From mboxrd@z Thu Jan  1 00:00:00 1970
From: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>
Subject: Re: [Patch 4/5] x86_emulator: add the assembler code for three
 operands
Date: Wed, 3 Dec 2008 16:00:10 +0100
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Cc: Avi Kivity <avi@redhat.com>
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On Tue, 25 Nov 2008 16:59:00 +0200
Avi Kivity <avi@redhat.com> wrote:

> That's actually better and could be used for the other emulations. 
> Please disassemble x86_emulate.o and verify that there are three 
> different shld instructions, one for each register size.

For generating the three shld instructions I need to do the following:

 
+/* Instruction has three operands like shld */
+#define __emulate_2op_cl(_op,_shift, _src, _dst,_eflags,_suffix) 		\
+	do {									\
+		unsigned long _tmp;						\
+		__asm__ __volatile__ (						\
+			_PRE_EFLAGS("0", "5", "2")				\
+			_op _suffix" %4,%1 \n\t"				\
+			_POST_EFLAGS("0", "5", "2")				\
+			: "=m" (_eflags), "+r" (_dst),			\
+			  "=&r" (_tmp)						\
+			: "c" (_shift) , "r" (_src), "i" (EFLAGS_MASK) \
+			); 							\
+	} while (0)
+
+#define emulate_2op_cl(_op, _shift, _src, _dst, _eflags)	\
+	do {								\
+		switch ((_dst).bytes) {					\
+		case 2:	{						\
+			  unsigned short shift = (_shift).val; \
+			  unsigned short src = (_src).val; \
+			  unsigned short dst = (_dst).val; \
+			__emulate_2op_cl(_op,shift, src,dst,_eflags,"w"); \
+			break;						\
+			} \
+		case 4:	{						\
+			  unsigned int shift = (_shift).val; \
+			  unsigned int src = (_src).val; \
+			  unsigned int dst = (_dst).val; \
+			__emulate_2op_cl(_op,shift, src,dst,_eflags,"l"); \
+			break;						\
+			} \
+		case 8:	{						\
+			  unsigned long shift = (_shift).val; \
+			  unsigned long src = (_src).val; \
+			  unsigned long dst = (_dst).val; \
+			ON64(__emulate_2op_cl(_op,shift, src,dst,_eflags,"q")); \
+			break;						\
+			} \
+		}							\
+	} while (0)
+

Otherwise the code for "case 4:" cannot be generated. I've got:

Error: Incorrect register `%rax' used with `l' suffix

Is it correct? If yes I will repost patches that emulate shld/shrd instructions.

Guillaume