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[Qemu-devel] [PATCH v4 1/3] tcg/aarch64: Introduce and use long branch t
From: |
Pranith Kumar |
Subject: |
[Qemu-devel] [PATCH v4 1/3] tcg/aarch64: Introduce and use long branch to register |
Date: |
Fri, 30 Jun 2017 10:36:12 -0400 |
We can use a branch to register instruction for exit_tb for offsets
greater than 128MB.
CC: Alex Bennée <address@hidden>
Reviewed-by: Richard Henderson <address@hidden>
Signed-off-by: Pranith Kumar <address@hidden>
---
tcg/aarch64/tcg-target.inc.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/tcg/aarch64/tcg-target.inc.c b/tcg/aarch64/tcg-target.inc.c
index 1fa3bccc89..8fce11ace7 100644
--- a/tcg/aarch64/tcg-target.inc.c
+++ b/tcg/aarch64/tcg-target.inc.c
@@ -819,6 +819,17 @@ static inline void tcg_out_goto(TCGContext *s,
tcg_insn_unit *target)
tcg_out_insn(s, 3206, B, offset);
}
+static inline void tcg_out_goto_long(TCGContext *s, tcg_insn_unit *target)
+{
+ ptrdiff_t offset = target - s->code_ptr;
+ if (offset == sextract64(offset, 0, 26)) {
+ tcg_out_insn(s, 3206, BL, offset);
+ } else {
+ tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_TMP, (intptr_t)target);
+ tcg_out_insn(s, 3207, BR, TCG_REG_TMP);
+ }
+}
+
static inline void tcg_out_goto_noaddr(TCGContext *s)
{
/* We pay attention here to not modify the branch target by reading from
@@ -1364,10 +1375,10 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,
case INDEX_op_exit_tb:
/* Reuse the zeroing that exists for goto_ptr. */
if (a0 == 0) {
- tcg_out_goto(s, s->code_gen_epilogue);
+ tcg_out_goto_long(s, s->code_gen_epilogue);
} else {
tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_X0, a0);
- tcg_out_goto(s, tb_ret_addr);
+ tcg_out_goto_long(s, tb_ret_addr);
}
break;
--
2.13.0
- [Qemu-devel] [PATCH v4 1/3] tcg/aarch64: Introduce and use long branch to register,
Pranith Kumar <=