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authorZachary Amsden <zach@vmware.com>2005-09-03 15:56:38 -0700
committerLinus Torvalds <torvalds@evo.osdl.org>2005-09-05 00:06:11 -0700
commit4d37e7e3fd851428dede4d05d3e69d03795a744a (patch)
treef830928a0baf81f462bc9176dacbaad2dac2bb65 /arch/i386/math-emu
parent245067d1674d451855692fcd4647daf9fd47f82d (diff)
downloadop-kernel-dev-4d37e7e3fd851428dede4d05d3e69d03795a744a.zip
op-kernel-dev-4d37e7e3fd851428dede4d05d3e69d03795a744a.tar.gz
[PATCH] i386: inline assembler: cleanup and encapsulate descriptor and task register management
i386 inline assembler cleanup. This change encapsulates descriptor and task register management. Also, it is possible to improve assembler generation in two cases; savesegment may store the value in a register instead of a memory location, which allows GCC to optimize stack variables into registers, and MOV MEM, SEG is always a 16-bit write to memory, making the casting in math-emu unnecessary. Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386/math-emu')
-rw-r--r--arch/i386/math-emu/get_address.c13
1 files changed, 3 insertions, 10 deletions
diff --git a/arch/i386/math-emu/get_address.c b/arch/i386/math-emu/get_address.c
index 9117573..9819b70 100644
--- a/arch/i386/math-emu/get_address.c
+++ b/arch/i386/math-emu/get_address.c
@@ -155,7 +155,6 @@ static long pm_address(u_char FPU_modrm, u_char segment,
{
struct desc_struct descriptor;
unsigned long base_address, limit, address, seg_top;
- unsigned short selector;
segment--;
@@ -173,17 +172,11 @@ static long pm_address(u_char FPU_modrm, u_char segment,
/* fs and gs aren't used by the kernel, so they still have their
user-space values. */
case PREFIX_FS_-1:
- /* The cast is needed here to get gcc 2.8.0 to use a 16 bit register
- in the assembler statement. */
-
- __asm__("mov %%fs,%0":"=r" (selector));
- addr->selector = selector;
+ /* N.B. - movl %seg, mem is a 2 byte write regardless of prefix */
+ savesegment(fs, addr->selector);
break;
case PREFIX_GS_-1:
- /* The cast is needed here to get gcc 2.8.0 to use a 16 bit register
- in the assembler statement. */
- __asm__("mov %%gs,%0":"=r" (selector));
- addr->selector = selector;
+ savesegment(gs, addr->selector);
break;
default:
addr->selector = PM_REG_(segment);
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