x86: add comments to processor.h

add comments to the FPU structures of processor.h.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/include/asm-x86/processor.h b/include/asm-x86/processor.h
index e49e5e69ebb07a373fdbcba16fa099f84cff612d..1f9501a3849321a8a87c8960394d638be51f73a0 100644 (file)
--- a/include/asm-x86/processor.h
+++ b/include/asm-x86/processor.h
@@ -289,42 +289,47 @@ struct orig_ist {
 #define        MXCSR_DEFAULT           0x1f80
 
 struct i387_fsave_struct {
-       u32                     cwd;
-       u32                     swd;
-       u32                     twd;
-       u32                     fip;
-       u32                     fcs;
-       u32                     foo;
-       u32                     fos;
-       /* 8*10 bytes for each FP-reg = 80 bytes: */
+       u32                     cwd;    /* FPU Control Word             */
+       u32                     swd;    /* FPU Status Word              */
+       u32                     twd;    /* FPU Tag Word                 */
+       u32                     fip;    /* FPU IP Offset                */
+       u32                     fcs;    /* FPU IP Selector              */
+       u32                     foo;    /* FPU Operand Pointer Offset   */
+       u32                     fos;    /* FPU Operand Pointer Selector */
+
+       /* 8*10 bytes for each FP-reg = 80 bytes:                       */
        u32                     st_space[20];
-       /* Software status information: */
+
+       /* Software status information [not touched by FSAVE ]:         */
        u32                     status;
 };
 
 struct i387_fxsave_struct {
-       u16                     cwd;
-       u16                     swd;
-       u16                     twd;
-       u16                     fop;
+       u16                     cwd; /* Control Word                    */
+       u16                     swd; /* Status Word                     */
+       u16                     twd; /* Tag Word                        */
+       u16                     fop; /* Last Instruction Opcode         */
        union {
                struct {
-                       u64     rip;
-                       u64     rdp;
+                       u64     rip; /* Instruction Pointer             */
+                       u64     rdp; /* Data Pointer                    */
                };
                struct {
-                       u32     fip;
-                       u32     fcs;
-                       u32     foo;
-                       u32     fos;
+                       u32     fip; /* FPU IP Offset                   */
+                       u32     fcs; /* FPU IP Selector                 */
+                       u32     foo; /* FPU Operand Offset              */
+                       u32     fos; /* FPU Operand Selector            */
                };
        };
-       u32                     mxcsr;
-       u32                     mxcsr_mask;
-       /* 8*16 bytes for each FP-reg = 128 bytes: */
+       u32                     mxcsr;          /* MXCSR Register State */
+       u32                     mxcsr_mask;     /* MXCSR Mask           */
+
+       /* 8*16 bytes for each FP-reg = 128 bytes:                      */
        u32                     st_space[32];
-       /* 16*16 bytes for each XMM-reg = 256 bytes: */
+
+       /* 16*16 bytes for each XMM-reg = 256 bytes:                    */
        u32                     xmm_space[64];
+
        u32                     padding[24];
 
 } __attribute__((aligned(16)));