Add missing IMUL pattern: reg64,imm8

Make "imul rax,byte 5" work as expected.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

insns.dat

@@ -569,6 +569,7 @@ IMUL		reg32,imm8			\321\1\x6B\100\15				386
 IMUL		reg32,sbyte32			\321\1\x6B\100\15				386,SM,ND
 IMUL		reg32,imm32			\321\1\x69\100\41				386
 IMUL		reg32,imm			\321\155\x69\100\151				386,SM,ND
+IMUL		reg64,imm8			\324\1\x6B\100\15				X64
 IMUL		reg64,sbyte64			\324\1\x6B\100\15				X64,SM,ND
 IMUL		reg64,imm32			\324\1\x69\100\255				X64
 IMUL		reg64,imm			\324\155\x69\100\251				X64,SM,ND

test/imul.asm

@@ -0,0 +1,89 @@
+;Testname=test; Arguments=-fbin -oimul.bin; Files=stdout stderr imul.bin
+
+%macro test 1-2 5
+	bits %1
+
+%undef MEM
+%if %1 == 16
+  %define MEM [di]
+%elif %1 == 32
+  %define MEM [edi]
+%elif %1 == 64
+  %define MEM [rdi]
+%endif
+
+	imul al
+	imul byte MEM
+	imul ax
+	imul word MEM
+	imul eax
+	imul dword MEM
+%if %1 == 64
+	imul rdx
+	imul qword MEM
+%endif
+	
+	imul ax,cx
+	imul ax,MEM
+	imul ax,word MEM
+	imul eax,ecx
+	imul eax,MEM
+	imul eax,dword MEM
+%if %1 == 64
+	imul rax,rcx
+	imul rax,MEM
+	imul rax,qword MEM
+%endif
+
+	imul ax,cx,%2
+	imul ax,cx,byte %2
+	imul ax,MEM,%2
+	imul ax,word MEM,%2
+	imul eax,ecx,%2
+	imul eax,ecx,byte %2
+	imul eax,MEM,%2
+	imul eax,dword MEM,%2
+%if %1 == 64
+	imul rax,rcx,%2
+	imul rax,rcx,byte %2
+	imul rax,MEM,%2
+	imul rax,qword MEM,%2
+%endif
+
+	imul ax,%2
+	imul ax,byte %2
+	imul eax,%2
+	imul eax,byte %2
+%if %1 == 64
+	imul rax,%2
+;	imul rax,byte %2	; ERROR
+%endif
+
+	imul ax,cx,0x1234
+	imul ax,MEM,0x1234
+	imul ax,word MEM,0x1234
+	imul eax,ecx,0x12345678
+	imul eax,MEM,0x12345678
+	imul eax,dword MEM,0x12345678
+%if %1 == 64
+	imul rax,rcx,0x12345678
+	imul rax,MEM,0x12345678
+	imul rax,qword MEM,0x12345678
+%endif
+
+	imul ax,0x1234
+	imul eax,0x12345678
+%if %1 == 64
+	imul rax,0x12345678
+%endif
+%endmacro
+
+	test 16
+	test 32
+	test 64
+
+%ifdef WARN
+	test 16,0x999
+	test 32,0x999999
+	test 64,0x999999999
+%endif