Title: Message
Hi
there,
I am running linux
on a MIPS64 5kc processor. From the Data Sheet and Software User's manual, I
could see that we can access the various MIPS Performance Counters (Coprocessor
0, Register 25) by using the "sel" field of the MTC0 or MFC0
registers.
Format: MTC0 rt, rd
(OR)
MTC0 rt, rd, sel
Based on the second format, I have written a new
assembly languauge routine:
#define
write_32bit_cp0_performance_register(register,value) \
__asm__ __volatile__( \
"mtc0\t%0,"STR(register)",sel\n\t"
\
"nop" \
: : "r" (value));
"sel" in the above assembly
instruction is a value of either 0, 1, 2 or 3 based on the register
which we would like to write.
"sel" in the above code is newly introduced by us
and if there is no sel then the code compiles properly but I guess we would
always be accessing one register only in that case.
(A similar routine is written using
"mfc0" also for reading the values back.)
But this code results in a
compilation error:
{standard input}: Assembler messages:
{standard input}:41: Error: illegal operands `mtc0
$3,$25,0'
{standard input}:45: Error: illegal operands `mfc0
$5,$25,1'
where $25 is CP0_PERFORMANCE
register.
The command used for compilation
is:
mipsel-linux-gcc -c -I /home/syam/linux-2.4.20with095LTT/include/ -Wall -O2
-fomit-frame-pointer -fno-common -finline-limit=5000 -G 0 -mno-abicalls -fno-pic
-mcpu=r4600 -mips2 -pipe -DMODULE -mlong-calls tempCache.c
Could someone help
me in making me understand what is wrong here? Is it a problem with the syntax
of the arguments or is there an assembler support which I am lacking for such an
instruction?
Any kind of pointers
would be of help.
Thank
you,
Syam
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