From 7a6f61057b0305515bb82e6697765a7fc36cfefe Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Thu, 28 Feb 2019 19:20:14 -0500
Subject: [PATCH] target/m68k: Correct instruction emulation

Previously we weren't even initializing the instruction table, so any
attempt at emulation would cause a segmentation fault.

This also moves the end address check after the decoding to correctly
perform exiting behavior with the new translator model.
---
 qemu/target/m68k/cpu.c       |  3 +++
 qemu/target/m68k/translate.c | 12 ++++++------
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/qemu/target/m68k/cpu.c b/qemu/target/m68k/cpu.c
index 55f9cd08..23809513 100644
--- a/qemu/target/m68k/cpu.c
+++ b/qemu/target/m68k/cpu.c
@@ -211,8 +211,11 @@ static void any_cpu_initfn(struct uc_struct *uc, Object *obj, void *opaque)
 static int m68k_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **errp)
 {
     CPUState *cs = CPU(dev);
+    M68kCPU *cpu = M68K_CPU(uc, dev);
     M68kCPUClass *mcc = M68K_CPU_GET_CLASS(uc, dev);
 
+    register_m68k_insns(&cpu->env);
+
     cpu_reset(cs);
     qemu_init_vcpu(cs);
 
diff --git a/qemu/target/m68k/translate.c b/qemu/target/m68k/translate.c
index dc9d00c6..bc2cdec3 100644
--- a/qemu/target/m68k/translate.c
+++ b/qemu/target/m68k/translate.c
@@ -6334,12 +6334,6 @@ static void m68k_tr_translate_insn(DisasContextBase *dcbase, CPUState *cpu)
     TCGContext *tcg_ctx = env->uc->tcg_ctx;
     uint16_t insn = read_im16(env, dc);
 
-    // Unicorn: end address tells us to stop emulation
-    if (dc->pc == dc->uc->addr_end) {
-        gen_exception(dc, dc->pc, EXCP_HLT);
-        return;
-    }
-
     // Unicorn: trace this instruction on request
     if (HOOK_EXISTS_BOUNDED(env->uc, UC_HOOK_CODE, dc->pc)) {
         gen_uc_tracecode(tcg_ctx, 2, UC_HOOK_CODE_IDX, env->uc, dc->pc);
@@ -6353,6 +6347,12 @@ static void m68k_tr_translate_insn(DisasContextBase *dcbase, CPUState *cpu)
 
     dc->base.pc_next = dc->pc;
 
+    // Unicorn: end address tells us to stop emulation
+    if (dc->pc == dc->uc->addr_end) {
+        gen_exception(dc, dc->pc, EXCP_HLT);
+        return;
+    }
+
     if (dc->base.is_jmp == DISAS_NEXT) {
         /* Stop translation when the next insn might touch a new page.
          * This ensures that prefetch aborts at the right place.