<< Previous | Next >>

_xalloc

long _xalloc( long * sz, word align, word type );

Description

Allocates memory in extended memory. If _xalloc() fails, a runtime error will occur.

Parameters

sz

On entry, pointer to the number of bytes to allocate. On return, the pointed- to value will be updated with the actual number of bytes allocated. This may be larger than requested if an odd number of bytes was requested, or if some space was wasted at the end because of alignment restrictions.

align

Storage alignment as the log (base 2) of the desired returned memory starting address. For example, if this parameter is "8," then the returned address will align on a 256-byte boundary. Values between 0 and 16 inclusive are allowed. Any other value is treated as zero, i.e., no required alignment.

type

This parameter is only meaningful on boards with more than one type of RAM. For example, boards with a fast RAM and a slower battery-backed RAM like the RCM3200 or RCM3300 Use one of the following values, any other value will have undefined results.

• XALLOC_ANY (0) - any type of SRAM storage allowed

• XALLOC_BB (1) - must be battery-backed program execution SRAM (a.k.a., fast RAM).

• XALLOC_NOTBB (2) - return non-BB SRAM only.

• XALLOC_MAYBBB (3) - return non-BB SRAM in preference to BB.

Return value

The 20-bit physical address of the allocated data on success. On error, a runtime error occurs.

NOTE	This return value cannot be used with pointer arithmetic.

Library

STACK.LIB

Exceptions

ERR_BADXALLOC - if could not allocate requested storage, or negative size passed.