Binary search optimization in c?

typedef struct
{
    char key[MAX_KEYLEN];
    int  rec;
} KeyRecPair;

typedef struct
{
    KeyRecPair *map;
    int         numRecs;
} KeyRecMap;

int GetRecFromKey(char *key, KeyRecMap *theMap)
{
    int cmpValue, bottom = 0;
    int half = theMap->numRecs / 2;
    int top = theMap->numRecs - 1;

    while (bottom != top)
    {
    	cmpValue = strncmp(key, theMap->map[half].key, MAX_KEY_LEN);

    	if (cmpValue > 0)
    	{
    		/*top stays*/
    		bottom = half + 1;
    		half  = bottom + (top - bottom) / 2;
    		continue;
    	}
    	if (cmpValue < 0)
    	{
    		/*bottom stays*/
    		top = half - 1;
    		half  = bottom + (top - bottom) / 2;
    		continue;
    	}
    	return theMap->map[half].rec;
    }

    if (0 == strncmp(key, theMap->map[half].key, MAX_KEY_LEN))
    	return theMap->map[half].rec;
    return 0;
}

if (cmpValue > 0)
        {
                /*top stays*/
                bottom = half + 1;
                half = bottom + (top - bottom) * 3 / 5;
                continue;
        }
        if (cmpValue < 0)
        {
                /*bottom stays*/
                top = half - 1;
                half = bottom + (top - bottom) * 2 / 5;
                continue;
        }

; 30   :         if (cmpValue > 0)
test	eax, eax
jle	SHORT $LN11@GetRecFrom
; 31   :         {
; omitted inner block for > case.
$LN11@GetRecFrom:
; 37   :         if (cmpValue < 0)
jge	SHORT $LN2@GetRecFrom