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authorRabin Vincent <rabin@rab.in>2010-02-15 00:02:35 +0530
committerPaul Brook <paul@codesourcery.com>2010-02-19 13:38:43 +0000
commitb8b45b68f8836c1db8422badf3c0c573a88f8b43 (patch)
treeeafa6de7aa74f40c44b822ff0f69a2cbe0413698
parentfa26df032ec3da7bf0db541e40b2ac1b19aea391 (diff)
downloadfocaccia-qemu-b8b45b68f8836c1db8422badf3c0c573a88f8b43.tar.gz
focaccia-qemu-b8b45b68f8836c1db8422badf3c0c573a88f8b43.zip
target-arm: implement Thumb-2 exception return
Support the "subs pc, lr" Thumb-2 exception return instruction.

Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Paul Brook <paul@codesourcery.com>
-rw-r--r--target-arm/translate.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/target-arm/translate.c b/target-arm/translate.c
index 10a516b909..8b3b12d67e 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -8001,8 +8001,16 @@ static int disas_thumb2_insn(CPUState *env, DisasContext *s, uint16_t insn_hw1)
                         gen_bx(s, tmp);
                         break;
                     case 5: /* Exception return.  */
-                        /* Unpredictable in user mode.  */
-                        goto illegal_op;
+                        if (IS_USER(s)) {
+                            goto illegal_op;
+                        }
+                        if (rn != 14 || rd != 15) {
+                            goto illegal_op;
+                        }
+                        tmp = load_reg(s, rn);
+                        tcg_gen_subi_i32(tmp, tmp, insn & 0xff);
+                        gen_exception_return(s, tmp);
+                        break;
                     case 6: /* mrs cpsr.  */
                         tmp = new_tmp();
                         if (IS_M(env)) {