请帮我看一下这段 msil 代码。。。。。。

[online1898]

public RGB(int red, int green, int blue)
{
this.red = red;
this.green = green;
this.blue = blue;
}

MSIL代码是：

.method public hidebysig specialname rtspecialname
instance void .ctor(int32 red,
int32 green,
int32 blue) cil managed
{
// 代码大小 22 (0x16)
.maxstack 2
IL_0000: ldarg.0
IL_0001: ldarg.1
IL_0002: stfld int32 MSIL_Test.RGB::red
IL_0007: ldarg.0
IL_0008: ldarg.2
IL_0009: stfld int32 MSIL_Test.RGB::green
IL_000e: ldarg.0
IL_000f: ldarg.3
IL_0010: stfld int32 MSIL_Test.RGB::blue
IL_0015: ret
} // end of method RGB::.ctor


请问为什么要用三次 ldarg.0 ，谢谢了