diff options
| -rw-r--r-- | target/i386/tcg/translate.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c index 7a3caf8b99..0a8f3c8951 100644 --- a/target/i386/tcg/translate.c +++ b/target/i386/tcg/translate.c @@ -1339,6 +1339,7 @@ static void do_gen_rep(DisasContext *s, MemOp ot, { TCGLabel *done = gen_new_label(); target_ulong cx_mask = MAKE_64BIT_MASK(0, 8 << s->aflag); + TCGv cx_next = tcg_temp_new(); bool had_rf = s->flags & HF_RF_MASK; /* @@ -1364,7 +1365,19 @@ static void do_gen_rep(DisasContext *s, MemOp ot, tcg_gen_brcondi_tl(TCG_COND_TSTEQ, cpu_regs[R_ECX], cx_mask, done); fn(s, ot); - gen_op_add_reg_im(s, s->aflag, R_ECX, -1); + + tcg_gen_subi_tl(cx_next, cpu_regs[R_ECX], 1); + + /* + * Write back cx_next to CX/ECX/RCX. There can be no carry, so zero + * extend if needed but do not do expensive deposit operations. + */ +#ifdef TARGET_X86_64 + if (s->aflag == MO_32) { + tcg_gen_ext32u_tl(cx_next, cx_next); + } +#endif + tcg_gen_mov_tl(cpu_regs[R_ECX], cx_next); gen_update_cc_op(s); /* Leave if REP condition fails. */ |