Changeset 52455 in vbox for trunk/include/iprt/asm-math.h

Timestamp:

Aug 22, 2014 7:47:06 AM (10 years ago)

Author:

vboxsync

Message:

Updated ASMMultU32ByU32DivByU32 and ASMMultU64ByU32DivByU32 documentation. (Don't put unscoped implementation details in the function description, or at least not immediately below the function brief!)

File:

• trunk/include/iprt/asm-math.h (modified) (3 diffs)

trunk/include/iprt/asm-math.h

@@ -331 +331 @@
  *
  * @remarks Architecture specific.
+ * @remarks Make sure the result won't ever exceed 32-bit, because hardware
+ *          exception may be raised if it does.
+ * @remarks On x86 this may be used to avoid dragging in 64-bit builtin
+ *          arithmetics functions.
  */
 #if RT_INLINE_ASM_EXTERNAL && (defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86))
@@ -358 +362 @@
  * Multiple a 64-bit by a 32-bit integer and divide the result by a 32-bit integer
  * using a 96 bit intermediate result.
- * @note    Don't use 64-bit C arithmetic here since some gcc compilers generate references to
- *          __udivdi3 and __umoddi3 even if this inline function is not used.
  *
  * @returns (u64A * u32B) / u32C.
@@ -367 +369 @@
  *
  * @remarks Architecture specific.
+ * @remarks Make sure the result won't ever exceed 64-bit, because hardware
+ *          exception may be raised if it does.
+ * @remarks On x86 this may be used to avoid dragging in 64-bit builtin
+ *          arithmetics function.
  */
 #if RT_INLINE_ASM_EXTERNAL || !defined(__GNUC__) || (!defined(RT_ARCH_AMD64) && !defined(RT_ARCH_X86))