no mul/div instruction

[Ian Lance Taylor]

Kunal Parmar <kunalparmar@gmail.com> writes:

> I am porting GCC to a new 16 bit RISC architecture which does not have
> multiplication and division instructions. I figured that I have to provide
> emulation routines for the multiplication and division which will be
> inserted into libgcc2.a. But I am confused about which versions of these
> routines to provide i.e. do I provide __mulsi3 or __mulhi3 or both.

It depends on UNITS_PER_WORD.  If UNITS_PER_WORD is 4, you need
__mulsi3.  If UNITS_PER_WORD is 2, you need __mulhi3, and, if you have
32-bit integer types, you will also need __mulsi3.  In the latter case
you can, if you like, get code for __mulsi3 from longlong.h--see the
comments at the top of the file.

Ian