From: Claudio Fontana <claudio.font...@linaro.org>
This patch implements the C3.4.2 Bitfield instructions:
SBFM, BFM, UBFM.
Signed-off-by: Claudio Fontana <claudio.font...@linaro.org>
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
Reviewed-by: Richard Henderson <r...@twiddle.net>
---
target-arm/translate-a64.c | 56 ++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 54 insertions(+), 2 deletions(-)
diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c
index 0663e4c..045a25e 100644
--- a/target-arm/translate-a64.c
+++ b/target-arm/translate-a64.c
@@ -698,10 +698,62 @@ static void disas_movw_imm(DisasContext *s, uint32_t insn)
unsupported_encoding(s, insn);
}
-/* Bitfield */
+/* C3.4.2 Bitfield
+ * 31 30 29 28 23 22 21 16 15 10 9 5 4 0
+ * +----+-----+-------------+---+------+------+------+------+
+ * | sf | opc | 1 0 0 1 1 0 | N | immr | imms | Rn | Rd |
+ * +----+-----+-------------+---+------+------+------+------+
+ */
static void disas_bitfield(DisasContext *s, uint32_t insn)
{
- unsupported_encoding(s, insn);
+ unsigned int sf, n, opc, ri, si, rn, rd, bitsize, pos, len;
+ TCGv_i64 tcg_rd, tcg_tmp;
+
+ sf = extract32(insn, 31, 1);
+ opc = extract32(insn, 29, 2);
+ n = extract32(insn, 22, 1);
+ ri = extract32(insn, 16, 6);
+ si = extract32(insn, 10, 6);
+ rn = extract32(insn, 5, 5);
+ rd = extract32(insn, 0, 5);
+ bitsize = sf ? 64 : 32;
+
+ if (sf != n || ri >= bitsize || si >= bitsize || opc > 2) {
+ unallocated_encoding(s);
+ return;
+ }
+
+ 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} */
+
+ if (opc != 1) { /* SBFM or UBFM */
+ tcg_gen_movi_i64(tcg_rd, 0);
+ }
+
+ /* do the bit move operation */
+ if (si >= ri) {
+ /* Wd<s-r:0> = Wn<s:r> */
+ tcg_gen_shri_i64(tcg_tmp, tcg_tmp, ri);
+ pos = 0;
+ len = (si - ri) + 1;
+ } else {
+ /* Wd<32+s-r,32-r> = Wn<s:0> */
+ pos = bitsize - ri;
+ len = si + 1;
+ }
+
+ tcg_gen_deposit_i64(tcg_rd, tcg_rd, tcg_tmp, pos, len);
+
+ if (opc == 0) { /* SBFM - sign extend the destination field */
+ tcg_gen_shli_i64(tcg_rd, tcg_rd, 64 - (pos + len));
+ tcg_gen_sari_i64(tcg_rd, tcg_rd, 64 - (pos + len));
+ }
+
+ if (!sf) { /* zero extend final result */
+ tcg_gen_ext32u_i64(tcg_rd, tcg_rd);
+ }
}
/* C3.4.3 Extract
--
1.8.5
