I need to use MMX and/or SSE registers in my code.
Have looked at arch/i386/lib/mmx.c,
kernel_fpu_begin();
muck_with_MMX_regs();
kernel_fpu_end();
seems to be the way to go.
My code is in .S, so I did the equivalent
(see <------), but routine crashed and burned
as soon as it tripped over kernel_fpu_begin.
Commenting KERNEL_FPU_BEGIN made code work
(I was able to boot with root=/dev/fd0)
but it won't be usable (will trash userspace
FP/MMX/SSE registers).
Does it have anything to do with the fact I'm
using this code from csum_partial[_copy_generic] ?
-- vda... #define KERNEL_FPU_BEGIN \ call kernel_fpu_begin #define KERNEL_FPU_END(r) \ movl %cr0, r ;\ orl $8, r ;\ movl r, %cr0 ... # "big chunks" loop PREFETCH((%esi)) # Prefetch _each_ cacheline PREFETCH(32(%esi)) PREFETCH(64(%esi)) PREFETCH(64+32(%esi)) PREFETCH(128(%esi)) PREFETCH(128+32(%esi)) PREFETCH(192(%esi)) PREFETCH(192+32(%esi)) KERNEL_FPU_BEGIN <-------------- clc #define ROUND(x,r) \ SRC( movq x(%esi), r ); \ adcl x(%esi), %eax ; \ adcl x+4(%esi), %eax ; \ DST( movntq r, x(%edi) ); 10: PREFETCH(256(%esi)) ROUND(%mm0) ROUND(8,%mm0) ROUND(16,%mm0) ROUND(24,%mm0) lea ITER_SZ(%esi), %esi lea ITER_SZ(%edi), %edi loop 10b
adcl $0, %eax sfence KERNEL_FPU_END(%ebx) <------------
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This archive was generated by hypermail 2b29 : Thu Nov 07 2002 - 22:00:20 EST