Stream
functions such as printf and putchar may not be used in
the C program. These functions are usually not necessary
for this chip because it is only equipped with a maximum
of 2 KB and has no serial interface. No
floating-point operations may be used in the C program.
Only operations using char, unsigned char, int,
unsigned int, long, unsigned long,
and bit data types are permitted.
The
C51 compiler must be invoked with the ROM(SMALL) control
directive. This control statement instructs the C51
compiler not to generate LJMP and LCALL instructions.
The
library file 80C751.LIB must be included in
the input module list of the L51 Linker/Locator. For
example:
L51 myprog.obj,
startup751.obj, 80C751.LIB
A
special startup module, START751.A51, is required.
This file contains startup code that is comparable to
that found in STARTUP.A51 but contains no LJMP or
LCALL instructions. See the “Customization
Files” section in the “Advanced Topics”
chapter for more information.