NAME
        AvailMem -- memory available given certain requirements

   SYNOPSIS
        size = AvailMem(attributes)
        D0              D1

        ULONG AvailMem(ULONG);

   FUNCTION
        This function returns the amount of free memory given certain
        attributes.

        To find out what the largest block of a particular type is, add
        MEMF_LARGEST into the requirements argument.  Returning the largest
        block is a slow operation.

   WARNING
        Due to the effect of multitasking, the value returned may not
        actually be the amount of free memory available at that instant.

   INPUTS
        requirements - a requirements mask as specified in allocmem.  any
                       of the allocmem bits are valid, as is memf_largest
                       which returns the size of the largest block matching
                       the requirements.

   RESULT
        size - total free space remaining (or the largest free block).

   NOTE
        For V36 Exec, AvailMem(MEMF_LARGEST) does a consistency check on
        the memory list.  alert an_memoryinsane will be pulled if any mismatch
        is noted.

   EXAMPLE
        AvailMem(MEMF_CHIP|MEMF_LARGEST);
        /* return size of largest available chip memory chunk */

   SEE ALSO
        exec/memory.h