Msg: 5319 *Conference*

08-15-94 01:31:37

From: COMET _

To : RON WIESEN

Subj: REPLY TO MSG #5280 (UNDOCUMENTED 80C85 OPCODES)

My ROM2/Cleuseau manual says that the instruction DEHL byte [which is hex 28,
BTW] has an action of HL<=HL+byte.  I believe this is an error--shouldn't the
action be DE<=HL+byte?
 
The RST V (hex CB) opcode is not listed at all; I believe it causes a branch to
hex 0040 if the V flag [Umm, I forget what flag this is] is set.  Of course,
this is useless, since this is a ROM address where the BASIC command table
lies....
 
The Flags register doesn't document bit 4, the half-carry flag.  It also
doesn't mention bit 1, the overflow bit, set if carry into sign bit <> carry
out of sign bit.  [This happens when an operation on 2 signed bytes cannot fit
the result in a single signed byte.]
 
If you [or anybody else
] know of any other erratum for the ROM2/Cleuseau, please let me know! 
Similarly for addenda, of course.