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MIPS -mmad operation

The gcc MIPS compiler suite / binutils supports
some ISA extensions: "-mmad" for the r4650 cpu

I have an IDT RC64574/RC64575 processor (R5000 based) with
64-bit FPU to which I'm porting linux.

It has the following ISA extensions:

MULT/MULTU	(16/32 bit)	Multiply - Signed/Unsigned
DMULT/DMULTU	(16/32/64 bit)	Double Multiply - Signed/Unsigned
DIV/DIVU	(16/32/64 bit)	Division
MAD/MADU	(16/32 bit)	Multiply and Add
MSUB/MSUBU	(16/32 bit)	Multiply and Subtract
MUL		(16/32 bit)	3 operand Multiply
CLZ/CLO				Count Leading Zeros/Ones

The first major issue is that when I enable the
"-mmad" option, GCC forces the R4650 CPU so
I loose 64-bit object format and more importantly
loose 64-bit FPU operations.

Is it planned to included these instructions for other
processors in the near future?

How difficult is it too add instructions to
binutils (more important) and gcc?




Carl van Schaik, <carl at openfuel dot com>    | Tel +27 21 650-3467
Electrical Engineering                         | Fax +27 21 650-4305
OpenFuel Pty Ltd.	South Africa

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