Subject:
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Re: anyone know how to check free space on RCX?
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Newsgroups:
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lugnet.robotics.rcx.legos
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Date:
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Thu, 11 Jul 2002 16:59:09 GMT
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Viewed:
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2270 times
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While the declaration for mm_free_mem is
int mm_free_mem(void)
The fact is that the RCX has only 32K of memory available. 32K in hex is
0x8000... there's never a need for more than 4 digits in hex. Looking at
key_handler() in kernel/program.c (the system key handler), the code for
displaying free memory is (kernel v0.2.6, no patches):
/*
* pressing the "view" button cycles through a display of the
* amount of the amount of free memory (in decimal and
* hexadecimal) and battery power. If a button other than "view"
* is pressed while cycling through, we handle that button
* ("goto gotkey").
*/
cputs("free");
if ((c = getchar()) != KEY_VIEW) goto gotkey;
lcd_int(mm_free_mem());
if ((c = getchar()) != KEY_VIEW) goto gotkey;
cputw(mm_free_mem());
if ((c = getchar()) != KEY_VIEW) goto gotkey;
The first call to mm_free_mem() is displayed as an integer via lcd_int(),
the second call is displayed as a hexword via cputw(). The two values are
the same... mm_free_mem() is just being called twice.
-Jason
In lugnet.robotics.rcx.legos, Joseph Woolley writes:
> Albert Huang,
>
> Sorry for the confusion. "most significant" = upper 16 bits and "least
> significant" = lower 16 bits (the free memory is a 32 bit value).
>
> If you write the values out, you will get the 32 bit value (both values are
> hex) ... for example:
>
> 999C + 54A0 = 999C54A0
>
> // Joe
>
> "Albert Huang" wrote
> > Joseph,
> >
> > what do you mean by most significant / least significant? I'm under the
> > impression that those two calls just display the same value, in decimal
> > first and then in hex.
> >
> > Cheers,
> > Albert
> >
> >
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