Macroassembler by Michal Kowalski, syntacs question

[barrym95838]

I support the notion that a BRK by itself should assemble to a $00 by itself, and a BRK #$EA should assemble to $00 $EA without complaint ... now I just need to write or modify an assembler to support that behavior, because expecting someone else to do it for me at this late date would be vainly optimistic.

[BigDumbDinosaur]

Chromatix wrote:

BigDumbDinosaur wrote:

Chromatix wrote:

It would indeed be logical to assemble "BRK #0" as 00 00, and some assemblers accept that syntax, but that's not what was specified here. This difference from standard assembler behaviour could indeed be considered a bug.

In the case of the Kowalski assembler, it's not a bug. It's a design feature that gives the programmer the option to have any signature byte assembled after a BRK instruction. The default if this feature is enabled is to assemble $EA (NOP) as the signature byte. If this feature is disabled, only $00 will be assembled for a BRK instruction.

Except that that's demonstrably *not* what happens here, and it makes it *more* difficult to assemble an arbitrary desired trailing byte.

The code given was

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BRK NOP NOP

and it assembled to

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00 00 EA EA

According to your description, it should have assembled to

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00 EA EA EA

According to every other assembler I know about, it would become

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00 EA EA

I have no problem with

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BRK #0

being assembled as

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00 00

.

I just tested the Kowalski assembler with a BRK instruction and the signature byte option enabled. The code assembled was $00 $EA.

[Klaus2m5]

You can set the BRK opcode behavior here:

Kowalski_set_BRK_behavior.png (13.78 KiB) Viewed 2284 times

barrym95838 wrote:

I support the notion that a BRK by itself should assemble to a $00 by itself, and a BRK #$EA should assemble to $00 $EA without complaint ... now I just need to write or modify an assembler to support that behavior, because expecting someone else to do it for me at this late date would be vainly optimistic.

This is what macros are for:

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; BRK instruction to assemble with or without signature
;   no matter what the assembler thinks it should do
myBRK   .macro ...
        .db 0
        .if %0>0
               .db %1
        .endif
        .endm
	
; usage example
        *=$200

        myBRK                   ; native BRK
        myBRK $12               ; BRK with signature byte

        .end

[BitWise]

Dev65 generates one byte unless an immediate operand is specified.

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00:00C4' 00                :         BRK
00:00C5' 0011              :         BRK #$11

[BigEd]

Best of both worlds!