Changeset 52443 in vbox

Timestamp:

Aug 21, 2014 4:16:19 PM (10 years ago)

Author:

vboxsync

Message:

Runtime: added ASMMultU32ByU32DivByU32() and fixed early clobber operands in ASMMultU64ByU32DivByU32

Location:

trunk

Files:

• include/iprt/asm-math.h (modified) (2 diffs)
• src/VBox/Runtime/Makefile.kmk (modified) (2 diffs)
• src/VBox/Runtime/common/asm/ASMMultU32ByU32DivByU32.asm (added)
• src/VBox/Runtime/testcase/tstRTInlineAsm.cpp (modified) (1 diff)

trunk/include/iprt/asm-math.h

@@ -322 +322 @@
 
 /**
+ * Multiple a 32-bit by a 32-bit integer and divide the result by a 32-bit integer
+ * using a 64 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 (u32A * u32B) / u32C.
+ * @param   u32A    The 32-bit value (A).
+ * @param   u32B    The 32-bit value to multiple by A.
+ * @param   u32C    The 32-bit value to divide A*B by.
+ *
+ * @remarks Architecture specific.
+ */
+#if RT_INLINE_ASM_EXTERNAL || !defined(__GNUC__) || (!defined(RT_ARCH_AMD64) && !defined(RT_ARCH_X86))
+DECLASM(uint32_t) ASMMultU32ByU32DivByU32(uint32_t u32A, uint32_t u32B, uint32_t u32C);
+#else
+DECLINLINE(uint32_t) ASMMultU32ByU32DivByU32(uint32_t u32A, uint32_t u32B, uint32_t u32C)
+{
+# if RT_INLINE_ASM_GNU_STYLE
+    uint32_t u32Result, u32Spill;
+    __asm__ __volatile__("mul %2\n\t"
+                         "div %3\n\t"
+                         : "=&a" (u32Result),
+                           "=&d" (u32Spill)
+                         : "r" (u32B),
+                           "r" (u32C),
+                           "0" (u32A),
+                           "1" (0));
+    return u32Result;
+# else
+    return (uint32_t)(((uint64_t)u32A * u32B) / u32C);
+# endif
+}
+#endif
+
+
+/**
  * Multiple a 64-bit by a 32-bit integer and divide the result by a 32-bit integer
  * using a 96 bit intermediate result.
@@ -344 +380 @@
     __asm__ __volatile__("mulq %2\n\t"
                          "divq %3\n\t"
-                         : "=a" (u64Result),
-                           "=d" (u64Spill)
+                         : "=&a" (u64Result),
+                           "=&d" (u64Spill)
                          : "r" ((uint64_t)u32B),
                            "r" ((uint64_t)u32C),

trunk/src/VBox/Runtime/Makefile.kmk

@@ -181 +181 @@
         win/amd64/ASMGetDR7.asm \
         common/asm/ASMAtomicCmpXchgU8.asm \
+        common/asm/ASMMultU32ByU32DivByU32.asm \
         common/asm/ASMMultU64ByU32DivByU32.asm \
         common/asm/ASMCpuId_Idx_ECX.asm \
@@ -197 +198 @@
 RuntimeWin32ASM_SOURCES = \
         common/asm/ASMAtomicCmpXchgU8.asm \
+        common/asm/ASMMultU32ByU32DivByU32.asm \
         common/asm/ASMMultU64ByU32DivByU32.asm \
         common/asm/ASMCpuId_Idx_ECX.asm \

trunk/src/VBox/Runtime/testcase/tstRTInlineAsm.cpp

@@ -1434 +1434 @@
     uint32_t u32 = ASMDivU64ByU32RetU32(UINT64_C(0x0800000000000000), UINT32_C(0x10000000));
     CHECKVAL(u32, UINT32_C(0x80000000), "%#010RX32");
+
+#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
+    u32 = ASMMultU32ByU32DivByU32(UINT32_C(0x00000001), UINT32_C(0x00000001), UINT32_C(0x00000001));
+    CHECKVAL(u32, UINT32_C(0x00000001), "%#018RX32");
+    u32 = ASMMultU32ByU32DivByU32(UINT32_C(0x10000000), UINT32_C(0x80000000), UINT32_C(0x20000000));
+    CHECKVAL(u32, UINT32_C(0x40000000), "%#018RX32");
+    u32 = ASMMultU32ByU32DivByU32(UINT32_C(0x76543210), UINT32_C(0xffffffff), UINT32_C(0xffffffff));
+    CHECKVAL(u32, UINT32_C(0x76543210), "%#018RX32");
+    u32 = ASMMultU32ByU32DivByU32(UINT32_C(0xffffffff), UINT32_C(0xffffffff), UINT32_C(0xffffffff));
+    CHECKVAL(u32, UINT32_C(0xffffffff), "%#018RX32");
+    u32 = ASMMultU32ByU32DivByU32(UINT32_C(0xffffffff), UINT32_C(0xfffffff0), UINT32_C(0xffffffff));
+    CHECKVAL(u32, UINT32_C(0xfffffff0), "%#018RX32");
+    u32 = ASMMultU32ByU32DivByU32(UINT32_C(0x10359583), UINT32_C(0x58734981), UINT32_C(0xf8694045));
+    CHECKVAL(u32, UINT32_C(0x05c584ce), "%#018RX32");
+    u32 = ASMMultU32ByU32DivByU32(UINT32_C(0x10359583), UINT32_C(0xf8694045), UINT32_C(0x58734981));
+    CHECKVAL(u32, UINT32_C(0x2d860795), "%#018RX32");
+#endif
 
 #if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)