介绍如何定义Wire/Reg/Memory/Prim。
1. DefWire
Wire()表明内括的Data的容器为线，用法为：
Wire()定义如下：
a. 获取一个t的克隆x；
b. 定义一个Definition, 即为DefWire：DefWire(sourceInfo, x)
c. DefWire同时也是一个Command，将其存下：pushCommand(DefWire(sourceInfo, x))
pushCommand()定义如下：
把命令c即DefWire，加入到forcedUserModule中。
2. DefReg
Reg()定义如下：
同样调用pushCommand()把定义寄存器的命令（DefReg），添加到forcedUserModule中。
3. DefMemory
Mem()定义如下：
调用pushCommand()把定义内存的命令（DefMemory），添加到forcedUserModule中。
4. DefPrim
以加法为例。
作为抽象方法，定义在Num中：
在子类UInt中实现，
5. 附录
Wire():
trait WireFactory {
def apply[T <: Data](t: T)(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): T = {
if (compileOptions.declaredTypeMustBeUnbound) {
requireIsChiselType(t, "wire type")
}
val x = t.cloneTypeFull
// Bind each element of x to being a Wire
x.bind(WireBinding(Builder.forcedUserModule))
pushCommand(DefWire(sourceInfo, x))
if (!compileOptions.explicitInvalidate) {
pushCommand(DefInvalid(sourceInfo, x.ref))
}
x
}
}
Reg():
object Reg {
/** Creates a register without initialization (reset is ignored). Value does
* not change unless assigned to (using the := operator).
*
* @param t: data type for the register
*/
def apply[T <: Data](t: T)(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): T = {
if (compileOptions.declaredTypeMustBeUnbound) {
requireIsChiselType(t, "reg type")
}
val reg = t.cloneTypeFull
val clock = Node(Builder.forcedClock)
reg.bind(RegBinding(Builder.forcedUserModule))
pushCommand(DefReg(sourceInfo, reg, clock))
reg
}
}
Mem():
object Mem {
@chiselRuntimeDeprecated
@deprecated("Mem argument order should be size, t; this will be removed by the official release", "chisel3")
def apply[T <: Data](t: T, size: Int)(implicit compileOptions: CompileOptions): Mem[T] = do_apply(size, t)(UnlocatableSourceInfo, compileOptions)
/** Creates a combinational/asynchronous-read, sequential/synchronous-write [[Mem]].
*
* @param size number of elements in the memory
* @param t data type of memory element
*/
def apply[T <: Data](size: Int, t: T): Mem[T] = macro MemTransform.apply[T]
def do_apply[T <: Data](size: Int, t: T)(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): Mem[T] = {
if (compileOptions.declaredTypeMustBeUnbound) {
requireIsChiselType(t, "memory type")
}
val mt = t.cloneTypeFull
val mem = new Mem(mt, size)
pushCommand(DefMemory(sourceInfo, mem, mt, size))
mem
}
}