For signed & unsigned int (16 bit) and long (32 bit) variables, division,
multiplication and modulus operations are implemented by support routines.
These support routines are all developed in ANSI-C to facilitate porting
to other MCUs, although some model specific assembler optimizations
are used. The following files contain the described routines, all
of them can be found in <installdir>/share/sdcc/lib.
| Function | Description |
|---|---|
| _mulint.c | 16 bit multiplication |
| _divsint.c | signed 16 bit division (calls _divuint) |
| _divuint.c | unsigned 16 bit division |
| _modsint.c | signed 16 bit modulus (calls _moduint) |
| _moduint.c | unsigned 16 bit modulus |
| _mullong.c | 32 bit multiplication |
| _divslong.c | signed 32 division (calls _divulong) |
| _divulong.c | unsigned 32 division |
| _modslong.c | signed 32 bit modulus (calls _modulong) |
| _modulong.c | unsigned 32 bit modulus |
Since they are compiled as non-reentrant, interrupt service routines should not do any of the above operations. If this is unavoidable then the above routines will need to be compiled with the --stack-auto option, after which the source program will have to be compiled with --int-long-reent option. Notice that you don't have to call these routines directly. The compiler will use them automatically every time an integer operation is required.