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标量(scalar)是没有范围声明的1-bit的线网(net)或reg。
向量(vector)是带有范围声明的multi-bit的线网(net)或reg。
例子:
wand w; // a scalar net of type "wand"
wire w1, w2; // declares two wires
tri [15:0] busa; // a three-state 16-bit bus
reg a; // a scalar reg
reg [3:0] v; // a 4-bit vector reg made up of v[3],
// v[2], v[1], and v[0]
reg signed [3:0] signed_reg; // a 4-bit vector in range -8 to 7
reg [4:-1] b; // a 6-bit vector reg
reg [4:0] x, y, z; // declares three 5-bit regs