Question

I have the following code:

struct cache_t *                /* pointer to cache created */
cache_create(char *name,        /* name of the cache */
             int nsets,         /* total number of sets in cache */
             int bsize,         /* block (line) size of cache */
             int balloc,        /* allocate data space for blocks? */
             int usize,         /* size of user data to alloc w/blks */
             int assoc,         /* associativity of cache */
             enum cache_policy policy,  /* replacement policy w/in sets */
             /* block access function, see description w/in struct cache def */
             unsigned int (*blk_access_fn) (enum mem_cmd cmd,
                                            md_addr_t baddr, int bsize,
                                            struct cache_blk_t * blk,
                                            tick_t now,
                                            int context_id),
             unsigned int hit_latency)
{                               /* latency in cycles for a hit */
    struct cache_t *cp;
    struct cache_blk_t *blk;
    int i, j, bindex;
----
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  cp->blk_access_fn = blk_access_fn;

----
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I WANT TO PRINT context_id and baddr . HOW CAN I DO IT ?
I have tried typecasting and everything but it keeps giving me error:
symbol “context_id” is invalid in current context.
HELP WOULD BE APPRECIATED.

Answer 1

I think you misunderstand the cache_create function. It doesn’t have context_id or baddr parameters at all. What it does have as a parameter is blk_access_fn which is a function pointer. That function which is presumably called by cache_create and it would have those 2 variables as parameters.

A way to better visualize this would be like so:

typedef unsigned int (*blk_access_fn_ptr)(enum mem_cmd cmd, md_addr_t baddr, int bsize, struct cache_blk_t *blk, tick_t now, int context_id);

struct cache_t *            /* pointer to cache created */
cache_create(char *name,        /* name of the cache */
     int nsets,         /* total number of sets in cache */
     int bsize,         /* block (line) size of cache */
     int balloc,        /* allocate data space for blocks? */
     int usize,         /* size of user data to alloc w/blks */
     int assoc,         /* associativity of cache */
     enum cache_policy policy,  /* replacement policy w/in sets */
     /* block access function, see description w/in struct cache def */
     blk_access_fn_ptr blk_access_fn,
     unsigned int hit_latency)  /* latency in cycles for a hit */
{
    ...
}

This code is identical in functionality to the code you posted. As you can see, cache_create doesn’t have the parameters you are looking for at all. You must pass a function with an appropriate prototype as the blk_access_fn parameter, and it will have them.