[Coco] BASIC09 problem

[Bob Devries]

Thanks. That was indeed the problem. I'd forgotten that the range of 
INTEGER values only goes to 32767. Changed INTEGER to REAL and it works.

I think that comes from working with BASIC in OS9/68000. :)

Regards, Bob Devries
Dalby, QLD, Australia


On 25/02/2015 1:14 PM, embsys dev wrote:
> 8-bit math overflow :  sector(1)*256 = more than 8 bits
>
> On Tue, Feb 24, 2015 at 7:56 PM, Bob Devries <devries.bob at gmail.com> wrote:
>
>> I'm trying to write a small procedure in Basic09 to write to the last
>> sector on a disk(image). It's not working the way I thought it should.
>> Maybe someone can see my error?
>>
>> DIM sector(256):BYTE
>> DIM path:INTEGER
>> DIM lof:INTEGER
>> BASE 0
>> OPEN #path,"/x0@":UPDATE
>> GET #path,sector
>> lof = sector(1)*256+sector(2) (* returns 2880 on the image I'm using *)
>> SEEK #path, (lof-1)*256 (* should go to the start of the last sector *)
>> (* 2880 - 1 = 2879. 2879 * 256 = 737024 *)
>> GET #path, sector
>> PUT #path, sector
>> CLOSE #path
>> END
>>
>> The line with SEEK #path is where it is going wrong. (lof-1)*256 returns
>> 16128.
>>
>> I'm sure it should be a simple error in my code, but I can't see it.
>>
>> Regards, Bob Devries
>> Dalby, QLD, Australia
>>
>>
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>>
>