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xa wide mode error?

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fachat

Post subject: xa wide mode error?

Posted: Tue Dec 08, 2020 9:14 pm

Joined: Tue Jul 05, 2005 7:08 pm
Posts: 1042
Location: near Heidelberg, Germany

Hi there, I'm trying to assemble a small test program and I'm getting an overflow error on loading X with a 16 bit value in xa, or comparing it with a 16bit value.
I'm using the "-w" option to enable 65816 mode, and the ".xl" pseudo opcode to tell the assembler to run in wide index register mode.

Code:

        
        *=$f000
vreset
        ; init the CPU
        sei
        cld
        ldx #$ff
        txs

        ; switch to native mode
        clc
        xce

        ; set ac to single byte ...
        sep #%00100000
        ; ... and tell the assembler about it
        .as

        ; set X/Y registers to 16 bit ...
        rep #%00010000
        ; ... and tell the assembler about it
        .xl

        ; -----------------------
        ; copy over charrom to RAM

        lda #0
        ldx #4095
copy
        lda $00e000,x   ; location in test ROM bank
        sta $07c000,x   ; location in RAM - uppermost RAM bank
        dex
        bpl copy

        ...

However, when I try to build it, I get

Code:

xa -w -o romtest02 romtest02.a65
 ldx #4095
romtest02.a65:line 37: f00f:Overflow error
 cpx #$c000
romtest02.a65:line 51: f022:Overflow error
 cpx #2000
romtest02.a65:line 59: f02d:Overflow error
Break after 3 errors

Anyone knows what's going on here?

That's on xa-2.3.11

Thanks!

_________________
Author of the GeckOS multitasking operating system, the usb65 stack, designer of the Micro-PET and many more 6502 content: http://6502.org/users/andre/

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handyandy

Post subject: Re: xa wide mode error?

Posted: Tue Dec 08, 2020 10:02 pm

Joined: Mon Sep 14, 2015 8:50 pm
Posts: 111
Location: Virginia USA

Floodgap.com seems to be down currently.
Isn't XA one of your projects?

Cheers,
Andy

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fachat

Post subject: Re: xa wide mode error?

Posted: Wed Dec 09, 2020 10:58 pm

Joined: Tue Jul 05, 2005 7:08 pm
Posts: 1042
Location: near Heidelberg, Germany

handyandy wrote:

Floodgap.com seems to be down currently.
Isn't XA one of your projects?

Cheers,
Andy

Floodgap is up again, but I haven't heard from Cameron so far.

Yes, it used to be my project, but Cameron has since long taken over the maintenance.
And 65816 support always was an outside contribution (i.e. not from me ;-)

)

André

_________________
Author of the GeckOS multitasking operating system, the usb65 stack, designer of the Micro-PET and many more 6502 content: http://6502.org/users/andre/

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handyandy

Post subject: Re: xa wide mode error?

Posted: Thu Dec 10, 2020 12:06 am

Joined: Mon Sep 14, 2015 8:50 pm
Posts: 111
Location: Virginia USA

Maybe try sep #$20
rep #$10?

Cheers,
Andy

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fachat

Post subject: Re: xa wide mode error?

Posted: Tue Dec 22, 2020 12:43 pm

Joined: Tue Jul 05, 2005 7:08 pm
Posts: 1042
Location: near Heidelberg, Germany

Actually, it was a bug in xa. Cameron confirmed it. Probably gives a new minor version.

@handyandy using SEP/REP only sets the processor state - but we need to tell the assembler that e.g. LDA #0 is a 3-byte instruction, as it would do two bytes only - therefore .al is used.

_________________
Author of the GeckOS multitasking operating system, the usb65 stack, designer of the Micro-PET and many more 6502 content: http://6502.org/users/andre/

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