5:58 AM Sub, 21.03.2020. Jiaxun Yang <jiaxun.y...@flygoat.com> је
написао/ла:
>
> Loongson multimedia condition instructions were previously implemented as
> write 0 to rd due to lack of documentation. So I just confirmed with
Loongson
> about their encoding and implemented them correctly.
>
> Signed-off-by: Jiaxun Yang <jiaxun.y...@flygoat.com>
> ---
Thanks, Jiaxun!
I feel relieved that this "mistery" is about to be solved. This patch
actually deals with a long-standing known bug, and, on that basis, it is
eligible to be integrated into QEMU 5.0 after soft-freeze.
I'll take a closer look at the details and their possible improvements in
next few days. But, again, in general, I salute this patch.
Yours,
Aleksansdar
> target/mips/translate.c | 40 ++++++++++++++++++++++++++++++++++------
> 1 file changed, 34 insertions(+), 6 deletions(-)
>
> diff --git a/target/mips/translate.c b/target/mips/translate.c
> index d745bd2803..43be8d27b5 100644
> --- a/target/mips/translate.c
> +++ b/target/mips/translate.c
> @@ -5529,6 +5529,8 @@ static void gen_loongson_multimedia(DisasContext
*ctx, int rd, int rs, int rt)
> {
> uint32_t opc, shift_max;
> TCGv_i64 t0, t1;
> + TCGCond cond;
> + TCGLabel *lab;
>
> opc = MASK_LMI(ctx->opcode);
> switch (opc) {
> @@ -5816,7 +5818,7 @@ static void gen_loongson_multimedia(DisasContext
*ctx, int rd, int rs, int rt)
> case OPC_DADD_CP2:
> {
> TCGv_i64 t2 = tcg_temp_new_i64();
> - TCGLabel *lab = gen_new_label();
> + lab = gen_new_label();
>
> tcg_gen_mov_i64(t2, t0);
> tcg_gen_add_i64(t0, t1, t2);
> @@ -5837,7 +5839,7 @@ static void gen_loongson_multimedia(DisasContext
*ctx, int rd, int rs, int rt)
> case OPC_DSUB_CP2:
> {
> TCGv_i64 t2 = tcg_temp_new_i64();
> - TCGLabel *lab = gen_new_label();
> + lab = gen_new_label();
>
> tcg_gen_mov_i64(t2, t0);
> tcg_gen_sub_i64(t0, t1, t2);
> @@ -5862,14 +5864,39 @@ static void gen_loongson_multimedia(DisasContext
*ctx, int rd, int rs, int rt)
>
> case OPC_SEQU_CP2:
> case OPC_SEQ_CP2:
> + cond = TCG_COND_EQ;
> + goto do_cc_cond;
> + break;
> +
> case OPC_SLTU_CP2:
> + cond = TCG_COND_LTU;
> + goto do_cc_cond;
> + break;
> +
> case OPC_SLT_CP2:
> + cond = TCG_COND_LT;
> + goto do_cc_cond;
> + break;
> +
> case OPC_SLEU_CP2:
> + cond = TCG_COND_LEU;
> + goto do_cc_cond;
> + break;
> +
> case OPC_SLE_CP2:
> - /*
> - * ??? Document is unclear: Set FCC[CC]. Does that mean the
> - * FD field is the CC field?
> - */
> + cond = TCG_COND_LE;
> + do_cc_cond:
> + {
> + int cc = (ctx->opcode >> 8) & 0x7;
> + lab = gen_new_label();
> + tcg_gen_ori_i32(fpu_fcr31, fpu_fcr31, 1 << get_fp_bit(cc));
> + tcg_gen_brcond_i64(cond, t0, t1, lab);
> + tcg_gen_xori_i32(fpu_fcr31, fpu_fcr31, 1 << get_fp_bit(cc));
> + gen_set_label(lab);
> + }
> + goto no_rd;
> + break;
> +
> default:
> MIPS_INVAL("loongson_cp2");
> generate_exception_end(ctx, EXCP_RI);
> @@ -5878,6 +5905,7 @@ static void gen_loongson_multimedia(DisasContext
*ctx, int rd, int rs, int rt)
>
> gen_store_fpr64(ctx, t0, rd);
>
> +no_rd:
> tcg_temp_free_i64(t0);
> tcg_temp_free_i64(t1);
> }
> --
> 2.26.0.rc2
>
>
>
