On Thu, 17 Mar 2005, Andrea wrote: > I'm trying to port gcc 4.1 for an architecture that has the following > memory layout BITS_PER_UNIT=32 and UNITS_PER_WORD=1.
Support for systems with bytes wider than 8 bits is somewhat bitrotten at present, as it seems little has been done on the c4x port lately and it is the only such port we currently have; various PRs indicate it simply doesn't work (won't build libgcc) at present. I have however CC:ed the maintainer of the c4x port in case he should wish to improve the state of this port and the general support for such ports. > It has support (16bit registers and operators) for 16bit signed > atithmetic used mainly for addressing. There are also operators for 32 > bit integer and floating point support. > I set SHORT_TYPE_SIZE=POINTER_SIZE=(BITS_PER_WORD/2). short needs to have at least the precision of char in C. (C99 made explicit various aspects of the ordering rules for type precision which C90 was insufficiently complete about.) However, types narrower than char do work in the compiler - we have them for bit-fields. As required by the C standard, types narrower that int are promoted to int in arithmetic. Bit-field types don't have their own modes, but in principle you should be able to have a special type with its own mode narrower than char: however, you may need to implement optimizations which convert operations on promoted types to operations on narrow types for targets with such types. -- Joseph S. Myers http://www.srcf.ucam.org/~jsm28/gcc/ [EMAIL PROTECTED] (personal mail) [EMAIL PROTECTED] (CodeSourcery mail) [EMAIL PROTECTED] (Bugzilla assignments and CCs)
