Quick DASM question

[+Propane13]

Hello!

 

I seem to remember being able to do something like the below with DASM, but I forgot the syntax:

  .set-byte (number of bytes), (value).

 

e.g. if I wanted to set 64 bytes in ROM to zero, instead of doing ".byte 0" 64 times, I could just do:

  .set-byte 0,64

 

Of course, the above isn't valid syntax, but I could swear there was a way to do this.  Any hints?

 

Thanks!

[+Propane13]

As a follow-up / alternative, I seem to remember that you could set a macro somewhere to set the default fill-in value for undeclared ROM space to whatever you wish (e.g. $FF or 0).  I would potentially also be interested in re-learning that as well.

 

I'd appreciate any help.

[+Andrew Davie]

 ds 64,0  ; define 64 bytes, value 0
 ds 32,5  ; define 32 bytes, value 5

 

[+Andrew Davie]

another way....

 

  REPEAT 64
  .byte 0
  REPEND

 

[+Andrew Davie]

As to default fill... DASM manual...

 

[label] ORG	    exp[,DefaultFillVal]

	    This pseudop sets the current origin.  You can also set the
	    global default fill character (a byte value) with this
	    pseudoop.  NOTE that no filler is generated until the first
	    data-generating opcode/psueoop is encountered after this one.
	    Sequences like:

		org  0,255
		org  100,0
		org  200
		dc   23

	    will result in 200 zero's and a 23. This allows you to specify
	    some ORG, then change your mind and specify some other (lower
	    address) ORG without causing an error (assuming nothing is
	    generated inbetween).

	    Normally, DS and ALIGN are used to generate specific filler
	    values.

 

[+Propane13]

This is EXTREMELY helpful.  Thank you very much!

[JohnnyRockets]

On 2/21/2020 at 7:47 AM, Andrew Davie said:

another way....

 

  REPEAT 64
  .byte 0
  REPEND

 

Hi all,

 

Newbie here.  I cannot find the REPEAT-REPEND command anywhere in any literature that I have.

 

Can you point me to where/what/how to use this command properly?

 

 

Thank you!

 

 

JR

[+SpiceWare]

6 minutes ago, JohnnyRockets said:

Newbie here.  I cannot find the REPEAT-REPEND command anywhere in any literature that I have.

 

 

[JohnnyRockets]

Hi Darrell,

 

Thank you.  I read the documentation and it was very insightful.

 

 

JR

 

[+SpiceWare]

Doh! Should have answered that better - questions like these are better handled in the new Club DASM. We set up a central area for dasm because it's used to develop for multiple systems.

[JohnnyRockets]

Thank you!  I was not even aware of the "club", LOL!

 

Now I am following it.

 

Is it okay to ask newbie DASM questions there?

 

 

JR

[+SpiceWare]

2 hours ago, JohnnyRockets said:

Is it okay to ask newbie DASM questions there?

Yep