On 26/1/23 05:38, Richard Henderson wrote:
This will allow targets to avoid rolling their own.
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
accel/tcg/tcg-runtime.h | 11 +++++
include/tcg/tcg-op.h | 5 +++
tcg/tcg-op.c | 85 +++++++++++++++++++++++++++++++++++
accel/tcg/atomic_common.c.inc | 45 +++++++++++++++++++
4 files changed, 146 insertions(+)
+void tcg_gen_nonatomic_cmpxchg_i128(TCGv_i128 retv, TCGv addr, TCGv_i128 cmpv,
+ TCGv_i128 newv, TCGArg idx, MemOp memop)
+{
+ if (TCG_TARGET_REG_BITS == 32) {
+ /* Inline expansion below is simply too large for 32-bit hosts. */
+ gen_atomic_cx_i128 gen = ((memop & MO_BSWAP) == MO_LE
+ ? gen_helper_nonatomic_cmpxchgo_le
+ : gen_helper_nonatomic_cmpxchgo_be);
+ MemOpIdx oi = make_memop_idx(memop, idx);
+
+ tcg_debug_assert((memop & MO_SIZE) == MO_128);
+ tcg_debug_assert((memop & MO_SIGN) == 0);
+
+ gen(retv, cpu_env, addr, cmpv, newv, tcg_constant_i32(oi));
+ } else {
+ TCGv_i128 oldv = tcg_temp_new_i128();
+ TCGv_i128 tmpv = tcg_temp_new_i128();
+ TCGv_i64 t0 = tcg_temp_new_i64();
+ TCGv_i64 t1 = tcg_temp_new_i64();
+ TCGv_i64 z = tcg_constant_i64(0);
+
+ tcg_gen_qemu_ld_i128(oldv, addr, idx, memop);
+
+ /* Compare i128 */
+ tcg_gen_xor_i64(t0, TCGV128_LOW(oldv), TCGV128_LOW(cmpv));
+ tcg_gen_xor_i64(t1, TCGV128_HIGH(oldv), TCGV128_HIGH(cmpv));
+ tcg_gen_or_i64(t0, t0, t1);
Can we skip the OR ...
+ /* tmpv = equal ? newv : oldv */
+ tcg_gen_movcond_i64(TCG_COND_EQ, TCGV128_LOW(tmpv), t0, z,
+ TCGV128_LOW(newv), TCGV128_LOW(oldv));
+ tcg_gen_movcond_i64(TCG_COND_EQ, TCGV128_HIGH(tmpv), t0, z,
... and test t1 here to partially update LO/HI? (we could remove t1 and
just use t0 as twice 'xor + movcond' but the code is less readable).
+ TCGV128_HIGH(newv), TCGV128_HIGH(oldv));
+
+ /* Unconditional writeback. */
+ tcg_gen_qemu_st_i128(tmpv, addr, idx, memop);
+ tcg_gen_mov_i128(retv, oldv);
+
+ tcg_temp_free_i64(t0);
+ tcg_temp_free_i64(t1);
+ tcg_temp_free_i128(tmpv);
+ tcg_temp_free_i128(oldv);
+ }
+}
Reviewed-by: Philippe Mathieu-Daudé <phi...@linaro.org>
