target-sh4: MMU: reduce the size of a TLB entry

Reduce the size of the TLB entry from 32 to 16 bytes, reorganising
members and using a bit field.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

diff --git a/target-sh4/cpu.h b/target-sh4/cpu.h
index 015d598..85f221d 100644 (file)
--- a/target-sh4/cpu.h
+++ b/target-sh4/cpu.h
@@ -72,21 +72,20 @@
  * The use of DELAY_SLOT_TRUE flag makes us accept such SR_T modification.
  */
 
-/* XXXXX The structure could be made more compact */
 typedef struct tlb_t {
-    uint8_t asid;              /* address space identifier */
     uint32_t vpn;              /* virtual page number */
-    uint8_t v;                 /* validity */
     uint32_t ppn;              /* physical page number */
-    uint8_t sz;                        /* page size */
-    uint32_t size;             /* cached page size in bytes */
-    uint8_t sh;                        /* share status */
-    uint8_t c;                 /* cacheability */
-    uint8_t pr;                        /* protection key */
-    uint8_t d;                 /* dirty */
-    uint8_t wt;                        /* write through */
-    uint8_t sa;                        /* space attribute (PCMCIA) */
-    uint8_t tc;                        /* timing control */
+    uint32_t size;             /* mapped page size in bytes */
+    uint8_t asid;              /* address space identifier */
+    uint8_t v:1;               /* validity */
+    uint8_t sz:2;              /* page size */
+    uint8_t sh:1;              /* share status */
+    uint8_t c:1;               /* cacheability */
+    uint8_t pr:2;              /* protection key */
+    uint8_t d:1;               /* dirty */
+    uint8_t wt:1;              /* write through */
+    uint8_t sa:3;              /* space attribute (PCMCIA) */
+    uint8_t tc:1;              /* timing control */
 } tlb_t;
 
 #define UTLB_SIZE 64