Use of the DFB directive in the Apple ][ Monitor program

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Hello all,

This is my first post on Applefritter. I do hope I am asking this question in the right area.

I am adapting the disassembler portion of the Apple monitor program that is listed in the Apple ][ Reference Manual on pages 155-171. My question relates to the use of the DFB directive ("define byte") in several tables.

For example, we often see code like the following on page 159:

F962: 04 20 54
F965: 30 00 DFB $04,$20,$54,$

What is the meaning of the '$' at the end of this list of bytes? You can see in memory that DFB defines the bytes 04 20 54, but then it appears that the $ produces bytes "30 00"? How does the '$' at the end of the list of bytes supposed to work? I can't see any rhyme or reason to it. In several places I see from 1-3 bytes being generated. Any help you can provide would be appreciated.

Thanks,
Tom

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david__schmidt's picture
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Re: Use of the DFB directive in the Apple ][ Monitor program

The trailing '$' is a typo, or an artifact of how lines got cut off when the listing was generated. It would not assemble as shown. What you can believe is correct is the listing of bytes next to the addresses, i.e.
F962: 04 20 54
F965: 30 0D
F967: 80 04 90
F96A: 03 22
etc.

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Re: Use of the DFB directive in the Apple ][ Monitor program

I am not sure which version of the Apple ][ Reference Manual you are using or where it is from, but the 1978 Version of the Apple ][ Reference Manual, located at ftp.apple.asimov.net has on PDF page 82 ( Manual Page 79 ) the section of code that you appear to be referencing...

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Re: Use of the DFB directive in the Apple ][ Monitor program

Thank you! I have a 1979 copy of the reference manual. The 1978 version of the reference manual posted here does NOT contain the '$' truncation in the listing. Thanks so much! Tom

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Re: Use of the DFB directive in the Apple ][ Monitor program

trieck wrote:

Thank you! I have a 1979 copy of the reference manual. The 1978 version of the reference manual posted here does NOT contain the '$' truncation in the listing. Thanks so much! Tom

Your Welcome..

Glad to be of assistance...

BTW, what are you going to do with the Modified Disassembler??

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Re: Use of the DFB directive in the Apple ][ Monitor program

I am adapting this disassembler for use in the Commodore 64.

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Re: Use of the DFB directive in the Apple ][ Monitor program

trieck wrote:

I am adapting this disassembler for use in the Commodore 64.

Excellent!!!

I have a nicely working SX-64, plus a couple Vic20's, of unknown operation a C-64, old C-1541, new C-1541 and a couple C-128s, a C-1571 plus a whole lot of Disks....

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Re: Use of the DFB directive in the Apple ][ Monitor program

MarkO wrote:
trieck wrote:

I am adapting this disassembler for use in the Commodore 64.

Excellent!!!

I have a nicely working SX-64, plus a couple Vic20's, of unknown operation a C-64, old C-1541, new C-1541 and a couple C-128s, a C-1571 plus a whole lot of Disks....

Awesome stuff, MarkO! I finally have the disassembler working on the C-64 now thanks to the help I received here!

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Re: Use of the DFB directive in the Apple ][ Monitor program

trieck wrote:
MarkO wrote:
trieck wrote:

I am adapting this disassembler for use in the Commodore 64.

Excellent!!!

I have a nicely working SX-64, plus a couple Vic20's, of unknown operation a C-64, old C-1541, new C-1541 and a couple C-128s, a C-1571 plus a whole lot of Disks....

Awesome stuff, MarkO! I finally have the disassembler working on the C-64 now thanks to the help I received here!

I have thought so.. Some of it I have owned since it was new... I have had the SX-64 since 1985 or 1986, bought it from a guy that was wanting to buy the C-128, and had to sell some C-64 stuff..

I have a box of Sinclair ZX81s as well.. But little software for them.....

Are you going to Release the C-64 Disassembler to the Public?? I would be interested in knowing where, if you are..

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Posts: 5
Re: Use of the DFB directive in the Apple ][ Monitor program

MarkO wrote:
trieck wrote:
MarkO wrote:
trieck wrote:

I am adapting this disassembler for use in the Commodore 64.

Excellent!!!

I have a nicely working SX-64, plus a couple Vic20's, of unknown operation a C-64, old C-1541, new C-1541 and a couple C-128s, a C-1571 plus a whole lot of Disks....

Awesome stuff, MarkO! I finally have the disassembler working on the C-64 now thanks to the help I received here!

I have thought so.. Some of it I have owned since it was new... I have had the SX-64 since 1985 or 1986, bought it from a guy that was wanting to buy the C-128, and had to sell some C-64 stuff..

I have a box of Sinclair ZX81s as well.. But little software for them.....

Are you going to Release the C-64 Disassembler to the Public?? I would be interested in knowing where, if you are..

Thanks. Absolutely, I am interested in releasing the disassembler to the public. I am integrating it into a larger monitor/disk-editor program I have been developing. If you are interested only in the disassembler portion, send me an email to and I will send you a .PRG or .D64 file containing only the adapted disassembler program.