[Coco] Errors in Leventhal's 6809 Subroutines book?

[lost]

LEAX -1,S is perfectly valid. Not generally useful but valid.
-------- Original message --------From: Robert Gault <robert.gault at att.net> Date: 2022-01-28  20:49  (GMT-07:00) To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com> Subject: Re: [Coco] Errors in Leventhal's 6809 Subroutines book? The instruction mentioned was leax -1,sthat should give an error although I have not yet tried it.Sent from AT&T Yahoo Mail on Android    On Fri, Jan 28, 2022 at 10:34 PM, Joel Rees<joel.rees at gmail.com> wrote:   2022年1月29日(土) 11:23 Robert Gault <robert.gault at att.net> said:> A Google search did not find corrections for the book. However, the second> error would have been quickly found if EDTASM had been used to compile the> code. It would have been reported as an error.>Are you sure?  LEAX -1,Xis valid syntax for a valid op-code.Sent from AT&T Yahoo Mail on Android>>  On Fri, Jan 28, 2022 at 8:50 PM, Don Barber<don at dgb3.net> wrote:  Hi> folks, I've been teaching myself 6809 assembly, and quickly ran> across Leventhal's books which have been invaluable. I have the> programming book, but have also been referencing the subroutine book> from online copies available at:>>> https://colorcomputerarchive.com/repo/Documents/Books/6809%20Assembly%20Language%20Subroutines%20(Lance%20Leventhal).pdf>> and>>> https://archive.org/details/assembly-language-subroutines-for-the-6809_Leventhal>> Both appear identical.>> However, I've already run across two bugs:>> One is on page 72, in MPBMUL, where a BNE is executed right after a> "LEAU -1,U". However, the LEAU does NOT set the Z flag, so the BNE is> actually working off either the preceding INCA or the STA instructions> (depending upon the STA's Carry result). One can test this does not work> by trying to multiply 0x0001 times 0x08a6; the result will be an> incorrect 0x00a6. One has to add a 'CMPU #0' after the LEAU statement to> get the correct behavior.>> The other is on page 78 in MPBDIV, where one will find a "LEAX -1,S"> that should instead be "LEAX -1,X" as the X register is being used as a> decrement counter. The original text will result in an infinite loop as> the S register is not modified in this loop.>> So my question is: is there an errata somewhere where known bugs are> listed? I imagine people ran across these back in the day too. Both of> these got me stuck for an hour or three each, though in hindsight they> should have been obvious.>>> Thanks,>> Don>>>>> --> Coco mailing list> Coco at maltedmedia.com> https://pairlist5.pair.net/mailman/listinfo/coco>>> --> Coco mailing list> Coco at maltedmedia.com> https://pairlist5.pair.net/mailman/listinfo/coco>-- Coco mailing listCoco at maltedmedia.comhttps://pairlist5.pair.net/mailman/listinfo/coco  -- Coco mailing listCoco at maltedmedia.comhttps://pairlist5.pair.net/mailman/listinfo/coco