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[Qemu-devel] [PATCH 1/3] tcg/ppc: Adjust exit_tb for change in prologue
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH 1/3] tcg/ppc: Adjust exit_tb for change in prologue placement |
Date: |
Tue, 13 Oct 2015 08:23:46 +1100 |
Changing the prologue to the beginning of the code_gen_buffer
changes the direction of the "return" branch. Need to change
the logic to match.
Signed-off-by: Richard Henderson <address@hidden>
---
tcg/ppc/tcg-target.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/tcg/ppc/tcg-target.c b/tcg/ppc/tcg-target.c
index 92ef719..fd7a3e0 100644
--- a/tcg/ppc/tcg-target.c
+++ b/tcg/ppc/tcg-target.c
@@ -1855,12 +1855,10 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,
const TCGArg *args,
if (USE_REG_RA) {
ptrdiff_t disp = tcg_pcrel_diff(s, tb_ret_addr);
- /* If we can use a direct branch, otherwise use the value in RA.
- Note that the direct branch is always forward. If it's in
- range now, it'll still be in range after the movi. Don't
- bother about the 20 bytes where the test here fails but it
- would succeed below. */
- if (!in_range_b(disp)) {
+ /* Use a direct branch if we can, otherwise use the value in RA.
+ Note that the direct branch is always backward, thus we need
+ to account for the possibility of 5 insns from the movi. */
+ if (!in_range_b(disp - 20)) {
tcg_out32(s, MTSPR | RS(TCG_REG_RA) | CTR);
tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_R3, args[0]);
tcg_out32(s, BCCTR | BO_ALWAYS);
--
2.4.3