Attempt to handle locked 16-bit cmpxchg

emu/decode.h

@@ -677,6 +677,18 @@ __no_instrument DECODER_RET glue(DECODER_NAME, OP_SIZE)(DECODER_ARGS) {
             switch (insn) {
                 case 0x65: TRACE("segment gs\n"); SEG_GS(); goto lockrestart;
 
+                case 0x66:
+                    // I didn't think this through
+#if OP_SIZE == 32
+                    TRACE("locked 16-bit mode\n");
+                    RESTORE_IP;
+                    return glue(DECODER_NAME, 16)(DECODER_PASS_ARGS);
+#else
+                    goto lockrestart;
+#endif
+
+
+
 #define MAKE_OP_ATOMIC(x, OP, op) \
         case x+0x0: TRACEI("lock " op " reg8, modrm8"); \
                    READMODRM_MEM; ATOMIC_##OP(modrm_reg, modrm_val,8); break; \

emu/interp.c

@@ -33,6 +33,7 @@ static bool modrm_compute(struct cpu_state *cpu, struct tlb *tlb, addr_t *addr_o
     }
 #define READADDR READIMM_(addr_offset, 32); addr += addr_offset
 
+#define RESTORE_IP cpu->eip = saved_ip
 #define _READIMM(name,size) \
     name = mem_read(cpu->eip, size); \
     cpu->eip += size/8

jit/gen.c

@@ -73,6 +73,7 @@ void gen_exit(struct gen_state *state) {
 #define FINISH \
     return !end_block
 
+#define RESTORE_IP state->ip = saved_ip
 #define _READIMM(name, size) \
     if (!tlb_read(tlb, state->ip, &name, size/8)) SEGFAULT; \
     state->ip += size/8