English Amiga Board - View Single Post - Best Way to Convert 32-bit Signed Value to 16 Bit?

AGS · 19 December 2013, 20:43

Hi,

I need an optimisation for this:

Code:

; convert d0 from 32 to 16 bit

        move.l    #$7fff,d1
        cmp.l    d1,d0
        blt    .low_d0
        move.w    d1,d0
        bra    .ready
.low_d0        cmp.l    #$ffff8000,d0
        bgt    .ready
        move.w    #$8000,d0
.ready

I guess it converts a SIGNED 32 bit value (comes in d0) into a 16 bit value into d0. Is there a better way to do this? The problem is, values greater than $7fff should become $7fff and values smaller than $8000 should become $8000. Right?

ags

19 December 2013, 20:43	#1
AGS XoXo/Tasko Developer Join Date: Dec 2013 Location: Munich Age: 48 Posts: 450	Best Way to Convert 32-bit Signed Value to 16 Bit? Hi, I need an optimisation for this: Code: ; convert d0 from 32 to 16 bit move.l #$7fff,d1 cmp.l d1,d0 blt .low_d0 move.w d1,d0 bra .ready .low_d0 cmp.l #$ffff8000,d0 bgt .ready move.w #$8000,d0 .ready I guess it converts a SIGNED 32 bit value (comes in d0) into a 16 bit value into d0. Is there a better way to do this? The problem is, values greater than $7fff should become $7fff and values smaller than $8000 should become $8000. Right? ags Last edited by AGS; 19 December 2013 at 20:51.