Re: branch computation

From: Greg King <*greg.king5_at_verizon.net*> Date: Tue, 15 Oct 2019 16:43:37 +0000 (UTC) Message-ID: <1182545366.1245888.1571157817143_at_mail.yahoo.com> · greg.king5_at_verizon.net

-----Original Message-----
From: smf <smf_at_null.net>
To: cbm-hackers <cbm-hackers_at_musoftware.de>
Sent: Mon, Oct 14, 2019 6:40 am
Subject: Re: branch computation

If you have some spare RAM, then you can simplify that.

    sec
    lda target
    sbc current
    sta result
    lda target+1
    sbc current+1
    eor result
    bmi out_of_range
    lda result
    ...
out_of_range:
-----End of Original Message-----
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target = $0500
current = $0400
result = $00.A = $01eor = $01
Not minus -- it fails to detect "branch out of range".