target/arm: Convert Neon 2-reg-misc VRINT insns to decodetree

Convert the Neon 2-reg-misc VRINT insns to decodetree.
Giving these insns their own do_vrint() function allows us
to change the rounding mode just once at the start and end
rather than doing it for every element in the vector.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200616170844.13318-18-peter.maydell@linaro.org

target/arm/neon-dp.decode

@@ -503,11 +503,19 @@ Vimm_1r          1111 001 . 1 . 000 ... .... cmode:4 0 . op:1 1 .... @1reg_imm
     SHA1SU1      1111 001 11 . 11 .. 10 .... 0 0111 0 . 0 .... @2misc_q1
     SHA256SU0    1111 001 11 . 11 .. 10 .... 0 0111 1 . 0 .... @2misc_q1
 
+    VRINTN       1111 001 11 . 11 .. 10 .... 0 1000 . . 0 .... @2misc
     VRINTX       1111 001 11 . 11 .. 10 .... 0 1001 . . 0 .... @2misc
+    VRINTA       1111 001 11 . 11 .. 10 .... 0 1010 . . 0 .... @2misc
+    VRINTZ       1111 001 11 . 11 .. 10 .... 0 1011 . . 0 .... @2misc
 
     VCVT_F16_F32 1111 001 11 . 11 .. 10 .... 0 1100 0 . 0 .... @2misc_q0
+
+    VRINTM       1111 001 11 . 11 .. 10 .... 0 1101 . . 0 .... @2misc
+
     VCVT_F32_F16 1111 001 11 . 11 .. 10 .... 0 1110 0 . 0 .... @2misc_q0
 
+    VRINTP       1111 001 11 . 11 .. 10 .... 0 1111 . . 0 .... @2misc
+
     VRECPE       1111 001 11 . 11 .. 11 .... 0 1000 . . 0 .... @2misc
     VRSQRTE      1111 001 11 . 11 .. 11 .... 0 1001 . . 0 .... @2misc
     VRECPE_F     1111 001 11 . 11 .. 11 .... 0 1010 . . 0 .... @2misc

target/arm/translate-neon.inc.c

@@ -3796,3 +3796,64 @@ DO_FP_CMP0(VCGE0_F, gen_helper_neon_cge_f32, FWD)
 DO_FP_CMP0(VCEQ0_F, gen_helper_neon_ceq_f32, FWD)
 DO_FP_CMP0(VCLE0_F, gen_helper_neon_cge_f32, REV)
 DO_FP_CMP0(VCLT0_F, gen_helper_neon_cgt_f32, REV)
+
+static bool do_vrint(DisasContext *s, arg_2misc *a, int rmode)
+{
+    /*
+     * Handle a VRINT* operation by iterating 32 bits at a time,
+     * with a specified rounding mode in operation.
+     */
+    int pass;
+    TCGv_ptr fpst;
+    TCGv_i32 tcg_rmode;
+
+    if (!arm_dc_feature(s, ARM_FEATURE_NEON) ||
+        !arm_dc_feature(s, ARM_FEATURE_V8)) {
+        return false;
+    }
+
+    /* UNDEF accesses to D16-D31 if they don't exist. */
+    if (!dc_isar_feature(aa32_simd_r32, s) &&
+        ((a->vd | a->vm) & 0x10)) {
+        return false;
+    }
+
+    if (a->size != 2) {
+        /* TODO: FP16 will be the size == 1 case */
+        return false;
+    }
+
+    if ((a->vd | a->vm) & a->q) {
+        return false;
+    }
+
+    if (!vfp_access_check(s)) {
+        return true;
+    }
+
+    fpst = get_fpstatus_ptr(1);
+    tcg_rmode = tcg_const_i32(arm_rmode_to_sf(rmode));
+    gen_helper_set_neon_rmode(tcg_rmode, tcg_rmode, cpu_env);
+    for (pass = 0; pass < (a->q ? 4 : 2); pass++) {
+        TCGv_i32 tmp = neon_load_reg(a->vm, pass);
+        gen_helper_rints(tmp, tmp, fpst);
+        neon_store_reg(a->vd, pass, tmp);
+    }
+    gen_helper_set_neon_rmode(tcg_rmode, tcg_rmode, cpu_env);
+    tcg_temp_free_i32(tcg_rmode);
+    tcg_temp_free_ptr(fpst);
+
+    return true;
+}
+
+#define DO_VRINT(INSN, RMODE)                                   \
+    static bool trans_##INSN(DisasContext *s, arg_2misc *a)     \
+    {                                                           \
+        return do_vrint(s, a, RMODE);                           \
+    }
+
+DO_VRINT(VRINTN, FPROUNDING_TIEEVEN)
+DO_VRINT(VRINTA, FPROUNDING_TIEAWAY)
+DO_VRINT(VRINTZ, FPROUNDING_ZERO)
+DO_VRINT(VRINTM, FPROUNDING_NEGINF)
+DO_VRINT(VRINTP, FPROUNDING_POSINF)

target/arm/translate.c

@@ -4959,6 +4959,11 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
                 case NEON_2RM_VCEQ0_F:
                 case NEON_2RM_VCLE0_F:
                 case NEON_2RM_VCLT0_F:
+                case NEON_2RM_VRINTN:
+                case NEON_2RM_VRINTA:
+                case NEON_2RM_VRINTM:
+                case NEON_2RM_VRINTP:
+                case NEON_2RM_VRINTZ:
                     /* handled by decodetree */
                     return 1;
                 case NEON_2RM_VTRN:
@@ -4993,32 +4998,6 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
                             }
                             neon_store_reg(rm, pass, tmp2);
                             break;
-                        case NEON_2RM_VRINTN:
-                        case NEON_2RM_VRINTA:
-                        case NEON_2RM_VRINTM:
-                        case NEON_2RM_VRINTP:
-                        case NEON_2RM_VRINTZ:
-                        {
-                            TCGv_i32 tcg_rmode;
-                            TCGv_ptr fpstatus = get_fpstatus_ptr(1);
-                            int rmode;
-
-                            if (op == NEON_2RM_VRINTZ) {
-                                rmode = FPROUNDING_ZERO;
-                            } else {
-                                rmode = fp_decode_rm[((op & 0x6) >> 1) ^ 1];
-                            }
-
-                            tcg_rmode = tcg_const_i32(arm_rmode_to_sf(rmode));
-                            gen_helper_set_neon_rmode(tcg_rmode, tcg_rmode,
-                                                      cpu_env);
-                            gen_helper_rints(tmp, tmp, fpstatus);
-                            gen_helper_set_neon_rmode(tcg_rmode, tcg_rmode,
-                                                      cpu_env);
-                            tcg_temp_free_ptr(fpstatus);
-                            tcg_temp_free_i32(tcg_rmode);
-                            break;
-                        }
                         case NEON_2RM_VCVTAU:
                         case NEON_2RM_VCVTAS:
                         case NEON_2RM_VCVTNU: