[frank_b]

Originally Posted by StingRay

Sure does. Might be that I needed this behaviour once and my mind was playing tricks on me.

I tested using this code albeit on the Hatari emulator.

d1 winds up being $ff00

oddsandends
        move.l sp,d0
        move.w #$3344,-(sp)
        move.b #$ff,d1
        move.b d1,-(sp)
        move.w (sp)+,d1   ; shift by 8
        move.l d0,sp
        rts

Seems my memory and test code was fuzzy. Here's a better test case.

oddsandends
        move.l sp,d0
        move.w #$3344,-(sp)  ; set four bytes up with garbage
        move.w #$1122,-(sp)  ; " " 
        
        addq   #2,sp         ; point the stack at $1122

        move.l sp,a1         ; stuff it in a1
        move.b -1(a1),d2     ; we load $22 
        
        move.b #$ff,d1       ; then move shift value
        move.b d1,-(sp)      ; boom high byte is $22 
        move.w (sp)+,d1      ; shift by 8 and d1 is now $ff22 
        move.l d0,sp
        rts

Indeed there's garbage in the lower byte. Care must be taken when using the stack with this trick