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target-arm: Recognize SXTB, SXTH, SXTW, ASR

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These are all special case aliases of SBFM.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Message-id: 1441909103-24666-8-git-send-email-rth@twiddle.net
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Richard Henderson 2015-09-14 14:39:48 +01:00 committed by Peter Maydell
parent 6e061029d7
commit ef60151bee
1 changed files with 23 additions and 1 deletions
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24
target-arm/translate-a64.c
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@ -3017,7 +3017,28 @@ static void disas_bitfield(DisasContext *s, uint32_t insn)
tcg_rd = cpu_reg(s, rd);
tcg_tmp = read_cpu_reg(s, rn, sf);
/* OPTME: probably worth recognizing common cases of ext{8,16,32}{u,s} */
/* Recognize the common aliases. */
if (opc == 0) { /* SBFM */
if (ri == 0) {
if (si == 7) { /* SXTB */
tcg_gen_ext8s_i64(tcg_rd, tcg_tmp);
goto done;
} else if (si == 15) { /* SXTH */
tcg_gen_ext16s_i64(tcg_rd, tcg_tmp);
goto done;
} else if (si == 31) { /* SXTW */
tcg_gen_ext32s_i64(tcg_rd, tcg_tmp);
goto done;
}
}
if (si == 63 || (si == 31 && ri <= si)) { /* ASR */
if (si == 31) {
tcg_gen_ext32s_i64(tcg_tmp, tcg_tmp);
}
tcg_gen_sari_i64(tcg_rd, tcg_tmp, ri);
goto done;
}
}
if (opc != 1) { /* SBFM or UBFM */
tcg_gen_movi_i64(tcg_rd, 0);
@ -3042,6 +3063,7 @@ static void disas_bitfield(DisasContext *s, uint32_t insn)
tcg_gen_sari_i64(tcg_rd, tcg_rd, 64 - (pos + len));
}
done:
if (!sf) { /* zero extend final result */
tcg_gen_ext32u_i64(tcg_rd, tcg_rd);
}