Show description

Display_queue(root); // traverse the queue ... newptr=pop_queue(); // pop the leading entry printf("%s\n", newptr->text); free(newptr); // deallocate it ... =NULL) { temp=root; root=root->next; free(temp); } } entry xdata *pop_queue(void) { // remove the top queue entry entry xdata *temp; if (root==NULL) { return NULL; } temp=root; root=root->next; temp->next=NULL; return temp; } Note that the usage of the dynamic memory allocation routines looks just like the usage of these same routines in ANSI C.

There are very few systems which require use of other memory models such as systems with large reentrant stacks. In general, a system which uses less than the amount of internal RAM available will always be compiled with the small memory model. In this model, the DATA segment is the default segment for location of any global and local variables. All parameter passing occurs in the DATA segment as well and if any functions are declared to be reentrant, the compiler will attempt to implement the invocation stack in internal RAM.

This will allow the floating point routines to limit the amount of work they do to only the degree of precision that is meaningful to your system. Make Use of bit Variables When you are using flags which will only contain a one or a zero, use the bit type instead of an unsigned char. This will help make your memory reserves go farther, since you will not be wasting seven bits. Additionally, bit variables are always in internal RAM and therefore will be accessed in one cycle. Page 47 CHAPTER 3 - USING C WITH THE 8051 Use Locals instead of Globals Variables which are declared to be global data will be less efficient than use of local variables.