3.17.12 IBM RT Options
These `-m' options are defined for the IBM RT PC:
- Use an in-line code sequence for integer multiplies. This is the
lmul$$ for integer multiples.
- Generate full-size floating point data blocks, including the minimum
amount of scratch space recommended by IBM. This is the default.
- Do not include extra scratch space in floating point data blocks. This
results in smaller code, but slower execution, since scratch space must
be allocated dynamically.
- Use a calling sequence incompatible with the IBM calling convention in
which floating point arguments are passed in floating point registers.
stdarg.h will not work with floating point operands
if this option is specified.
- Use the normal calling convention for floating point arguments. This is
- Return structures of more than one word in memory, rather than in a
register. This provides compatibility with the MetaWare HighC (hc)
compiler. Use the option -fpcc-struct-return for compatibility
with the Portable C Compiler (pcc).
- Return some structures of more than one word in registers, when
convenient. This is the default. For compatibility with the
IBM-supplied compilers, use the option -fpcc-struct-return or the