇接到一个入连接域 连接符只用于迁移过程，不可连接状态和触发事件 迁移过程-汇接 图形语法 out connector area ::= out connector symbol contains connector name out connector symbol ::= in connector symbol in connector area ::= in c