Assembling

[Darrell N.]

Bruce wrote:

> I keep getting numerous:
> Invalid Opcode / Psuedo-Op  error messages.
> 
> In the following if get that error code for BD, D6, 3D, 05, and 25.   I'm
> missing something, but just don't understand what.
> 
> LC7C2: BD FC00 ;    JSR    LKUP2DAF
>              D6 A4      ;    LDA B  AECOOLF
>              3D           ;     MUL
>              05            ;     ASL D
>       25 04(37CF)   ;     BCS    LV8AE3C
> 
> And what does the (37CF), mean?
> TIA
> Bruce

There's a couple of things that I'm not sure about here.  Is this snippet of 
code exactly as you entered it?  If so, you have a comment character [;] 
before the opcodes, so the assembler will ignore them.  But, in this 
case, you wouldn't get the machine code values on the left, which 
appear to be correct.  Or, is this the output from a disassembler, which 
would print the mnemonics as comments?

Could you send me this piece of code exactly as it appears on your 
editor, with a few more lines above and below?  I need to see the 
context of what happens before and after this code segment.

As far as the (37CF) goes, it is likely the absolute address of where the 
branch instruction is pointing.  In this case, your branch instruction will 
go 4 locations ahead.  Is this absolute address 37CF?  This is where 
the listing file comes in handy, as it gives the absolute address for each 
instruction in front of the line of code.

regards
darrell
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