Fix EVEX vmovq encoding (#6192)

The vmovq entries that sit in the prefix_extension table have incorrect
encoding information. Specifically, the final byte 0x10, in EVEX mode,
sets EVEX.b. 0x40 sets EVEX.W, which is what's needed here. This was
likely simply copied over from the VEX entries without adjustment.

The vmovq entries in evex_Wb_extensions are already correct.

Fixes #6190

core/ir/x86/decode_table.c

@@ -3899,7 +3899,7 @@ const instr_info_t prefix_extensions[][12] = {
     {VEX_W_EXT, 0x660f7e10, "(vex_W ext 109)", xx, xx, xx, xx, xx, mrm|vex, x, 109},
     {INVALID, 0xf20f7e10, "(bad)", xx, xx, xx, xx, xx, no, x, NA},
     {INVALID,   0x0f7e10, "(bad)", xx, xx, xx, xx, xx, no, x, NA},
-    {OP_vmovq, 0xf30f7e10, "vmovq", Vdq, xx, Wq_dq, xx, xx, mrm|evex, x, tpe[61][6]},
+    {OP_vmovq, 0xf30f7e40, "vmovq", Vdq, xx, Wq_dq, xx, xx, mrm|evex, x, tpe[61][6]},
     {EVEX_Wb_EXT, 0x660f7e10, "(evex_Wb ext 137)", xx, xx, xx, xx, xx, mrm|evex, x, 137},
     {INVALID, 0xf20f7e10, "(bad)", xx, xx, xx, xx, xx, no, x, NA},
   }, /* prefix extension 52: all assumed to have Ib */
@@ -4041,7 +4041,7 @@ const instr_info_t prefix_extensions[][12] = {
     {INVALID, 0xf20fd610, "(bad)", xx, xx, xx, xx, xx, no, x, NA},
     {INVALID,   0x0fd610, "(bad)", xx, xx, xx, xx, xx, no, x, NA},
     {INVALID, 0xf30fd610, "(bad)", xx, xx, xx, xx, xx, no, x, NA},
-    {OP_vmovq, 0x660fd610, "vmovq", Wq_dq, xx, Vq_dq, xx, xx, mrm|evex, x, tvexw[108][1]},
+    {OP_vmovq, 0x660fd640, "vmovq", Wq_dq, xx, Vq_dq, xx, xx, mrm|evex, x, tvexw[108][1]},
     {INVALID, 0xf20fd610, "(bad)", xx, xx, xx, xx, xx, no, x, NA},
   }, /* prefix extension 62 */
   {

suite/tests/api/ir_x86.c

@@ -1544,6 +1544,23 @@ test_x64_vmovq(void *dc)
                               false /*no bytes*/, dbuf, BUFFER_SIZE_ELEMENTS(dbuf), &len);
     ASSERT(pc == &b2[7]);
     ASSERT(strcmp(dbuf, "vmovq  (%rdx,%rcx)[8byte] -> %xmm25\n") == 0);
+
+    const byte expected1[] = { 0x62, 0xc1, 0xfe, 0x08, 0x7e, 0x45, 0x00 };
+    const byte expected2[] = { 0x62, 0xc1, 0xfd, 0x08, 0xd6, 0x45, 0x00 };
+
+    instr_t *instr =
+        INSTR_CREATE_vmovq(dc, opnd_create_reg(DR_REG_XMM16),
+                           opnd_create_base_disp_ex(DR_REG_R13, DR_REG_NULL, 0, 0, OPSZ_8,
+                                                    true, false, false));
+    test_instr_encode(dc, instr, 7);
+    ASSERT(!memcmp(expected1, buf, 7));
+
+    instr = INSTR_CREATE_vmovq(dc,
+                               opnd_create_base_disp_ex(DR_REG_R13, DR_REG_NULL, 0, 0,
+                                                        OPSZ_8, true, false, false),
+                               opnd_create_reg_partial(DR_REG_XMM16, OPSZ_8));
+    test_instr_encode(dc, instr, 7);
+    ASSERT(!memcmp(expected2, buf, 7));
 }
 #endif