malloc.c 2.13 KB

/**************************************************************************
 *									  *
 *		 Copyright (C) 1994, Silicon Graphics, Inc.		  *
 *									  *
 *  These coded instructions, statements, and computer programs  contain  *
 *  unpublished  proprietary  information of Silicon Graphics, Inc., and  *
 *  are protected by Federal copyright law.  They  may  not be disclosed  *
 *  to  third  parties  or copied or duplicated in any form, in whole or  *
 *  in part, without the prior written consent of Silicon Graphics, Inc.  *
 *									  *
 **************************************************************************/

/**************************************************************************
 *
 *  Module: malloc.c
 *
 *  $Revision: 1.1.1.2 $
 *  $Date: 2002/10/29 08:06:43 $
 *  $Author: blythe $
 *  $Source: /root/leakn64/depot/rf/sw/n64os20l/libultra/monegi/rg/malloc.c,v $
 *
 **************************************************************************/


#include "os.h"
#include "os_internal.h"
#include "region.h"
#include "ultraerror.h"
#include "assert.h"


/*
 * Name:   osMalloc
 *
 * Description:
 *	This routine allocates a buffer of fixed size from the region
 *	pointed by 'region'.
 *
 *	Upon success, the routine returns a pointer to a buffer of
 *	of size 'bufferSize' as defined in osCreateRegion().
 *	Otherwise, it will return NULL if there is not enough available
 *	free buffers in the region.
 *
 * Globals Referenced: 
 *	None
 */
void *
osMalloc(void *region) 
{
    register OSRegion *rp = region;
    char *addr;

#ifdef _DEBUG
    /* Validate region id: not null and aligned to equal starting address */
    assert(rp != NULL);
    if (((char *)rp + ALIGN(sizeof(OSRegion), RP(alignSize))) != 
        RP(startBufferAddress)) {
	__osError(ERR_OSMALLOC, 1, region);
	return((void *)NULL);
    }
#endif

    /* If there is no more free buffer, simply return NULL */
    if (RP(freeList) == BUF_FREE_WO_NEXT)
    	return(NULL);

    /* Adjust the free list pointer */
    addr = RP(startBufferAddress) + (RP(freeList)*RP(bufferSize));
    RP(freeList) = *(unsigned short *)addr;

    return((void *)addr);

}  /* end of osMalloc */