Changeset 87194 in vbox for trunk/src/VBox/Runtime/common

Timestamp:

Jan 7, 2021 9:02:43 PM (4 years ago)

Author:

vboxsync

Message:

iprt/asm.h: Added generic C version of ASMBitNextSet. bugref:9898

Location:

trunk/src/VBox/Runtime/common/asm

Files:

• ASMBitNextClear-generic.cpp (modified) (1 diff)
• ASMBitNextSet-generic.cpp (copied) (copied from trunk/src/VBox/Runtime/common/asm/ASMBitNextClear-generic.cpp ) (4 diffs)
• asm-fake.cpp (modified) (1 diff)

trunk/src/VBox/Runtime/common/asm/ASMBitNextClear-generic.cpp

@@ -46 +46 @@
          * Inspect the 32-bit word containing the unaligned bit.
          */
-        uint32_t  u32 = ~RT_LE2H_U32(pau32Bitmap[iBitPrev / 32]) >> iBit;
+        uint32_t u32 = ~RT_LE2H_U32(pau32Bitmap[iBitPrev / 32]) >> iBit;
         if (u32)
             return iBitPrev + ASMBitFirstSetU32(u32) - 1;

trunk/src/VBox/Runtime/common/asm/ASMBitNextSet-generic.cpp

@@ -1 +1 @@
 /* $Id$ */
 /** @file
- * IPRT - ASMBitNextClear - generic C implementation.
+ * IPRT - ASMBitNextSet - generic C implementation.
  */
 
@@ -35 +35 @@
 
 
-DECLASM(int) ASMBitNextClear(const volatile void RT_FAR *pvBitmap, uint32_t cBits, uint32_t iBitPrev) RT_NOTHROW_DEF
+DECLASM(int) ASMBitNextSet(const volatile void RT_FAR *pvBitmap, uint32_t cBits, uint32_t iBitPrev) RT_NOTHROW_DEF
 {
     const volatile uint32_t RT_FAR *pau32Bitmap = (const volatile uint32_t RT_FAR *)pvBitmap;
@@ -46 +46 @@
          * Inspect the 32-bit word containing the unaligned bit.
          */
-        uint32_t  u32 = ~RT_LE2H_U32(pau32Bitmap[iBitPrev / 32]) >> iBit;
+        uint32_t u32 = RT_LE2H_U32(pau32Bitmap[iBitPrev / 32]) >> iBit;
         if (u32)
             return iBitPrev + ASMBitFirstSetU32(u32) - 1;
@@ -60 +60 @@
 
     /*
-     * 32-bit aligned search, let ASMBitFirstClear do the dirty work.
+     * 32-bit aligned search, let ASMBitFirstSet do the dirty work.
      */
-    iBit = ASMBitFirstClear(&pau32Bitmap[iBitPrev / 32], cBits - iBitPrev);
+    iBit = ASMBitFirstSet(&pau32Bitmap[iBitPrev / 32], cBits - iBitPrev);
     if (iBit >= 0)
         iBit += iBitPrev;

trunk/src/VBox/Runtime/common/asm/asm-fake.cpp

@@ -297 +297 @@
 }
 
-RTDECL(int) ASMBitNextSet(const volatile void *pvBitmap, uint32_t cBits, uint32_t iBitPrev)
-{
-    const volatile uint8_t *pau8Bitmap = (const volatile uint8_t *)pvBitmap;
-    int                      iBit = ++iBitPrev & 7;
-    if (iBit)
-    {
-        /*
-         * Inspect the byte containing the unaligned bit.
-         */
-        uint8_t u8 = pau8Bitmap[iBitPrev / 8] >> iBit;
-        if (u8)
-        {
-            iBit = 0;
-            while (!(u8 & 1))
-            {
-                u8 >>= 1;
-                iBit++;
-            }
-            return iBitPrev + iBit;
-        }
-
-        /*
-         * Skip ahead and see if there is anything left to search.
-         */
-        iBitPrev |= 7;
-        iBitPrev++;
-        if (cBits <= iBitPrev)
-            return -1;
-    }
-
-    /*
-     * Byte search, let ASMBitFirstSet do the dirty work.
-     */
-    iBit = ASMBitFirstSet(&pau8Bitmap[iBitPrev / 8], cBits - iBitPrev);
-    if (iBit >= 0)
-        iBit += iBitPrev;
-    return iBit;
-}
-
 RTDECL(unsigned) ASMBitFirstSetU32(uint32_t u32)
 {