target/arm: Convert MOVI, FMOV, ORR, BIC (vector immediate) to decodetree

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240912024114.1097832-14-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 59 insertions, 67 deletions

diff --git a/target/arm/tcg/a64.decode b/target/arm/tcg/a64.decode
index e11e293..278d787 100644
--- a/target/arm/tcg/a64.decode
+++ b/target/arm/tcg/a64.decode
@@ -1184,3 +1184,12 @@ FMINV_s         0110 1110 10 11000 01111 10 ..... .....     @rr_q1e2
 # Floating-point Immediate
 
 FMOVI_s         0001 1110 .. 1 imm:8 100 00000 rd:5         esz=%esz_hsd
+
+# Advanced SIMD Modified Immediate
+
+%abcdefgh       16:3 5:5
+
+FMOVI_v_h       0 q:1 00 1111 00000 ... 1111 11 ..... rd:5  %abcdefgh
+
+# MOVI, MVNI, ORR, BIC, FMOV are all intermixed via cmode.
+Vimm            0 q:1 op:1 0 1111 00000 ... cmode:4 01 ..... rd:5 %abcdefgh
diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index 0e29006..53022f4 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -6913,6 +6913,52 @@ static bool trans_FMOVI_s(DisasContext *s, arg_FMOVI_s *a)
     return true;
 }
 
+/*
+ * Advanced SIMD Modified Immediate
+ */
+
+static bool trans_FMOVI_v_h(DisasContext *s, arg_FMOVI_v_h *a)
+{
+    if (!dc_isar_feature(aa64_fp16, s)) {
+        return false;
+    }
+    if (fp_access_check(s)) {
+        tcg_gen_gvec_dup_imm(MO_16, vec_full_reg_offset(s, a->rd),
+                             a->q ? 16 : 8, vec_full_reg_size(s),
+                             vfp_expand_imm(MO_16, a->abcdefgh));
+    }
+    return true;
+}
+
+static void gen_movi(unsigned vece, uint32_t dofs, uint32_t aofs,
+                     int64_t c, uint32_t oprsz, uint32_t maxsz)
+{
+    tcg_gen_gvec_dup_imm(MO_64, dofs, oprsz, maxsz, c);
+}
+
+static bool trans_Vimm(DisasContext *s, arg_Vimm *a)
+{
+    GVecGen2iFn *fn;
+
+    /* Handle decode of cmode/op here between ORR/BIC/MOVI */
+    if ((a->cmode & 1) && a->cmode < 12) {
+        /* For op=1, the imm will be inverted, so BIC becomes AND. */
+        fn = a->op ? tcg_gen_gvec_andi : tcg_gen_gvec_ori;
+    } else {
+        /* There is one unallocated cmode/op combination in this space */
+        if (a->cmode == 15 && a->op == 1 && a->q == 0) {
+            return false;
+        }
+        fn = gen_movi;
+    }
+
+    if (fp_access_check(s)) {
+        uint64_t imm = asimd_imm_const(a->abcdefgh, a->cmode, a->op);
+        gen_gvec_fn2i(s, a->q, a->rd, a->rd, imm, fn, MO_64);
+    }
+    return true;
+}
+
 /* Shift a TCGv src by TCGv shift_amount, put result in dst.
  * Note that it is the caller's responsibility to ensure that the
  * shift amount is in range (ie 0..31 or 0..63) and provide the ARM
@@ -9092,69 +9138,6 @@ static void disas_data_proc_fp(DisasContext *s, uint32_t insn)
     }
 }
 
-/* AdvSIMD modified immediate
- *  31  30   29  28                 19 18 16 15   12  11  10  9     5 4    0
- * +---+---+----+---------------------+-----+-------+----+---+-------+------+
- * | 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
- * With ARMv8.2 we also have:
- *   FMOV half-precision
- */
-static void disas_simd_mod_imm(DisasContext *s, uint32_t insn)
-{
-    int rd = extract32(insn, 0, 5);
-    int cmode = extract32(insn, 12, 4);
-    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;
-
-    if (o2) {
-        if (cmode != 0xf || is_neg) {
-            unallocated_encoding(s);
-            return;
-        }
-        /* FMOV (vector, immediate) - half-precision */
-        if (!dc_isar_feature(aa64_fp16, s)) {
-            unallocated_encoding(s);
-            return;
-        }
-        imm = vfp_expand_imm(MO_16, abcdefgh);
-        /* now duplicate across the lanes */
-        imm = dup_const(MO_16, imm);
-    } else {
-        if (cmode == 0xf && is_neg && !is_q) {
-            unallocated_encoding(s);
-            return;
-        }
-        imm = asimd_imm_const(abcdefgh, cmode, is_neg);
-    }
-
-    if (!fp_access_check(s)) {
-        return;
-    }
-
-    if (!((cmode & 0x9) == 0x1 || (cmode & 0xd) == 0x9)) {
-        /* MOVI or MVNI, with MVNI negation handled above.  */
-        tcg_gen_gvec_dup_imm(MO_64, vec_full_reg_offset(s, rd), is_q ? 16 : 8,
-                             vec_full_reg_size(s), imm);
-    } else {
-        /* ORR or BIC, with BIC negation to AND handled above.  */
-        if (is_neg) {
-            gen_gvec_fn2i(s, is_q, rd, rd, imm, tcg_gen_gvec_andi, MO_64);
-        } else {
-            gen_gvec_fn2i(s, is_q, rd, rd, imm, tcg_gen_gvec_ori, MO_64);
-        }
-    }
-}
-
 /*
  * Common SSHR[RA]/USHR[RA] - Shift right (optional rounding/accumulate)
  *
@@ -10635,8 +10618,10 @@ static void disas_simd_shift_imm(DisasContext *s, uint32_t insn)
     bool is_u = extract32(insn, 29, 1);
     bool is_q = extract32(insn, 30, 1);
 
-    /* data_proc_simd[] has sent immh == 0 to disas_simd_mod_imm. */
-    assert(immh != 0);
+    if (immh == 0) {
+        unallocated_encoding(s);
+        return;
+    }
 
     switch (opcode) {
     case 0x08: /* SRI */
@@ -11644,8 +11629,6 @@ static void disas_simd_two_reg_misc_fp16(DisasContext *s, uint32_t insn)
 static const AArch64DecodeTable data_proc_simd[] = {
     /* pattern  ,  mask     ,  fn                        */
     { 0x0e200800, 0x9f3e0c00, disas_simd_two_reg_misc },
-    /* simd_mod_imm decode is a subset of simd_shift_imm, so must precede it */
-    { 0x0f000400, 0x9ff80400, disas_simd_mod_imm },
     { 0x0f000400, 0x9f800400, disas_simd_shift_imm },
     { 0x5e200800, 0xdf3e0c00, disas_simd_scalar_two_reg_misc },
     { 0x5f000400, 0xdf800400, disas_simd_scalar_shift_imm },