[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>

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 91175738e948..9819b705efa4 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);