Fix VMAC compile on 32-bit Solaris

The change tested good on 32-bit Linux and 32-bit OS X

1 files changed, 21 insertions, 12 deletions

diff --git a/vmac.cpp b/vmac.cpp
index 5c59a771..2d1ddfee 100644
--- a/vmac.cpp
+++ b/vmac.cpp
@@ -193,22 +193,24 @@ void VMAC_Base::VHASH_Update_SSE2(const word64 *data, size_t blocksRemainingInWo
 	CRYPTOPP_UNUSED(blocksRemainingInWord64);

 

 	// This inline ASM is tricky, and down right difficult when PIC is

-	// in effect. The ASM uses all the general purpose registers. When

-	// PIC is in effect, GCC uses EBX as a base register. Saving EBX with

+	// in effect. The ASM uses all the general purpose registers and all

+	// the XMM registers on 32-bit machines. When PIC is in effect on a

+	// 32-bit machine, GCC uses EBX as a base register. Saving EBX with

 	// 'mov %%ebx, %0' and restoring EBX with 'mov %0, %%ebx' causes GCC

 	// to generate 'mov -0x40(%ebx), %ebx' for the restore. That obviously

-	// won't work. We can push and pop EBX, but then we have to be careful

-	// because GCC references %1 (L1KeyLength) relative to ESP, which is

-	// also used in the function and no longer accurate. Attempting to

-	// sidestep the issues with clobber lists results in "error: ‘asm’

-	// operand has impossible constraints", though we were able to tell

-	// GCC that ESP is dirty. The problems with GCC are the reason for the

-	// pushes and pops rather than the original moves.

+	// won't work because EBX is no longer accurate. We can push and pop

+	// EBX, but that breaks stack-based references. Attempting to sidestep

+	// the issues with clobber lists results in "error: ‘asm’ operand has

+	// impossible constraints". Eventually, we found we could save EBX to

+	// ESP-20, which is one word below our stack in the frame.

 #ifdef __GNUC__

 	__asm__ __volatile__

 	(

-	AS1(	push	%0)         // L1KeyLength

-	AS1(	pop 	%%ebx)

+# if defined(__i386__) || defined(__i686__)

+    // Save EBX for PIC

+	AS2(	mov 	%%ebx, -20(%%esp))

+# endif

+	AS2(	mov 	%0, %%ebx)  // L1KeyLength

 	INTEL_NOPREFIX

 #else

 	#if defined(__INTEL_COMPILER)

@@ -427,11 +429,18 @@ void VMAC_Base::VHASH_Update_SSE2(const word64 *data, size_t blocksRemainingInWo
 	AS_POP_IF86(	bp)

 	AS1(	emms)

 #ifdef __GNUC__

+

 	ATT_PREFIX

+

+# if defined(__i386__) || defined(__i686__)

+	// Restore EBX for PIC

+	AS2(	mov 	-20(%%esp), %%ebx)

+# endif

+

 		:

 		: "m" (L1KeyLength), "c" (blocksRemainingInWord64), "S" (data),

 		  "D" (nhK+tagPart*2), "d" (m_isFirstBlock), "a" (polyS+tagPart*4)

-		: "ebx", "memory", "cc"

+		: "memory", "cc"

 	);

 #endif

 }