Red Hat ENTERPRISE LINUX 4 Manual page 105

Chapter 4. GCC Command Options
-mupdate
-mno-update
Generate code that uses (does not use) the load or store instructions that update the base register
to the address of the calculated memory location. These instructions are generated by default.
If you use
-mno-update
updated and the address of the previous frame is stored, which means code that walks the stack
frame across interrupts or signals may get corrupted data.
-mfused-madd
-mno-fused-madd
Generate code that uses (does not use) the floating point multiply and accumulate instructions.
These instructions are generated by default if hardware floating is used.
-mno-bit-align
-mbit-align
On System V.4 and embedded PowerPC systems do not (do) force structures and unions that
contain bit-fields to be aligned to the base type of the bit-field.
For example, by default a structure containing nothing but 8
would be aligned to a 4 byte boundary and have a size of 4 bytes. By using
the structure would be aligned to a 1 byte boundary and be one byte in size.
-mno-strict-align
-mstrict-align
On System V.4 and embedded PowerPC systems do not (do) assume that unaligned memory
references will be handled by the system.
-mrelocatable
-mno-relocatable
On embedded PowerPC systems generate code that allows (does not allow) the program to be
relocated to a different address at runtime. If you use
linked together must be compiled with
-mrelocatable-lib
-mno-relocatable-lib
On embedded PowerPC systems generate code that allows (does not allow) the program to be
relocated to a different address at runtime. Modules compiled with
be linked with either modules compiled without
with modules compiled with the
-mno-toc
-mtoc
On System V.4 and embedded PowerPC systems do not (do) assume that register 2 contains a
pointer to a global area pointing to the addresses used in the program.
-mlittle
-mlittle-endian
On System V.4 and embedded PowerPC systems compile code for the processor in little endian
mode. The
-mlittle-endian
, there is a small window between the time that the stack pointer is
-mrelocatable
-mrelocatable
option is the same as
unsigned
-mrelocatable
or
-mrelocatable-lib
and
-mrelocatable
options.
.
-mlittle
bit-fields of length 1
-mno-bit-align
on any module, all objects
.
-mrelocatable-lib
-mrelocatable-lib
97
,
can
or