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| author | Keir Fraser <keir.fraser@citrix.com> | 2008-03-04 11:20:22 +0000 |
|---|---|---|
| committer | Keir Fraser <keir.fraser@citrix.com> | 2008-03-04 11:20:22 +0000 |
| commit | be4824afef02c23c565e1abb39008dd05d4c21b5 (patch) | |
| tree | b77bce387f80fc257f94bd8aa3d99e5b28592ea2 /xen/arch/x86/i387.c | |
| parent | 53a82fd949458b65af022a4d3a882db181bc36a3 (diff) | |
| download | xen-be4824afef02c23c565e1abb39008dd05d4c21b5.tar.gz xen-be4824afef02c23c565e1abb39008dd05d4c21b5.tar.bz2 xen-be4824afef02c23c565e1abb39008dd05d4c21b5.zip | |
x86: Clean up FPU code style and add a comment about FNSAVE/FWAIT
instruction pair.
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
Diffstat (limited to 'xen/arch/x86/i387.c')
| -rw-r--r-- | xen/arch/x86/i387.c | 21 |
1 files changed, 9 insertions, 12 deletions
diff --git a/xen/arch/x86/i387.c b/xen/arch/x86/i387.c index f376a67754..ca63dbab86 100644 --- a/xen/arch/x86/i387.c +++ b/xen/arch/x86/i387.c @@ -18,7 +18,7 @@ void init_fpu(void) { - __asm__ __volatile__ ( "fninit" ); + asm volatile ( "fninit" ); if ( cpu_has_xmm ) load_mxcsr(0x1f80); current->fpu_initialised = 1; @@ -36,7 +36,7 @@ void save_init_fpu(struct vcpu *v) if ( cpu_has_fxsr ) { #ifdef __i386__ - __asm__ __volatile__ ( + asm volatile ( "fxsave %0" : "=m" (*fpu_ctxt) ); #else /* __x86_64__ */ @@ -45,14 +45,14 @@ void save_init_fpu(struct vcpu *v) * older versions the rex64 prefix works only if we force an * addressing mode that doesn't require extended registers. */ - __asm__ __volatile__ ( + asm volatile ( REX64_PREFIX "fxsave (%1)" : "=m" (*fpu_ctxt) : "cdaSDb" (fpu_ctxt) ); #endif /* Clear exception flags if FSW.ES is set. */ if ( unlikely(fpu_ctxt[2] & 0x80) ) - __asm__ __volatile__ ("fnclex"); + asm volatile ("fnclex"); /* * AMD CPUs don't save/restore FDP/FIP/FOP unless an exception @@ -63,7 +63,7 @@ void save_init_fpu(struct vcpu *v) */ if ( boot_cpu_data.x86_vendor == X86_VENDOR_AMD ) { - __asm__ __volatile__ ( + asm volatile ( "emms\n\t" /* clear stack tags */ "fildl %0" /* load to clear state */ : : "m" (*fpu_ctxt) ); @@ -71,9 +71,8 @@ void save_init_fpu(struct vcpu *v) } else { - __asm__ __volatile__ ( - "fnsave %0 ; fwait" - : "=m" (*fpu_ctxt) ); + /* FWAIT is required to make FNSAVE synchronous. */ + asm volatile ( "fnsave %0 ; fwait" : "=m" (*fpu_ctxt) ); } v->fpu_dirtied = 0; @@ -91,7 +90,7 @@ void restore_fpu(struct vcpu *v) */ if ( cpu_has_fxsr ) { - __asm__ __volatile__ ( + asm volatile ( #ifdef __i386__ "1: fxrstor %0 \n" #else /* __x86_64__ */ @@ -125,9 +124,7 @@ void restore_fpu(struct vcpu *v) } else { - __asm__ __volatile__ ( - "frstor %0" - : : "m" (v->arch.guest_context.fpu_ctxt) ); + asm volatile ( "frstor %0" : : "m" (v->arch.guest_context.fpu_ctxt) ); } } |