[Coco] assembler directive

Dave Philipsen dave at davebiz.com
Thu Oct 5 12:09:19 EDT 2017


Thanks, Robert.  I’m not actually using LWASM else it would have been easy to figure it out. I am assembling the source for the modules with the native OS9 assembler which, obviously, does not recognize the directive. If there were a version of LWASM for OS9 I would consider using it.

I’m very familiar with using a cross assembler on another system to generate code and then uploading the code to the target system for testing.  Usually this is done because the target system does not have the resources to run an assembler. But in this case I have a full-blown operating system and an assembler and enough speed to do it right on the same box.  I also realize that, for the CoCo, this could be done fairly quickly with an emulator on a PC.  However, to my knowledge, neither the CoCo3FPGA nor my non-CoCo 6809 system are emulated so that’s another reason I’m converting this stuff over.

Dave

> On Oct 5, 2017, at 8:15 AM, Robert Gault <robert.gault at att.net> wrote:
> 
> Dave Philipsen wrote:
>> So I'm doing a little work with the Sysgo source file and I ran into an unfamiliar directive,
>> "dtb".  In context:
>> 
>> * Default time packet
>> DefTime   dtb
>> 
>> 
>> Anyone know what it does?  There does seem to be any mention of it in the LWASM manual.
>> 
>> Dave
> 
> DefTime can be found in several source code files and is a hard coded default time presumably when the source code was put in the project. In the case of sysgo, if you look at the compiled result, you will find that code was indeed generated.
> The most likely interpretation of "dtb" is that it results in a read of the PC system clock. That would result in a new deftime equal to the time of assembly.
> 
> It should be easy enough to compile sysgo several times and monitor the change of the block starting at $C6.
> 
> Robert
> 
> 
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