1. Multiple Entry Points
Multiple entry points allow different function names, different parameter lists, default parameters, etc.
Example
int fn( int a = 1, int b = 2 ) {
return( a + b ); }

2. Multiple Entry Points
Multiple entry points allow different function names, different parameter lists, default parameters, etc.
Example
int fn( int a = 1, int b = 2 ) {
return( a + b ); }
can be written in assembly as
.global %function fn_ab, fn_b, fn, sum
push {lr}
fn_ab:
mov r0, # /* default first parameter */
fn_b:
mov r1, # /* default second parameter */

3. Multiple Entry Points
The previous example can be written in assembly as
.text
.global fn_ab, fn_b, fn, sum
.type fn_ab, %function
.type fn_b, %function
.type fn, %function
.type sum, %function
fn_ab:
mov r0, # /* default first parameter */
fn_b:
mov r1, # /* default second parameter */
fn:
sum:
add r0, r0, r /* add parameters and return sum */
bx lr

4. Multiple Entry Points with fn() becoming call fn_ab
fn(3) becoming call fn_b after the caller places 3 in r0
fn(4,6) becoming call fn (or call sum) after the caller
places 4 in r0 and 6 in r1
so that a driver like this
#include<stdio.h>
int fn_ab();
int fn_b(int);
int fn(int, int);
int sum(int, int);
int main() {
printf("fn_ab() returns %d\n",fn_ab());
printf("fn_b(3) returns %d\n",fn_b(3));
printf("fn(4,6) returns %d\n",fn(4,6));
printf("sum(5,7) returns %d\n",sum(5,7));
return 0; }

5. Multiple Entry Points will print
fn_ab() returns 3
fn_b(3) returns 5
fn(4,6) returns 10
sum(5,7) returns 12
Of course, multiple exit paths are also possible.