/* xsh_memstat.c - xsh_memstat */

#include 
#include 
#include 

static  void    printMemUse(void);
static  void    printFreeList(void);

/*------------------------------------------------------------------------
 * xsh_memstat - Print statistics about memory use and dump the free list
 *------------------------------------------------------------------------
 */
shellcmd xsh_memstat(int nargs, char *args[])
{

        /* For argument '--help', emit help about the 'memstat' command */

        if (nargs == 2 && strncmp(args[1], "--help", 7) == 0) {
                printf("use: %s \n\n", args[0]);
                printf("Description:\n");
                printf("\tDisplays the current memory use and prints the\n");
                printf("\tfree list.\n");
                printf("Options:\n");
                printf("\t--help\t\tdisplay this help and exit\n");
                return 0;
        }

        /* Check for valid number of arguments */

        if (nargs > 1) {
                fprintf(stderr, "%s: too many arguments\n", args[0]);
                fprintf(stderr, "Try '%s --help' for more information\n",
                                args[0]);
                return 1;
        }

        printMemUse();
        printFreeList();

        return 0;
}


/*------------------------------------------------------------------------
 * printFreeList - Walk the list of free memory blocks and print the
 *                      location and size of each
 *------------------------------------------------------------------------
 */
static void printFreeList(void)
{
        struct memblk *block;

        /* Output a heading for the free list */

        printf("Free List:\n");
        printf("Block address  Length (dec)  Length (hex)\n");
        printf("-------------  ------------  ------------\n");
        
        for (block = memlist.mnext; block != NULL; block = block->mnext) {
                printf("  0x%08x    %9d     0x%08x\n", block,
                        block->mlength, block->mlength);
        }
        printf("\n");
}

extern void start(void);
extern void *_end;

/*------------------------------------------------------------------------
 * printMemUse - Print statistics about memory use
 *------------------------------------------------------------------------
 */
static void printMemUse(void)
{
        int i;                          /* Index into process table     */
        uint32 code = 0;                /* Total Xinu code memory       */
        uint32 stack = 0;               /* Total used stack memory      */
        uint32 kheap = 0;               /* Free kernel heap memory      */
        uint32 kfree = 0;               /* Total free memory            */
        struct memblk *block;           /* Ptr to memory block          */

        /* Calculate amount of text memory */

        code = (uint32)&_end - (uint32)start;

        /* Calculate amount of allocated stack memory */
        /*  Skip the NULL process since it has a private stack */

        for (i = 1; i < NPROC; i++) {
                if (proctab[i].prstate != PR_FREE) {
                        stack += (uint32)proctab[i].prstklen;
                }
        }

        /* Calculate the amount of memory on the free list */

        for (block = memlist.mnext; block != NULL; block = block->mnext) {
                kfree += block->mlength;
        }

        /* Calculate the amount of free kernel heap memory */

        kheap = kfree - stack;

        /* Output statistics on current memory use */

        printf("Current system memory statistics:\n");
        printf("---------------------------------\n");
        printf("%10d bytes (0x%08x) of Xinu code\n", code, code);
        printf("%10d bytes (0x%08x) of allocated stack space\n", stack, stack);
        printf("%10d bytes (0x%08x) of available kernel heap space\n\n", kheap, kheap);
}