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EG at offset 0x4519 in http://bbcmicro.co.uk/explore.php?id=30

we have

4519 b1 72 91 LDA (&9172,Y)

where the disassembly should have been

4519 b1 72 LDA (&72),Y

So it's a two-byte not a three-byte instruction and the rest of the disassembly goes off alignment.

I think you have the same issue with &91 STA (zp),Y and indeed with all instructions with bottom 5 bits b10001.

The Web disassembly view is really handy but this issue makes it much less usable.

The current code disassembles $A9 as a "TAY #" but this should be "LDA #" (see line "ops[0xA9] = ['TAY #' , 4];").

E.g. in CORE file in Stunt Car Racer http://bbcmicro.co.uk/explore.php?id=3112 the follow instructions display as ???

2043   da          ???
2044   5a          ???
2045   20 38 22    JSR &2238
2048   7a          ???
2049   fa          ???
204a   ee 5d 21    INC &215d
204d   80          ???
204e   e2          ???
204f   da          ???
2050   5a          ???
2051   20 2b 22    JSR &222b
2054   7a          ???
2055   fa          ???
2056   80          ???

But should be:

 2043   DA         PHX
 2044   5A         PHY
 2045   20 38 22   JSR &2238
 2048   7A         PLY
 2049   FA         PLX
 204A   EE 5D 21   INC &215D
 204D   80 E2      BRA &2031
 204F   DA         PHX
 2050   5A         PHY
 2051   20 2B 22   JSR &222B
 2054   7A         PLY
 2055   FA         PLX
 2056   80 D9      BRA &2031

E.g. the first 3 instructions of CORE in Stunt Car Racer: http://bbcmicro.co.uk/explore.php?id=3112 appear as:

0e00   86 16       STX (&16)
0e02   a5 52       LDA (&52)
0e04   85 14       STA (&14)

But actually should just be:

0e00   86 16       STX  &16
0e02   a5 52       LDA &52
0e04   85 14       STA &14

Using the catalog within bbcmicro.co.uk, I've noticed certain instances where the DFS Catalog doesn't appear to list all of the BBC Basic code.

One example can be found here - http://bbcmicro.co.uk//explore.php?id=602#bas - this is for a Beebug game, Labyrinth. When I download the file LAB2 and open it in any text editor, I can see that it is BBC Basic, albeit untokenised. But the in-page output of the code only lists one line:

10VDU28,0,0,0,0:CALLTOP

I can find further examples if required, but it would be nice to see if this is indeed an issue, and whether it can be resolved.