Forum Post: Problems with migrating from small memory model to large memory model in C55x Compiler

Codecomposer version 5.1

Compiler :C55x

Q1.What exactly happens if we change our memory model from small to large

Q2.what exactly is difference between small and large(as far i know small memory model adress length is 16bit where as large it is 23),is the code size limited or restricted in small memory model ? (some one said its 64KB restricted) ?

Q3.Problem Occured to me 

here is a snipped from my code 

ptr = (void *) (((int)spxGlobalHeapPtr + BLOCK_MASK) & ~BLOCK_MASK); //Start on 8 boundary

spxGlobalHeapPtr = (char *)((int)ptr + size); // Update pointer to next free location

in above code spxGlobalHeapPtr is actually a char* holding adress when its type casted by int in large memory model the adress actually changed from 0x00008000 to 0xffff8000 it should not actually happen with this i faced several problems at last i have identified 

up on changing it to unsigned int i have some how overcomed the problem

Please suggest me what care i must be taking while migrating from one memory  model to another