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IBM
RT Options
The following ‘-m’
options are defined for the IBM RT PC.
-min-line-mul
Use an in-line
code sequence for integer multiplies. This is the default.
-mcall-lib-mul
Call lmul$$
for integer multiples.
-mfull-fp-blocks
Generate full-size
floating point data blocks, including the minimum amount of scratch space
recommended by IBM. This is the default.
-mminimum-fp-blocks
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.
-mfp-arg-in-fpregs
Use a calling
sequence incompatible with the IBM calling convention in which floating
point arguments are passed in floating point registers.
- Note:
‘varargs.h’
and ‘stdargs.h’
will not work with floating point operands if this option is specified.
-mfp-arg-in-gregs
Use the normal
calling convention for floating point arguments. This is the default.
-mhc-struct-return
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).
-mnohc-struct-return
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 option ‘-mhc-struct-return’.