Thread: Bitfields BFFFO
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Old 21 November 2015, 14:37   #6
flype
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Join Date: Dec 2014
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Quote:
Originally Posted by Toni Wilen View Post
Confirmed.

Interesting unexpected behavior, low 5 bits are used for offset when EA is register but when calculating result, all 32-bits are used.

(For example D0 = 0, D2 = 7FFFFFE0: D3 = 80000000)
Yep, other samples :

Code:
    ;              d0,       d1,       d2,       d3
    dc.l    $ffffff00,$ffffff00,$7fffffe0,$ffffff00 ; uae : d4=$00000000
    dc.l    $00000000,$ffffffff,$7fffffe0,$0000001f ; uae : d4=$0000003f
    dc.l    $00000000,$00000000,$7fffffe0,$00000020 ; uae : d4=$00000020 (ok)
    dc.l    $00000000,$00000020,$7fffffe0,$00000040 ; uae : d4=$00000020
    dc.l    $1badcafe,$000000ff,$000000ff,$00000103 ; uae : d4=$00000023
    dc.l    $1badcafe,$0000007f,$0000007f,$00000083 ; uae : d4=$00000023
    dc.l    $1badcafe,$00000020,$00000020,$00000023 ; uae : d4=$00000003
    dc.l    $1badcafe,$00000020,$00000003,$00000023 ; uae : d4=$00000003
    dc.l    $1badcafe,$00000020,$00000002,$00000022 ; uae : d4=$00000002
    dc.l    $1badcafe,$00000020,$00000001,$00000021 ; uae : d4=$00000001

Last edited by flype; 21 November 2015 at 14:44.
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