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phx · 08 June 2022, 22:18

This is a standard 64-bit shift-right operation, which you find in any m68k C-compiler's clib.
For example:

Code:

        tst.w   d3
        beq     .2
        moveq   #32,d2
        sub.l   d3,d2
        bgt.b   .1
        move.l  d0,d1
        neg.l   d2
        add.l   d0,d0
        subx.l  d0,d0
        asr.l   d2,d1
        bra.b   .2
.1:     move.l  d0,d4
        lsr.l   d3,d1
        lsl.l   d2,d4
        asr.l   d3,d0
        or.l    d4,d1
.2:     rts

EDIT: Don't know if this is faster than the jotd/ross version. Probably not. Too lazy to count.

08 June 2022, 22:18	#212
phx Natteravn Join Date: Nov 2009 Location: Herford / Germany Posts: 2,500	This is a standard 64-bit shift-right operation, which you find in any m68k C-compiler's clib. For example: Code: tst.w d3 beq .2 moveq #32,d2 sub.l d3,d2 bgt.b .1 move.l d0,d1 neg.l d2 add.l d0,d0 subx.l d0,d0 asr.l d2,d1 bra.b .2 .1: move.l d0,d4 lsr.l d3,d1 lsl.l d2,d4 asr.l d3,d0 or.l d4,d1 .2: rts EDIT: Don't know if this is faster than the jotd/ross version. Probably not. Too lazy to count.