[Coco] DLOAD (was: Re: Stupid Cassette Port Tricks, (was: Re: Coco and .WAV files))

[Neil Morrison]

Also see http://tech.groups.yahoo.com/group/ColorComputer/files/DLOADM Bug.htm 

"The mystery surrounding the DLOADM command"

DLOADM Bug
      The mystery surrounding the DLOADM command in Extended Color Basic as discussed in "CC DLOAD" (80 Micro, March 1983, p. 140) is easily cleared up. A bug in the ROMs prevents a DLOADM command from being recognized as such.

      For a simple fix, use

CLOSE #-l : POKE &H78, ASC("M"): DLOADM "filename," baud, offset.

Baud has the same value as DLOAD and offset has the same value as CLOADM.

      As with CSAVEM and CLOADM, there is no DLOADM token, just DLOAD followed by an ASCII M. On encountering a DLOAD or DLOADM command, the next byte from the Basic program loads into the A register (an ASCII M if the command was DLOADM). This first step is common to most commands and occurs before jumping to the DLOAD routine.

      Second, a subroutine closes the cassette file if it's open (DLOAD or DLOADM needs the buffer). Then the A register is checked to see if it contains an ASCII M, and a flag byte is set or cleared accordingly.

      Unfortunately, the second step causes the contents of the A register to change; consequently, the third step does not recognize DLOADM. This bug could have been corrected by exchanging the second step for the third.

Ralph Fox

4212 Wadsworth Ct. #102

Annandale, VA 22003


Neil

----- Original Message ----- 
From: "Arthur Flexser" <flexser at fiu.edu>

> That message, by the way, is the only known reference in the CoCo literature to
> the talented author of the CoCo ROMs (other than Super Extended Basic), Mark
> L. Chamberlin, who also apparently wrote the ROM for the Micro CoCo and hid his
> name within it.
> 
> Art