The new placement of the TB means that we can use one insn
to load the goto_tb destination directly from the TB.
Signed-off-by: Richard Henderson <r...@twiddle.net>
---
tcg/arm/tcg-target.inc.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/tcg/arm/tcg-target.inc.c b/tcg/arm/tcg-target.inc.c
index 18708b1..b640fb9 100644
--- a/tcg/arm/tcg-target.inc.c
+++ b/tcg/arm/tcg-target.inc.c
@@ -1669,14 +1669,27 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode
opc,
}
break;
case INDEX_op_goto_tb:
- tcg_debug_assert(s->tb_jmp_insn_offset == 0);
{
/* Indirect jump method */
- intptr_t ptr = (intptr_t)(s->tb_jmp_target_addr + args[0]);
- tcg_out_movi32(s, COND_AL, TCG_REG_R0, ptr & ~0xfff);
- tcg_out_ld32_12(s, COND_AL, TCG_REG_PC, TCG_REG_R0, ptr & 0xfff);
+ intptr_t ptr, dif, dil;
+ TCGReg base = TCG_REG_PC;
+
+ tcg_debug_assert(s->tb_jmp_insn_offset == 0);
+ ptr = (intptr_t)(s->tb_jmp_target_addr + args[0]);
+ dif = ptr - ((intptr_t)s->code_ptr + 8);
+ dil = sextract32(dif, 0, 12);
+ if (dif != dil) {
+ /* The TB is close, but outside the 12 bits addressable by
+ the load. We can extend this to 20 bits with a sub of a
+ shifted immediate from pc. In the vastly unlikely event
+ the code requires more than 1MB, we'll use 2 insns and
+ be no worse off. */
+ base = TCG_REG_R0;
+ tcg_out_movi32(s, COND_AL, base, ptr - dil);
+ }
+ tcg_out_ld32_12(s, COND_AL, TCG_REG_PC, base, dil);
+ s->tb_jmp_reset_offset[args[0]] = tcg_current_code_size(s);
}
- s->tb_jmp_reset_offset[args[0]] = tcg_current_code_size(s);
break;
case INDEX_op_goto_ptr:
tcg_out_bx(s, COND_AL, args[0]);
--
2.9.4
