[Coco] VCC possible bug in 6309 & 6809 emulation and general Wally news!
robert.gault at att.net
Mon Jun 11 09:41:55 EDT 2018
Your observations of non-standard operations from the pdf are very interesting. The exchanges
between 8-bit and 16-bit registers and a Zero register are definitely not in the Hitachi Data book.
This information is also not mentioned in one of the better books on programming: "6809 Assembly
Language Programming" by Lance A. Leventhal, McGraw-Hill.
Nevertheless, I did run a test on my Coco3 which has a 6309 chip and non-equal register transfers
work and there does seem to be a Zero register.
A note to anyone using Tandy's EDTASM or my EDTASM6309, you can only perform these operations by
manually programming them with FCB statements. The assemblers will reject code such as:
TFR X,A or TFR Z,A . You can, however, enter ex. FCB $1F,$C8 which makes the 6309 clear regA.
$1F=TFR and %1100xxxx or %1101xxxx = from Z and %xxxx1000 = to regA.
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