Re: [PATCH v2 19/23] target/i386: Use gen_jmp_rel for gen_jcc

[Richard Henderson]

On 9/21/22 06:09, Paolo Bonzini wrote:

On Tue, Sep 6, 2022 at 12:09 PM Richard Henderson
<richard.hender...@linaro.org> wrote:

-static inline void gen_jcc(DisasContext *s, int b,
-                           target_ulong val, target_ulong next_eip)
+static void gen_jcc(DisasContext *s, MemOp ot, int b, int diff)
  {
-    TCGLabel *l1, *l2;
+    TCGLabel *l1 = gen_new_label();

-    if (s->jmp_opt) {
-        l1 = gen_new_label();
-        gen_jcc1(s, b, l1);
-
-        gen_goto_tb(s, 0, next_eip);
-
-        gen_set_label(l1);
-        gen_goto_tb(s, 1, val);
-    } else {
-        l1 = gen_new_label();
-        l2 = gen_new_label();
-        gen_jcc1(s, b, l1);
-
-        gen_jmp_im(s, next_eip);
-        tcg_gen_br(l2);
-
-        gen_set_label(l1);
-        gen_jmp_im(s, val);
-        gen_set_label(l2);
-        gen_eob(s);
-    }
+    gen_jcc1(s, b, l1);
+    gen_jmp_rel(s, ot, 0, 1);
+    gen_set_label(l1);
+    gen_jmp_rel(s, ot, diff, 0);

Might be worth a comment that jumps with 16-bit operand size truncate
EIP even if the jump is not taken.

Hmm.  But is that correct?  That's not reflected by the pseudocode for Jcc.


r~