So, you're saying that whether it works or not is platform-dependent - therefore, you need to inspect the code for platform-dependencies


I don't know specifically about TEA, but "Endian-ness" is a prime suspect in any platform-dependence issue.
This will affect things like using unions and casting pointers to access individual bytes of larger objects.

Other general things to consider are:

Data sizes - a PC's int is probaly 32 bits; it's only 16 with Keil C51.
To avoid such problems, never use the "raw" 'C' data types - always make your own typedefs to give you a known size & signedness; eg, U8, U16, S32.

Data alignment - a PC may well have issues about data alignment; eg, ints must start on an even address. This may cause the compiler to add "padding" in structures, etc.
Keil C51 doesn't do this.

Default signed or unsigned? This may be an option in your compiler settings.

Specifically for Keil C51, remember that "normal" 'C' functions are inherently reentrant, but C51 functions are not!

Of course, you could also have plain simple bugs - your code only works on a PC by pure luck!