此bsr.l指令有什么作用？

Question

I'm playing with coldfire disassembler and find out this piece of code:

loc_F7E:
    bsr.l loc_F7E+2
    lea 12(sp),sp
    pea (284).w
    clr.l -(sp)
    move.l  a6,d0
    addi.l  #-636,d0
    move.l  d0,-(sp)

loc_F98:
    bsr.l loc_F98+2
    lea $C(sp),sp
    pea (284).w
    clr.l -(sp)
    move.l  a6,d0
    addi.l  #-$398,d0
    move.l  d0,-(sp)

I'm trying to figure out what is the need for those bsr.l. For me it is only jumping itself.

Answer 1

根据手册， bsr.l *+2十六进制代码$61FF $0000 $0000 ，所以很可能是由于Igor Skochinsky在上面提到的未解析重定位而使对象代码失效。

Answer 2

I think these might be the result of a compiler optimization for more compact code. See "Short BRA Optimization" in the compiler guide.

Recent IDA versions disassemble such branches as skip2 (there is also skip1 ) for HC08 and HC12 code. I haven't seen such optimization in ColdFire code before.

EDIT: or it could be just an object file with unresolved relocations.