Hi,
i would like to know the way to go for NON-FPU cpus - Currently its
partly an Compile Time thing and partly run time config.
I stumbled over the current tree as on the 3912 we dont have a FPU
so we cant use the default "exit_thread" which simply causes the
CPU to halt (not even an cpu reset works)
arch/mips/process.c
55 void exit_thread(void)
56 {
57 /* Forget lazy fpu state */
58 if (last_task_used_math == current) {
59 set_cp0_status(ST0_CU1, ST0_CU1);
60 __asm__ __volatile__("cfc1\t$0,$31");
61 last_task_used_math = NULL;
62 }
63 }
The Linux-vr people IFDEFed this with CONFIG_NO_FPU which is an option
but then we could even remove the whole cpu probing as everything
would be compile time.
A question here - Which way to go - Compile or Run time config for
CPUs and is
if(!(mips_cpu.options & MIPS_CPU_FPU))
this also valid for R3k CPU cores ? From my reading it is not as it doesnt
get initialized for R3000 ? As a lot architectures have the R3010
so this should get detected. The R3081 definitly has an FPU from
what i found on the web so this should be correct.
Index: arch/mips/kernel/setup.c
===================================================================
RCS file: /cvs/linux/arch/mips/kernel/setup.c,v
retrieving revision 1.49
diff -u -r1.49 setup.c
--- arch/mips/kernel/setup.c 2001/02/05 01:33:01 1.49
+++ arch/mips/kernel/setup.c 2001/02/07 13:39:16
@@ -182,15 +182,16 @@
mips_cpu.tlbsize = 64;
break;
case PRID_IMP_R3000:
+ mips_cpu.options = MIPS_CPU_TLB;
if ((mips_cpu.processor_id & 0xff) == PRID_REV_R3000A)
- if (cpu_has_confreg())
+ if (cpu_has_confreg()) {
mips_cpu.cputype = CPU_R3081E;
- else
+ mips_cpu.options |= MIPS_CPU_FPU;
+ } else
mips_cpu.cputype = CPU_R3000A;
else
mips_cpu.cputype = CPU_R3000;
mips_cpu.isa_level = MIPS_CPU_ISA_I;
- mips_cpu.options = MIPS_CPU_TLB;
mips_cpu.tlbsize = 64;
break;
case PRID_IMP_R4000:
Flo
--
Florian Lohoff flo@rfc822.org +49-5201-669912
Why is it called "common sense" when nobody seems to have any?
