function arguments and return values layout

+------+-----+-------------------+--------+
|      |     |                   |        |
| func | Foo | (a bool, b int16) | []byte | unsafe.Sizeof(struct{a bool; b int16; c []byte})
| c1AB | c1AB| cRED              | cRED   |
+------+-----+-------------------+--------+
                      |              |
        +-----------=-+              +-=--------------------------+
        |                                                         |
        v                                                         v
+-----------------+-------------------------------+--------------------------------------+
|                 |                               |                                      |
| a bool, b int16 |                               |        c reflect.SliceHeader         |
| cRED            |                               |  cRED                                |
+-----------------+-=-----------------------------+--------------------------------------+
    |        |                                             |            |         |
    :        :                                             :            :         :
    |        |                                             |            |         |
    v        v                                             v            v         v
+---------+----------+----------------------------+-----------------+--------+-----------+
|         |          |                            |                 |        |           |
| a bool, | b int16, |                            | c.Data uintptr, | c.Len, | c.Cap int |
| cBLU    | cPNK     |                            | cGRE            | cGRE   | cGRE      |
+---------+----------+-=--------------------------+-----------------+--------+-----------+
    |         |                                        |              |         |
    +---------+                   argsize+32(FP)---=-+ |              |         |
    :                                                | |              |         |
    |      +-------------------------------------+ <-+ |              |         |
    |      | cGRE                                |     |              |         :
    |      |              c.Cap                  |     |              |         |
    |      |              64bit                  |     |              |         |
    |      +-------------------------------------+ <-=-|-=------------|---------+
    |      | cGRE                                |     |              |    c.Cap+24(FP)
    |      |              c.Len                  |     |              |
    |      |              64bit                  |     |              |
    |      +-------------------------------------+ <-=-|-=------------+c.Len+16(FP)
    |      | cGRE                                |     |
    |      |              c.Data                 |     |
    |      |              64bit                  |     |
    |      +----+----+--------+------------------+ <-=-+c.Data+8(FP)
    |      |cBLU|cAAA|cPNK    |cAAA              |
    +----> | a  |    |   b    |                  |
           |8bit|8bit| 16bit  |     32bit        |
           +----+----+--------+------------------+ <--=-0(FP)
            ^         ^
            |         |
            |         +-=-b+2(FP)
            |
            +-=-a+0(FP)