[Qemu-devel] [PULL 09/38] target-arm: A64: Add SIMD modified immediate group

[Peter Maydell <peter.maydell@linaro.org>]

From: Alex Bennée <alex.bennee@linaro.org>

This patch adds support for the AdvSIMD modified immediate group
(C3.6.6) with all its suboperations (movi, orr, fmov, mvni, bic).

Signed-off-by: Alexander Graf <agraf@suse.de>
[AJB: new decode struct, minor bug fixes, optimisation]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
---
 target-arm/translate-a64.c | 120 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 119 insertions(+), 1 deletion(-)

diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c
index 6521f73..69c75c0 100644
--- a/target-arm/translate-a64.c
+++ b/target-arm/translate-a64.c
@@ -5293,10 +5293,128 @@ static void disas_simd_copy(DisasContext *s, uint32_t insn)
  * +---+---+----+---------------------+-----+-------+----+---+-------+------+
  * | 0 | Q | op | 0 1 1 1 1 0 0 0 0 0 | abc | cmode | o2 | 1 | defgh |  Rd  |
  * +---+---+----+---------------------+-----+-------+----+---+-------+------+
+ *
+ * There are a number of operations that can be carried out here:
+ *   MOVI - move (shifted) imm into register
+ *   MVNI - move inverted (shifted) imm into register
+ *   ORR  - bitwise OR of (shifted) imm with register
+ *   BIC  - bitwise clear of (shifted) imm with register
  */
 static void disas_simd_mod_imm(DisasContext *s, uint32_t insn)
 {
-    unsupported_encoding(s, insn);
+    int rd = extract32(insn, 0, 5);
+    int cmode = extract32(insn, 12, 4);
+    int cmode_3_1 = extract32(cmode, 1, 3);
+    int cmode_0 = extract32(cmode, 0, 1);
+    int o2 = extract32(insn, 11, 1);
+    uint64_t abcdefgh = extract32(insn, 5, 5) | (extract32(insn, 16, 3) << 5);
+    bool is_neg = extract32(insn, 29, 1);
+    bool is_q = extract32(insn, 30, 1);
+    uint64_t imm = 0;
+    TCGv_i64 tcg_rd, tcg_imm;
+    int i;
+
+    if (o2 != 0 || ((cmode == 0xf) && is_neg && !is_q)) {
+        unallocated_encoding(s);
+        return;
+    }
+
+    /* See AdvSIMDExpandImm() in ARM ARM */
+    switch (cmode_3_1) {
+    case 0: /* Replicate(Zeros(24):imm8, 2) */
+    case 1: /* Replicate(Zeros(16):imm8:Zeros(8), 2) */
+    case 2: /* Replicate(Zeros(8):imm8:Zeros(16), 2) */
+    case 3: /* Replicate(imm8:Zeros(24), 2) */
+    {
+        int shift = cmode_3_1 * 8;
+        imm = bitfield_replicate(abcdefgh << shift, 32);
+        break;
+    }
+    case 4: /* Replicate(Zeros(8):imm8, 4) */
+    case 5: /* Replicate(imm8:Zeros(8), 4) */
+    {
+        int shift = (cmode_3_1 & 0x1) * 8;
+        imm = bitfield_replicate(abcdefgh << shift, 16);
+        break;
+    }
+    case 6:
+        if (cmode_0) {
+            /* Replicate(Zeros(8):imm8:Ones(16), 2) */
+            imm = (abcdefgh << 16) | 0xffff;
+        } else {
+            /* Replicate(Zeros(16):imm8:Ones(8), 2) */
+            imm = (abcdefgh << 8) | 0xff;
+        }
+        imm = bitfield_replicate(imm, 32);
+        break;
+    case 7:
+        if (!cmode_0 && !is_neg) {
+            imm = bitfield_replicate(abcdefgh, 8);
+        } else if (!cmode_0 && is_neg) {
+            int i;
+            imm = 0;
+            for (i = 0; i < 8; i++) {
+                if ((abcdefgh) & (1 << i)) {
+                    imm |= 0xffULL << (i * 8);
+                }
+            }
+        } else if (cmode_0) {
+            if (is_neg) {
+                imm = (abcdefgh & 0x3f) << 48;
+                if (abcdefgh & 0x80) {
+                    imm |= 0x8000000000000000ULL;
+                }
+                if (abcdefgh & 0x40) {
+                    imm |= 0x3fc0000000000000ULL;
+                } else {
+                    imm |= 0x4000000000000000ULL;
+                }
+            } else {
+                imm = (abcdefgh & 0x3f) << 19;
+                if (abcdefgh & 0x80) {
+                    imm |= 0x80000000;
+                }
+                if (abcdefgh & 0x40) {
+                    imm |= 0x3e000000;
+                } else {
+                    imm |= 0x40000000;
+                }
+                imm |= (imm << 32);
+            }
+        }
+        break;
+    }
+
+    if (cmode_3_1 != 7 && is_neg) {
+        imm = ~imm;
+    }
+
+    tcg_imm = tcg_const_i64(imm);
+    tcg_rd = new_tmp_a64(s);
+
+    for (i = 0; i < 2; i++) {
+        int foffs = i ? fp_reg_hi_offset(rd) : fp_reg_offset(rd, MO_64);
+
+        if (i == 1 && !is_q) {
+            /* non-quad ops clear high half of vector */
+            tcg_gen_movi_i64(tcg_rd, 0);
+        } else if ((cmode & 0x9) == 0x1 || (cmode & 0xd) == 0x9) {
+            tcg_gen_ld_i64(tcg_rd, cpu_env, foffs);
+            if (is_neg) {
+                /* AND (BIC) */
+                tcg_gen_and_i64(tcg_rd, tcg_rd, tcg_imm);
+            } else {
+                /* ORR */
+                tcg_gen_or_i64(tcg_rd, tcg_rd, tcg_imm);
+            }
+        } else {
+            /* MOVI */
+            tcg_gen_mov_i64(tcg_rd, tcg_imm);
+        }
+        tcg_gen_st_i64(tcg_rd, cpu_env, foffs);
+    }
+
+    tcg_temp_free_i64(tcg_imm);
 }
 
 /* C3.6.7 AdvSIMD scalar copy
-- 
1.8.5